07 Accelerator Technology
T31 Subsystems, Technology and Components, Other
Paper Title Page
MOZGBE1 Development of Gas Stripper at RIBF 41
  • H. Imao
    RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan
  Charge strippers are almost inevitable for accelerations in heavy-ion accelerator complex. The fixed solid strip-pers including carbon-foil strippers are difficult to be used in on-going or upcoming new-generation in-flight RI beam facilities, e.g., RIBF (RIKEN, Japan), FAIR (GSI, Germany), FRIB (NSCL/MSU, US), HIAF (IMP, China) and RAON (RISP, Korea). The He gas stripper developed at RIBF is the first successful stripper significantly be-yond the applicable limit of the fixed carbon-foil strip-pers. We discuss the development of the gas strippers at RIBF and overview the related new-generation strippers being developed in the world.  
slides icon Slides MOZGBE1 [11.802 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOZGBE1  
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MOZGBE3 Primary Study of High-Power Graphene Beam Window 47
  • H. Wang, C. Meng, H. Qu, D.H. Zhu
    IHEP, Beijing, People's Republic of China
  • X. Sun, P.C. Wang
    DNSC, Dongguan, People's Republic of China
  Beam windows are usually used to isolate vacuum or other special environments, which is a key device for high-power accelerators. Graphene has extremely high thermal conductivity, high strength and high transparency to high energy ions. It is highly suitable for beam windows if the technology is allowable. This paper will discuss the primary tests of graphene films, including vacuum per-formance and thermal conductivity performance, as well as the simulated performance of an assumed graphene window.  
slides icon Slides MOZGBE3 [1.756 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOZGBE3  
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WEPMF004 The Saclay Test Stand for Conditioning the ESS RFQ Power Couplers at High RF Power 2375
  • N. Misiara, A.C. Chauveau, D. Chirpaz-Cerbat, P. Daniel-Thomas, M. Lacroix, L. Maurice
    CEA/IRFU, Gif-sur-Yvette, France
  • M. Desmons, A. Dubois, A. Gaget, L. Napoly, M. Oublaid, G. Perreu, O. Piquet, B. Pottin, Y. Sauce
    CEA/DRF/IRFU, Gif-sur-Yvette, France
  The RF power coupler system for the RFQ of the ESS LINAC will feed 1.6 MW peak power through two coaxial loop couplers for a 352.21 MHz operation at the expected duty cycle. A specific test stand has been designed to condition the power couplers, and test the different auxiliary components in the nominal conditions of the RFQ. The power couplers were successfully assembled, installed and instrumented on the test cavity. This paper presents the general layout of the test stand, the installation and preparation of the power couplers for their conditioning at high RF power up to the ESS nominal conditions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF004  
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WEPMF033 RF Study And Cold Test of an S-band Spherical Cavity Pulse Compressor 2429
  • J. Lei, X. He, M. Hou, X.P. Li, G. Pei, H. Wang, J.B. Zhao
    IHEP, Beijing, People's Republic of China
  • S. Shu
    Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
  An S-band (2856 MHz) spherical cavity pulse compressor has been designed, fabricated and tested in the Institute of High Energy Physics (IHEP), Chinese Academy of Sciences (CAS). The pulse compressor consists of a special 3 dB coupler and only one spherical energy storage cavity, two TE114 modes are chosen to oscillate in which for fairly high unload Q factor. The prototype was made of aluminum for studying the performance of the pulse compressor and checking the validity of the simulations. The cold test results of the aluminum cavity are also presented. The copper coating on the whole internal surface of the aluminum spherical cavity is in progress and the test results will also be presented in the future.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF033  
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WEPMF054 Design and Status of the MicroTCA.4 Based LLRF System for TARLA 2490
  • Gumus, C. Gumus, M. Hierholzer, K.P. Przygoda, H. Schlarb, Ch. Schmidt
    DESY, Hamburg, Germany
  • A.A. Aksoy, A. Aydin
    Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
  The Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) is constructing a 40 MeV Free Electron Laser with continuous wave (CW) RF operation. In order to control and monitor the four superconducting (SC) TESLA type cavities as well as the two normal conducting (NC) buncher cavities, a MicroTCA.4 based LLRF system is foreseen. This highly modular system is further used to control the mechanical tuning of the SC cavities by control of piezo actuators and mechanical motor tuners. This paper focuses on giving brief overview on hardware and software components of LLRF control of TARLA, as well as updates on the ongoing integration tests at DESY.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF054  
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WEPMF056 Cs2Te Photocathode Lifetime at Flash and European XFEL 2496
