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Hayashi, Naoki; Hatakeyama, Shuichiro; Fukuta, Shimpei*
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.679 - 682, 2021/10
In order to achieve a high availability in a user facility accelerator complex, it is necessary to understand in detail not only the simple failure cause of the magnet or the acceleration cavity power supply, but also complex interlocked events. At J-PARC, not only the primary interlock information but also the data recorded by the beam diagnostic system before the interlocked event is used to carefully reconstruct the event and clarify the cause more accurately. This time, we proceeded with the analysis based on more detailed waveform of the RCS Beam Loss Monitor and the events during simultaneous operation of MLF and MR. We present various events of the beam destination switching problem, the influence of the ion source discharged, and the events related to the RCS extraction kicker.
Hayashi, Naoki; Yoshimoto, Masahiro; Hatakeyama, Shuichiro*
JPS Conference Proceedings (Internet), 33, p.011017_1 - 011017_6, 2021/03
The J-PARC Rapid-Cycling Synchrotron (RCS) is designed as an 1-MW high intensity proton accelerator. Beam intensity diagnostics is an important device to prove the accelerator performance. The RCS has two instruments based on different principles, namely Direct-current Current Transformer (DCCT) and Slow-CT (SCT). It was realized that SCT showed strange behavior when continuous 1-MW demonstration had been performed, although there were no problem under 1-MW equivalent operation with single shot. The origin of the problem seems to be limited band width at higher frequency and asymmetric circulating beam current pattern. On the other hand, DCCT also showed output signal saturation with 1.2-MW equivalent single shot. But, SCT worked properly with this conditions. These problems have to be solved for future continuous 1-MW and higher intensity operation. On this presentation, we will show beam and test pulse data and discuss about how to measure these problems.
Hayashi, Naoki
Proceedings of 17th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.478 - 481, 2020/09
Measurement of beam intensity or beam current is the one of the most important beam diagnostic in an accelerator. At J-PARC Rapid-Cycling Synchrotron (RCS), there are two kinds of beam intensity monitors and multiple Current Transformers (CT) with various bandwidth. The RCS is a high intensity proton accelerator and its designed beam power of 1 MW. The beam power delivered to users gradually increases in the recent year. Single pulse or short term with designed beam power has been also demonstrated. In addition, beyond 1-MW equivalent intensity has been attempted. Through the experience with achievement of the design goal and the operation beyond it, intensity dependence of beam current measurement has been summarized.
Hayashi, Naoki; Yoshimoto, Masahiro; Moriya, Katsuhiro; Hatakeyama, Shuichiro*
Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1096 - 1100, 2019/07
It is necessary to understand the reason why the accelerator has been interrupted due to beam loss or other machine mal function in order to keep high availability in long term period. At J-PARC RCS, 25 Hz rapid-cycling synchrotron, there is a system to record beam intensity and beam loss monitor signal for all pulses with 10 ms period. At this time, in addition, new system to archive data with better time resolution if interlocked events occurred has been introduced. Using these archived data, the events only RCS BLM gives MPS have been analyzed and it turns out that these events are related to the ion source discharge which makes very low intensity within less than a second. In this paper other typical events are presented and discuss how to improve the accelerator performance in future.
Matsuda, Makoto; Takeuchi, Suehiro; Yoshida, Tadashi; Hanashima, Susumu; Fujii, Yoshio*
Dai-14-Kai Kasokuki Kagaku Kenkyu Happyokai Hokokushu, p.170 - 172, 2003/00
no abstracts in English
Matsuda, Makoto; Kobayashi, Chiaki*; Takeuchi, Suehiro
Proc. of 14th Int. Workshop on ECR Sources (ECRIS99), p.176 - 179, 1999/00
no abstracts in English
Matsuda, Makoto; Kobayashi, Chiaki*; Takeuchi, Suehiro
Proc. of 8th Int. Conf. on Heavy Ion Accelerator Technology, p.65 - 73, 1998/00
no abstracts in English
Ohara, Yoshihiro;
JAERI-M 82-066, 68 Pages, 1982/07
no abstracts in English
Hayashi, Naoki; Hatakeyama, Shuichiro; Yoshimoto, Masahiro
no journal, ,
The J-PARC Rapid-Cycling Synchrotron (RCS) is an 1-MW high intensity proton accelerator and its performance has been improved step-by-step. Beam intensity diagnostics is an important device and RCS is equipped two instruments based on different principles, namely DCCT (DC Current Transformer) and SCT (Slow-CT). RCS already achieved 1-MW equivalent operation under very low repetition like single shot. Both basic monitors, DCCT and SCT, did not show any problem. However, SCT showed strange behavior in July 2018 under short-term but continuous 25 Hz 1-MW operation. On the other hand, DCCTalso showed output signal saturation with 1.2-MW equivalent single shot. But, SCT worked properly with this conditions. These problems have to be solved for future continuous 1-MW and higher operation. On this presentation, we will present detailed 700 kW operational data and reproduced data obtained by test-pulse particularly for SCT. We will also try to explain these phenomena by circuit simulation and discuss about how to measure these issues.
Hayashi, Naoki; Yoshimoto, Masahiro
no journal, ,
A beam intensity monitor is one of the most fundamental diagnostics for an accelerator. For a high duty rapid-cycling synchrotron, such intensity monitor must have very long time constant and the circulating beam current must be divided by revolution velocity in order to determine the intensity. It is realized by analogue circuit. The J-PARC Rapid-Cycling Synchrotron (RCS) is equipped two instruments, namely DCCT (DC Current Transformer) and SCT (Slow-CT). Recently, the beam intensity approaches to the designed value, the present intensity monitor sometimes shows overroad behavior with certain beam conditions. Although Medium-CT (MCT), which main purpose is to monitor the intensity during injection period, has its time constant about 2 seconds, it can be used as a backup instrument for DCCT or SCT with digital signal processing.
