Keyword: timing
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MOPGW047 Analysis and Simulation of the "After-Pulse" RF Breakdown cavity, simulation, GUI, experiment 196
 
  • X. Lin, H.B. Chen, Z.N. Liu, J. Shi, H. Zha
    TUB, Beijing, People’s Republic of China
  • X.W. Wu
    CERN, Meyrin, Switzerland
 
  During the high power experiment of a single-cell standing-wave accelerating structure, it was observed that many RF breakdowns happen when the field inside cavity is decaying after the input rf pulse is off. The distribution of breakdown timing shows a peak at the moment of RF power switches off. A series of simulation was performed to study the after-pulse breakdown effect in such a standing-wave structure. A method of calculating poynting vector over time is proposed in this article to study the modified poynting vector at critical points in the cavity. Field simulation and thermal simulation were also carried out to analyse possible reasons for the after-pulse breakdown effect.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW047  
About • paper received ※ 14 May 2019       paper accepted ※ 17 May 2019       issue date ※ 21 June 2019  
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TUPMP015 Magnet Power Supply Calibration with a Portable Current Measuring Unit at the J-PARC Main Ring power-supply, feedback, operation, controls 1263
 
  • K. Miura, Y. Kurimoto, Y. Morita, D. Naito, T. Oogoe, T. Shimogawa
    KEK, Ibaraki, Japan
  • Y. Kuniyasu
    Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
  • K. Ooya
    SANKYU PLANT TECHNO CO., LTD., 6-5-3, Kachidoki, Japan
  • R. Sagawa
    Universal Engineering, Ibaraki-ken, Japan
 
  In the J-PARC MR, 96 bending magnets (BMs) are used in total. They are divided into 6 groups of 16 BMs. The 16 BMs in each group are connected in series and driven by a single power supply. Since all 96 BMs are symmetrically located in the ring, the magnet currents regulated by the 6 power supplies need to be same. Each power supply performs output current feedback control using electronic circuits including analog amplifications and AD / DA conversions. Due to individual differences of the electronic circuits, output current is generally expected to be different for each power supply. Therefore, we developed a current measurement unit with the portable DCCT as an independent reference. Further, we measured the magnet currents regulated by the 6 BM power supplies using the unit. We report the details of the unit as well as the results of the current measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP015  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW011 Status of the PETRA IV project emittance, lattice, brightness, synchrotron 1404
 
  • I.V. Agapov, R. Bacher, M. Bieler, R. Bospflug, R. Brinkmann, Y.-C. Chae, H.C. Chao, H.T. Duhme, M. Ebert, H.-J. Eckoldt, H. Ehrlichmann, X.N. Gavaldà, M. Hüning, U. Hurdelbrink, J. Keil, J. Klute, M. Körfer, B. Krause, G. Kube, W. Leemans, L. Lilje, F. Obier, A. Petrov, N. Plambeck, J. Prenting, G.K. Sahoo, H. Schlarb, M. Schlösser, F. Schmidt-Föhre, M. Schmitz, C.G. Schroer, T. Tempel, M. Thede, M. Tischer, R. Wanzenberg, E. F. Weckert, T. Wilksen, K. Wittenburg, J.X. Zhang
    DESY, Hamburg, Germany
 
  Since 2016 DESY has been pursuing R&D towards upgrading its PETRA synchrotron light source to a fourth-generation machine, PETRA IV, which is expected to start operation in 2027. The conceptual design of a 6 GeV seven-bend-achromat-based lattice with an approx. 10pm emittance along with critically important technical systems has been completed. We will present the status of the project, the expected parameter space of the facility, and lattice design and beam dynamics issues for the main ring.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW011  
About • paper received ※ 13 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPMP010 8 Gev Slow Extraction Beam Test for Muon to Electron Conversion Search Experiment at J-PARC kicker, extraction, injection, electron 2322
 
  • M. Tomizawa, Y. Arakaki, Y. Fukao, Y. Hashimoto, Y. Igarashi, T. Kimura, S. Mihara, M. Moritsu, S. Murasugi, R. Muto, H. Nishiguchi, K. Okamura, Y. Shirakabe, K. Ueno, E. Yanaoka
    KEK, Ibaraki, Japan
  • Y. Fujii
    Monash University, Faculty of Science, Clayton, Victoria, Australia
  • F. Tamura
    JAEA/J-PARC, Tokai-mura, Japan
 
  A muon to electron conversion search experiment (COMET) planned at J-PARC needs 8 GeV bunched proton beams with a continuous 1 MHz pulse structure. In this experiment, an intensity ratio of the residual to the main pulsed beam, which is expressed as extinction, should be less than the level of 10-10. In RUN78 (Jan. to Feb., 2018), we have succeeded in slow extraction of 8 GeV protons with 7.3×1012 ppp, satisfies the COMET phase-I requirement, and the extinction derived from a timing measurement of secondary particles from the target shows a promising result. A mechanism to explain the measured extinction will be also described in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP010  
About • paper received ※ 01 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPMP042 Reduction of Stored Beam Oscillations During Injection at Diamond Light Source kicker, injection, simulation, storage-ring 2426
 