  • S. Lederer, S. Schreiber
    DESY, Hamburg, Germany
  The photo-injectors of FLASH and the European XFEL at DESY (Hamburg, Germany) use Cs2Te photocathodes. In this contribution we give an update on the lifetime and quantum efficiency of the cathodes operated in both facilities. Cathode #680.1 was operated at the European XFEL from the injector commissioning to the first user run for over 700 days. At FLASH cathode #73.3 has been operated with a record of more than 1000 days.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF056  
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WEPMF058 Anomaly Detection for Cavity Signals - Results from the European XFEL 2502
  • A.S. Nawaz, S. Pfeiffer
    DESY, Hamburg, Germany
  • G. Lichtenberg
    HAW, Hamburg, Germany
  • P. Rostalski
    Institute for Electrical Engineering in Medicine, Lübeck, Germany
  The data throughput of the European XFEL DAQ is about 1.5 Gb/s. Data depicting the cavity signal behavior is currently only saved manually. This either happens, when cavity tests are being performed, or an operator detects a fault in the cavity system, that has to be further investigated. Those instances of interest are neither systematically nor automatically stored. It can therefore be assumed that unwanted or degraded cavity behavior is detected late or not at all. It is proposed to change the focus from detecting known faults (such as quenches) to additionally detect anomalies in the cavity system behavior. In order to detect anomalies in the cavity signals, an algorithm is proposed using a cavity model. It aims on finding those data sets, which diverge from the nominal cavity behavior, saving those instances for later analysis. The nominal behavior is defined by the cavity electromagnetic resonance model with beam loading as well as the model for the mechanical oscillations due to the Lorentz Forces. By using such an approach, the detection of anomalies, as well as faults could be automated. This contribution aims to summarize the influence of beam loading on the detection and gives examples for anomalies that were found in several cavities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF058  
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WEPMF079 Experimental Modal Analysis of Lightweight Structures used in Particle Detectors: Optical non-contact Method 2565
  • M. Guinchard, M. Angeletti, F.B. Boyer, A. Catinaccio, C.G. Gargiulo, L.L. Lacny, E.L. Laudi, L.S. Scislo
    CERN, Geneva, Switzerland
  CERN's specialized structures such as particle detectors are built to have high rigidity and low weight, which comes at a cost of their high fragility. Shock and vibration issues are a key element for their successful transport, handling operations around the CERN infra-structure, as well as for their operation underground. The experimental modal analysis measurement technique is performed to validate the Finite Element Analysis in the case of complex structures (with cables and substructure coupling). In the case of lightweight structures, standard contact measurements based on accelerometers are not possible due to the high mass ratio between the accelerometers and the structure itself. In such a case, the vibration of the structure can be calculated based on the Doppler shift of the laser beam reflected off the vibrating surface. This paper details the functioning and application of an advanced laser-scanning vibrometry system, which utilizes the fore-mentioned non-contact method. The results of the Experimental Modal Analysis of selected lightweight structure using this instrument is also presented and discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF079  
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WEPMF081 Mechanical Strain Measurements Based on Fiber Bragg Grating Down to Cryogenic Temperature - R&D Study and Applications 2572
  • M. Guinchard, A. Bertarelli, L. Bianchi, F.B. Boyer, M. Cabon, M. Calviani, O. Capatina, A. Catinaccio, P. Ferracin, P. Grosclaude
    CERN, Geneva, Switzerland
  In recent years, optical fiber sensors have been increasingly used due to their outstanding performances. Their application is preferable in case of special requirements that exclude the application of conventional electrical sensors. The scientific background of optical fiber sensors is well developed. However, the characteristic of sensors employed in rather harsh environments is often different from the one determined in laboratory conditions or prior to their installation. In order to achieve long-term stable functioning and reliable measurement under severe working environments, such as those occurring at CERN (radiation, cryogenics, high magnetic and electrical field), a statistical measurement campaign was carried out following the international standard ISO 5725. The paper describes the ongoing study to define the accuracy of optical fiber sensors based on Fiber Bragg Grating (FBG) for strain measurements, from room temperature down to 4.2 K. It also describes some of the demanding applications for which optical fiber sensors have been deployed to perform experimental strain measurements (e.g. detectors components, high-energy beam targets and dumps, superconducting magnets).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF081  
