06 Beam Instrumentation, Controls, Feedback, and Operational Aspects
T03 Beam Diagnostics and Instrumentation
Paper Title Page
TUXGBF2 Higher-Order-Mode Effects in Tesla-Type Superconducting RF Cavities on Electron Beam Quality 612
 
  • A.H. Lumpkin, N. Eddy, D.R. Edstrom, P.S. Prieto, J. Ruan, R.M. Thurman-Keup
    Fermilab, Batavia, Illinois, USA
  • K. Bishofberger, B.E. Carlsten
    LANL, Los Alamos, New Mexico, USA
  • O. Napoly
    CEA/DSM/IRFU, France
 
  Funding: *Work at Fermilab supported by FRA, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Dept. of Energy. **Work at LANL supported by U.S. Dept. of Energy through the LANL/LDRD Program.
We report the direct observations of the correlation of higher order modes (HOMs) generated by off-axis electron beam steering in TESLA-type SCRF cavities and sub-macropulse beam centroid shifts (with the concomitant effect on averaged beam size and emittance). The experiments were performed at the Fermilab Accelerator Science and Technology (FAST) facility using its unique configuration of a PC rf gun injecting beam into two separated 9-cell cavities in series with corrector magnets and beam position monitors (BPMs) located before, between, and after them. The ~100-kHz oscillations with up to 300-µm amplitudes at downstream locations were observed in a 3-MHz micropulse repetition rate beam with charges of 500 and 1000 pC/b, although the effects were much reduced at 100 pC/b. The studies were based on HOM detector circuitry targeting the first and second dipole passbands, rf BPM bunch-by-bunch data, and imaging cameras viewing multi-slit images for emittance assessments at 33 MeV. Initial calculations reproduced a key feature of the phenomena. In principle, these results may be scaled to cryomodule configurations of major accelerator facilities.
 
slides icon Slides TUXGBF2 [3.636 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUXGBF2  
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TUZGBD1
Beam Instrumentation and Controls for High Repitition-rate Superconducting Linacs  
 
  • T.J. Maxwell
    SLAC, Menlo Park, California, USA
 
  The high beam rate and flexible pulse structure of the LCLS-II combined with the high brightness requirements necessitates the development of new diagnostics and a new accelerator control system. This talk summarizes the requirements, implementation challenges, and current development status of this system for LCLS-II.  
slides icon Slides TUZGBD1 [3.626 MB]  
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TUZGBD3 Beam Diagnostics for the APS MBA Upgrade 1204
 
  • N. Sereno, N.D. Arnold, R.W. Blake, A.R. Brill, H. Bui, J. Carwardine, G. Decker, L. Emery, T. Fors, P.S. Kallakuri, R.T. Keane, R.M. Lill, D.R. Paskvan, A.F. Pietryla, H. Shang, X. Sun, S. Veseli, J. Wang, S. Xu, B.X. Yang
    ANL, Argonne, Illinois, USA
 
  The Advanced Photon Source (APS) is currently in the preliminary design phase for a multi-bend acromat (MBA) lattice upgrade. Beam stability is critical where the requirements are driven from the beam size which is expected to approach 4 microns vertically at the insertion device (ID) source points. AC rms beam stability requirements are defined as 10 % the minimum source size at the ID in the band 0.01-1000 Hz. The vertical plane stability goal is the most ambitious requiring a stability of 400 nm at the ID source point. In addition, long term drift defined as motion over a seven day timescale can be no more than 1 micron. In order to achieve these demanding beam stability requirements, a suite of beam diagnostics will be required including rf BPMs, X-ray BPMs, a mechanical motion measurement system, beam size monitors and a real time orbit feedback system. In addition, a tune measurement system, transverse multi-bunch feedback system and current monitors are planned for the upgrade. We report on the beam diagnostics design and APS storage ring R&D results used to inform the design.  
slides icon Slides TUZGBD3 [16.753 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUZGBD3  
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WEPAF001 A Diagnostic Test Bench for the LIGHT Accelerator 1808
 
  • A. Jeff, A. Benot-Morell, M. Caldara, P. Nadig
    A.D.A.M. SA, Meyrin, Switzerland
 
  The LIGHT accelerator is the first compact Linac that will deliver proton beams up to 230 MeV for cancer treatment. The accelerator is only 24m long and is being built to be modular and capable of changing proton beam energy and intensity pulse-to-pulse at up to 200Hz. The LIGHT prototype is currently being commissioned by AVO / ADAM at CERN, while the first full installation is foreseen in 2019. Here we present the design and implementation of a moveable diagnostic test bench which is used to measure a full set of beam properties at each commissioning step. Parameters measured include beam current, pulse length, energy, position, transverse profile and emittance. The compact instruments, the electronics and the controls that equip the test bench are the same as those who will be permanently installed along the accelerator after the commissioning. The first results obtained with the test bench for beams up to 16 MeV are shown here. We demonstrate that the chosen instrumentation achieves a very high sensitivity, dynamic range, reliability and immunity to EM noise. Procedures for on-line calibration of the instruments are also discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF001  
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WEPAF006 Fast Photodetector Bunch Duration Monitor for the Advanced Photon Source Particle Accumulator Ring 1819
 
  • J.C. Dooling, J.R. Calvey, K.C. Harkay, B.X. Yang, C. Yao
    ANL, Argonne, Illinois, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A fast photodetector is used to monitor the bunch duration in the Advanced Photon Source (APS) Particle Accumulator Ring (PAR). The Bunch Duration Monitor (BDM) diagnostic provides an accurate measure of the PAR bunch length. PAR BDM data show good agreement with streak camera measurements. The BDM is based on the metal-semiconductor-metal (MSM) photodetector Hamamatsu G4176-03 MSM with specified rise and fall times of 30 ps. The BDM has sufficient frequency response to resolve the PAR bunch near extraction where, under low-charge conditions, minimum rms pulse durations of 200-300 ps are observed. Beam from the PAR is injected into the Booster; for efficient capture, injected rms bunch duration from the PAR must be less than 600 ps. The MSM detector exhibits a ringing response to fast input signals. To overcome this, the BDM output is de-convolved with the impulse response function of the detector-amplifier circuit. Turn-by-turn bunch duration data is presented versus charge and time in the PAR cycle. Charge calibration is used to determine fit parameters for bunch duration measurements in peak-detection mode. Observations relevant to APS Upgrade high-charge studies are presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF006  
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WEPAF010 Fast Glitch Detection of Coupled Bunch Instabilities and Orbit Motions 1829
 
  • W.X. Cheng, B. Bacha, K. Ha, Y. Li
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by DOE contract No: DE-SC0012704
During high current operation at NSLS-II storage ring, vertical beam size spikes have been noticed. The spikes are believed due to ion instability associates with vacuum activities localized in the ring. A new tool has been developed using gated BPM turn-by-turn (TBT) data to detect beam centroid glitches. When one turn orbit deviates outside the predefined window, a global event will be generated. This allows synchronized data acquisition of TBT beam positions around the ring. Bunch by bunch data is acquired at the same time to analyze the possible coupled bunch instabilities (CBI). Besides CBI mainly due to ion bursts, fast orbit glitches have been captured with the new tool. Sources of the glitches can be identified.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF010  
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WEPAF012 Improvements of NSLS-II X-ray Diagnostic Beamlines 1837
 
  • W.X. Cheng, B. Bacha, B.N. Kosciuk, D. Padrazo Jr
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by DOE contract No: DE-SC0012704
There are two X-ray diagnostic beamlines (XDB) developed at NSLS-II storage ring to measure emittance, energy spread, and other machine parameters. The first beamline utilizes a soft bending magnet radiation has been in operation since 2014. The tungsten pinhole originally located in the air had corrosion issue. The beamline has been improved by extending the vacuum to the imaging system. The second X-ray pinhole beamline using three-pole wiggler (TPW) radiation has been constructed and commissioned recently. Energy spread is able to be precisely measured due to large dispersion at the source point. A gated camera is equipped with the new beamline to acquire profiles within one turn. Recent operation experience and beam measurements will be presented in this paper.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF012  
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WEPAF016 Application of Quad-Scan Measurement Techniques to Muon Beams in the Muon g-2 Experiment 1852
 
  • J. Bradley
    Edinburgh University, Edinburgh, United Kingdom
  • J.D. Crnkovic
    BNL, Upton, Long Island, New York, USA
  • B.E. Drendel, D. Stratakis
    Fermilab, Batavia, Illinois, USA
  • N.S. Froemming
    CENPA, Seattle, Washington, USA
 
  Determination of the properties of a beam during transport is a vital process for most accelerator-related experiments; for example Fermilab's Muon g-2 experiment requires large numbers of muons to be stored in a storage ring of 7 meter radius, and the transmission fraction has been shown to depend strongly on the properties of the beam, specifically the Twiss parameters. The current equipment in the muon campus beamlines allows only measurement of beam profiles which limits how well propagation can be predicted, however by using the well-studied quad-scan technique it is possible to obtain all of the Twiss parameters at a point using these profiles. Experimental quad-scans of muon beams have not yet been reported, this paper introduces the quad-scan technique and then goes on to discuss the analysis of one such experiment and the results obtained, showing that such a technique is applicable in the muon g-2 experiment to obtain the Twiss parameters without requiring installation of new equipment.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF016  
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WEPAF017 Correction of ID-Induced Transverse Linear Coupling at NSLS-II 1856
 
  • Y. Hidaka, Y. Li, T.V. Shaftan, T. Tanabe, Y. Tian, G.M. Wang
    BNL, Upton, Long Island, New York, USA
 
  Funding: The study is supported by U.S. DOE under Contract No. DE-AC02-98CH10886.
Sizeable lifetime jumps have been observed sporadically since March 2016 at NSLS-II. These jumps were found to coincide with insertion device (ID) gap motions. Particularly, one of the in-vacuum undulators (IVUs) at Cell 17 was discovered to have large localized skew quadrupole component variation with gap. To allow the machine to operate stably in the low-emittance mode, a global coupling feedforward system has been recently implemented and successfully deployed. After installation of a new additional skew quadrupole, coupling compensation of this ID is now performed by a local coupling feedforward system. Furthermore, the maximum gap limit of all the existing IVUs has been decreased from 40 mm to 25 mm to limit the skew component variation during user operation.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF017  
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WEPAF018 Proposed BPM-Based Bunch Crabbing Angle Monitor 1860
 
  • P. Thieberger, M.G. Minty, C. Montag
    BNL, Upton, Long Island, New York, USA
 
  Funding: This work was supported by Brookhaven Science Associates, LLC, under Contract No. DE-AC02-98CH10886 with the US Department of Energy.
A tilted bunch traversing a button beam profile monitor will produce signals on opposite pickup electrodes that will have different degrees of distortion depending on the tilt angle. In particular, the zero-crossing time difference between the two signals will be approximately proportional to the tilt angle. We perform simulations to study this effect as a possible diagnostic tool for measuring the crabbing angles in a future electron-ion collider.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF018  
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WEPAF019 Fast Readout Algorithm for Cylindrical Beam Position Monitors Providing Good Accuracy for Particle Bunches with Large Offsets 1864
 
  • P. Thieberger, D.M. Gassner, R.L. Hulsart, R.J. Michnoff, T.A. Miller, M.G. Minty, Z. Sorrell
    BNL, Upton, Long Island, New York, USA
  • A.C. Bartnik
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: This work was supported by Brookhaven Science Associates, LLC, under Contract No. DE-AC02-98CH10886 with the US Department of Energy.
A simple, analytically correct algorithm is developed for calculating 'pencil' beam coordinates using the signals from an ideal cylindrical beam position monitor (BPM) with four pickup electrodes (PUEs) of infinitesimal widths. The algorithm is then applied to simulations of realistic BPMs with finite width PUEs. Surprisingly small deviations are found. Simple empirically determined correction terms reduce the deviations even further. Finally, the algorithm is used to study the impact of beam-size upon the precision of BPMs in the non-linear region. As an example of the data acquisition speed advantage, a FPGA-based BPM readout implementation of the new algorithm has been developed and characterized
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF019  
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WEPAF024 Turn-by-Turn Position Measurements at CNAO with the Libera Spark HR Prototype 1870
 
  • M. Cargnelutti, M. Žnidarčič
    I-Tech, Solkan, Slovenia
  • G.M.A. Calvi, A. Parravicini, E. Rojatti, C. Viviani
    CNAO Foundation, Milan, Italy
 
  CNAO in Pavia is one of the first centers for hadrontherapy in Europe, treating patients since 2011. The center is an international reference for a whole new concept of machines being constructed for this purpose. The synchrotron BPM electronics is based on analog boards that compute the ratio between difference and sum signals from the shoebox pickup, later acquired by digital cards. Although the system operates reliably, it just calculates the position with 1kHz rate, while the revolution frequency ranges from 0.5 to 3 MHz. To extend the measurement possibilities for these new hadron synchrotrons, Instrumentation Technologies is developing a data acquisition system capable of acquiring the pickup signals with 125MSps ADCs and calculating bunchbybunch positions of the accelerated beam. The first prototype was tested at CNAO: the turnbyturn beam position was analyzed off line, at different energies and positions with both Protons and Carbon ions beam. This paper will presents the results achieved with the system and compares them with the measurements of the current system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF024  
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WEPAF025 Fast Intensity Monitor Based on Channeltron Electron Multiplier 1873
 
  • G.M.A. Calvi, V. Lante, L. Lanzavecchia, G. Magro, A. Parravicini, E. Rojatti, C. Viviani
    CNAO Foundation, Milan, Italy
 
  The paper concerns the Fast Intensity Monitor (FIM) designed for the CNAO (Centro Nazionale di Adroterapia Oncologica), the Italian facility of Oncological Hadrontherapy. The FIM detector has been designed with the purpose of having a continuous and non-destructive measurement of the beam intensity in the High Energy Beam Transfer (HEBT) line. The passage of the beam through a thin aluminum foil produces secondary electrons whose yield depends on beam species (protons or carbon ions), intensity and energy. Secondary electrons are focused on the Channeltron Electron Multiplier (CEM) input, multiplied and sensed over a precision resistor. In order to minimize the perturbation to the beam, the foil is grounded and the read out electronics is floating. This makes electronics design harder but it is a key point to make FIM use possible continuously even during patients treatment. Measurements performed with the FIM are discussed and checked against reference detectors.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF025  
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WEPAF026 Beam Induced Fluorescence Measurements of 100 keV Deuterons in LIPAc Accelerator 1877
SUSPL052   use link to see paper's listing under its alternate paper code  
 
