Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Ishizaka, Tomohisa; Agematsu, Takashi; Yuri, Yosuke; Yuyama, Takahiro; Ishibori, Ikuo; Okumura, Susumu
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.642 - 644, 2010/08
no abstracts in English
Yoshida, Kenichi; Nara, Takayuki; Ishibori, Ikuo; Kurashima, Satoshi; Yuyama, Takahiro; Ishizaka, Tomohisa; Agematsu, Takashi; Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; et al.
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.23 - 26, 2010/08
no abstracts in English
Kobayashi, Tetsuya; Ikegami, Masanori*
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.696 - 698, 2010/08
The function of the chopped beam loading compensation was implemented into the digital feedback/feed-forward control system of the J-PARC Linac LLRF system to stabilize the ACS cavity fields for the 400-MeV upgrade. The beam test of the chopped beam loading compensation was performed with the present 324-MHz cavity system. As the result, the chopped beam loading was successfully compensated and that this system is valid.
Kobayashi, Tetsuya
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.1082 - 1084, 2010/08
For 400-MeV upgrade of the J-PARC Linac. ACS (Annular Coupled Structure) cavities, which are driven by 972-MHz RF, will be installed. The ACS cavity has complicated structure. Its Q-value is very low and the operation frequency is tree times high in comparison with that of the SDTL cavity. So the stabilizing control of the ACS accelerating field will be more difficult than present RF system. Further more the chopped beam loading compensation is required. Especially, a debuncher will be located very far from the klystron, then the feedback loop delay will be about 1.5 us. This presentation will show the simulation results of the feedback control of the ACS cavity field including long loop delay and the effect of the chopped beam loading.
Hatakeyama, Shuichiro; Saha, P. K.; Yoshimoto, Masahiro; Yamamoto, Kazami; Hayashi, Naoki; Sato, Kenichiro*
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.1013 - 1015, 2010/08
In J-PARC (Japan Proton Accelerator Research Complex), the negative hydrogen ions (H
) accelerated by LINAC are converted to protons (H
) by the Charge Stripping Foil before injecting into RCS (Rapid Cycling Synchrotron). About 99.7% of H are stripped it's two electrons by the 1st foil. The rest of H0 and H are converted to H by 2nd and 3rd foils and abandoned into H0 dump. Monitoring of the fraction of beam current into the H0 dump gives useful information for the stable beam supply during accelerator user's operation. This report describes the method of online monitoring to estimate the beam current of the H0 dump line.
Hatakeyama, Shuichiro; Toyama, Takeshi*; Tejima, Masaki*
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.631 - 633, 2010/08
The beam commissioning of J-PARC MR (Main Ring) started in 2008. The current beam power of the user operation is 40 kW - 70 kW which corresponds 1/10 of the designed value of 1st stage. One of the hurdle to clear for the power up is the beam loss at the injection. A candidate of the origin of the injection beam loss is the error of bending angles of RCS extraction magnets and MR injection magnets, therefore it is required to monitor continuously the transverse injection error. The transverse injection error can be calculated using beam bunch positions at the injection. For this purpose a dedicated digitizer is used to acquire the waveform of BPM. It is also monitored the betatron tune using the same digitizer. Processing the injected 93 turns beam bunch positions by FFT it is realized the continuous monitoring with 3.52 s operating cycle. When determining the beam bunch position, the digital-high-pass filtering is adapted to the waveform of BPM to remove the slow component of noise.
Sawabe, Yuki*; Suzuki, Takahiro; Ishiyama, Tatsuya; Fukuta, Shimpei; Kikuzawa, Nobuhiro
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.680 - 682, 2010/08
The output energy of the J-PARC proton LINAC will be upgraded from 181 to 400 MeV in the next two years by adding ACS modules. The present status of upgrade of the control system for the ACS section will be presented in this paper.
Kikuzawa, Nobuhiro; Suzuki, Takahiro; Ito, Yuichi; Miura, Akihiko; Fukuta, Shimpei; Ikegami, Masanori*; Sako, Hiroyuki; Kobayashi, Tetsuya; Suzuki, Hiroyuki; Hasegawa, Kazuo
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.677 - 679, 2010/08
To avoid heat damage and radioactivation by beam loss of the J-PARC accelerator, Machine Protection System (MPS) has been developed. Actually, high responsibility and high reliability have been achieved in J-PARC. Beam-stop method in addition to a way of RFQ OFF has been requested in order to avoid damage to the RFQ. Therefore, we have been developing a fast beam-stop system by using a RF chopper. The fast beam-stop system, including beam test, is described in this paper.
Nagai, Ryoji; Nishimori, Nobuyuki; Hajima, Ryoichi; Muto, Toshiya*; Yamamoto, Masahiro*; Miyajima, Tsukasa*; Honda, Yosuke*; Iijima, Hokuto*; Kuriki, Masao*; Kuwahara, Makoto*; et al.
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.806 - 808, 2010/08
A 500-kV, 10-mA photocathode DC gun which is designed for next-generation light- sources based on energy-recovery linac has been developed in a collaboration effort of JAEA, KEK, Hiroshima University and Nagoya University. We have utilized a segmented cylindrical ceramic insulator and guard-ring electrodes to prevent any damage to the insulator from electrons emitted by the support-rod electrode. The 500-kV gun was successfully conditioned up to a voltage of 550 kV and a long-time holding test for 8 h was demonstrated at an acceleration voltage of 500 kV. The cathode electrode, anode electrode, and beam line apparatuses are now under fabrication and beam tests of the gun will be started soon.