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WEPMG003 Analysis and Operational Feedback of the New High-Energy Beam Dump in the CERN SPS 2608
  • A. Perillo-Marcone, M. Calviani, R. Illan Fiastre, P. Rios Rodriguez, G. Romagnoli
    CERN, Geneva, Switzerland
  The CERN Super Proton Synchrotron (SPS) high-energy internal dump (TIDVG) is used to intercept beam dumps from 102.2 to 450 GeV. An inspection in 2013 revealed significant beam induced damage to the aluminium absorbing block, resulting in operational limitations to minimize the risk of reproducing this phenomenon. Additionally, in 2016 a vacuum leak was detected in the dump assembly, which imposed further limitations, i.e., a reduction of the beam intensity that could be dumped. In the winter stop of 2016-2017, a new version of the TIDVG (featuring several design modifications) was installed. This paper analyses the performance of the dump observed during the commissioning period and subsequent operation in 2017 of the most recent installed version of the TIDVG. The temperature measurements recorded during this time were used to benchmark numerical models that allow predicting the performance of the dump under different conditions. After several iterations, a good agreement between simulations and real measurements was obtained; resulting in numerical models that can produce reliable results for this and other devices with similar design.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMG003  
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WEPMG004 Design of the Future High Energy Beam Dump for the CERN SPS 2612
  • S. Pianese, J.A. Briz Monago, M. Calviani, D. Grenier, P.B. Heckmann, J. Humbert, R. Illan Fiastre, A. Perillo-Marcone, G. Romagnoli, S. Sgobba, D. Steyart, V. Vlachoudis
    CERN, Geneva, Switzerland
  The future CERN Super Proton Synchrotron (SPS) internal dump (Target Internal Dump Vertical Graphite, known as TIDVG#5), to be installed during CERN's Long Shutdown 2 (2019-2020), will be required to intercept beam dumps from 26 to 450 GeV, with increased intensity and repetition rates with respect to its predecessor (TIDVG#4). The beam power to be managed by the dump will increase by approximately a factor of four; resulting in new challenges in terms of design in order to fulfil the highly demanding specification, which is based on guaranteeing a good performance of the machine with little or no limitations imposed by this device. This paper presents the proposed design, including material selection, manufacturing techniques and thermo-mechanical simulations under different operational scenarios expected during the lifetime of the device.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMG004  
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WEPMG006 Experimental Setup to Characterize the Radiation Hardness of Cryogenic Bypass Diodes for the HL-LHC Inner Triplet Circuits 2620
  • A. Will, G. D'Angelo, R. Denz, M.F. Favre, D. Hagedorn, G. Kirby, T. Koettig, A. Monteuuis, F. Rodriguez-Mateos, A.P. Siemko, K. Stachon, M. Valette, A.P. Verweij, D. Wollmann
    CERN, Geneva, Switzerland
  • A. Bernhard, A.-S. Müller
    KIT, Karlsruhe, Germany
  • L. Kistrup
    KEA, Copenhagen, Denmark
  Funding: Work supported by the Wolfgang Gentner Programme of the German Federal Ministry of Education and Research
For the high luminosity upgrade of the Large Hadron Collider (LHC), it is planned to replace the existing triplet quadrupole magnets with Nb3Sn quadrupole magnets, which provide a comparable integrated field gradient with a significantly increased aperture. These magnets will be powered through a novel superconducting link based on MgB2 cables. One option for the powering layout of this triplet circuit is the use of cryogenic bypass diodes, where the diodes are located inside an extension to the magnet cryostat and operated in superfluid helium. Hence, they are exposed to radiation. For this reason the radiation hardness of existing LHC type bypass diodes and more radiation tolerant prototype diodes needs to be tested up to the radiation doses expected at their planned position during their lifetime. A first irradiation test is planned in CERN's CHARM facility starting in spring 2018. Therefore, a cryo-cooler based cryostat to irradiate and test LHC type diodes in-situ has been designed and constructed. This paper will describe the properties of the sample diodes, the experimental roadmap and the setup installed in CHARM. Finally, the first measurement results will be discussed.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMG006  
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WEPMK015 Optimization of Vertical Electro-Polishing Process: Experiments with Updated Cathode on Single-Cell Cavity and Performance Achieved in Vertical Test 2662
  • F. Éozénou, L. Maurice
