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Yuri, Yosuke; Yuyama, Takahiro; Ishizaka, Tomohisa; Yoshida, Kenichi; Ishibori, Ikuo; Okumura, Susumu
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.138 - 142, 2014/06
no abstracts in English
Miyawaki, Nobumasa; Fukuda, Mitsuhiro*; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Okumura, Susumu; Arakawa, Kazuo*; Kamiya, Tomihiro
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.500 - 502, 2014/06
no abstracts in English
Hirano, Koichiro; Ito, Takashi; Kondo, Yasuhiro; Shinozaki, Shinichi; Chishiro, Etsuji; Miura, Akihiko; Morishita, Takatoshi; Ikegami, Masanori*; Kubota, Chikashi*; Sugimura, Takashi*; et al.
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.858 - 861, 2014/06
Two RF-deflecting cavities as a chopper and a beam scraper have been used in the MEBT between a 324 MHz RFQ and a 50-MeV DTL of the J-PARC Linac. We plan to increase a peak beam current up to 50 mA by replacing an ion source and a RFQ after the summer shutdown in 2014. Beam loss occurs in the RF chopper for the 50 mA operation. Moreover, the beam scraper cannot fully stand the beam load with 50 mA, 0.5 ms, 3 MeV, and 25 Hz. We have studied the new RF chopper cavity by using HFSS code and the tandem scraper system with two scrapers.
Tamura, Fumihiko; Yamamoto, Masanobu; Omori, Chihiro*; Yoshii, Masahito*; Schnase, A.*; Nomura, Masahiro; Tomizawa, Masahito*
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.125 - 129, 2014/06
For the slow extraction in the J-PARC MR, the rf voltage ins the cavities is turned off after finishing the acceleration to obtain a coasting beam. During the debunching process, the average momentum decrease due to the longitudinal coupling impedances in the MR. The decelatation continues until a well debunchedbeam is foarmed. The deceraration causes a reduction of the extraction efficiency due to the chromatic effects. In the J-PARC MR, a momentum loss has been observed at a relatively low beam power. To achieve higher beam power with keeping the high extraction efficiency, measures against the momentum loss are necessary. In this article, we report the observations and simulation results of the momentum losses. We adopt the rf feedforward method to cancel the wake voltage in the cavity as a measure of the momentum loss. By the feedforward, the momentum loss is significantly reduced. We achieve a high extraction efficiency, 99.5%, at the beam power of 20 kW.
Oguri, Hidetomo
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.313 - 317, 2014/06
no abstracts in English
Miura, Akihiko; Feschenko, A. V.*; Mirzojan, A. N.*; Miyao, Tomoaki*; Ouchi, Nobuo; Oguri, Hidetomo; Hasegawa, Kazuo; Ikegami, Masanori*
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.705 - 708, 2014/06
In J-PARC linac, a project for energy and intensity upgrade has been progressed since 2009 using Annular-ring Coupled Structure (ACS) cavities. Because the longitudinal matching of the injection beam to the ACS cavities is required as well as the transverse matching, we decided to employ the bunch shape monitors (BSM's) to measure the longitudinal beam profile. We developed three BSM's in collaboration with INR (Institute for Nuclear Research: Russia) for the upstream part of the ACS section. We introduce the structure of BSM and mention the measured results taken during the commissioning of BSM.
Miyao, Tomoaki*; Miura, Akihiko; Kondo, Yasuhiro; Morishita, Takatoshi; Sugimura, Takashi*; Ouchi, Nobuo; Oguri, Hidetomo; Maruta, Tomofumi*; Naito, Fujio
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1049 - 1052, 2014/06
In J-PARC linac, a project for energy and intensity upgrade has been progressed using 50 mA RFQ(Radio-Frequency-Quadrupole) linac cavity. Because the RFQ had already fabricated, test stand for its performance test was newly produced. In the test stand, we designed and fabricated the monitoring system including beam current monitors for the beam transmission measurement and the beam phase monitors for the energy measurement. We will refer the detail of the monitoring system and the data obtained during the performance test. New testing devices are also mentioned.
Nomura, Masahiro; Yamamoto, Masanobu; Shimada, Taihei; Tamura, Fumihiko; Omori, Chihiro*; Toda, Makoto*; Hasegawa, Katsushi*; Hara, Keigo*; Yoshii, Masahito*; Schnase, A.*
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.217 - 220, 2014/06
J-PARC RCS and MR employ RF cavities loaded with Magnetic Alloy (MA) cores. To achieve the high shunt impedance, we measured the shunt impedance with changing the core filling factor, ribbon thickness, and magnetization process. The shunt impedance was reduced in despite of the filling factor increase because the strong winding tension deteriorate the magnetic property. The MA core with thin ribbons and the MA core that is magnetized by a rotation process show high permeability in the accelerating frequency region, and those MA cores show the high shunt impedance consequently.
Kato, Shinichi*; Harada, Hiroyuki; Hotchi, Hideaki; Okabe, Kota; Omori, Chihiro*; Tamura, Fumihiko; Kinsho, Michikazu
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.444 - 447, 2014/06
The incoherent tune spread occurs by the space charge force and this becomes one of beam loss sources for the high intensity proton accelerator. This kind of beam loss was measured in the 3 GeV rapid cycling synchrotron (RCS) in J-PARC in the high intensity beam test. To measure the incoherent tune spread we have started to develop for a magnetic dipole exciter with magnetic alloy. It was found that it would be realized the exciter with several-kW electric power in the range of 3 MHz from our experimental results.