Oguri, Hidetomo; Ikegami, Kiyoshi*; Okoshi, Kiyonori; Namekawa, Yuya; Ueno, Akira
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.829 - 831, 2010/08
The J-PARC ion source has succeeded in providing the required beam to the accelerator for approximately 3.5 years without any serious trouble. At the recent beam run, approximately 600 hours continuous operation was achieved. Although the ion source can produce a maximum beam current of 36 mA, the beam current has been restricted to less than 16 mA for the stable operation of the RFQ linac which has serious discharge problem. After each beam run, we perform the ion source maintenance to replace some elements for the plasma production such as a filament, a plasma chamber and so on. Approximately three days was necessary to accomplish the maintenance. In order to enhance the availability of the accelerator, reduction of the maintenance time is indispensable. At present, we succeed in cutting the maintenance time in half by using the filament pre-baking system. We will make another attempt to shorten the time by unitizing the replacement elements in the near future.
Ueno, Tomoaki; Takayanagi, Tomohiro; Togashi, Tomohito; Kinsho, Michikazu
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.965 - 968, 2010/08
The injection bump system of the 3-GeV RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Research Complex) consists of the pulse bending magnets for the injection bump orbit, which are four horizontal bending magnets (shift bump), four horizontal painting magnets (h-paint bump) and two vertical painting magnets (v-paint bump). The power supplies of the magnets are composed of multiple-connections of the IGBT (Insulated Gate Bipolar Transistor) assemblies. They excite the current waveform of the trapezoid pattern with the flat top for 500 
s and the flexible decay pattern. The exciting current and magnetic field were measured. The power supplies executed the good accuracy less than 1percent deviation to programmed pattern. Furthermore, the continuous long-term with stable has been performed. In this paper, the current status of the operation of the injection bump system is described.
Togashi, Tomohito; Watanabe, Masao; Suganuma, Kazuaki; Takayanagi, Tomohiro; Ueno, Tomoaki; Tani, Norio; Watanabe, Yasuhiro
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.579 - 583, 2010/08
The 3-GeV RCS (Rapid Cycling Synchrotron) at J-PARC (Japan Proton Accelerator Research Complex) has the pulse kicker power supply system which uses the thyratron switches for beam extraction. There were many troubles caused by unstable operation of thyratrons after beam commissioning started in January 2009. The, failure rate of the kicker power supply system was about 13%. To improve this status, we have been managed the operations of the thyratron in detail. As a result, the unstable operation has been improved and the failure rate has been achievement less than 0.5% (Run33) in April, 2010. In this paper, we report current status of the thyratron operation of the kicker power supply system.
Saeki, Riuji; Yoshimoto, Masahiro; Yamazaki, Yoshio; Takeda, Osamu; Kinsho, Michikazu
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.1025 - 1028, 2010/08
no abstracts in English
Nomura, Masahiro; Tamura, Fumihiko; Schnase, A.; Yamamoto, Masanobu; Hasegawa, Katsushi*; Shimada, Taihei; Hara, Keigo*; Toda, Makoto*; Omori, Chihiro*; Yoshii, Masahito*
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.877 - 879, 2010/08
J-PARC 3 GeV RCS and 50 GeV MR employ the Magnetic Alloy (MA) loaded RF cavities. We observed the impedance reductions of the RF cavities in RCS three times during 3 years of operation. We figured out that the impedance reductions were resulting from the MA core buckling. We also observed the impedance reductions of MR RF cavities during 1.5 years of operation. Opening the RF cavities, we found that the impedance reductions were caused by the corrosion on the MA core cutting surface. The copper ions and colloids in the cooling water might accelerate the corrosion process.
ion sourceNamekawa, Yuya; Ueno, Akira; Okoshi, Kiyonori; Oguri, Hidetomo; Ikegami, Kiyoshi*
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.484 - 487, 2010/08
The J-PARC H ion source driven with a lanthanum hexaboride filament (LaB
-fil.) is successfully producing a stable beam for each J-PARC operation cycle of about 500 hours. However, its maximum peak H ion current of 36 mA does not satisfy the requirement of 60 mA for the J-PARC design beam power of 1 MW. In this paper, two results of the experiments to increase the current with a sufficient life-time are presented. That using a flat quintuple-hairpin LaB-fil. resulted in the lower current of 33 mA and the lower life-time of less than 230 hours. The deterioration seemed to be caused by the localized emission area due to too large magnetic field on it. On the other hand, that using two triple-hairpin tungsten filaments (W-fil.) connected in parallel with a short distance resulted in a life-time of 500 hours with a 15 kW arc power operation, which should produce an H ion current of more than 60 mA if cesium was seeded.
Wei, G.; Ikegami, Masanori*; Sako, Hiroyuki; Miura, Akihiko; Ao, Hiroyuki; Ito, Takashi; Asano, Hiroyuki
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.453 - 455, 2010/08
Tandem Accelerator Section
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.15 - 19, 2010/08
no abstracts in English
Narita, Takahiro; Kojima, Toshiyuki; Tsutsumi, Kazuyoshi; Takahashi, Hiroki; Sakaki, Hironao
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.673 - 676, 2010/08
no abstracts in English
Miura, Akihiko; Kobayashi, Tetsuya; Hasegawa, Kazuo; Sako, Hiroyuki; Ikegami, Masanori*
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.939 - 941, 2010/08
MEBT-Chopper tuning procedure was proposed using a downstream wire scanner monitor and this has been employed for the beam commissioning of the J-PARC Linac. This paper introduces the results obtained by several tuning experiences and its tendencies. Finally, tolerance depending on the tank level of RFQ (Radio-Frequency Quadrupole Linac) is introduced.
Kawase, Masato; Yoshimoto, Masahiro; Takeda, Osamu; Kinsho, Michikazu
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.1065 - 1067, 2010/08
no abstracts in English