  • R. Varela, A. Guirao, L.M. Martínez, J. Mollá, I. Podadera
    CIEMAT, Madrid, Spain
  • T. Akagi, R. Ichimiya, Y. Ikeda, M. Sugimoto
    QST, Aomori, Japan
  • B. Bolzon, N. Chauvin
    CEA/IRFU, Gif-sur-Yvette, France
  • P. Cara
    Fusion for Energy, Garching, Germany
  • H. Dzitko
    F4E, Germany
  • J. Knaster
    IFMIF/EVEDA, Rokkasho, Japan
 
  Funding: Work partially supported by the Spanish Ministry of Science and Innovation under project FIS2013-40860-R
The LIPAc accelerator will be a linear CW deuteron accelerator capable of delivering a 9 MeV, 125 mA beam which aims to validate the technology that will be used in the future high power accelerator-driven neutron source, IFMIF. In summer 2017 a campaign of measurements was done during the injector commissioning, in which a Fluorescence Profile Monitor based on an Intensified CID camera (ICID) was used to measure the beam transverse profile at the extraction of the ion source. In this contribution we review the design of the ICID, its performance and discuss the measurements carried out. The performance of ICID monitors for its use in future accelerators will be assessed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF026  
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WEPAF027 Low Q Cavity BPM Study for the Beam Position Measurement of Nanosecond Spaced Electron Bunches 1881
 
  • L. Yang, X. He, L.W. Zhang
    CAEP/IFP, Mainyang, Sichuan, People's Republic of China
  • S.S. Cao, Y.B. Leng, L.Y. Yu, R.X. Yuan
    SINAP, Shanghai, People's Republic of China
 
  Funding: National natural science foundation of China, 11705184
Low Q cavity BPM is a key to distinguish closely spaced electron bunches allowing precise beam handling for XFEL facilities operating in a multi-bunch mode at high repetition rate up to hundreds MHz. The inter-bunch signal pollution issue becomes significant when bunch separation is down to nanosecond and causes the position detection to be increasingly overestimated. Solely relying on extreme low Q to achieve sufficient decay within bunch interval leads to appreciable interference from non-signal modes due to strong overcoupling of antenna design is required. The error imposed on measured position raises a challenge to meet the goal of high resolution. Alternatively, a concept is proposed to remove the dominant part of signal pollution at the moment of sampling by intentionally shifting the phase of the last bunch signal 90degree respect to that of current bunch signal, where signal sampling is normally taken for nanosecond spaced bunches. This quadrature phase shift is defined by properly choosing the operational frequency of dipole mode regarding to the bunch frequency. A low Q cavity BPM prototype to identify technical challenges and verify this concept is under development in the R&D plan for future XFEL with high repetition rate
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF027  
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WEPAF034 A Supersonic Gas Jet-Based Beam Profile Monitor Using Fluorescence for HL-LHC 1891
 
  • H.D. Zhang, A.S. Alexandrova, R. Schnuerer, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • M. Ady, E. Barrios Diaz, N. Chritin, O.R. Jones, R. Kersevan, T. Marriott-Dodington, S. Mazzoni, A. Rossi, G. Schneider, R. Veness
    CERN, Geneva, Switzerland
  • A.S. Alexandrova, A. Salehilashkajani, R. Schnuerer, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  • P. Forck, S. Udrea
    GSI, Darmstadt, Germany
  • P. Smakulski
    WRUT, Wroclaw, Poland
 
  Funding: The HL-LHC project, the Helmholtz Association under contract VH-NG-328, the EU's 7th Framework Programme under grant agreement no 215080 and the STFC Cockcroft core grant No. ST/G008248/1.
The High-Luminosity Large Hadron Collider (HL-LHC) project aims to increase the machine luminosity by a factor of 10 as compared to the LHC's design value. To achieve this goal, a special type of electron lens is being developed. It uses a hollow electron beam which co-propagates with the hadron beam to act on any halo particles without perturbing the core of the beam. The overlapping of both beams should be carefully monitored. This contribution presents the design principle and detailed characteristics of a new supersonic gas jet-based beam profile monitor. In contrast to earlier monitors, it relies on fluorescence light emitted by the gas molecules in the jet following interaction with the primary hadron beams. A dedicated prototype has been designed and built at the Cockcroft Institute and is being commissioned. Details about monitor integration, achievable resolution and dynamic range will be given.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF034  
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WEPAF035 Coherent Diffraction Radiation Imaging as an RMS Bunch Length Monitor 1895
 
  • J. Wolfenden, R.B. Fiorito, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • R.B. Fiorito, C.P. Welsch, J. Wolfenden
    The University of Liverpool, Liverpool, United Kingdom
  • T.H. Pacey, T.H. Pacey
    UMAN, Manchester, United Kingdom
  • A.G. Shkvarunets
    UMD, College Park, Maryland, USA
 
  Funding: This work was supported by the EU under Grant Agreement No. 624890 and the STFC Cockcroft Institute core Grant No. ST/G008248/1.
High-resolution bunch length measurement is of the utmost importance for current and future generations of light sources and linacs. It is also key to the optimisation of the final beam quality in plasma-based acceleration. We present progress in the development of a novel RMS bunch length monitor based on imaging the coherent diffraction radiation (CDR) produced by a non-invasive circular aperture. Due to the bunch lengths involved, the radiation produced is in the THz range. This has led to the development of a novel THz imaging system, which can be applied to low energy electron beams. For high energy beams the imaging system can be used as a single shot technique. Simulation results show that the profile of a CDR image of a beam is sensitive to bunch length and can thus be used as a diagnostic. The associated benefits of this imaging distribution methodology over the typical angular distribution measurement are discussed. Plans for experiments conducted at the SwissFEL (PSI, Switzerland), along with plans for future high energy single shot measurements are also presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF035  
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WEPAF036 Energy Independence in Optical Transition Radiation Imaging 1898
 
  • J. Wolfenden, R.B. Fiorito, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • R.B. Fiorito, C.P. Welsch, J. Wolfenden
    The University of Liverpool, Liverpool, United Kingdom
 
  Funding: This work was supported by the EU under Grant Agreement No. 624890 and the STFC Cockcroft Institute core Grant No. ST/G008248/1.
The exploitation of optical transition radiation (OTR) in imaging-based diagnostics for charged particle beams is a well-established technique. Simulations of the expected OTR transverse beam profiles are therefore important in both the design of such imaging systems and the analysis of the data. Simulating OTR images is relatively straightforward for low energy electron beams. However, in the near future electron machines will be using high-energy and low-emittance beams. Using such parameters can be challenging to simulate, and can be limiting in their account of practical factors, e.g. chromatic aberrations. In this work we show systematically that the use of low-energy parameters in high-energy OTR image simulations induces little deviation in the resulting transverse beam profiles. Simulations therefore become much easier to perform, and further analysis may be performed. This opens up exciting opportunities to perform simulations quicker and with reduced demands on the computation requirements. It will be shown in this contribution how this approach will enable enhanced ways to optimize OTR diagnostics.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF036  
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WEPAF042 Measurement of Beam yz Crabbing Tilt Due to Wake Fields Using Streak Camera at CESR 1905
 
  • S. Wang, D. L. Rubin
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: This research was supported by NSF PHYS-1068662, PHYS-1416318 and DMR-1332208.
Transverse vertical wake fields can increase the vertical emittance and distort the phase space of a bunch in a storage ring. Recently, we observed charge-dependent vertical beam size growth with a single scraper inserted through the top of the storage ring vacuum chamber. This apparent growth was due in large part to the yz coupling (vertical crabbing) induced by the wake field from the asymmetric scraper configuration. Here, we report a direct measurement of a small beam yz crabbing tilt using a streak camera. The recorded images (projected beam profiles in yz plane) are analyzed with three different methods, which yield consistent beam yz tilts. We found the directly-measured current-dependent beam tilts by the streak camera are consistent with the beam tilts calculated from a wake field model.
 
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WEPAF046 RF Electronics for the Measurement of Beam Induced Higher Order Modes (HOM) Implemented in the MicroTCA.4 Form Factor 1916
 
  • S. Jabłoński, N. Baboi, U. Mavrič, H. Schlarb
    DESY, Hamburg, Germany
 
  Higher order modes (HOM) excited in RF accelerating cavities by a particle beam can be used for electron beam diagnostics. Phase of a monopole HOM provides information about the beam phase relative to the externally induced RF field in a cavity (BPhM) [1]. Furthermore, the amplitude of a dipole mode is proportional to the beam position in the cavity, hence it can be used for beam position monitoring (BPM). In this paper we present a prototype of an instrument implemented in the MicoTCA.4 form factor for the measurement of the HOMs at FLASH and Eu-XFEL. The prototype consists of an analog module, which is used for filtering and conditioning of the selected modes, and a digital module responsible for digitization and signal processing. We present the instruments performance and discuss its influence on the precision of the HOM-based diagnostics.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF046  
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WEPAF047 Status and Commissioning of the Wire Scanner System for the European XFEL 1919
 
  • T. Lensch, S. Liu
    DESY, Hamburg, Germany
 
  The European-XFEL (E-XFEL) is an X-ray Free Electron Laser facility located in Hamburg (Germany). The superconducting accelerator for up to 17.5 GeV electrons will provide photons simultaneously to several user stations. Currently 12 Wire Scanner stations are used to image transverse beam profiles in the high energy sections. These scanners provide a slow scan mode which is currently used to measure beam emittance and beam halo distributions. When operating with long bunch trains (>100 bunches) also fast scans are planned to measure beam sizes in an almost nondestructive manner. This paper describes the current installations and the latest developments of the system at European-XFEL. Furthermore, the commissioning status of the system and first results of beam halo studies will be shown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF047  
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WEPAF048 High Resolution and Low Charge Button and Strip-Line Beam Position Monitor Electronics Upgrade at Flash 1923
 
  • B. Lorbeer, N. Baboi, H.T. Duhme, Re. Neumann
    DESY, Hamburg, Germany
 
  Historically the FLASH (Free Electron Laser in Hamburg) facility at DESY (Deutsches Elektronen-Synchrotron) in Germany has foreseen operation in a charge range from 1nC-3nC for which a VME based BPM(Beam Position Monitor) system has been in operation since 2005. For a couple of years the standard machine operation has been settled at a few hundreds of pC with the tendency for smaller charges down to 100pC and smaller. The availability and resolution performance of the BPM system at charges below 300pC in many locations along the machine was unsatisfactory. In the last couple of years a new BPM electronic system based on the utca standard has been developed to overcome these limitations. A substantially improved version of the analog frontend and digital electronics has been developed in 2016 and tested successfully. During shutdown works at FLASH in summer 2017 all old button and strip-line BPM electronics has been replaced with the new type of electronics. This paper summarizes the features and performance of the new BPM system, compares the beam jitter free resolution of old and new BPM system and highlights its high single shot resolution of better than 10um at a charge of 15pC.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF048  
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WEPAF049 Energy Beam Position Monitor Button Array Electronics for the European XFEL 1927
 
  • B. Lorbeer, B. Beutner, H.T. Duhme, L. Fröhlich, D. Lipka, D. Nölle
    DESY, Hamburg, Germany
 
  The European XFEL(X-Ray Free Electron Laser) at DESY(Deutsches Elektronen-Synchrotron) in Hamburg/Schenefeld started commissioning in early 2017. Before the pulsed electron beam is accelerated to its final energy of 14 GeV, the energy of the bunch can be compressed in three bunch compression chicanes at 130 MeV, 700 MeV and 2400 MeV. The vacuum chamber in these sections is tapered from 40 mm round beam pipe to a 40 cm rectangular shaped vacuum section. A custom made button array type of BPM(Beam position Monitor) is installed in this section with 26 button electrode feed-throughs. The analog and digital readout electronics for this monitor and the first experience with the calibration and operational aspects of this system are presented in this poster.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF049  
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WEPAF050 Simulations of 3D Charge Density Measurements for Commissioning of the PolariX-TDS 1930
SUSPF104   use link to see paper's listing under its alternate paper code  
 
  • D. Marx, R.W. Aßmann, R.T.P. D'Arcy, B. Marchetti
    DESY, Hamburg, Germany
 
  The prototype of a novel X-band transverse deflection structure, the Polarizable X-band (PolariX) TDS*, is currently being prepared for installation in the FLASHForward beamline** at DESY in early 2019. This structure will have the novel feature of variable polarization of the deflecting mode, allowing bunches to be streaked at any transverse angle, rather than at just one angle as in a conventional cavity. By combining screen profiles from several streaking angles using tomographic reconstruction techniques, the full 3D charge density of a bunch can be obtained***. It is planned to perform this measurement for the first time during commissioning of the structure. In this paper, simulations of this measurement are presented and the effects of jitter are discussed.
*P Craievich et al. paper THPAL068, this conference
**A Aschikhin et al. Nucl. Instr. Meth. Phys. Res. A., vol.806, pp.175-183, 2018
***D Marx et al. J. Phys.: Conf. Ser., vol.874, p.012077, 2017
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF050  
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WEPAF055 Time-Synchronized Beam Diagnostics at SPEAR3 1948
SUSPF102   use link to see paper's listing under its alternate paper code  
 
  • Q. Lin, Z.H. Sun
    Donghua University, Shanghai, People's Republic of China
  • P. Boussina, W.J. Corbett, D.J. Martin, J.A. Safranek, K. Tian
    SLAC, Menlo Park, California, USA
  • D. Teytelman
    Dimtel, San Jose, USA
 
  The SPEAR3 timing system supplies a 10Hz trigger pulse synchronous with charge injection into the main storage ring. In the past the 10Hz pulse train has been used to study injected charge transients as seen by visible-light synchrotron radiation diagnostics and turn-by-turn BPMs. More recently the 10Hz pulse has been used to synchronize the bunch-by-bunch feedback data acquisition system with other triggered diagnostic systems. The suite of measurement systems can be used to study injected beam dynamics, grow/damp instability transients and drive/damp physics.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF055  
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WEPAF056 A Graphical User Interface for Transverse Bunch-by-Bunch Feedback at SPEAR3 1951
 
  • K. Tian, W.J. Corbett, D.J. Martin, J.J. Sebek
    SLAC, Menlo Park, California, USA
  • Q. Lin
    Donghua University, Shanghai, People's Republic of China
  • D. Teytelman
    Dimtel, San Jose, USA
 