Matsuda, Makoto; Osa, Akihiko; Abe, Shinichi; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; et al.
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.307 - 309, 2014/06
no abstracts in English
Fukuta, Shimpei; Sawabe, Yuki; Suzuki, Takahiro*; Ishiyama, Tatsuya*; Kawase, Masato*; Ito, Yuichi; Kato, Yuko; Yoshii, Akinobu; Kikuzawa, Nobuhiro; Ouchi, Nobuo
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1122 - 1125, 2014/06
The installation of Cs-seeded RF-driven H
ion source (RF ion source) to J-PARC LINAC is scheduled in 2014. Similarly the replacement of RFQ III from RFQ is scheduled in 2014. The test stand of the cooperation of RF ion source & RFQ III is being made in the J-PARC LINAC building for the beam acceleration examination now. The J-PARC control group designed test stand control system by thinking that test stand control system had to be equal to J-PARC accelerator control system. Specifically, Introduction of MPS for protect an apparatus. Implementation of EPICS environment for remotely controlling the equipment. It is construction of the timing system for sending a timing signal to each accelerator component device. This report describes construction of the control system in a test stand.
Sawamura, Masaru; Nagai, Ryoji; Nishimori, Nobuyuki; Hajima, Ryoichi
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.956 - 959, 2014/06
no abstracts in English
Nishimori, Nobuyuki; Nagai, Ryoji; Matsuba, Shunya; Hajima, Ryoichi; Yamamoto, Masahiro*; Miyajima, Tsukasa*; Honda, Yosuke*; Uchiyama, Takashi*; Iijima, Hokuto*; Kuriki, Masao*; et al.
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.174 - 178, 2014/06
no abstracts in English
Shinoe, Kenji*; Sakai, Hiroshi*; Umemori, Kensei*; Enami, Kazuhiro*; Sato, Masato*; Furuya, Takaaki*; Sawamura, Masaru; Cenni, E.*
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.950 - 952, 2014/06
no abstracts in English
Takeuchi, Yasunao*; Sawamura, Masaru
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.597 - 601, 2014/06
no abstracts in English
Sato, Masato*; Umemori, Kensei*; Enami, Kazuhiro*; Sakai, Hiroshi*; Shinoe, Kenji*; Furuya, Takaaki*; Sawamura, Masaru; Cenni, E.*
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.973 - 976, 2014/06
no abstracts in English
Sakai, Hiroshi*; Umemori, Kensei*; Enami, Kazuhiro*; Sato, Masato*; Shinoe, Kenji*; Furuya, Takaaki*; Sawamura, Masaru; Cenni, E.*
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.212 - 216, 2014/06
no abstracts in English
Enami, Kazuhiro*; Furuya, Takaaki*; Sakai, Hiroshi*; Sato, Masato*; Shinoe, Kenji*; Umemori, Kensei*; Sawamura, Masaru; Cenni, E.*
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.602 - 604, 2014/06
no abstracts in English
Harada, Hiroyuki; Meigo, Shinichiro; Shirakata, Masashi*; Sato, Yoichi*; Tamura, Fumihiko; Tejima, Masaki*; Hashimoto, Yoshinori*; Igarashi, Susumu*; Koseki, Tadashi
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.39 - 43, 2014/06
The J-PARC 3-50 BT line is the beam transport line of extracted beam from 3-GeV rapid-cycling synchrotron (RCS) to 50-GeV main ring (MR). The RCS is the high-intensity proton accelerator, which designed beam power is 1 MW, and has the complex source of space charge effect, etc. Therefore, the uncontrolled emittance growth and beam halo increase nonlinearly with the increasing the beam power. Additionally, physical aperture of MR with 81 
mm mrad is smaller than that of RCS with 486 mm mrad. Therefore, the 3-50 BT line has the collimators in order to scrape the tail/halo of extracted beam from the RCS. The designed collimator aperture is 54 mm mrad. It is required to measure and optimize the optics parameter in the collimator area for taking full advantage of beam collimation. This paper will introduce the method of optics measurement and report the result of the measurement and optimization based on the simulation.
Okoshi, Kiyonori; Ikegami, Kiyoshi*; Koizumi, Isao; Ueno, Akira; Takagi, Akira*; Yamazaki, Saishun; Oguri, Hidetomo
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.946 - 949, 2014/06
A J-PARC ion source driven with a LaB6 filament is being operated without any serious trouble since the restoration from the earthquake. The H ion current from the source is routinely restricted 19 mA for the filament lifetime. In order to increase the beam power at the linac beam operation, the beam current from the ion source was increased to 22 mA. At this operation, the filament lifetime was estimated by the reduction in the filament current. According to the steep reduction in the filament current, the break of the filament was predicted. Although the filament has broken after 10 h from the steep current reduction, the beam operation was restarted 8 h later by the preparation for the exchange of new filament. At the study time for the 3 GeV synchrotron, the ion source was operated at 30 mA for 8 days.
