04 Hadron Accelerators
A14 Neutron Spallation Facilities
Paper Title Page
TUPAF065 Opportunities and Challenges in Planning the Installation, Testing and Commissioning of Large Accelerator Facilities 878
 
  • D.C. Plostinar, D. Bergenholtz, H. Danared, L. Gunnarsson, M.I. Israelsson, A. Jansson, M. Lindroos, A. Sunesson, L. Tchelidze, J.G. Weisend
    ESS, Lund, Sweden
 
  Delivering major accelerator facilities requires complex project preparation, organisation and scheduling. Often, multiple factors have to be taken into account including technical, financial and political. This makes planning particularly difficult, but at the same time opens opportunities for improving and optimising the project prospects. In this paper, we discuss the major drivers governing the installation, testing and commissioning of major accelerators in general, with particular emphasis on the European Spallation Source (ESS) accelerator, currently under construction in Lund, Sweden.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF065  
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TUPAF066 Transverse Dynamics and Software Integration of the ESS Low Energy Beam Transport 882
 
  • N. Milas, K.S. Louisy, D.C. Plostinar
    ESS, Lund, Sweden
 
  The first part of the ESS linac, also called front-end, comprising the Ion Source and the Low Energy Beam Transport (LEBT) section, will be installed and commissioned in 2018. The LEBT is used to focus and correct the proton beam trajectory and clean the head and tail of the proton pulse from the flat top before entering the RFQ. During the ion source and LEBT commissioning a full beam characterization at the RFQ entrance interface is planned. It is thus important to have an application in the control room able to display quantities measured by the diagnostic devices and also to quickly run a simulation including not only centre of mass dynamics but also envelope. This paper presents the efforts in modelling the LEBT elements, as accurately as possible, and implementing the dynamics calculation and integration with diagnostics tools. The final result is a Java FX GUI based on the OpenXAL library.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF066  
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TUPAL002 Numerical Calibration of the Injection Bump Sizes During the Beam Commissioning for CSNS 1011
 
  • M.Y. Huang, S. Wang, S.Y. Xu
    IHEP, Beijing, People's Republic of China
 
  In order to control the strong space charge effects, which cause large beam loss during the injection and acceleration processes, phase space painting method was used for injecting a small emittance beam from the linac into the large acceptance of the Rapid Cycling Synchrotron (RCS). During the beam commissioning, in order to control and optimize the painting results, the positions and ranges of the horizontal and vertical painting should be adjusted accurately. Therefore, the numerical calibration of the injection bump sizes was very important and need to be done as soon as possible. In this paper, a method to calibrate the horizontal and vertical bump sizes was presented and applied to China Spallation Neutron Source (CSNS). The numerical calibration results would be given and discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL002  
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TUPAL046 Construction, Test, and Operation of a new RFQ at the Spallation Neutron Source (SNS) 1113
 
  • Y.W. Kang, A.V. Aleksandrov, W.E. Barnett, M.S. Champion, M.T. Crofford, B. Han, S.W. Lee, J. Moss, R.T. Roseberry, J.P. Schubert, A.P. Shishlo, M.P. Stockli, C.M. Stone, R.F. Welton, D.C. Williams, A.P. Zhukov
    ORNL, Oak Ridge, Tennessee, USA
  • C.C. Peters, J. Price
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Funding: * This work was supported by SNS through UT-Battelle, LLC, under contract DEAC0500OR22725 for the U.S. DOE.
A new RFQ was successfully installed recently in the SNS linac to replace the old RFQ that was used for more than a decade with certain operational limitations. The new RFQ was completely tested with H ion source in the Beam Test Facility (BTF) at SNS. For robust operation of SNS at 1.4 MW, the full design beam power and to satisfy the beam current requirement of the forthcoming SNS proton power upgrade (PPU) project, an RFQ with enhanced performance and reliability was needed. The new RFQ was built to have the beam parameters identical to those of the first RFQ but with improved RF and mechanical stability and reliability for continuous operation of neutron production. The tests confirmed that the new RFQ can run with high beam transmission efficiency at around 90 % and notably improved operational stability. In this paper, construction, test, installation, and operation of the new RFQ in SNS are discussed with the performance improvements.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL046  
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TUPAL049 SNS Proton Power Upgrade Status 1120
 