  Recently a transverse bunch-by-bunch feedback kicker was installed in SPEAR3 to control beam instabilities, remove unwanted satellite bunches and test resonant bunch excitation schemes for short pulse x-ray production. In conjunction with DIMTEL processing electronics, the feedback system can successfully stabilize undesirable beam modes and opens up the potential for more advanced investigations of bunch-by-bunch beam dynamics. To streamline the process, a graphical user interface was developed that allows the user to 'script' beam physics measurements from a single panel. At the press of a button the panel automatically downloads the measurement parameters, acquires the raw data and provides graphical displays of the beam response with calculated metadata. In this paper we present the interface format and examples of automated measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF056  
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WEPAF057 Electron Beam Diagnostics Concept for the ELI LUX Project 1954
 
  • K.O. Kruchinin, D. Kocon, A.Y. Molodozhentsev, L. Pribyl
    ELI-BEAMS, Prague, Czech Republic
  • A. Lyapin
    JAI, Egham, Surrey, United Kingdom
 
  Nowadays the popularity of Laser Wakefield Accelerators (LWFA) is increasingly growing. Although the quality of the beams produced by LWFA is still lower than provided by conventional accelerators, they have great potential to be considered as a new basis for future FELs and even colliders. Laser Undulator X-ray (LUX) source is being commissioned at ELI-beamlines in Czech Republic. The goal of this machine is to provide photon beam in so called "water window" wavelength region for user experiments. Possible upgrade of the facility towards the LWFA based FEL is also considered. The electron beam diagnostics is absolutely crucial for achieving the aim of LUX. Specific properties of the beam produced by current LWFA, such as low charge, poor beam stability, big beam divergence and energy spread, require rethinking and adaptation of the conventional diagnostic tools and, in some cases, development of new ones. Ideally, they have to be compact, stable, non-invasive and allow measurements in single-shot mode. In this report we will present an overview and design considerations for the LUX electron beam main diagnostics. We will also discuss the hardware status and future plans.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF057  
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WEPAF059 A Low Cost Beam Position Monitor System 1961
 
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • J.G. Power, J.H. Shao
    ANL, Argonne, Illinois, USA
  • C. Yin
    University of Chicago, Chicago, Illinois, USA
 
  A Beam Position Monitor (BPM) system is essential to beam diagnostics for almost all particle accelerators. However, a typical BPM system contains customized hardware and complicated processing electronics which considerably drive the cost for large facilities where hundreds of them may be used. It also limits its use in the small scale accelerator facilities. In the paper, we present a low cost BPM system which consists of a commercial available CF flange based signal pickup device, a low cost integrated circuit adjacent to the pickup to filter, sample, digitize, and broadcast the signals out of the pickup electrodes. The digital signal is transmitted out for post processing through noise-protected Wi-Fi router. We will briefly discuss the working principle and experimental progress to date.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF059  
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WEPAF060 Non-Invasive Bunch Length Diagnostics for High Intensity Beams 1964
 
  • S.V. Kuzikov, S.P. Antipov
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S.V. Kuzikov, A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
 
  Modern particle accelerators utilize photoinjectors and compression schemes to produce short high peak current electron bunches for various applications like x-ray free electron lasers, high gradient beam driven acceleration and others. Bunch length detection is a desired diagnostics for such machines. In this paper we describe a non-invasive, real-time detector which can be retrofitted into an existing beamline and measure the bunch length in real time using interferometric methods. Diffraction radiation is the mechanism to be used to produce a measurable signal without intercepting the beam. This became possible as sensitivity of pyrodetectors improved over the years, while peak beam power grew. For high peak current beams there is a possibility of a single shot measurement. This can be done with a pair of closely placed vacuum breaks that create a spatial correlation of the generated signals which can be measured by a pyro-detector array or a THz camera. The bunch length is determined from the correlation data using an iterative beam profile recovery algorithm.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF060  
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WEPAF070 Commissioning of Beam Instrumentation at the CERN AWAKE Facility After Integration of the Electron Beam Line 1993
 
  • I. Gorgisyan, C. Bracco, S. Burger, S. Döbert, S.J. Gessner, E. Gschwendtner, L.K. Jensen, S. Jensen, S. Mazzoni, D. Medina, K. Pepitone, L. Søby, F.M. Velotti, M. Wendt
    CERN, Geneva, Switzerland
  • M. Cascella, S. Jolly, F. Keeble, M. Wing
    UCL, London, United Kingdom
  • V.A. Verzilov
    TRIUMF, Vancouver, Canada
 
  The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) is a project at CERN aiming to accelerate an electron bunch in a plasma wakefield driven by a proton bunch*. The plasma is induced in a 10 m long Rubidium vapour cell using a pulsed Ti:Sapphire laser, with the wakefield formed by a proton bunch from the CERN SPS. A 16 MeV electron bunch is simultaneously injected into the plasma cell to be accelerated by the wakefield to energies in GeV range over this short distance. After successful runs with the proton and laser beams, the electron beam line was installed and commissioned at the end of 2017 to produce and inject a suitable electron bunch into the plasma cell. To achieve the goals of the experiment, it is important to have reliable beam instrumentation measuring the various parameters of the proton, electron and laser beams such as transverse position, transverse profile as well as temporal synchronization. This contribution presents the status of the beam instrumentation in AWAKE, including the new instruments incorporated into the system for measurements with the electron beam line, and reports on the performance achieved during the AWAKE runs in 2017.
* Gschwendtner E., et al. "AWAKE, the Advanced Proton Driven Plasma Wakefield Experiment at CERN", NIM A 829 (2016)76-82
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF070  
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WEPAF074 Non-invasive Beam Diagnostics with Cherenkov Diffraction Radiation 2005
 
  • T. Lefèvre, M. Bergamaschi, O.R. Jones, R. Kieffer, S. Mazzoni
    CERN, Geneva, Switzerland
  • L.Y. Bartnik, M.G. Billing, Y.B.P. Bordlemay Padilla, J.V. Conway, M.J. Forster, J.P. Shanks, S. Wang
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • M. Bergamaschi, P. Karataev
    Royal Holloway, University of London, Surrey, United Kingdom
  • V.V. Bleko, A.S. Konkov, J.S. Markova, A. Potylitsyn
    TPU, Tomsk, Russia
  • L. Bobb
    DLS, Oxfordshire, United Kingdom
  • K. Lekomtsev
    JAI, Egham, Surrey, United Kingdom
 
  Based on recent measurements of incoherent Cherenkov Diffraction Radiation (ChDR) performed on the Cornell Electron Storage Ring, we present here a concept for the centering of charged particle beams when passing close to dielectric material. This would find applications as beam instrumentation in dielectric capillary tubes, typically used in novel accelerating technologies, as well as in collimators using bent crystals for high-energy, high-intensity hadron beams, such as the Large Hadron Collid-er or Future Circular Collider. As a charged particle beam travels at a distance of a few mm or less from the surface of a dielectric material, incoherent ChDR is produced inside the dielectric. The photons are emitted at a large and well-defined angle that allows their detection with a limited contribution of background light. A set of ChDR detectors distributed around a dielectric would enable both the beam position and tilt angle to be measured with a good resolution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF074  
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WEPAF080 Beam Size Measurements Based on Movable Quadrupolar Pick-ups 2028
 
  • A. Sounas, M. Gąsior, T. Lefèvre, A. Mereghetti, J. Olexa, S. Redaelli, G. Valentino
    CERN, Geneva, Switzerland
 
  Measurements with quadrupolar pick-ups (PU) have attracted particular interest as non-intercepting diagnostics for determining the transverse beam size. They are based on processing the signals of an electromagnetic PU for the extraction of the second-order moment, which contains information about the beam size. Despite the simplicity of the concept, quadrupololar measurements have always been highly challenging in reality. This comes from the fact that the quadrupolar moment constitutes only a very small part of the total PU signal dominated by the intensity and the position signals. Therefore, the beam size information can easily be lost due to small imperfections in the signal processing chain, such as asymmetries in the electronics and cables. In this paper, we present a new method for quadrupolar measurements using movable PUs. Through position and aperture scans, our technique minimizes the parasitic beam position signal and takes into account imperfections of the PU, cables and electronics, thus enabling an efficient auto-calibration of the measurement system. Preliminary studies, using collimators with embedded electrostatic PUs in the LHC at CERN, have shown very promising results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF080  
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WEPAF084 Commissioning the ELENA Beam Diagnostics Systems at CERN 2043
 
  • G. Tranquille, S. Burger, M. Gąsior, P. Grandemange, T.E. Levens, O. Marqversen, L. Søby
    CERN, Geneva, Switzerland
 
  The Extra Low ENergy Antiproton ring (ELENA) at CERN entered the commissioning phase in November 2016 using H ions and antiprotons to setup the machine at the different energy plateaus. The low intensities and energy of the ELENA beam generate very weak signals making beam diagnostics very challenging. With a circulating beam current of less than 1 µA and an energy where the beam annihilates in less than a few microns of matter, special care was taken during the design phase to ensure an optimal performance of these measurement devices once installed on the ring and transfer lines. A year on we present the performance of the various devices that have been deployed to measure the beam parameters from the extraction point of the Antiproton Decelerator (AD), through the ELENA ring and in the experimental lines.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF084  
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WEPAF085 Upgrade of the CERN SPS Beam Position Measurement System 2047
 
  • M. Wendt, M. Barros Marin, A. Boccardi, T.B. Bogey, V. Kain, C. Moran Guizan, A. Topaloudis
    CERN, Geneva, Switzerland
  • I. Degl'Innocenti
    Università di Pisa, Pisa, Italy
 
  The CERN Super Proton Synchrotron (SPS) is a fast cycling hadron accelerator delivering protons with momenta of up to 450 GeV/c for the Large Hadron Collider (LHC), fixed target experiments and other users such as the AWAKE plasma acceleration experiment, and also used to accelerate heavy ions. This paper presents the upgrade initiative for the SPS beam position measurement system in the frame of the CERN LHC Injector Upgrade (LIU) project. The new SPS beam position read-out electronics will be based on logarithmic amplifiers, using signals provided by the 216 existing beam position monitors, the majority of which are based on split-plane 'shoebox' technology. It will need to cover a dynamic range sufficient to manage the wide range of SPS beam intensities and bunch formatting schemes to provide turn-by-turn and averaged beam orbits along the SPS acceleration cycles. In order to avoid long coaxial cables, the front-end electronics including the digitisation, will be located inside the accelerator tunnel, with optical transmission to surface processing electronics. This represents an additional challenge in terms of radiation tolerance of electronics components and materials.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF085  
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WEPAF087 The First Experience and Results of Beam Diagnostics Deployment at the ESS Accelerator 2054
 
  • V. Grishin, E.C. Bergman, B. Cheymol, C.S. Derrez, T.J. Grandsaert, H. Hassanzadegan, A. Jansson, H. Kocevar, Ø. Midttun, S. Molloy, J. Norin, T.J. Shea, C.A. Thomas
    ESS, Lund, Sweden
  • W. Ledda
    Vitrociset s.p.a, Roma, Italy
  • F. Senée, O. Tuske
    CEA/IRFU, Gif-sur-Yvette, France
 
  The European Spallation Source (ESS) will produce neutrons for science by subjecting a tungsten target to the high-intensity proton beam from a superconducting linear accelerator. A complete suite of beam diagnostics will enable tuning, monitoring and protection of the accelerator during commissioning, studies and operation. As an initial step toward neutron production, the Ion Source and the 75 keV Low Energy Transport Line is installed on the ESS site in Lund, Sweden. To support the commissioning and characterization of this first beam-producing system, a subset of the full diagnostics suite is deployed. This includes the following equipment: a faraday cup, current transformers, an emittance measurement unit, beam-induced fluorescence monitors, and a doppler-shift spectroscopy system. All aspects of the deployment experience, from acceptance testing through installation, verification, and commissioning will be presented.
*Beam Instrumentation
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF087  
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WEPAG002 Tunable Q-Factor Gas-Filled RF Cavity 2064
SUSPF092   use link to see paper's listing under its alternate paper code  
 
  • M.D. Balcazar, A. Moretti, A.V. Tollestrup, A.C. Watts, K. Yonehara, R.M. Zwaska
    Fermilab, Batavia, Illinois, USA
  • M.A. Cummings, A. Dudas, R.P. Johnson, G.M. Kazakevich, M.L. Neubauer
    Muons, Inc, Illinois, USA
 
  Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013795.
Fermilab is the main institution to produce the most powerful and wide-spectrum neutrino beam. From that respective, a radiation robust beam diagnostic system is a critical element in order to maintain the quality of the neutrino beam. Within this context, a novel radiation-resistive beam profile monitor based on a gas-filled RF cavity has been proposed. The goal of this measurement is to study a tunable Q-factor RF cavity to determine the accuracy of the RF signal as a function of the quality factor. Specifically, the measurement error of the Q-factor in the RF calibration is investigated. Then, the RF system will be improved to minimize signal error.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAG002  
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WEPAG003 Hadron Beam Monitor Design with Gas-Filled RF Resonators in Intense Neutrino Source 2067
 
  • M.D. Balcazar, K. Yonehara
    Fermilab, Batavia, Illinois, USA
 
  Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013795.
For the future Long Baseline Neutrino Facility at Fermilab, a new radiation-robust hadron beam profile monitor has been proposed consisting of an interface of gas-filled radiofrequency cavity detectors in the backward region of the LBNF decay pipe. A tailored monitor layout will be used along with the new RF instrumentation. Proposed designs for the detector configuration include a variety of radially symmetric arrangements of RF resonators located at the position of maximum gradient in the beam distribution across the monitor. Until the final detector cavities are available, a prototype tunable Q-factor RF cavity will provide functional emulation for studies of the monitor layout configurations presented here.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAG003  
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WEPAG005 Synchrotron Radiation Beam Diagnostics for the Integrable Optics Test Accelerator 2073
SUSPF100   use link to see paper's listing under its alternate paper code  
 
  • N. Kuklev, Y.K. Kim
    University of Chicago, Chicago, Illinois, USA
  • A.L. Romanov
    Fermilab, Batavia, Illinois, USA
 
  Funding: Work supported by the U.S. National Science Foundation under Award PHY-1535639. Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy.
The Integrable Optics Test Accelerator (IOTA) is a research electron and proton storage ring currently being commissioned at Fermilab's Accelerator Science and Technology (FAST) facility. An extensive beam physics research program is planned, including tests of novel techniques for improving beam intensity, stability, and emittance. A key part of IOTA beam diagnostics suite are synchrotron light beam monitors, mounted onto each dipole. In this paper, we present the hardware and software design of this system. Mechanical layout and actuator control electronics are described. High throughput image acquisition and analysis architecture is outlined, and its preliminary performance is explored. Integration of the system within accelerator control network and possible user applications, such as camera auto-focusing, are discussed.
 
