Beam Diagnostics for the J-PARC Main Ring Synchrotron

Toyama, T.; Arakawa, Dai; Hashimoto, Y.; Lee, S.; Miura, Takako; Muto, S.; Hayashi, Naoki; Toyokawa, R.; Kishiro, J.

doi:10.1109/pac.2005.1590624

Cited by 3 publications

(3 citation statements)

References 2 publications

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“…The transverse beam distribution was a Gaussian and the longitudinal beam distribution was a parabola in the simulations. The longitudinal beam size was determined by the data of the wall current monitor [8]. The momentum spread dp/p was set to 0.003.…”

Section: Simulation Of Coherent Quadrupole-mode Space-charge Tune Shiftmentioning

confidence: 99%

Injection Optics Matching of the High Intensity Beam at J-PARC MR

Yasui

Igarashi

Sato

et al. 2021

Proceedings of the 3rd J-Parc Symposium (J-Parc2019)

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In the main ring (MR) of Japan Proton Accelerator Research Complex (J-PARC), transverse beam size oscillations were measured by making quadrupole-mode mismatch at the beam injection. The intensity dependence of quadrupole-mode coherent tune shifts derived from the space-charge effect was evaluated by comparing quadrupole-mode oscillations with dipole-mode oscillations. The results were reproduced by the simulation including the space-charge effect. The incoherent tunes were also simulated. They were consistent with analytical calculations. The incoherent betatron functions were simulated at the same time. At the action corresponding to the aperture of the MR, the modulations of betatron functions were +2% − +4% owing to the sextupole fields and the space-charge effect.

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Section: Simulation Of Coherent Quadrupole-mode Space-charge Tune Shiftmentioning

confidence: 99%

Injection Optics Matching of the High Intensity Beam at J-PARC MR

Yasui

Igarashi

Sato

et al. 2021

Proceedings of the 3rd J-Parc Symposium (J-Parc2019)

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“…Figure 2 shows the typical mountain plot of the beam signal at the beam power of 480 kW. The beam signal from an Wall Current Monitor (WCM) [4] is recorded by an oscilloscope. The longitudinal dipole oscillation keeps growing from the middle of the acceleration.…”

Section: B Longitudinal Bunch Oscillation In the J-parc Mrmentioning

confidence: 99%

Longitudinal Mode-by-Mode Feedback System for The J-PARC Main Ring

Sugiyama,

Tamura,

Yoshii

2018

Preprint

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The J-PARC Main Ring (MR) is a high intensity proton synchrotron, which accelerates protons from 3 GeV to 30 GeV. The MR delivers 2.6 × 10 14 protons per pulse, which corresponds to the beam power of 500 kW, to the neutrino experiment as of May 2018, and the studies to reach higher beam intensities are in progress. During studies, we observed the longitudinal dipole coupled-bunch instabilities in the MR for the beam power beyond 470 kW. To mitigate them for higher beam intensities, we have developed a longitudinal mode-by-mode feedback system. The feedback system consists of a wall current monitor, a FPGA-based feedback processor, RF power amplifiers, and a RF cavity as a longitudinal kicker. In the feedback processor, we utilize the single sideband filtering technique to detect the oscillation components of the individual coupled-bunch mode in the beam signal. The frequency response of the filters in the feedback processor matched well with the simulation. The oscillation amplitude of the coupled bunch oscillation measured by the system agreed with the oscilloscope analysis.

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“…The maximum alignment errors of transverse position and rotation for beam direction are less than 0.15 mm and less than 0.2 mrad, respectively. Each BPM has electrostatic pickup with diagonal-cut cylinder [4]. For vacuum system, 90 % of beam ducts in the arc sections have been connected.…”

Section: Beam Abort Linementioning

confidence: 99%