  • R.T. Fielder, M. Apollonio, R. Bartolini, C. Bloomer, I.P.S. Martin
    DLS, Oxfordshire, United Kingdom
 
  At Diamond injection is performed by means a of a four kicker off-axis system, relying on a perfect timing and amplitude setting to produce a closed bump. Ageing of some of the kicker vessel components has progressively spoiled the performance of the system, causing oscillations in the stored beam. Various schemes to control these oscillations have been considered including introducing an additional compensating kicker, and installing a non-linear injection kicker. Results of simulations analysing these schemes are presented, along with measurements taken in the storage ring using an existing pinger magnet. The effects of the reduction on the quality of beam seen by beamlines is also considered.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP042  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPGW104 The CBETA Beam Position Monitor (BPM) System Design and Strategy for Measuring Multiple Simultaneous Beams in the Common Beam Pipe injection, hardware, electron, MMI 2736
 
  • R.J. Michnoff, R.L. Hulsart
    BNL, Upton, Long Island, New York, USA
  • J. Dobbins
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
CBETA, a 4-pass electron Energy Recovery Linac (ERL) is presently under construction at Cornell University and is a collaboration between Brookhaven National Laboratory (BNL) and Cornell University. Beam commissioning began in March 2019 with a single pass ERL configuration. Commissioning of the complete 4-pass machine is scheduled to begin in fall 2019. The fixed field alternating gradient (FFA) return loop for CBETA uses Halbach permanent magnets with a common beam pipe for seven different energy beams (4 accelerating energies and 3 decelerating energies). One of the most challenging requirements for the CBETA BPM system is to independently measure the position of each of these beams. The overall design of the CBETA BPM system and the techniques planned to measure the position of each energy beam will be presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW104  
About • paper received ※ 13 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPTS029 The Synchronization between BPMs and Corrector Power Supplies in AC Mode of RCS of CSNS power-supply, MMI, pick-up, neutron 3164
 
  • M.T. Li
    IHEP CSNS, Guangdong Province, People’s Republic of China
  • Y.W. An, S. Wang, S.Y. Xu
    IHEP, Beijing, People’s Republic of China
  • S.Y. Xu
    DNSC, Dongguan, People’s Republic of China
 
  This paper introduces our effort for synchronizing BPMs and Corrector Power Supplies in AC mode of RCS of CSNS. This work helps to increase the accuracy of the response matrix measurement, the obit correction, and other commissioning task.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS029  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPMP044 Radiation Hard Sensor for Reactor Applications laser, GUI, radiation, detector 3545
 
  • R.J. Abrams, M.A. Cummings, R.P. Johnson, T.J. Roberts
    Muons, Inc, Illinois, USA
  • D.M. Kaplan
    Illinois Institute of Technology, Chicago, Illinois, USA
 
  A novel method of measuring temperature of the coolant inside a reactor core is presented. The method, which is both standoff and non-invasive, is based on the interaction between an ultrasonic pulse and a delayed light pulse in the coolant. In the interaction, the light pulse, which is scattered backward by Brillouin scattering, is frequency-shifted. The frequency shift is dependent on the temperature and other parameters of the coolant. The light pulses and the ultrasound pulses are generated and detected outside of the core.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP044  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPRB034 Timing Synchronization System for Beam Injection from the SACLA Linac to the SPring-8 Storage Ring linac, injection, storage-ring, laser 3882
 
  • T. Ohshima, N. Hosoda, S. Matsubara
    JASRI, Hyogo, Japan
  • N. Hosoda, H. Maesaka, T. Ohshima
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
 
  We developed a timing synchronization system for beam injections from the linac of the X-ray free-electron laser (XFEL), SACLA, to the current SPring-8 storage ring. This injection scheme is beneficial for the next upgraded ring, SPring-8-II, where low emittance injection beams is required. The developed timing system aims at synchronizing the timing between the RF frequencies of the two accelerators which do not have a common subharmonic frequency. An important point is to keep the high performance of the current timing system which provides stable XFEL operation at SACLA. For this purpose, we designed and constructed a MicroTCA.4 system comprised of a high-speed ADC and an RF front-end for the synchronization. The RF signal of SACLA is digitized by the ADC whose clock is synchronized to SPring-8. A digital down-converter in the FPGA on the ADC module gives the phase difference instantaneously and a feedback logic applies a frequency modulation (FM) to the master oscillator of SACLA so as to synchronize SACLA with SPring-8. A bench test result showed that the timing jitter between the two frequency at injection timing was 1.2 ps rms, which was sufficient for the required value of 3 ps rms for the beam injection to the ring. In this presentation, we report an overview of the synchronization system, details of the developed electronics and the system performance obtained by a beam injection experiment from SACLA to SPring-8.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB034  
About • paper received ※ 30 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPRB046 The Preliminary Long-Term Slow Drift Calibration Study in Low-Level Rf System LLRF, experiment, monitoring, controls 3918
 