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WEPAK004 Beam Instrumentation for CRYRING@ESR 2084
 
  • A. Reiter, C. Andre, H. Bräuning, C. Dorn, P. Forck, R. Haseitl, T. Hoffmann, W. Kaufmann, N. Kotovski, P. Kowina, K. Lang, R. Lonsing, P.B. Miedzik, T. Milosic, A. Petit, H. Reeg, C. Schmidt, M. Schwickert, T. Sieber, R. Singh, G. Vorobjev, B. Walasek-Höhne, M. Witthaus
    GSI, Darmstadt, Germany
 
  We present the beam instrumentation of CRYRING@ESR, a low-energy experiment facility at the GSI Helmholtz-Centre for heavy ion research. The 1.44 Tm synchrotron and storage ring, formerly hosted at the Manne Siegbahn laboratory in Stockholm, Sweden, was modified in its configuration and installed behind the existing ESR, the experimental storage ring. As the first machine within the ongoing FAIR project, the facility for antiproton and ion research, it is built on the future timing system and frameworks for data supply and acquisition. Throughout the past year CRYRING was commissioned including its electron cooler with hydrogen beams from the local linear accelerator. Storage, acceleration and cooling have been demonstrated. The contribution provides an overview of the beam instrumentation. The design of the detector systems and their current performance are presented. Emphasis is given to beam position monitors, detectors for intensity measurements, and the ionization profile monitors.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK004  
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WEPAK005 A Cryogenic Current Comparators (CCC) Customized for FAIR-Project 2088
SUSPF098   use link to see paper's listing under its alternate paper code  
 
  • J. Golm, R. Neubert, F. Schmidl, P. Seidel
    FSU Jena, Jena, Germany
  • J. Golm, T. Stöhlker, V. Tympel
    HIJ, Jena, Germany
  • D.M. Haider, F. Kurian, M. Schwickert, T. Sieber, T. Stöhlker
    GSI, Darmstadt, Germany
  • R. Neubert
    Thuringia Observatory Tautenburg, Tautenburg, Germany
  • M. Schmelz, R. Stolz
    IPHT, Jena, Germany
  • T. Stöhlker
    IOQ, Jena, Germany
  • V. Zakosarenko
    Supracon AG, Jena, Germany
 
  The principle of non-destructive measurement of ion beams by detection of the azimuthal magnetic field, using low temperature Superconducting Quantum Interference Device (SQUID) sensors, has been established at GSI already in the mid 90's. After more recent developments at Jena, GSI and CERN, a CCC was installed in the CERN Antiproton Decelerator (AD) and is operated there routinely as the first stand-alone CCC system. For the Facility for Antiproton and Ion Research (FAIR) a new version of the CCC with eXtended Dimensions (CCC-XD) - especially with a larger inner diameter and adapted parameters - was constructed and first lab tests have already been performed. In parallel, a concept for a dedicated UHV beamline cryostat has been worked out. The CCC-XD system - together with the new cryostat - will be ready for testing in the CRYRING at GSI before the end of 2018. In this contribution, experimental results for the resolution, frequency range, slew rate and pulse-signal obtained by electrical laboratory measurements with the CCC-XD are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK005  
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WEPAK006 Bunch Shape Measurements at the GSI CW-Linac Prototype 2091
 
  • T. Sieber, W.A. Barth, P. Forck, V. Gettmann, M. Heilmann, H. Reeg, A. Reiter, S. Yaramyshev
    GSI, Darmstadt, Germany
  • F.D. Dziuba, T. Kürzeder, M. Miski-Oglu
    HIM, Mainz, Germany
  • A. Feschenko, S.A. Gavrilov
    RAS/INR, Moscow, Russia
 
  The existing GSI accelerator will become the injector for FAIR. To preserve and enhance the current experimental program at UNILAC, a new Linac is under development, which shall run in parallel to the FAIR injector, providing cw-beams of ions at energies from 3.5 - 7.3 MeV/u. For this cw-Linac a superconducting prototype cavity has been developed and was first operated with beam in summer 2017. The resonator is a cross-bar H-structure (CH) of 0.7 m length, with a resonant frequency of 216.8 MHz. It has been installed behind the GSI High Charge State Injector (HLI), which provided 108 MHz bunches of 1.4 MeV/u Ar6+/9+/11+ ions at a duty cycle of 25 %. Due to the frequency jump and small longitudinal acceptance of the CH, proper matching of the HLI beam to the prototype was required. The bunch properties of the injected beam as well as the effect of different phase- and amplitude-settings of the cavity were measured in detail with a bunch shape monitor (BSM) fabricated at INR, Moscow, while the mean energy was analyzed by time of flight method. In this contribution, the bunch shape measurements are described and the capabilities of the used BSM measurement principle are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK006  
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WEPAK007 Slow Extraction Spill Characterization From Micro to Milli-Second Scale 2095
 
  • R. Singh, P. Boutachkov, P. Forck, S. Sorge, H. Welker
    GSI, Darmstadt, Germany
 
  This contribution deals with the topic of slow extraction spill quality characterization based on the measurements performed at GSI SIS-18. The sensitivity of the spill to power supply ripples are studied by introducing external ripples. An estimate of sources of inherent power supply ripples along with ripple magnitude are thus obtained. Spill characterization in time and frequency domain are discussed and exemplified by a typical spill and the differences from an ideal or Poisson spill. An appropriate spill characterization aims to provide a suitable abstraction for communication about the spill quality requirements between accelerator operations and users.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK007  
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WEPAK008 Reconstructing Space-Charge Distorted IPM Profiles with Machine Learning Algorithms 2099
 
  • D.M. Vilsmeier, M. Sapinski, R. Singh
    GSI, Darmstadt, Germany
  • J.W. Storey
    CERN, Geneva, Switzerland
 
  Measurements of undistorted transverse profiles via Ionization Profile Monitors (IPMs) may pose a great challenge for high brightness or high energy beams due to interaction of ionized electrons or ions with the electromagnetic field of the beam. This contribution presents application of various machine learning algorithms to the problem of reconstructing the actual beam profile from measured profiles that are distorted by beam space-charge interaction. (Generalized) linear regression, artificial neural network and support vector machine algorithms are trained with simulation data, obtained from the Virtual-IPM simulation tool, in order to learn the relation between distorted profiles and original beam dimension. The performance of different algorithms is assessed and the obtained results are very promising for testing with simulation data.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK008  
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WEPAK009 Applications of the Interferometric Beam Size Monitor at BESSY II 2103
 
  • M. Koopmans, P. Goslawski, J.G. Hwang, A. Jankowiak, M. Ries, A. Schälicke, G. Schiwietz
    HZB, Berlin, Germany
 
  For the upgrade project of the BESSY~II storage ring to BESSY~VSR * an interferometric beam size monitor was designed and set up. Since this system uses visible light it can be upgraded efficiently to provide bunch resolved measurements. These are required for machine commissioning, development and to ensure long term quality and stability of user operation of BESSY~VSR. Various applications of the system are outlined and measurements are presented.
* A. Jankowiak et al., eds., BESSY VSR Technical Design Study, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany, June 2015. DOI: 10.5442/R0001
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK009  
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WEPAK010 Simulations and Measurements of the BPM Non Linearity and Kicker Timing Influence on the Tune Shift With Amplitude (TSWA) Measurement at BESSY II 2107
 
  • F. Kramer, P. Goslawski, J.G. Hwang, A. Jankowiak, P. Kuske, M. Ruprecht, A. Schälicke
    HZB, Berlin, Germany
 
  The Tune Shift With Amplitude (TSWA) does not only determine the position of the stable fix points for the Transverse Resonant Island Buckets (TRIBs) but also represents a global observable for the nonlinear optics in general. For theoretical investigations of the TRIBs a reliable nonlinear optics of the machine is required and thus all measurable global observables for the nonlinear optics are of great interest. The measurement of the TSWA for the BESSY II standard optics was performed using an injection kicker to excite high amplitude betatron oscillations and then extract the amplitude dependant frequency from the synchrotron radiation damped oscillation with a Hilbert transformation. With TRIBs optics the injection kicker was not able to sufficienty excite the beam. The impact and correctability of the BPM nonlinearity at the reached amplitudes and the reason for the failure of the excitation method for our TRIBs optics shall be looked onto in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK010  
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WEPAK011 Development of the Electron-Beam Diagnostics for the Future BESSY-VSR Storage Ring 2110
 
  • G. Schiwietz, J.G. Hwang, M. Koopmans, M. Ries, A. Schälicke
    HZB, Berlin, Germany
 
  This contribution focusses on the different types of new or improved electron-beam monitors at BESSY II for bunch resolved measurements under future BESSY-VSR conditions. A new diagnostics platform, involving three different dipole beam lines will be built for different di-pole-related optical and THz methods. Our main concepts for robust future monitors for bunch length, beam size and position are presented in the following.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK011  
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WEPAL004 The Algorithm Research of DBPM for HEPS 2147
 
  • F. Liu, J.S. Cao, Y.Y. Du, S.J. Wei
    IHEP, People's Republic of China
 
  The High Energy Photon Source (HEPS) is a 6-GeV, low-emittance, 1300m scale new generation photon source to be built in China [1]. As a key component, digital beam positon monitor (DBPM) needs to make the beam slow acquisition's resolution up to 0.1um. Because of the high requirements and large expenses, we designed our own DBPM system. In this paper, I will present the algorithm of our BPM. The algorithm is based on Discrete Fourier Transform (DFT) method and tested in BEPCII with using our own designed hardware. The Turn-by-Turn's resolution tested in BEPCII is 0.62um (STD value, 65080 counts, 1.2432MHz), the fast acquisition's resolution is 0.32um (STD value, 65080 counts, 10kHz), the slow acquisition's resolution is 0.18um (STD value, 65080 counts, 10Hz).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL004  
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WEPAL005 Beam Size Measurement and PSF Evaluate of KB Mirror Monitor at SSRF 2151
 
  • D.C. Zhu, J.S. Cao, Y.F. Sui, J.H. Yue
    IHEP, Beijing, People's Republic of China
 
  Funding: Work supported by National Nature Science Foundation of China(11605213)
A Kirkpatrick Baez mirror imaging system was designed and installed to measure the transverse beam size and emittance of SSRF storage ring. Two crossed cylindrical mirrors are used to image the dipole source point in the horizontal and vertical direction. Both mirrors could be moved in and out in order to interchangeable with an original X-ray pinhole system. Hard X-ray with peak energy of 20.5 keV was focused at the X-ray scintillator camera. Aberration and point spread function which would cause image blur were evaluated. System commissioning and optimization have been done. PSF measurement was acquired using beam based calibration scheme by varying the beam images with different quadrupole settings and fitting them with the corresponding theoretical beam sizes.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL005  
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WEPAL006 Experimental Study of a Differential Beam Intensity Monitoring for the CIADS LINAC 2155
 
  • Z.P. Xie, Y.K. Ding, J. Liang
    Hohai University, Nanjing, People's Republic of China
  • Y. He, Z.J. Wang, J.X. Wu, Y. Zhang
    IMP/CAS, Lanzhou, People's Republic of China
 
  Funding: Work supported by the National Natural Science Foundation of China (Grant No. 91026001) and the Fundamental Research Funds for the Chinese Central Universities
A BPM based beam loss monitoring scheme for the China initiative accelerator driven subcritical (CIADS) facility has been proposed for the MEBT section of its high power Linac. In this scheme, a differential beam monitoring algorithm is utilized that relies on beam intensity measurements using BPM electrodes. Discussions of the experimental results for the scheme are presented. Further experiments have been performed with some promising results. This paper describes the experimental results with some analyses on measurement errors of the system. The proposed physical design of this system is described and further development is presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL006  
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WEPAL011 iPipe: An Innovative Fiber Optic Monitoring System for Beam Induced Heating on Accelerator Pipes 2166
 
  • F. Fienga, S. Buontempo, M.R. Masullo
    INFN-Napoli, Napoli, Italy
  • A. Ball, N. Beni, B. Salvant, W. Zeuner
    CERN, Geneva, Switzerland
  • G. Breglio, A. Irace
    University of Napoli Federico II, Napoli, Italy
  • Z. Szillasi
    ATOMKI, Debrecen, Hungary
  • V.G. Vaccaro
    Naples University Federico II and INFN, Napoli, Italy
 
  The iPipe project consists in the instrumentation, with Fiber Bragg Grating sensors (FBGs), of the beam pipe of the CMS experiment, which is part of the LHC. Being spectrally encoded, the FBGs are not sensitive to electromagnetic interference and broadband-radiation-induced losses. These characteristics allow to realize long distance punctual sensing systems, capable to operate in harsh environments like the underground experimental and accelerator facilities at CERN. The iPipe secures the measurement of any deformation induced on the central beam pipe by any motion in the CMS detector due to element displacement or to magnetic field induced deformations. Moreover, the iPipe FBG temperature sensors represent a unique solution to monitor the beam pipe thermal behavior during the various operational and maintenance phases. This paper reports the use of the iPipe to measure the beam induced heating on the CMS vacuum chamber throughout 2016 and 2017. A first comparison between the measurements and the heat load predicted from beam induced RF heating due to the coupling impedance of the CMS pipe is also reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL011  
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WEPAL012 Measurements with the ELI-NP Cavity Beam Position Monitor Read-out Electronics at FLASH 2169
 
  • G. Franzini, D. Pellegrini, M. Serio, A. Stella, A. Variola
    INFN/LNF, Frascati (Roma), Italy
  • B.B. Baricevic, M. Cargnelutti
    I-Tech, Solkan, Slovenia
  • D. Lipka
    DESY, Hamburg, Germany
  • M. Marongiu
    INFN-Roma, Roma, Italy
  • A. Mostacci
    Sapienza University of Rome, Rome, Italy
 
  The Extreme Light Infrastructure - Nuclear Physics Gamma Beam Source (ELI-NP GBS) will be installed and commissioned starting within the next year in Magurele, Romania. It will generate gamma beam through Compton back-scattering of a recirculated laser and a multi-bunch electron beam, produced by a 720 MeV LINAC. In order to obtain bunch by bunch position measurements, four cavity beam position monitors (cBPM) near the two interaction points are foreseen. Extensive tests on the cBPM read-out electronics, recently developed by Instrumentation Technologies and acquired for ELI-NP GBS, were performed in laboratory at INFN-LNF and at FLASH in DESY, during the user operation. In the latter case, three cBPMs installed along the LINAC, with similar features as the ones of ELI-NP GBS, were used as measuring devices and signal sources for the read-out electronics under test. We present here the measurements collected and the related analysis, with a particular focus on the beam position measurement resolution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL012  
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WEPAL013 Design of the Diagnostic Stations for the ELI-NP Compton Gamma Source 2173
SUSPF103   use link to see paper's listing under its alternate paper code  
 