    CEA/DSM/IRFU, France
  • P. Carbonnier, C. Madec, Th. Proslier, C. Servouin
    CEA/DRF/IRFU, Gif-sur-Yvette, France
  • V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi
    MGH, Hyogo-ken, Japan
  • H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
    KEK, Ibaraki, Japan
  Marui Galvanizing Co.Ltd., and CEA have been studying Vertical Electro-Polishing (VEP) on Nb single-cell accelerating superconducting accelerator cavity with the goal of mass-production and cost-reduction, in collaboration with KEK within TYL-FJPPL Particle Physics Laboratory. Marui has invented and patented a rotative cathode called ‘i-Ninja'. The version 5 has been tested for the first time in Europe at CEA Saclay. The four wings of the cathode remove efficiently, bubbles of hydrogen, and the chosen parameters make it possible to achieve better surface and uniform material removal compared to VEP with a fixed cathode. The effect of the temperature of the cavity walls on current oscillations has been precisely studied. Two single-cell cavities have been electro-polished and tested at 2 K in vertical cryostat and the results will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMK015  
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WEPML038 Plasma Window as a Pressure Valve for FAIR 2776
  • B. F. Bohlender, M. Iberler, J. Jacoby
    IAP, Frankfurt am Main, Germany
  • A. Michel
    Goethe Universität Frankfurt, Frankfurt am Main, Germany
  Funding: Funded by BMBF, Ref. No: 05P15 RFRBA and HIC for FAIR
This contribution shows the progress in the development of a plasma window at the institute for applied physics at Goethe University Frankfurt. A plasma window* is a membrane free transition between two regions of different pressure, enabling beam transmission from a rough vacuum area (~1 mbar) to a higher pressure (up to 1 bar) region on short length scales. In comparison to differential pumping stages a length reduction by a factor of up to 100 is achievable, while the absence of a solid membrane yields prolonged operation time. The sealing effect is based on the high temperature arc discharge sustained in a cooled copper channel between the pressure regimes. Due to a bulk temperature around 10,000K** the viscosity of the gas is dramatically increased, leading to a slower gas flow, enabling a higher pressure gradient. This contribution will present first results regarding the pressure gradient in dependence of the discharge current and the aperture. Until now, a pressure factor around 100 has been established for well over 50 min. This contribution goes along with the one from Mr. A. Michel, he focuses on the spectroscopic analysis of the arc plasma.
*A. Hershcovitch, J. Appl. Phys., AIP Publishing (1995) 78, 5283
**Y.E. Krasik et al., "Plasma Window Characterization", J. Appl. Phys., AIP Publishing (2007) 101, 053305.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML038  
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WEPML044 Design of HOM Couplers for Superconducting 400 MHz RF Cavities 2793
  • N.F. Petry, M. Busch, K. Kümpel, O. Meusel, H. Podlech
    IAP, Frankfurt am Main, Germany
  The Future Circular Collider (FCC) is one possible future successor of the Large Hadron Collider (LHC). The proton-proton collider center-of-mass collision energy is set to 100 TeV with a beam current of 0.5 A. To reach this goal a stable acceleration is critical and therefore higher order modes (HOM) need to be damped. To avoid a high power level in the HOM dampers, further described as couplers, the loaded Q-factor should be below 1000 for the cavity with mounted HOM couplers. Besides a low Q-factor the R/Q value should also be in the range of 1 Ω or below. Two different types of couplers are used to achieve a high damping. The two types are a narrowband Hook-type HOM coupler and a broadband Probe-type HOM coupler. The recent results of the design of the HOM couplers attached to a superconducting 400 MHz RF cavity will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML044  
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WEPML075 Test of Magnet Girder Prototypes for HEPS-TF 2863
  • H. Wang, C. H. Li, S.J. Li, J. Liu, H. Qu, Z. Wang, L. Wu
    IHEP, Beijing, People's Republic of China
  • H.Y. Zhu
    Institute of High Energy Physics (IHEP), People's Republic of China
  Auto-tuning magnet girder is one of the key technolo-gies to be solved for HEPS-TF (Test Facility of High Ener-gy Photon Source). The girder should have high adjusting accuracy, high stability and can be beam-based aligned, to obtain the stability requirements of beam orbit. There are two girders developed, and the tests have been done. The accuracy of girder motion is within 10 microns while the adjusting range is 1 mm and the resolution is better than 1 microns, the natural frequency is higher than 24 Hz.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML075  
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THPAK091 Design of the New Proton Synchrotron Booster Absorber Scraper (PSBAS) in the Framework of the Large Hadron Collider Injection Upgrade (LIU) Project 3444