  • Z.Y. Lin, Y.-C. Du, W.-H. Huang, C.-X. Tang, J. Tang
    TUB, Beijing, People’s Republic of China
  • G. Huang, Y.L. Xu
    LBNL, Berkeley, California, USA
  • Z. Sun, D. Zhang
    HZCY Technologies Co., Ltd., Beijing, People’s Republic of China
 
  The phase drift of the RF signal in the low-level radio frequency (LLRF) system is observed in the long-term operation, which limits the performance and stability of the LLRF system. The long-term drift was reproduced in the lab. Its effect and sources of error were explored in the simple LLRF46 board and the simplest LLRF system. It is founded that the temperature will significantly lead to the phase distortion of the two signal channels, although with the same electron device. The distortion will finally cause the long-term drift with temperature floating. A fixed phase calibration signal (CAL signal) is applied to deal with the signal channels difference. The preliminary tests were conducted and the results were analysed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB046  
About • paper received ※ 22 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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THPRB098 FETS Personnel & Machine Interlock Systems controls, ion-source, status, radiation 4057
 
  • J.H. Macgregor
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
 
  The Front End Test Stand (FETS) [1] is a high energy pulsed proton driver that aims to produce a perfectly chopped 50 Hz, 60 mA, 2 ms H’ beam. FETS consists of a Penning Ion source, Low Energy Beam Transport (LEBT), 4 m long bolted construction 324 MHz four vane Radio Frequency Quadrupole (RFQ). The H’ Beam will be perfectly chopped so that bunches of particles can be trapped and accelerated with very low loss into a circular accelerator. To protect personnel from X-ray radiation along with prompt neutrons & gamma radiation, a concrete block-house has been built around the facility and a personnel interlock and search system developed. This paper discusses the mechanical and electrical systems used to ensure personnel safety via the Personnel Protection System (PPS) and machine safety by use of a Programmable Logic Controller, (PLC), used as the Machine Interlock Systems.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB098  
About • paper received ※ 09 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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FRXXPLS2 Extinction Measurement of J-PARC MR with 8 GeV Proton Beam for the New Muon-to-Electron Conversion Search Experiment - COMET proton, experiment, extraction, kicker 4372
 
  • H. Nishiguchi, Y. Fukao, Y. Hashimoto, Y. Igarashi, S. Mihara, M. Moritsu, R. Muto, M. Tomizawa, K. Ueno
    KEK, Tsukuba, Japan
  • Y. Fujii
    Monash University, Faculty of Science, Clayton, Victoria, Australia
  • P. Sarin
    Indian Institute of Technology Bombay, Mumbai, India
  • F. Tamura
    JAEA/J-PARC, Tokai-mura, Japan
 
  Funding: This work is partially supported by JSPS (Japan Society for the Promotion of Science) : KAKENHI 15K13492 and 16H00876
At J-PARC, extraction tests of a 8GeV pulsed proton beam from Main Ring (MR) have been successfully completed by a team drawn from the Accelerator Laboratory Group and the COherent Muon to Electron Transition (COMET) Experimental Group. The COMET Experiment aims to find new physics beyond the Standard Model by searching for the coherent neutrinoless conversion of a muon to an electron in muonic atoms, so-called mu-e conversion. This requires an extremely clean pulsed beam, and development of this beam plays a key role in the pursuit of the highest level of sensitivity. This successful extraction test is the clearing of a major milestone for the forthcoming experiment. The goal of the extraction tests was to confirm the beam quality under the customized MR operation mode. The J-PARC MR usually accelerates the proton beam (at one bunch per 600ns) up to 30GeV. But in the test, the MR instead accelerates the proton beam (at one bunch per 1.2us) up to 8GeV. The number of protons leaking between proton bunches, so-called EXTINCTION, must be less than one for every 1010 protons in the bunch. Extraction tests in the customized mode were conducted in January and February 2018 and resulted in many successes. In this test, leakage protons between bunches was successfully reduced below the objective of 10−10 of the number of protons in a bunch. This is a great success to guarantee the quality of proton beam required by COMET experiment. In addition, the time development of proton leakage was also precisely studied with several RF settings which enables us to further improve the extinction. In this paper, the result of extinction measurement and future prospect of beam extinction improvement is presented in addition to the detailed description of customized MR operation.
 
slides icon Slides FRXXPLS2 [13.427 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-FRXXPLS2  
About • paper received ※ 15 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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