  • M. Marongiu
    INFN-Roma, Roma, Italy
  • M. Castellano, E. Chiadroni, G. Di Pirro, G. Franzini, A. Giribono, V. Shpakov, A. Stella, A. Variola
    INFN/LNF, Frascati (Roma), Italy
  • A. Cianchi
    Università di Roma II Tor Vergata, Roma, Italy
  • A. Mostacci, L. Palumbo
    Sapienza University of Rome, Rome, Italy
 
  A high brightness electron Linac is being built in the Compton Gamma Source at the ELI Nuclear Physics facility in Romania. To achieve the design luminosity, a train of 32 bunches, 16 ns spaced, with a nominal charge of 250 pC will collide with the laser beam in the interaction point. Electron beam spot size is measured with optical transition radiation (OTR) profile monitors. Furthermore, OTR angular distribution strongly depends on beam energy. Since OTR screens are typically placed in several positions along the Linac to monitor beam envelope, one may perform a distributed energy measurement along the machine. This will be useful, for instance, during the commissioning phase of the GBS in order to verify the correct functionality of the C-Band accelerating structures, due to the fact that there are OTR screens after each accelerating module. This paper deals with the studies of different optic configurations to achieve the field of view, resolution and accuracy in order to measure the energy of the beam. Several configurations of the optical detection line will be studied with simulation tools (e.g. Zemax).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL013  
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WEPAL014 Non-Distructive 2-D Beam Profile Monitor Using Gas Sheet in J-PARC LINAC 2177
 
  • J. Kamiya, Y. Hikichi, M. Kinsho, A. Miura, N. Ogiwara
    JAEA/J-PARC, Tokai-mura, Japan
 
  We have been developed a beam profile monitor using interaction between the beam and the gas molecules distributed in sheet shape*. Generated luminescence or ions by passing the beam through the gas sheet has the information of cross-section shape of the beam. The gas sheet beam monitor will become a useful tool to measure the profile of high power beams because it has no breakable element such as wires and a 2-D beam profile at a certain position of beam line can be immediately obtained by just injecting the gas. Previously, the development of the gas sheet generator and successful demonstration of the beam profile measurement were reported. This time, we applied a gas sheet monitor to J-PARC LINAC, where the negative hydrogen atoms (H) are accelerated to the energy of 400 MeV in the normal operation. Most challenging factor was the development of the gas sheet monitor system, which generates the enough dense gas sheet to detect the clear image of the beam profile without harmful effect on the ultra-high vacuum in the beam line. We will report the gas sheet beam monitor system for J-PARC LINAC and the results of the first measurement of the beam profile.
* N. Ogiwara, et al., Proceedings of IPAC2016, p.2102.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL014  
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WEPAL016 Tensile Fracture Test of Metallic Wire of Beam Profile Monitors 2183
 
  • A. Miura, Y. Kawane, K. Moriya
    JAEA/J-PARC, Tokai-mura, Japan
  • S. Fukuoka
    Nihon Koshuha Co. Ltd, Yokohama, Japan
  • K. Futatsukawa, T. Miyao
    KEK, Ibaraki, Japan
 
  In order to mitigate the beam loss during a beam transportation in a high-brilliant accelerator facilities, wire-based profile monitors are used to measure by both transverse and longitudinal beam profiles using wire-scanner monitors (WSMs) and bunch-shape monitors (BSMs) for the tuning of quadrupole magnets and bunching cavities. Signals are come from the direct interaction between a metallic wire and beam. We have used the tungsten wire as a high melting-point material by estimation of heat loading during the impact of beam particles. In addition, a spring is applied for the relaxing a sag under wire's own weight. A tensile fracture test is conducted by supplying an electrical current as a simulated beam-heat loading. As the results, we obtained the relation between the thermal limit to break down and tension loading of tungsten wire.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL016  
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WEPAL018 A Non-destructive 2D Profile Monitor Using a Gas Sheet 2190
 
  • N. Ogiwara, Y. Namekawa
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • M. Fukuda, K. Hatanaka, T. Shima, K. Takahisa
    RCNP, Osaka, Japan
  • Y. Hikichi, J. Kamiya, M. Kinsho
    JAEA/J-PARC, Tokai-mura, Japan
  • Y. Hori
    KEK, Tokai, Ibaraki, Japan
 
  We are developing a non-destructive and fast-response beam profile monitor using a dense gas sheet target. To make a gas sheet, we use the beaming effect, which is well known in vacuum science and technology. The emitted molecules through a long rectangular channel, which has a very small ratio of the gap to the width, are forced to concentrate on a plane. The gas sheet with a thickness of 1.5 mm and the density of 2×10-4 Pa was easily generated by the combination of the deep slit and the thin slit. Here, the gas sheet was produced by the deep slit, and the shape of the sheet was improved by the thin slit. The usefulness of this monitor was shown by the following experiments: 1) For the electron beam of 30 keV with a diameter greater than 0.35 mm, the position and the two-dimensional profiles were well measured using the gas sheet. 2) Then the profiles of the 10 and 400 MeV proton beam with a current of several microamperes were well measured, too. 3) Recently, the profiles of the 400 MeV H ion beams in J-PARC linac were measured.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL018  
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WEPAL019 A Novel Field Cage Design for the CPS IPM and Systematic Errors in Beam Size and Emittance 2193
 
  • K. Satou
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • D. Bodart, S. Levasseur, G. Schneider, J.W. Storey
    CERN, Geneva, Switzerland
  • M. Sapinski
    GSI, Darmstadt, Germany
 
  An ionization profile monitor has been recently installed in the CERN proton synchrotron. We design a novel and simple structure field cage that suppresses the secondary electrons that are induced by the ionized ions. We discuss a field cage design, and the systematic error on the basis of beam size and emittance, considering the non-uniformity of the fields, the space-charge effect of the beam, and the lattice parameter errors.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL019  
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WEPAL020 Measurement of Transverse Dipole and Quadrupole Moments with the BPMS in the J-PARC 3-50 BT 2197
 
  • T. Toyama
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • H. Kuboki, K. Satou, M. Tejima
    KEK, Tokai, Ibaraki, Japan
 
  We measure dipole and quadrupole moments of the beam using the BPMs in the beam transport line 3-50BT of J-PARC and obtain differences of squared horizontal- and vertical-rms-sizes for those BPMs. Then we obtain rms emittances and rms momentum by fitting with given Twiss parameters.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL020  
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WEPAL021 Study of a Tuner for a High-Accuracy Bunch Shape Monitor 2200
 
  • K. Moriya, Y. Kawane, A. Miura
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • K. Futatsukawa, T. Miyao
    KEK, Ibaraki, Japan
 
  In the J-PARC Linac, development and higher precision of Bunch Shape Monitor (BSM) have been progressed for measuring the longitudinal beam distribution. To transform a longitudinal beam-profile into transverse one with an rf field, we need the field having an acceleration synchronizing frequency. An rf deflector of BSM consists of a half λ cylindrical cavity and two electrodes for deflection. In general, the resonance frequency can be tuned by adjusting the electrode length. We designed the new tuner with CST Studio. We can control the resonance frequency by Adjusting not only the electrode length but the cavity volume. We found the optimum lengths of electrode and volume for tuning. We introduce development of the new rf tuner for BSM in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL021  
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WEPAL023 Pulsed Operation at MAMI with High Beam Loading 2206
 
  • M. Dehn, K. Aulenbacher, F. Fichtner, P. Jennewein, W. Klag, H.-J. Kreidel, J.R. Röthgen
    IKP, Mainz, Germany
 
  Funding: Work supported by DFG (CRC 1044) and the German federal state of Rhineland-Palatinate
The Mainz Microtron Accelerator (MAMI) is a microtron cascade which is normally operated CW for particle physics experiments. For certain investigations it is necessary to use a pulsed beam (macro pulses, several milliseconds). Up to now this pulsed mode can only be applied if the beam loading for the accelerating RF structures is negligible. To achieve higher pulse intensities the accelerator RF infrastructure needs to be equipped with feed-forward techniques to compensate for the expected beam loading. To monitor beam losses the machine protection system at MAMI needs to be extended to be able to localize fast occurrences of beam losses. This paper will present the possibilities being investigated to allow pulsed operation of MAMI within the near future.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL023  
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WEPAL026 High Repetition Rate, Single-Shot Electro-Optical Monitoring of Longitudinal Electron Bunch Dynamics Using the Linear Array Detector KALYPSO 2216
 
  • G. Niehues, E. Blomley, M. Brosi, E. Bründermann, M. Caselle, S. Funkner, A.-S. Müller, M.J. Nasse, L. Rota, M. Schuh, P. Schönfeldt, M. Weber
    KIT, Eggenstein-Leopoldshafen, Germany
  • N. Hiller
    PSI, Villigen PSI, Switzerland
 
  Funding: This work is funded by the BMBF contract numbers: 05K13VKA and 05K16VKA.
High repetition rate diagnostics are required when detecting single-shot electro-optical (EO) bunch profiles. The KIT storage ring KARA (KArlsruhe Research Accelerator) is the first storage ring in the world that has a near-field EO bunch-profile monitor in operation. By imprinting longitudinal electron bunch profiles onto chirped laser pulses, single-shot detection is feasible. However, limitations of available detection systems are challenging: The constraints are either given by the repetition rate or the duration of the consecutive acquisitions. Two strategies can overcome these limitations: Based on the photonic time-stretch method, the ps laser pulses can be stretched to the ns range using km long fibers. The readout with a high-bandwidth oscilloscope then enables a single-shot detection at high repetition rates. The other strategy is the development of dedicated ultra-fast photodetector arrays allowing direct detection of the ps pulses at MHz repetition rates. We developed KALYPSO, a linear detector array with a DAQ allowing to record high data-rates over long time scales. Here, we present recent results of studies of the longitudinal electron bunch dynamics using KALYPSO.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL026  
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WEPAL027 Filling Pattern Measurements Using Dead-Time Corrected Single Photon Counting 2219
 
  • B. Kehrer, E. Blomley, M. Brosi, E. Bründermann, A.-S. Müller, M. Schuh, P. Schönfeldt, J.L. Steinmann
    KIT, Karlsruhe, Germany
 
  Time-correlated single photon counting (TCSPC) is a versatile tool for various accelerator diagnostics aspects. Amongst others it allows a precise determination of the filling pattern. At the visible light diagnostics port at the Karlsruhe Research Accelerator (KARA), the KIT storage ring, a Single-Photon Avalanche Diode (SPAD) in combination with a histogramming device (PicoHarp) is used. To compensate for possible dead-time effects, a correction scheme was developed and tested successfully. The compensation increases the dynamic range in which accurate measurements are possible and avoids distortion of the measured filling pattern. This contribution presents the experimental setup, as well as a series of benchmark measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL027  
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WEPAL028 Study of the Influence of the CSR Impedance on the Synchronous Phase Shift at KARA 2223
 
  • P. Schönfeldt, E. Blomley, M. Brosi, E. Bründermann, J. Gethmann, B. Kehrer, A.-S. Müller, A.I. Papash, J.L. Steinmann
    KIT, Karlsruhe, Germany
 
  Funding: This work has been supported by the German Federal Ministry of Education and Research (Grant No. 05K16VKA) and the Helmholtz Association (Contract No. VH-NG-320).
Measurements of the bunch current dependent synchronous phase shift are a standard method to characterize the impedance of a storage ring. To study this shift, different experimental approaches can be used. In this contribution, we first derive the phase shift caused by the impedance describing the emission of coherent synchrotron radiation (CSR) based on numerical simulations of the longitudinal phase space. The predicted shift is compared to measurement results obtained by time-correlated single photon counting.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL028  
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WEPAL029 FLUTE Diagnostics Integration 2227
 
  • M. Yan, A. Bernhard, E. Bründermann, S. Funkner, A. Malygin, S. Marsching, W. Mexner, A. Mochihashi, A.-S. Müller, M.J. Nasse, G. Niehues, R. Ruprecht, T. Schmelzer, M. Schuh, N.J. Smale, P. Wesolowski, S. Wüstling
    KIT, Karlsruhe, Germany
  • I. Križnar
    Cosylab, Ljubljana, Slovenia
 
  FLUTE (Ferninfrarot Linac- Und Test-Experiment) will be a new compact versatile linear accelerator at KIT. Its primary goal is to serve as a platform for a variety of accelerator studies as well as to generate strong ultra-short THz pulses for photon science. The machine consists of an RF gun, a traveling wave linac and a D-shaped bunch compressor chicane with corresponding diagnostics sections. In this contribution, we report on the latest developments of the diagnostics components. An overview of the readout and control system integration will be given.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL029  
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WEPAL033 Development of Real-Time Mass Analysis System with Permanent Magnet for Ion Beam 2236
SUSPL051   use link to see paper's listing under its alternate paper code  
 
  • Y. Takeuchi, Y. Iwashita, H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
 
  In order to analyze time variation of the ion species in a pulse, we are developing a mass analysis system that has multiple collector electrodes to detect several ion species simultaneously. Strong permanent magnets can generate 1T magnetic field and the size of the analyzing magnet system can be compact. The detected signals are scanned by a fast multiplexer. The scanning rate is 2 MHz, so that all electrode signals of the 16 channels are scanned in 8 μs period. In this paper, details of the design of the analysis system, and preliminary beam extraction test results with prototype of the system are described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL033  
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WEPAL034 Bunch Length Measurements Using Coherent Smith-Purcell Radiation With Several Gratings at CLIO 2239
 
  • N. Delerue, S. Jenzer, V. Khodnevych, A. Migayron
    LAL, Orsay, France
  • J.P. Berthet, N. Jestin, J.-M. Ortega, R. Prazeres
    CLIO/ELISE/LCP, Orsay, France
 
  Funding: Financially supported by the Université Paris-Sud (programme "attractivité"), by the French ANR (contract ANR-12-JS05-0003-01) and by IN2P3.
Coherent Smith Purcell radiation allows the measurement of a beam longitudinal profile through the study of the emission spectrum of the radiation emitted when a grating is brought close from the beam. In order to increase the dynamic range of our measurements we have used several gratings and we report on the measured bunch form factor using this technique. We report on these measurements and on the background rejection used.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL034  
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WEPAL044 ENSOLVE : A Simulation Code for FXR LIA Downstream Section 2271
 