  • L. Teofili, M. Migliorati
    Sapienza University of Rome, Rome, Italy
  • J.A. Briz Monago, M. Calviani, N. Chritin, J.J. Esala, S.S. Gilardoni, I. Lamas Garcia, J. Maestre, T. Polzin, T.L. Rijoff
    CERN, Geneva, Switzerland
  • T.L. Rijoff
    TU Darmstadt, Darmstadt, Germany
  The Large Hadron Collider (LHC) Injector Upgrade (LIU)Project at CERN calls for increasing beam intensity for the LHC accelerator chain. Some machine components will not survive the new beam characteristics and need to be rebuilt for the new challenging scenario. This is particularly true for beam intercepting devices (BIDs) such as dumps, collimators, and absorber/scrapers, which are directly exposed to beam impacts. In this context, this work summarizes conceptual design studies on the new Proton Synchrotron Booster (PSB) Absorber/Scraper (PSBAS), a device aimed at cleaning the beam halo at the very early stage of the PSB acceleration. This paper outlines the steps performed to fulfil the component design requirements. It discusses thermo-mechanical effects as a consequence of the beam-matter collisions, simulated with the FLUKA Monte Carlo code and ANSYS finite element software; and the impedance minimization study performed to prevent beam instabilities and to reduce RF-heating on the device.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK091  
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THPAL005 Construction and Commissioning of the S-Band High-Gradient RF Laboratory at IFIC 3619
  • D. Esperante Pereira, C. Blanch Gutiérrez, M. Boronat, J. Fuster, D. Gonzalez Iglesias, A. Vnuchenko
    IFIC, Valencia, Spain
  • N. Catalán Lasheras, G. McMonagle, I. Syratchev, W. Wuensch
    CERN, Geneva, Switzerland
  • A. Faus-Golfe
    LAL, Orsay, France
  • B. Gimeno
    UVEG, Burjasot (Valencia), Spain
  An S-Band High-Gradient (HG) Radio Frequency (RF) laboratory is under construction and commissioning at IFIC. The purpose of the laboratory is to perform investigations of high-gradient phenomena and to develop normal-conducting RF technology, with special focus on RF systems for hadron-therapy. The layout of the facility is derived from the scheme of the Xbox-3 test facility at CERN* and uses medium peak-power (7.5 MW) and high repetition rate (400 Hz) klystrons, whose RF output is combined to drive two testing slots to the required power. The design and construction of the various components of the system started in 2016 and has been completed. The installation and commissioning of the laboratory is progressing, with first results expected before mid 2018. The technical characteristics of the different elements of the system and the commissioning status together with preliminary results are described.
* N. Catalan Lasheras, et al., 'Commissioning of Xbox3: a very high capacity X-band RF test stand', Proc. LINAC2016, East Lansing, USA, September 2016.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL005  
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THPAL009 A TM01 Mode Launcher With Quadrupole Field Components Cancellation for High Brightness Applications 3631
  • G. Castorina
    INFN-Roma1, Rome, Italy
  • A.D. Cahill, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • F. Cardelli, G. Franzini, A. Marcelli, B. Spataro
    INFN/LNF, Frascati (Roma), Italy
  • L. Celona, S. Gammino, G. Torrisi
    INFN/LNS, Catania, Italy
  • V.A. Dolgashev
    SLAC, Menlo Park, California, USA
  • L. Ficcadenti
    Rome University La Sapienza, Roma, Italy
  • M. Migliorati, A. Mostacci, L. Palumbo
    Sapienza University of Rome, Rome, Italy
  • G. Sorbello
    University of Catania, Catania, Italy
  The R&D of high gradient radiofrequency (RF) devices is aimed to develop innovative accelerating structures based on new manufacturing techniques and materials in order to construct devices operating with the highest accelerating gradient. Recent studies have shown a large increase in the maximum sustained RF surface electric fields in copper structures operating at cryogenic temperatures. These novel approaches allow significant performance improvements of RF photoinjectors. Indeed the operation at high surface fields results in considerable increase of electron beam brilliance. This increased brilliance requires high field quality in the RF photoinjector and specifically in its power coupler. In this work we present a novel power coupler for the RF photoinjector. The coupler is a compact X-band TM01 mode launcher with a fourfold symmetry which minimized both the dipole and the quadrupole RF components.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL009  
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THPAL016 Study of the Performances of a 3D Printed BPM 3656
  • N. Delerue, D. Auguste, J. Bonis, F. Gauthier, A. Gonnin, S. Jenzer, O. Trofimiuk
    LAL, Orsay, France
  • A. Vion
    BV Proto, Sévenans, France
  Funding: Work supported by IN2P3 ‘‘3D Metal'' innovation program; Oleh Trofimiuk stay in France is supported by the IDEATE International Associated Laboratory (LIA) between France and Ukraine.