  • M.A. Plum, G. A. Bloom, M.S. Champion, J. Galambos, M.P. Howell, S.-H. Kim, J. Moss, B.W. Riemer, K.S. White
    ORNL, Oak Ridge, Tennessee, USA
  • R.B. Saethre, R. W. Steffey
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. This research was supported by the DOE Office of Science, Basic Energy Science, Scientific User Facilities.
The Spallation Neutron Source (SNS) Proton Power Upgrade (PPU) project aims to double the proton accelerator beam power from 1.4 to 2.8 MW. Over the past year PPU has completed the reviews necessary for Critical Decision-1 approval. The baseline design choices are being refined, and a cost-effective approach has been identified. The beam energy will be increased by 30% and the beam current capability improved by ~50%. The sub-system improvements and anticipated schedule will be discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL049  
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TUPAL054 Experimental Measurements of Resonances near to the ISIS Working Point 1132
 
  • P.T. Griffin-Hicks, B. Jones, B.G. Pine, C.M. Warsop, M. Wright
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
 
  ISIS is the pulsed spallation neutron source located at the Rutherford Appleton Laboratory in the UK. Operation is based on a 50 Hz, 800 MeV proton synchrotron, accelerating up to 3·1013 protons per pulse (ppp), which provides beam to two target stations. ISIS is beam loss limited, so to achieve greater beam intensity and optimal operation, losses must be reduced. Some beam loss may be attributed to resonance lines found in betatron tune space. These could be driven by higher order magnet field components, errors or misalignment. This paper describes work measuring losses against tune space around the ISIS working point. Experiments have been carried out to measure beam loss against tune in the ISIS synchrotron. The experiments were done at low intensity to minimise space charge and intensity effects. Resonance lines that cause beam loss can be clearly identified and provide new information about the machine. The experimental process has been automated in order to decrease experiment duration and to reduce systematic human error. MAD-X models that compare the beam envelope at different points in tune space to the beam pipe aperture are used to distinguish between losses caused by increased envelope size and losses induced by driven resonances.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL054  
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TUPAL056 High Order Image Terms and Harmonic Closed Orbits at the ISIS Synchrotron 1140
 
  • B.G. Pine, C.M. Warsop
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
 
  ISIS is the spallation neutron source at Rutherford Appleton Laboratory in the UK. Protons are accelerated from 70 to 800 MeV in a 50 Hz rapid cycling synchrotron. Due to the intense beam, space charge forces are high during the first part of the acceleration cycle. The vacuum vessel in the synchrotron has a rectangular shape where the apertures are conformal to the design beam envelopes. At high intensities image forces interact with the beam, especially when the closed orbit is large. An analysis of image forces has been made and used to classify higher order image terms. These have been identified using simulations of round beams in rectangular vacuum vessels. The higher order image terms from harmonic closed orbits have been used with single particle resonance theory, taking account of the coherent nature of the beam response. Several predictions of beam resonance have been made. A simulation study has been carried out using a smooth focusing lattice and uniform density beams. Resonant beam behaviour has been observed and explained by the proposed theory.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL056  
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THXGBF3
Beam Commissioning of CSNS Accelerators  
 
  • S. Wang
    IHEP, Beijing, People's Republic of China
 
  China Spallation Neutron Source (CSNS)) is a high intensity proton accelerator based facility for delivering spallation neutrons to users. It consists of an 80-MeV H DTL linac, and a 1.6-GeV Rapid Cycling Synchrotron and a neutron production target. The accelerators will provide 100 kW proton beam for neutron target. The construction began in 2011, and up to date, the construction of accelerator components has been completed. The beam commissioning will be started soon. It is planned the beam commissioning for the first run will be completed in the end of 2017, and 10 kW proton beam will be available for neutron target. This invited talk presents he detailed commissioning process, with results given for both H linac and proton rapid cycling synchrotron.  
slides icon Slides THXGBF3 [12.419 MB]  
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