  • Y.H. Wu, Y.-J. Chen
    LLNL, Livermore, California, USA
 
  Funding: This work was performed under the auspi-ces of the U.S. Department of Energy by Law-rence Livermore National Laboratory under Contract DE-AC52-07NA27344.
In this paper, we describe an envelope code, ENSOLVE. It solves the rms beam envelope equation by including space change depression of the potential, spherical aberration of the so-lenoidal lens, emittance growth and focusing effects of backstreaming ions in the final focus region. In this paper, we focus on the physics included for beam transport simulations in the downstream section of flash x-ray radiography linear induction accelerators, such as FXR LIA. We have used ENSOLVE to design final focus tunes for FXR LIA downstream section
 
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WEPAL045 An Electrostatic Fixed-Slit Emittance Measurement System 2274
 
  • J.W. Lewellen, H.L. Andrews, R.L. Fleming, K.E. Nichols, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
 
  Funding: Los Alamos National Laboratory LDRD Program
The emittance of a field emission cathode can be difficult to measure close to the emitter, due to the high average current density of the beam and the potential for desorbed material from an imaging screen to contaminate the cathode. We present the design for a dual fixed-slit emittance measurement system for a field emitter cathode, implemented using electrostatic deflecting plates. Results from fabrication and initial testing will be presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL045  
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WEPAL049 Simulating Non-Relativistic Beams Using Helical Pulse Lines 2288
SUSPL049   use link to see paper's listing under its alternate paper code  
 
  • C.J. Richard
    NSCL, East Lansing, Michigan, USA
  • S.M. Lidia
    FRIB, East Lansing, USA
 
  Funding: Work supported by the US Department of Energy, Office of Science, High Energy Physics under Cooperative Agreement award number DE-SC0018362.
Benchtop calibration of capacitive beam position monitors (BPMs) in low energy beamlines is challenging due to non-relativistic effects. Typical benchtop calibrations cannot account for these effects because they rely on speed of light fields transmitted along a straight wire. However, it is possible to replicate the electromagnetic fields generated by non-relativistic beams using a helical line pulse instead of a straight wire. In order to properly replicate the fields from a beam, a method must be developed for tailoring input pulses into the helical line to match bunch shape and a model of the impedance of the helix should be developed to assist with matching. This paper uses the sheath helix model to analyze signal propagation along a helical line in the time domain, with attention to dispersive effects and impedance matching. The results from this model are then compared to Microwave Studio simulations.
 
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WEPAL051 Mirascope Residual-Gas Luminescent Beam Profile Monitors 2291
 
  • V.G. Dudnikov, R.J. Abrams, M.A. Cummings
    Muons, Inc, Illinois, USA
 
  Muons, Inc. proposes to develop a Residual-Gas Beam Profile Monitor for Transfer Lines with pulse-to-pulse precision of better than 0.1 mm in position and size that will operate over a wide range of proton beam intensities including those needed for multi-MW beams of future facilities. Traditional solid-based beam intercepting instrumentation produces unallowable levels of radiation at high powers. Our alternative approach is to use a low mass residual-gas profile monitor, where ionization electrons are collected along extended magnetic field lines and the gas composi-tion and pressure in the beam pipe are locally controlled to minimize unwanted radiation and to improve resolu-tion. Beam Induced Fluorescence profile monitor with micrascope light collection is proposed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL051  
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WEPAL062 Bunch Length Measurements with a Streak Camera in Low Alpha Lattice Operation at the TPS 2316
 
  • C.H. Chen, J.Y. Chen, M.-S. Chiu, P.J. Chou, K.T. Hsu, K.H. Hu, C.-C. Kuo, C.C. Liang, C.Y. Liao, Y.-C. Liu, G.-H. Luo, H.-J. Tsai, F.H. Tseng
    NSRRC, Hsinchu, Taiwan
 
  We developed and tested lattice with lower momentum compaction factor (low alpha) in TPS (Taiwan Photon Source) recently. Operating low alpha lattice can provide picosecond bunch length for time-resolved research and coherent IR/THz synchrotron light. The bunch length around 2.5 picosecond rms was measured by a streak camera* in low alpha mode while operating in the routine users mode** it was around 10 picosecond. This paper presents the related processes and measurements.
* L.Y. Liao et al., "Preliminary beam test of synchrotron radiation monitoring system at Taiwan Photon Source", IPAC'15.
** C.C. Kuo et al., "Commissioning of Taiwan Photon Source", IPAC'15.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL062  
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WEPAL063 A Method to Tune Pulse Magnets' Waveforms 2320
 
  • T.Y. Lee, B.Y. Chen, S. Fann, C.S. Huang, C.H. Kuo, C.C. Liang, W.Y. Lin, Y.-C. Liu, Y.C. Yang
    NSRRC, Hsinchu, Taiwan
 
  Pulse magnets are used in storage ring injection kickers. The waveform of the the four kickers have strong relation with injection efficiency. A slightly offset of waveform may cause the four kickers mismatched, which would lead to storaged beam loss and decrease injection efficiency. In order to define the peak value and timing of the half-sine waveform which has noises interfering diagnosis, a curve-fitting method was introduced to monitor and fine-tuning the waveform. The waveforms' data are also archived for reference in case of replacing power supplies. By using this method, it helps to retain a consistent injection efficiency after the power supplies maintenance or replacement.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL063  
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WEPAL065 Development of a Gas Sheet Beam Profile Monitor for IOTA 2326
SUSPL050   use link to see paper's listing under its alternate paper code  
 
  • S. Szustkowski, B.T. Freemire
    Northern Illinois University, DeKalb, Illinois, USA
  • S. Chattopadhyay
    Northern Illinois Univerity, DeKalb, Illinois, USA
  • D.J. Crawford
    Fermilab, Batavia, Illinois, USA
 
  Funding: US Department of Energy, Office of High Energy Physics, General Accelerator Research and Development (GARD) Program
A nitrogen gas sheet will measure the two dimensional transverse profile of the 2.5 MeV proton beam in IOTA. The beam lifetime is limited by the interaction with the gas, thus a minimally invasive instrument is required. To produce a gas sheet with the desired density and thickness, various nozzle types are being investigated, including rectangular capillary tubes for gas injection and skimmers for final shaping of the gas. It is essential to meet vacuum requirements in the interaction chamber while maintaining the precise thickness and density of the gas, without significantly affecting the beam lifetime. The current design of a gas sheet beam profile monitor and present status will be discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL065  
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WEPAL066 Determination of RF Resonator Axis Inclination to Beam Axis in Electron-Positron Storage Ring 2330
SUSPF101   use link to see paper's listing under its alternate paper code  
 
  • Leshenok D. Leshenok
    NSU, Novosibirsk, Russia
  • S.A. Nikitin
    BINP SB RAS, Novosibirsk, Russia
 
  We proposed and tested the method that allows obtaining of an upper limit for an angle of the RF resonator axis inclination relative to a beam axis. Such disturbance gives an additional contribution to separation of electron and positron orbits due to action of the transverse component of the electric field. In the horizontal plane, this effect can lead to increase of the difference between electrons and positrons spin precession frequencies in a storage mono-ring collider. This effect can play a great role in FCC. At the angular disturbance of axis in the certain VEPP-4M RF resonators ~10-3 rad, the difference between the spin frequencies is about 10-8. Our method is based on resonant excitation of betatron oscillations using phase modulation of the master oscillator of the RF system. The maximal amplitude of the enforced oscillations is measured by the counting rate of the VEPP-4M Touschek polarimeter scintillation counters. Comparison of the obtained results with the data of the special calibration experiment allows estimating the value of the inclination angle. In this calibrated experiment the betatron oscillations excite using the VEPP-4M kicker.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL066  
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WEPAL067 Number of Turn Measurements on the HIPA Cyclotrons at PSI 2334
 
  • P.-A. Duperrex, A. Facchetti
    PSI, Villigen PSI, Switzerland
 
  The number of turns is an important parameter for the tuning of a cyclotron; it is even more important for high intensity machines such as the 1.4 MW High Intensity Proton Accelerator (HIPA) facility. Up to recently, the number of turns had to be measured using radial probes, which cannot be performed during user operation but only during beam development shifts. For user shifts, the estimate of the number of turns was based on the acceleration voltage measurements, with the inherent limited precision of RF measurements. A new scheme based on the time of flight (ToF) measurements has been deployed on the two cyclotrons of HIPA. It is based on the cross-correlation of fast sampled data from pickups located at the entrance and at the exit of the cyclotrons. For the first cyclotron, called Injector 2 (accelerating the beam from 870 keV to 72MeV), the beam had to be externally modulated whereas, for the Ring Cyclotron (72 MeV to 590 MeV), no external modulation was necessary. This paper will present the details of both implementations, their limitations and the quality of the results that can be obtained with the ToF techniques.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL067  
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WEPAL069 Reentrant Cavity Resonator for Low Intensities Proton Beam Measurements 2341
 
  • S. Srinivasan, P.-A. Duperrex
    PSI, Villigen PSI, Switzerland
 
  A non-interceptive beam current monitor has been developed to investigate the measurement possibilities of low-intensity beams down to 1 nA for proton therapy machines without the drawback of interceptive monitors. This works on the principle of a reentrant cavity resonator such that its fundamental mode resonance frequency of 145.7 MHz matches the second harmonic of the pulse repetition rate of the cyclotron beam i.e. 72.85 MHz. The Driven Modal analysis from the simulation tool ANSYS HFSS was used for parametric model development and to optimize design parameters such as e.g. the position of the inductively coupled pick-ups. A ceramic plate has been inserted in the resonator gap to relax the precision required during manufacturing. A test bench has been designed and constructed for the characterization tests of the prototype. Comparison of the simulated and the experimental scattering parameter from the test bench shows a good agreement.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL069  
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WEPAL072 A Novel Longitudinal Laserwire to Non-Invasively Measure 6-Dimensional Bunch Parameters at High Current Hydrogen Ion Accelerators 2349
 
  • S.M. Gibson, A. Bosco
    Royal Holloway, University of London, Surrey, United Kingdom
  • S.E. Alden, A. Bosco, S.M. Gibson
    JAI, Egham, Surrey, United Kingdom
  • A.P. Letchford
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • J.K. Pozimski
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • J.K. Pozimski
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
 
  Funding: We acknowledge funding by the STFC Grant ST/P003028/1 and the John Adams Institute at Royal Holloway, University of London.
Optical methods for non-invasive beam diagnostics of high current H ion accelerators have been developed in recent years*, **. Such laserwires typically measure a 1D beam profile and/or 2D transverse emittance from the products of photo-detached ions as a laser beam is scanned across the H beam. For laser pulse durations (~80ns) longer than the RF period (~3ns), the detector integrates many complete bunches, enabling only transverse beam monitoring. This paper presents a new technique to capture a series of time resolved transverse emittance measurements along the bunch train. A fast (~10ps) pulsed laser photo-detaches ions within each bunch and is synchronized to sample consecutive bunches at certain longitudinal positions along each bunch. A fast detector records the spatial distribution and time-of-flight of the neutralized H0, thus both the transverse and longitudinal emittance are reconstructed. We present simulations of a time varying pulsed laser field interacting within an H bunch, and estimate the yield, spatial and time distributions of H0 arriving at the detector. We summarise the design of a recently funded longitudinal laserwire being installed in FETS at RAL, UK.
* NIM-A, 830, p526-531, T. Hofmann et al
** T. Hofmann et al, 'Commissioning of the Operational Laser Emittance Monitors for LINAC4 at CERN' IPAC18.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL072  
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WEPAL073 Enhanced Bunch Monitoring by Interferometric Electro-Optic Methods 2353
 
  • S.M. Gibson, A. Arteche, A. Bosco
    Royal Holloway, University of London, Surrey, United Kingdom
  • S.E. Bashforth, A. Bosco, S.M. Gibson
    JAI, Egham, Surrey, United Kingdom
  • M. Krupa, T. Lefèvre
    CERN, Geneva, Switzerland
 
  Funding: We acknowledge funding by UK STFC grant ST/N001583/1, JAI at Royal Holloway University of London and CERN
A prototype Electro-Optic Beam Position Monitor has been installed for tests* in the CERN SPS to develop the concept for high-bandwidth (6-12GHz) monitoring of crabbed-bunch rotation and intra-bunch instabilities at the High Luminosity LHC**. The technique relies on the ultrafast response of birefringent MgO:LiNO3 crystals to optically measure the intra-bunch transverse displacement of a passing relativistic bunch. This paper reports on recent developments, including a new interferometric electro-optic pick-up that was installed in the CERN SPS in September 2017; in first beam tests with nominal bunch charge, a corresponding interferometric signal has been observed. The interferometric arrangement has the advantages of being sensitive to the strongest polarisation coefficient of the crystal, and the phase offset of the interferometer is controllable by frequency scanning of the laser, which enables rapid optimisation of the working point. Novel concepts and bench tests for enhancements to the pick-up design are reviewed, together with prospects for sensitivity during the first crab-cavity beam tests at the CERN SPS in 2018.
* A. Arteche et al "First beam tests at the CERN SPS of an electro-optic beam position monitor for the HL-LHC" TUPCF23, IBIC 2017.
** HL-LHC TDR v0.1 doi.org/10.23731/CYRM-2017-004
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL073  
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WEPAL074 Commissioning of the Operational Laser Emittance Monitors for LINAC4 at CERN 2357
 
  • T. Hofmann, G.E. Boorman, A. Bosco, S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  • F. Roncarolo
    CERN, Geneva, Switzerland
 
  A laser-based emittance monitor has been developed to non-invasively measure the transverse emittance of the LINAC4 H beam at its top energy of 160MeV. After testing several sub-systems of the instrument during linac commissioning at intermediate energies, two instruments are now permanently installed. These instruments use a pulsed laser beam delivered to the accelerator tunnel by optical fibres before final focusing onto the H beam. The photons in the laser pulse detach electrons from the H ions, which can then be deflected into an electron multiplier. In addition, the resulting neutral H0 atoms can be separated from the main beam by a dipole magnet before being recorded by downstream diamond strip-detectors. By scanning the laser in the horizontal and vertical plane the beam profiles are obtained from the electron signals and the emittance can be reconstructed by the H0 profiles at the diamond detectors. This paper describes the final system layout that consists of two independent instruments, each measuring profile and emittance of the H beam in the horizontal and vertical plane and discusses the preliminary commissioning results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL074  
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WEPAL075 Time-Resolved Transverse Beam Profile Measurements with a Rest Gas Ionisation Profile Monitor Based on Hybrid Pixel Detectors 2361
 