Following previous results which have shown that some components built using additive manufacturing (3D printing) are compatible with ultra high vacuum, we have adapted the design of a stripline BPM to the requirements of additive manufacturing and built it. We report here on the design adaptation and on its mechanical and electrical performances.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL016  
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THPAL023 Assessing the Continued Suitability of an Existing Water System for an Accelerator Upgrade 3673
  • W.C. Barkley, C.E. Buechler, E.N. Pulliam
    LANL, Los Alamos, New Mexico, USA
  This paper assesses the continued suitability of an existing Water Cooling System (WCS) for cooling intermediate and high-power RF power amplifiers at the Los Alamos Neutron Science Center (LANSCE). At LANSCE, the high-power and intermediate power amplifiers installed in the 70s were at end-of-life with obsolete parts and no suitable replacements available to extend their life. The LANSCE Refurbishment Project was initiated (now complete) to replace these amplifiers and to utilize already existing WCSs. Two existing WCSs were repurposed and one new WCS was designed and installed. Unscheduled, intermittent water system trips on one of the WCSs has prompted the engineering group to drill down into the original decision, build a flow model and assess some of the legacy components' suitability to solve the problem. This paper discusses the general approach, troubleshooting and solution recommendations to be made for resolution of the intermittent issues.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL023  
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THPAL024 A Simple Variable Focus Lens for Field Emitter Cathodes 3677
  • R.L. Fleming, H.L. Andrews, K. Bishofberger, D. Kim, J.W. Lewellen, K.E. Nichols, D.Y. Shchegolkov, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  Funding: Los Alamos National Laboratory LDRD Program
We present the design for a simple, variable-focus solenoidal lens with integrated emittance filtering. The design was developed as a first-iteration injection optics solution for transport of a beam from a field-emitter cathode into a dielectric laser accelerator structure. The design is easy to fabricate and, while based on permanent magnets, can readily be modified to allow for remote control of the focal length. The emittance is controlled via selection of collimating irises. The focal length can be changed by altering the spacing between two permanent ring magnets. Results from fabrication and initial testing will be presented.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL024  
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THPAL034 Dynamic Tuner Development for Medium β Superconducting Elliptical Cavities 3709
SUSPL090   use link to see paper's listing under its alternate paper code  
  • C. Contreras-Martinez, P.N. Ostroumov
    FRIB, East Lansing, USA
  • E. Borissov, S. Cheban, Y.M. Pischalnikov, V.P. Yakovlev, J.C. Yun
    Fermilab, Batavia, Illinois, USA
  Funding: Work supported by U.S. DOE SCGSR program under contract number DE-SC0014664, Michigan State University, and Fermi Research Alliance under contract N. DEAC02-07CH11959 with the U.S. DOE
The Facility for Rare Isotope Beams (FRIB) is developing a 5-cell 644 MHz βopt=0.65 elliptical cavity for a future linac energy upgrade to 400 MeV/u for the heaviest uranium ions. Superconducting elliptical cavities operated in continuous wave, such as the ones for FRIB, are prone to microphonics which can excite mechanical modes of the cavities. It has been shown that the detuning due to microphonics can be mitigated with the use of piezo actuators (fast tuner) as opposed to the costly option of increasing the input RF power. The FRIB slow/fast dynamic tuner will be based on the Fermilab experience with similar tuners like those developed for the linac coherent light source (LCLS) II and proton improvement plan (PIP) II. This paper will present the results of tuner properties on the bench.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL034  
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THPAL116 Development and Installation of the CANREB RFQ Buncher at TRIUMF 3914
  • B. Barquest, F. Ames, T. Au, L. Graham, M.R. Pearson, V. Zvyagintsev
    TRIUMF, Vancouver, Canada
  • J. Bale, J. Dilling, R. Kruecken, Y. Lan
    UBC & TRIUMF, Vancouver, British Columbia, Canada
  • G. Gwinner
    University of Manitoba, Manitoba, Canada
  • N. Janzen, R.A. Simpson
    UW/Physics, Waterloo, Ontario, Canada
  • R. Kanungo
    Saint Mary's University, Halifax, Canada
  Funding: TRIUMF receives federal funding via the National Research Council of Canada. CANREB is funded by the Canada Foundation for Innovation (CFI), the Provinces NS, MB and TRIUMF.
