Beam position monitor system of J-PARC RCS

Hayashi, Naoki; Kawase, M.; Hatakeyama, Shuichiro; Hiroki, Seiji; Saeki, Riuji; Takahashi, Hiroki; Teruyama, Y.; Toyokawa, R.; Arakawa, Dai; Hiramatsu, S.; Lee, S.; Satou, Kenichirou; Takeuchi, Masaki; Toyama, T.

doi:10.1016/j.nima.2012.02.013

Cited by 16 publications

(3 citation statements)

References 6 publications

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“…The left plot in Fig. 16 shows the turn-by-turn coherent position oscillation for the first 1.3 ms measured with a beam position monitor (BPM) [21]. By analyzing the BPM data, the kick angle of the dipole field ripple was evaluated as a function of time, as shown in the right plot in Fig.…”

Section: Source Of Dipole Field Ripplementioning

confidence: 99%

Achievement of a low-loss 1-MW beam operation in the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Hotchi

Harada

Hayashi

et al. 2017

Phys. Rev. Accel. Beams

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The 3-GeV rapid cycling synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC) is now in the final beam commissioning phase, aiming for a design output beam power of 1 MW. With a series of injector linac upgrades in 2013 and 2014, RCS developed a high-intensity beam test, and launched 1-MW beam tuning in October 2014. The most important issues in realizing such a high-power continuous beam operation are to control and minimize beam loss for maintaining machine activations within permissible levels. In RCS, numerical simulation was successfully utilized along with experimental approaches to isolate the mechanism of beam loss and find its solution. By iteratively performing actual beam experiments and numerical simulations, and also by several hardware improvements, we have recently established a 1-MW beam operation with very low fractional beam loss of a couple of 10 −3 . In this paper, our recent efforts toward realizing such a low-loss high-intensity beam acceleration are presented as a follow-up of our previous article, H. Hotchi et al. Phys. Rev. ST Accel. Beams 12, 040402 (2009), in which the initial beam commissioning status of RCS has been reported.

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Section: Source Of Dipole Field Ripplementioning

confidence: 99%

Achievement of a low-loss 1-MW beam operation in the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Hotchi

Harada

Hayashi

et al. 2017

Phys. Rev. Accel. Beams

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“…Figure 11 shows the instability results obtained in the simulation for an output beam power of 0.5 MW. The horizontal axis represents the acceleration time, while the vertical axis represents the turn-by-turn horizontal beam position at a beam position monitor (BPM) located in the injection area [39]. The difference between the data in the left and the right plots is the beam energy at injection, which was 0.181 and 0.4 GeV, respectively.…”

Section: Beam Instabilities: Comparison Between Simulated and Measmentioning

confidence: 99%

Simulation, measurement, and mitigation of beam instability caused by the kicker impedance in the 3-GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex

Saha

Shobuda

Hotchi

et al. 2018

Phys. Rev. Accel. Beams

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The transverse impedance of eight extraction pulsed kicker magnets is a strong beam instability source in the 3-GeV rapid cycling synchrotron (RCS) at the Japan Proton Accelerator Research Complex. Significant beam instability occurs even at half of the designed 1 MW beam power when the chromaticity (ξ) is fully corrected for the entire acceleration cycle by using ac sextupole (SX) fields. However, if ξ is fully corrected only at the injection energy by using dc SX fields, the beam is stable. In order to study realistic beam instability scenarios, including the effect of space charge and to determine practical measures to accomplish 1 MW beam power, we enhance the ORBIT particle tracking code to incorporate all realistic time-dependent machine parameters, including the time dependence of the impedance itself. The beam stability properties beyond 0.5 MW beam power are found to be very sensitive to a number of parameters in both simulations and measurements. In order to stabilize a beam at 1 MW beam power, two practical measures based on detailed and systematic simulation studies are determined, namely, (i) proper manipulation of the betatron tunes during acceleration and (ii) reduction of the dc SX field to reduce the ξ correction even at injection. The simulation results are well reproduced by measurements, and, as a consequence, an acceleration to 1 MW beam power is successfully demonstrated. In this paper, details of the ORBIT simulation and the corresponding experimental results up to 1 MW of beam power are presented. To further increase the RCS beam power, beam stability issues and possible measures beyond 1 MW beam power are also considered.

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“…In order to improve the precision of the machine, a beam-based alignment method is applied to align the magnetic centers of the quadrupole magnets and the BPMs. This beam-based alignment method has been applied at electron [6][7][8] and hadron [9,10] machines before. This procedure requires the quadrupoles to be mechanically aligned.…”

Section: Introductionmentioning

confidence: 99%

Beam-based alignment at the Cooler Synchrotron COSY as a prerequisite for an electric dipole moment measurement

Wagner¹,

Nass²,

Pretz³

et al. 2021

J. Inst.

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The Jülich Electric Dipole moment Investigation (JEDI) collaboration aims at a direct measurement of the Electric Dipole Moment (EDM) of protons and deuterons using a storage ring. The measurement is based on a polarization measurement. In order to reach highest accuracy, one has to know the exact trajectory through the magnets, especially the quadrupoles, to avoid the influence of magnetic fields on the polarization vector. In this paper, the development of a beam-based alignment technique is described that was developed and implemented at the COoler SYnchrotron (COSY) at Forschungszentrum Jülich. Well aligned quadrupoles permit one to absolutely calibrate the Beam Position Monitors (BPMs). The method is based on the fact that a particle beam, which does not pass through the center of a quadrupole, experiences a deflection. The precision reached by the method is approximately 40μm. Some consequences for the design of a new high precision storage ring for EDM mesasurements are discussed.

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Beam position monitor system of J-PARC RCS

Cited by 16 publications

References 6 publications

Achievement of a low-loss 1-MW beam operation in the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Achievement of a low-loss 1-MW beam operation in the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Simulation, measurement, and mitigation of beam instability caused by the kicker impedance in the 3-GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex

Beam-based alignment at the Cooler Synchrotron COSY as a prerequisite for an electric dipole moment measurement

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