  • S. Levasseur, S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  • W. Bertsche, H. Sandberg
    UMAN, Manchester, United Kingdom
  • D. Bodart, A. Huschauer, G. Schneider, J.W. Storey, R. Veness
    CERN, Geneva, Switzerland
  • M. Sapinski
    GSI, Darmstadt, Germany
  • K. Satou
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
 
  A novel rest gas ionisation profile monitor which aims to provide continuous, bunch-by-bunch and turn-by-turn measurement of the transverse beam profile has recently been in- stalled in the CERN Proton Synchrotron (PS) as part of the LHC Injector Upgrade (LIU) project. The instrument consists of an electric drift field to transport ionisation electrons produced by beam-gas interaction onto a measurement plane, and a magnetic field to maintain the transverse position of the ionisation electrons. The electron detector located at the measurement plane is based on four in-vacuum hybrid pixel detectors. The detectors record the position, time and energy of single ionisation electrons with unprecedented precision compared to traditional MCP based techniques. Continuous transverse beam profile measurements for LHC-type beams in the PS will be presented, demonstrating the unique capabilities of the instrument to provide new insights into beam dynamics throughout the acceleration cycle.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL075  
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THXGBE1 6D Beam Measurement, Challenges and Possibilities 2890
 
  • A.V. Aleksandrov, S.M. Cousineau, A.P. Zhukov
    ORNL, Oak Ridge, Tennessee, USA
  • B.L. Cathey
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  A system to measure the full 6D beam parameters (not 3x2D) has been built at the SNS RFQ test stand. Such a measurement will allow detailed analysis of the beam physics from a properly measured input term. This invited provides an overview of the principles and design of this system, and reports on status and results.  
slides icon Slides THXGBE1 [4.476 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THXGBE1  
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THXGBE2 Optical Diagnostics for Extreme Beam Conditions 2896
 
  • R.B. Fiorito
    The University of Liverpool, Liverpool, United Kingdom
 
  The development of simple, fast, precise and robust beam diagnostics is absolutely necessary to optimize the performance of present accelerators and to satisfy the needs of future accelerators, in particular those with ex-treme properties such as high brightness FELs and plasma wake-field accelerators. This invited talk will present the underlying physics and results from simulation and experiments for a number of advanced optical beam diagnostics currently under development at various accelerator re-search laboratories including efforts at the Cockcroft Institute.  
slides icon Slides THXGBE2 [13.922 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THXGBE2  
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THXGBE3
Proof of Principle Experiment for Single Shot Transverse Phase Space Measurement  
 
  • M.E. Conde, W. Liu, J.G. Power, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  • G. Ha
    PAL, Pohang, Republic of Korea
 
  Funding: Department of Energy, Office of HEP and BES under Contract No. DE-AC02-06CH11357.
We introduce a new method for single-shot transverse phase-space measurement. Existing phase space measurement methods are based on either average multiple shots of the full beam (e.g. scanning slit and quad scan tomography) or a single-shot sample of the beam (e.g. pepper pot and multi-slit). To achieve a single-shot measurement of the full beam, we project the beam's x-coordinate to the y-coordinate and its x'-coordinate to the x-coordinate using a skew quadrupole magnet followed by a normal quadrupole magnet. We present a theoretical description of this projection scheme and a proof-of-principle experimental demonstration done at the Argonne Wakefield Accelerator facility.
 
slides icon Slides THXGBE3 [2.909 MB]  
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THPMK147 Measurement of Slice-Emittance of Electron Bunch Using RF Transverse Deflector 4648
 
  • T. Sasaki, Y. Nakazato, M. Washio
    Waseda University, Tokyo, Japan
  • Y. Koshiba
    RISE, Tokyo, Japan
  • K. Sakaue
    Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
 
  We have been studying a compact electron accelerator based on an S-band Cs-Te photocathode rf electron gun at Waseda University. We are applying this high quality electron beam to soft X-ray generation, coherent THz wave generation and pulse radiolysis experiment. In these applications, longitudinal parameters of the electron beam are important. Thus, we developed the RF deflecting cavity which can directly convert longitudinal distribution of the beam to transverse with high temporal resolution, and succeeded in measuring longitudinal profile of an electron beam from the RF gun. Encouraged by these successful results, we started to measure slice emittance. Slice emittance would be very useful for improving the RF electron gun cavity. Therefore, we tried to measure the slice emittance of the electron beam by applying the Q-scan method to deflected beam by RF deflecting cavity. In this conference, we will report the principle, experimental results of the slice emittance measurement, and future prospects.
C. Vaccarezza et al., "Slice emittance measurements at SPARC photoinjector with a RF deflector", Proc. of EPAC08, Genoa, Italy
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK147  
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THPML022 Application of Surface Plasmon Polaritons on Charged particle Beam Diagnostics 4699
 
  • Z.G. Jiang, D. Gu, Q. Gu, M.H. Zhao
    SINAP, Shanghai, People's Republic of China
 
  In Recent years, the Cherenkov light radiation transformed from surface plasmon polaritons has been found and proposed for a compact and adjustable light source. As the process is motivated by charged particle beam, the characteristics of the light are not only related with the device but can also reflect certain characteristics of the beam. In this paper, a beam position and energy measurement method has been proposed based on the Cherenkov light radiation transformed from surface plasmon polaritons. Early-stage numerical and analytical investigations are also presented for a planar structure device.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML022  
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THPML044 Operation of a Cryogenic Current Comparator with Nanoampere Resolution for Continuous Beam Intensity Measurements in the Antiproton Decelerator at CERN 4741
 
  • M.F. Fernandes, D. Alves, T. Koettig, A. Lees, J. Tan
    CERN, Geneva, Switzerland
  • M.F. Fernandes, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • M. Schwickert, T. Stöhlker
    GSI, Darmstadt, Germany
  • T. Stöhlker
    IOQ, Jena, Germany
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: This project has received funding from the European Union's Seventh Framework Programme, under grant agreement number 289485.
Low-intensity charged particle beams are particularly challenging for non-perturbative beam diagnostics due to the small amplitude of induced electromagnetic fields. The Antiproton Decelerator (AD) and Extra Low ENergy Antiproton (ELENA) rings at CERN decelerate beams containing 107 antiprotons. An absolute intensity measurement of the circulating beam is essential to monitor the operational efficiency and to provide important calibration data for the antimatter experiments. This paper reviews the design of an operational Cryogenic Current Comparator (CCC) based on Superconducting QUantum Interference Device (SQUID) for current and intensity monitoring in the AD. Such a system has been operational throughout 2017, relying on a stand-alone cryogenic infrastructure based on a pulse-tube cryocooler. System performance is presented and correlated with different working environments, confirming a resolution in the nanoampere range.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML044  
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THPML061 X-Band Low Q Cavity Beam Position Monitor Study 4777
SUSPF093   use link to see paper's listing under its alternate paper code  
 
  • S.S. Cao
    SINAP, Shanghai, People's Republic of China
  • Y.B. Leng, R.X. Yuan
    SSRF, Shanghai, People's Republic of China
 
  The high repetition-rate and high peak brilliance of X-ray free-electron laser (XFEL) allow studying many scientific experiments that have not been feasible. To realize such high performance, a sub-micron beam transverse position measurement is required. The cavity-type beam position monitor (CBPM), as a non-destructive diagnostics tool with high potential in resolution performance, has been applied in different free electron laser facilities (FELs). In this research, an X-band high bandwidth CBPM has been studied and used for pre-research on bunch-by-bunch diagnostic for the pulsed FEL with high repetition-rate. Its bandwidth reaches 300 MHz. Design considerations and simulation results of the CBPM have been discussed and presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML061  
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THPML062 A Beam Based Method to Optimize the SBPM System 4780
SUSPF095   use link to see paper's listing under its alternate paper code  
 
  • J. Chen
    SINAP, Shanghai, People's Republic of China
  • L.W. Lai, Y.B. Leng, T. Wu, R.X. Yuan
    SSRF, Shanghai, People's Republic of China
 
  For the electron accelerator, it is hoped that the trajec-tory of the beam can pass through the magnetic center of the quadrupole to minimize the orbital motion caused by the instability of the power supply. The relative deviation between the magnetic center of quadrupole and the elec-tric center of adjacent BPM is measured by electron beam usually in various accelerator facilities. But for the stripline BPM (SBPM) system, in order to achieve the best performance, the beam trajectory should also need to pass through the electrical center of the SBPM system. In this paper, a beam based method to optimize the SBPM system was proposed, the intensity of the magnet power was scanned to change the beam position in two-dimension and combine the change trend of the sum signal of adjacent SBPM to find out the relative deviation of BPM electric center and mechanical center. Relevant beam experiment work on the Shanghai Soft X-ray free electron laser (SXFEL) and the benefit of this method will be addressed as well.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML062  
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THPML065 Preliminary Results of the Bunch Arrival-Time Monitor at SXFEL 4787
 
  • J.G. Wang, B. Liu
    SINAP, Shanghai, People's Republic of China
 
  Based on an electro-optical intensity modulation detection scheme, a Bunch Arrival-time Monitor (BAM) is under study at Shanghai soft X-ray Free Electron Laser (SXFEL) to meet the high-resolution requirements of the measurement of bunch arrival time. The first BAM is installed and is being tested at the SXFEL upstream of the first short undulator (modulator) near the seed laser injection point. In this paper, we present the basic working principle, the design of the BAM system and report the preliminary test results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML065  
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THPML066 Filling Pattern Measurement System Upgrade in SSRF* 4791
 
  • N. Zhang, F.Z. Chen, Y.M. Zhou
    SSRF, Shanghai, People's Republic of China
 
  Funding: Work supported by National Natural Science Foundation of China (No.11575282 No.11375255 No.11305253)
Filling pattern affects various operation performance of a synchrotron light source. A new diagnostic beam charge monitor (BCM) with high bandwidth multi-channels digitizer was developed to perform bunch-by-bunch charge measurement and record filling pattern for SSRF storage ring. Signals picked up from button elec-trodes were sampled synchronously with RF frequency, and IQ (In-phase and Quadrature phase) sampling meth-od was employed for noise-filtering and phase independ-ence calibration. Layout and evaluation experiment of the system are presented in this paper.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML066  
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THPML067 SXFEL Linac BPM System Development and Performance Evaluation 4794
SUSPF094   use link to see paper's listing under its alternate paper code  
 
  • F.Z. Chen, T. Wu
    SSRF, Shanghai, People's Republic of China
  • J. Chen, L.W. Lai, Y.B. Leng, L.Y. Yu, R.X. Yuan
    SINAP, Shanghai, People's Republic of China
 
  Shanghai Soft X-ray Free Electron Laser (SXFEL) is a test facility to study key technologies and new FEL physics. In order to deliver high quality electron beams to the undulator section, a high resolution (better than 10 microns with 200pC beam) Linac beam position monitor system has been developed. The system consists of stripline pickup and custom designed DBPM processor. The hardware and software architecture will be introduced in this paper. The online performance evaluation results will be presented as well.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML067  
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THPML068 Upgrade of Bunch Phase Monitor at SSRF Storage Ring 4797
 
  • Y.M. Zhou, Y.B. Leng, T. Wu, N. Zhang
    SSRF, Shanghai, People's Republic of China
 
  Beam instability is a serious problem for physics in beam diagnosis technology. With regard to the evaluation of longitudinal phase oscillations during the transient injection process, bunch-by-bunch phase measurement is a useful tool for studying the behavior of the refilled bunches. A new upgraded beam phase monitor system with 1.2GHz bandwidth PXI waveform digitizer has been developed at Shanghai synchrotron radiation source (SSRF). Bunch-by-bunch phase information, retrieved from button pickup signals, is calculated by the zero-crossing detection method with the best phase resolution of 0.4ps. The refilled bunches can be separated from the stored ones, and the longitudinal offset of each refilled bunch has been measured. Several groups of experiments have been performed to verify the repeatability of bunch-by-bunch phase measurement, and some results regarding refilled bunches will be discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML068  
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THPML070 Point Spread Function Study of Quasi-Monochromatic X-Ray Pinhole Camera at SSRF 4803
 
  • B. Gao, H.J. Chen
    SINAP, Shanghai, People's Republic of China
  • J. Chen, Y.B. Leng
    SSRF, Shanghai, People's Republic of China
 
  Since 2009 an X-ray pinhole camera that has been used to present the transverse beam size and emittance on diagnostic beam line of the storage ring at SSRF. The real beam size is a function of the image size of the CCD camera and point spread function (PSF) of the system. The performance of the measurement of the transverse electron beam size is given by the width of the PSF of X-ray pinhole camera. The contributions to the PSF width are the PSF of pinhole itself due to diffraction, and the PSF of the screen and camera. An X-ray monochromatic system has been established to measure the PSF accurately, and decrease the variation in the beam size between the theoretical values and the measured ones at SSRF. In this article, both calculated and measured PSF of quasi-monochromatic X-ray pinhole camera will be presented in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML070  
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THPML071 Upgrade of Digital BPM Processor at DCLS and SXFEL 4807
 
  • L.W. Lai, F.Z. Chen, Y.B. Leng, T. Wu, Y.B. Yan
    SSRF, Shanghai, People's Republic of China
  • J. Chen
    SINAP, Shanghai, People's Republic of China
 
  A digital BPM processor has been developed at 2016 in SINAP for DCLS and SXFEL, which are FEL facilities built in China. The stripline BPM and cavity BPM processors share the same hardware platform and firmware, but the processing algorithms implemented in EPICS IOC on the ARM CPU are different. The capability of the ARM limits the processing speed to 10 bunches per second. Now the bunch rate of DCLS and SXFEL are going to increase from 10Hz to 50Hz. To meet the higher processing speed requirements, the processor firmware and software are upgraded in 2017. All BPM signal processing algorithms are implemented in FPGA, and EPICS IOC reads results only. After the upgrade, the processing speed reach 120 bunches per second. And this is also a good preparation for future Shanghai Hard-X ray FEL, which bunch rate is about 1MHz.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML071  
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THPML072 Injection Comparison using Bunch-by-Bunch Beam Size Measurement System at SSRF 4811
 
  • H.J. Chen, J. Chen, B. Gao, Y.B. Leng
    SINAP, Shanghai, People's Republic of China
 