Pure, intense rare isotope beams at a wide range of energies are crucial to the nuclear science programs at TRIUMF. The CANREB project will deliver a high resolution spectrometer (HRS) for beam purification, and a charge breeding system consisting of a radiofrequency quadrupole (RFQ) beam cooler and buncher, an electron beam ion source (EBIS), and a Nier-type spectrometer to prepare the beam for post-acceleration. Bunching the beam prior to charge breeding will significantly enhance the efficiency of the EBIS. The RFQ buncher will accept continuous §I{60}{keV} rare isotope beams from the ARIEL or ISAC production targets and efficiently deliver low emittance bunched beams. A pulsed drift tube (PDT) will adjust the energy of the bunched beam for injection into the EBIS to match the acceptance of the post-accelerating RFQ. Ion optical simulations were carried out to inform the design of the RFQ buncher and PDT. Simulations indicate that delivery of up to 107~ions per bunch with high efficiency is possible. Experience with previous beam bunchers was also brought to bear in the design effort. Installation of the RFQ is under way, and tests with offline beam are expected to be performed in late 2018.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL116  
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THPAL128 Autonomous Topography Detection and Traversal for an Inspection Robot Within the Beamline of Particle Accelerators 3943
  • N. Schweizer
    Technische Universität Darmstadt (TU Darmstadt, RMR), Darmstadt, Germany
  • I. Pongrac
    GSI, Darmstadt, Germany
  Particle accelerators feature ultra-high vacuum pipe systems with unique topography, i.e. with a multitude of different vacuum chambers of varying dimensions and varying pipe apertures. In order to be able to examine the interior of the entire vacuum system, even those parts which are not accessible without disassembling large parts of the accelerator, a semi-autonomous robot is being developed which shall traverse and visually inspect the vacuum system of particle accelerators. We present a generic concept based on distance sensors for the inspection robot to detect steps between vacuum chambers and gaps in the beamline. Movement strategies to autonomously overcome these basic obstacles are introduced. For evaluation we use simulations of ideal environments with flat surfaces as well as realistic beam pipe environments of the SIS100 particle accelerator. Additionally, a prototype of our robot concept confirms the implementation of all maneuvers. Results show that obstacles of previously unknown dimensions can be detected and reliably traversed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL128  
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THPML110 EPICS Driver for Siemens CP1616 Communication Module 4923
  • Z. Huang, G. Liu, Y. Song, X.K. Sun
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  Funding: Work supported by National Natural Science Foundation of China (11375186)
Siemens communication module CP1616 is a high-performance PROFINET controller, which can support both Real-time (RT) and Isochronous Real-Time (IRT) communication. Experimental Physics and Industrial Control System (EPICS) is a wildly used distributed control system in large scientific devices. In order to integrate PROFINET protocol into EPICS environment, we developed this driver based on CP1616 and established the prototype system. This paper will describe the design of EPICS driver for CP1616 and the test result of the prototype system.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML110  
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THPML127 Alignment and Installation for the FELiChEM project 4977
  • W. Wang, Zhang, H.T. H.T, X.Y. He, D.R. Xu
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  Funding: Work supported by National Natural Science Foundation of China (11705199) and China Postdoctoral Science Foundation (2017M622024)
FELiChEM is a new experimental facility under construction at the University of Science and Technology of China. There are more than one hundred important devices to construct it, which core device is two free electron laser oscillators generating middle-infrared and far-infrared laser and covering the spectral range of 25-200μm. The optical cavity is an important component of oscillator which very sensitive to misalignment errors of the mirror, due to its near-concentric and symmetric structure. High precision alignment and installation is necessary to ensure the smooth implementation of the FELiChEM project. Laser tracker and Level are used to install this devices according to the alignment control network. An efficient and high-precision alignment method based on autocollimator and photoelectric auto-collimator is used to align optical cavity of oscillator. This methods is proven to be effective and meet the tolerances by multiple means.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML127  
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