  Injection transient process happens every 5-10 minutes in storage ring during normal top-up operating mode at SSRF, which is a proper window for machine status and injection performance evaluation. In the recent year, a bunch-by-bunch beam size measurement system has been implemented at SSRF, which has the capability to offer transverse bunch-by-bunch position and size information and is a powerful tool for injection study. In this paper, we summarize three injection study results from July 2017 to April 2018, including betatron oscillation amplitude, spectrum, horizontal tune and damping time comparison. The oscillation amplitude and temporal behavior of recent injection are all better than results before contributed to the injection optimization work during maintenance in 2018 winter. In addition, the principal component analysis method is also applied to further study the injection behavior in turn-by-turn or bunch-by-bunch direction to the refilled bucket.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML072  
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THPML074 Image Reconstruction Technique Based on Coded Aperture Imaging for SuperKEKB X-ray Beam Size Monitor 4819
SUSPF105   use link to see paper's listing under its alternate paper code  
 
  • E. Mulyani, J.W. Flanagan
    Sokendai, Ibaraki, Japan
  • J.W. Flanagan, H. Fukuma, H. Ikeda, M. Tobiyama
    KEK, Ibaraki, Japan
 
  The fast reconstruction techniques based on principles originally developed for coded aperture imaging have been investigated for SuperKEKB accelerator. The establishment of this technique will very important for measuring the beam sizes of all 2500 bunches in the SuperKEKB accelerator over thousands of turns, as needed for instability studies and luminosity tuning, due to the vast quantity of data that needs to be processed in a timely manner.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML074  
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THPML090 Optical Beam Loss Monitors Based on Fibres for the CLARA Phase 1 Beam-Line 4869
 
  • A.S. Alexandrova, L.J. Devlin, V. Tzoganis, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • A.D. Brynes, F. Jackson
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • A.D. Brynes, F. Jackson, V. Tzoganis, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • E. Effinger, E.B. Holzer
    CERN, Geneva, Switzerland
 
  Funding: Work supported by STFC Cockcroft Institute core Grant No. ST/G008248/1
Fibre based Optical Beam Loss Monitors (oBLMs) are on-line devices used in-situ to measure losses along a beam-line. The technology is based on the detection of Cherenkov radiation, produced inside quartz fibres placed alongside the beampipe, from the interaction of secondary showers generated from losses hitting the vacuum pipe. This contribution presents ongoing developments of an oBLM system installed along the Compact Linear Accelerator for Research and Applications (CLARA). The oBLM system consists of 4 channels which allows for sub-metre loss resolution with two dimensional coverage along the entirety of the beam line, as opposed to conventional localised BLM systems. The system was first commissioned to measure dark current from the injector. The ability of the system to locate longitudinal positions of known beam loss locations has also been measured and has shown excellent agreement. We present measurements acquired from the detector during regular operation and during dedicated beam tests. We also discuss the incorporation of the monitor into the accelerator diagnostics system and its use in assisting accelerator characterisation and performance.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML090  
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THPML096 A Non-Invasive Magnetic Momentum Monitor Using a TE011 Cavity 4889
 
  • J. Guo, J. Henry, M. Poelker, R.A. Rimmer, R. Suleiman, H. Wang
    JLab, Newport News, Virginia, USA
 
  Funding: Authored by Jefferson Science Associates, LLC with Laboratory Directed Research and Development funding, under U.S. DOE Contract No. DE-AC05-06OR23177.
The Jefferson Lab Electron-Ion Collider (JLEIC) design relies on cooling of the ion beam with bunched electron beam. The bunched beam cooler complex consists of a high current magnetized electron source, an energy recovery linac, a circulating ring, and a pair of long solenoids where the cooling takes place. A non-invasive real time monitoring system is highly desired to quantify electron beam magnetization. The authors propose to use a passive copper RF cavity in TE011 mode as such a monitor. In this paper, we will show the mechanism and scaling law of this device, as well as the design and testing results of the prototype cavity.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML096  
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THPML098 Design of Beam Profile Monitor Used at the Xi'an Proton Application Facility (XiPAF) 4892
 
  • D. Wang, Z.M. Wang
    State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Shannxi, People's Republic of China
  • W. Chen
    NINT, Xi'an, People's Republic of China
  • P.F. Ma, Y.G. Yang
    TUB, Beijing, People's Republic of China
  • W. Wang
    Tsinghua University, Beijing, People's Republic of China
 
  A pixel ionization chamber for beam profile monitor (BPrM) is designed and manufactured by a new technology .The detector will be installed on the beam line just upstream of the target device of XiPAF. It has many advantages such as high resolution, high radiation hardness and it can work as a real-time monitor to show the distribution of the delivered relative dose. The physics design and construction of the detector are described in this paper, and its performances are tested offline.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML098  
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THPML106 Electron Microscopy Inspired Setup for Single-Shot 4-D Trace Space Reconstruction of Bright Electron Beams 4909
 
  • J. Giner Navarro, D.B. Cesar, P. Musumeci
    UCLA, Los Angeles, California, USA
  • R.W. Aßmann, B. Marchetti, D. Marx
    DESY, Hamburg, Germany
 
  Funding: This work has been partially supported by the National Science Foundation under Grant No. 1549132 and Department of Energy under award No. DE-SC0009914.
In the development of low charge, single-shot diagnostics for high brightness electron beams, Transmission Electron Microscopy (TEM) grids present certain advantages compared to pepper pot masks due to higher beam transmission. In this paper, we developed a set of criteria to optimize the resolution of a point projection image. However, this configuration of the beam with respect to the grid and detector positions implies the measurement of a strongly correlated phase space which entails a large sensitivity to small measurement errors in retrieving the projected emittance. We discuss the possibility of an alternative scheme by inserting a magnetic focusing system in between the grid and the detector, similar to an electron microscope design, to reconstruct the phase space when the beam is focused on the grid.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML106  
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THPML111 Test of the Tune Measurement System Based on BBQ at HLS-II Storage Ring 4926
 
  • L.T. Huang, F.L. Gao, P. Lu, B.G. Sun, H.Q. Wang, J.G. Wang, Q. Wang, F.F. Wu, Y.L. Yang, T.Y. Zhou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  Funding: Supported by the National Science Foundation of China (Grant No. 11705203, 11575181)
The HLS-II storage ring is a crucial part of Hefei Light Source. Tune is one of the most important parameters of the electron storage ring, of which the tune measurement system is an integral component. In this paper, the design of a new tune measurement system based on BBQ (base band tune), is presented. Some experiments are performed to test this system. The new system is compared with the original system and the TBT (turn-by-turn) method respectively. The obtained results illustrate higher accuracy and higher stability for the new system. A new approach of calculating the betatron oscillation amplitude is proposed, and the betatron oscillation amplitudes in the normal running stage for the HLS-II storage ring are estimated at 95 nm (horizontal) and 60 nm (vertical).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML111  
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THPML112 Preliminary Design and Calculation of Button BPM for the HALS Storage Ring 4929
 
  • F.F. Wu, F.L. Gao, L.T. Huang, X.Y. Liu, P. Lu, B.G. Sun, J.H. Wei, Y.L. Yang, T.Y. Zhou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  • L. Lin
    Huizhou University, Huizhou, People's Republic of China
 
  Funding: Supported by the National Science Foundation of China (Grant No.11705203, 11575181,11605202) and the National Key Research and Development Program of China(No. 2016YFA0402000)
Button BPM is being designed for the HALS storage ring, which is a diffraction-limited storage ring (DLSR) located at the NSRL in Hefei city. Since beam size is very small, the required resolution of 50 nm for beam position measurement need to be obtained. The parameters of the HALS Button BPM are initially determined. According to theoretical formulas, electrode induced signal is calculated and the relationship between electrode induced signal and beam current is obtained. Signal to noise ratio(SNR)of the HALS Button BPM is calculated with different beam current when the required resolution is 50 nm. The results show that the SNR is well when beam current is very low. In addition, the effects of BPM RF frequency and button electrode radius on SNR are analyzed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML112  
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THPML113 Design and Simulation of the Waveguide Coupler for the Cavity Beam Monitor 4932
 
  • Q. Wang, Q. Luo, B.G. Sun, F.F. Wu, Y.L. Yang, Z.R. Zhou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  • Y.W. Wu
    USTC, Hefei, Anhui, People's Republic of China
 
  Funding: Supported by The National Key Research and Development Program of China (2016YFA0401900), NSFC (11375178, 11575181) and the Fundamental Research Funds for the Central Universities (WK2310000046)
The waveguide coupling is an important way to extract the signals of the specific eigenmodes required. The design of the waveguide coupler, including the waveguide-to-coaxial adapter behind it for the cavity bunch length monitor is presented. The influence of the dimension parameters is analyzed, which offers the theoretical support for the design and application of cavity bunch length monitor or cavity beam position monitor (CBPM). A series simulation based on CST is performed to verify the feasibility, and the simulation results show good performance.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML113  
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THPML119 A Time-of-Flight Based Energy Measurement System for the LIGHT Medical Accelerator 4951
SUSPF096   use link to see paper's listing under its alternate paper code  
 
  • F. Galizzi
    University of Bergamo, Bergamo, Italy
  • M. Caldara, F. Galizzi, A. Jeff
    A.D.A.M. SA, Meyrin, Switzerland
 
  The LIGHT proton therapy facility is the first compact Linac that will deliver proton beams up to 230 MeV for cancer treatment. The proton beam is pulsed; pulses repetition rate can reach 200 Hz. LIGHT prototype is currently being commissioned by AVO/ADAM at CERN, while the first full installation is foreseen in 2019. Beam energy translates directly to range penetration in the body, so it is of the utmost importance to monitor it accurately especially for Linacs, since each beam pulse is directly transported to the patient. We present the implementation of a non-interceptive beam energy measurement system based on the Time-of-Flight technique. Unlike state of the art ToF systems this one has been designed to measure autonomously the mean energy of the beam with medical resolution (0.03 %) by processing as little as 1 us of data providing the result within 1 to 2 ms over an energy range from 5 to 230 MeV. The first results for beams up to 7.5 MeV are shown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML119  
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THPML130 Applications of a Distributed Beam Loss Monitor at the Australian Synchrotron 4986
SUSPF097   use link to see paper's listing under its alternate paper code  
 
  • P.J. Giansiracusa, T.G. Lucas, R.P. Rassool, M. Volpi
    The University of Melbourne, Melbourne, Victoria, Australia
  • M.J. Boland
    CLS, Saskatoon, Saskatchewan, Canada
  • G. LeBlanc
    SLSA, Clayton, Australia
 
  A distributed beam loss monitoring system, based on Cherenkov silica fibres, has been installed at the Australian Synchrotron. The fibres are installed parallel to the beam pipe and cover the majority of the injection system and storage ring. Relativistic charged particles from beam loss events that have a velocity above the Cherenkov threshold produce photons in the fibres. These photons are then guided along the fibres to detectors outside of the accelerator tunnels. Originally the system was installed to determine its suitability for measuring losses at a future linear collider, such as the Compact Linear Collider, with single pass 150 ns bunch trains. This study builds on these results and attempts to use the system to measure loss locations with a circulating beam. We present the preliminary results and describe how the system could be improved.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML130  
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FRXGBD2 Fast Kicker for High Current Beam Manipulation: Experimental Facility 5019
 
  • V.V. Gambaryan, A.A. Starostenko
    BINP SB RAS, Novosibirsk, Russia
  • A.A. Starostenko
    NSU, Novosibirsk, Russia
 
  The pulsed deflecting magnet (kicker) project was worked out in Budker Institute of Nuclear Physics. The kicker design parameters are: impulsive force, 1 mT*m; pulse edge, 5 ns; impulse duration, 200 ns. The unconventional approach is that the plates must be replaced by a set of cylinders. The obtained magnet construction enables the field homogeneity to be controlled by changing current magnitudes in cylinders. Furthermore, we demonstrated the method of field optimization. In addition, measurement technique for the harmonic components was considered and the possibility of control harmonic components value was demonstrated. The results with electron beam on actual facility was considered.  
slides icon Slides FRXGBD2 [4.869 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBD2  
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FRXGBD3 Application of Carbon Nanotube Wire for Beam Profile Measurement of Negative Hydrogen Ion Beam 5022
 
  • A. Miura, K. Moriya
    JAEA/J-PARC, Tokai-mura, Japan
  • T. Miyao
    KEK, Ibaraki, Japan
 
  A wire scanner monitor using metallic wire is reliably employed for the beam profile measurement in the J-PARC linac. Because the loading of negative hydrogen (H) ion beam on a wire increases under high-current beam operation, we focus on using a high-durability beam profile monitors by attaching another wire material. Carbon nanotubes (CNT) are made of graphite in a cylindrical shape and have a tensile strength not less than 100 times that of steel. The electric conductivity has higher than that of metals, and hardness is endured thermally around 3000°C in a vacuum circumstance. We applied the CNT wires to WSM and measured transverse profiles with a 3-MeV and 191-MeV H beam. As a result, we obtained the equivalent signal levels taken by carbon wire made of polyacrylonitrile without any damage. In this paper, the signal response when the CNT is irradiated with an H beam and the result of beam profile measurement. In addition, the surface of CNT after 3-MeV beam operation was observed.  
slides icon Slides FRXGBD3 [2.562 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBD3  
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FRXGBD4 Observation of Saw-Tooth Effect Orbit in the VEPP-4 M Collider 5026
 
  • Leshenok D. Leshenok, E.A. Bekhtenev
    NSU, Novosibirsk, Russia
  • E.A. Bekhtenev, G.V. Karpov, S.A. Nikitin, O.A. Plotnikova
    BINP SB RAS, Novosibirsk, Russia
 
  We study the relative position of the electron and posi-tron closed orbits in the VEPP-4M single storage ring collider in experiments on orbit precision monitoring. A difference in the orbits can affect the accuracy of several fundamental experiments, e.g. precise comparison of the electron and positron spin frequencies (the CPT invari-ance test) [1]. In this case, the spin precession frequencies of particles should be compared within at least 5·10-9. The distinction of frequencies depends on the features of the radial orbits. Ideally, the difference in the electron and positron orbits is set only by distributed radiation losses of particle energy. The corresponding contribution to the total orbit distortions is called the Saw-Tooth effect orbit. Another example of possible precision experiment at VEPP-4M is search for the light speed anisotropy (LSA). In this case, it is necessary to ensure a stability of the difference in the radial orbits of electrons and positrons at a level of 1μm.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBD4  
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