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Yokota, Wataru; Nara, Takayuki; Ishibori, Ikuo; Kurashima, Satoshi; Yoshida, Kenichi; Yuyama, Takahiro; Ishizaka, Tomohisa; Agematsu, Takashi; Uno, Sadanori; Chiba, Atsuya; et al.
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.22 - 24, 2008/08
no abstracts in English
Shinto, Katsuhiro; Vermare, C.*; Harami, Taikan*; Sugimoto, Masayoshi; Garin, P.*; Maebara, Sunao; Sakaki, Hironao; Ohira, Shigeru; Okumura, Yoshikazu; Mosnier, A.*; et al.
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.255 - 258, 2008/00
Kobayashi, Tetsuya; Anami, Shozo*; Michizono, Shinichiro*; Fang, Z.*; Suzuki, Hiroyuki; Yamaguchi, Seiya*; Chishiro, Etsuji
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.488 - 490, 2008/00
For the J-PARC linac low level RF system, in order to compensate beam-loading change by pulses in the operation of 25-Hz repetition, a function that switches the feed-forward control parameters in every pulse were installed into the digital accelerating-field control system. The linac provides a 50-mA peak current proton beam to a 3-GeV rapid-cycling synchrotron (RCS). Then the RCS distributes the 3-GeV beam into a following 50-GeV synchrotron (main ring, MR) and the Materials and Life Science Facility (MLF), which is one of the experimental facilities in the J-PARC. The 500-us long macro pulses from the ion source of the linac should be chopped into medium pulses for injection into the RCS. The duty (width or repetition) of the medium pulse depends on which facility the RCS provides the beam to the MR or MLF. Therefore the beam loading compensation needs to be corrected for the change of the medium pulse duty in the 25-Hz operation.
Fang, Z.*; Anami, Shozo*; Michizono, Shinichiro*; Yamaguchi, Seiya*; Kobayashi, Tetsuya; Suzuki, Hiroyuki
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.476 - 478, 2008/00
In the J-PARC proton linac, each klystron drives two RF cavities. The RF amplitude and phase of the cavities are controlled by an FPGA-based digital feedback control system. The tuning of each cavity is also controlled by a DSP of this control system. In this paper, three methods of f
setting of RF cavity will be discussed. The tuning method of RF cavity with flat cavity-phase decay is adopted in the actual operation of the J-PARC linac. In our RF system, the tuning information including detuned frequency and phase, and Q-value of each cavity are measured in real-time and displayed in the PLC Touch Panel of the control system.
Hotchi, Hideaki; Kinsho, Michikazu
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.4 - 6, 2008/00
The J-PARC 3GeV RCS (Rapid Cycling Synchrotron) has been commissioned since September 2007. The initial tuning of the basic parameter has been completed in February 2008, and then since May 2008 the RCS beam has been supplied to the succeeding MR (50GeV Main Ring) and MLF (Material and Life Science Facility) for their commissioning. We have achieved 52 kW output so far. Now the RCS is in transition to the challenging phase for aiming at the higher current operation. Our immediate goal is to realize the stable operation with 100 kW output which corresponds to 10% of the designed output beam power.
Suzuki, Hiroyuki; Chishiro, Etsuji; Kobayashi, Tetsuya; Hori, Toshihiko; Yamazaki, Masayoshi; Anami, Shozo*; Yamaguchi, Seiya*; Kawamura, Masato*; Fukui, Yuji*; Fang, Z.*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.467 - 469, 2008/00
no abstracts in English
Hori, Toshihiko; Yamazaki, Masayoshi; Chishiro, Etsuji; Suzuki, Hiroyuki; Ao, Hiroyuki; Hirano, Koichiro; Hasegawa, Kazuo; Yamaguchi, Seiya*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.482 - 484, 2008/00
no abstracts in English
Nomura, Masahiro; Tamura, Fumihiko; Schnase, A.; Yamamoto, Masanobu; Hasegawa, Katsushi; Shimada, Taihei; Suzuki, Hiromitsu; Ezura, Eiji*; Hara, Keigo*; Toda, Makoto*; et al.
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.246 - 248, 2008/00
We have been developing MA core for J-PARC Ring RF Cavity. From long run tests, we found that poor electrical isolation between layers caused damages to the cores. We improved the electrical isolation mainly by introducing a smooth tension control system to the winding process. The degree of the each core's electrical isolation was evaluated by the results of DC resistance and radial RF impedance measurements. After long run tests of all of the cores, we installed 10 RF cavities in a tunnel in May 2007 and beam commissioning was started from October 2007. Until now, total operation time of the RF cavities in the tunnel is about 1500 hours. To check the condition of the cores, we measured the RF cavity impedance at intervals of beam operations. The result of impedance measurements shows that no impedance reduction related to core damage was observed.
Miyawaki, Nobumasa; Okumura, Susumu; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Yuri, Yosuke; Yuyama, Takahiro; Ishizaka, Tomohisa; Ishibori, Ikuo; Nara, Takayuki; et al.
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.400 - 402, 2008/00
The beam phase structure in the JAEA AVF cyclotron was measured for three acceleration harmonic modes with the radial probe equipped with a plastic scintillator to investigate the relation between the beam phase and the position of the puller electrode or two pairs of beam-phase-defining slits in the cyclotron central region. A number of simulations on the beam phase structure were also performed for confirmation of the experimental results. The beam phase structure measured inside the cyclotron was agreed with the simulation result. The radial probe has been improved for increasing the detection efficiency of accelerating ions with a short range in the plastic scintillator. The improvement was confirmed for 75 MeV-
Ne
beam.
Yamamoto, Masanobu; Anami, Shozo*; Ezura, Eiji*; Hasegawa, Katsushi; Hara, Keigo*; Horino, Mitsuyoshi*; Nomura, Masahiro; Omori, Chihiro*; Schnase, A.; Shimada, Taihei; et al.
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.358 - 360, 2008/00
The beam commissioning has been started at the J-PARC RCS in October 2007, and the beam acceleration and the extraction at 3 GeV has been succeeded. Some longitudinal bunch gymnastics has been tested toward the high intensity operation, one of the issues is arriviating the space charge effect at the injeciton. Since the multi-turn injection scheme is employed at the RCS, the electric charge density of the bunch near the center of the RF bucket tends to be high with only normal fundamental RF capture. Some schemes such as adding 2nd higher harmonic RF, the momentum offset and the phase offset of the 2nd one are simulated by longitudinal particle tracking code to make the bunching factor low. The comparison between the beam test result and the particle tracking simulation is described.
Kawase, Masato; Takahashi, Hiroki; Ito, Yuichi; Sawa, Shiori*; Sugimoto, Makoto*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.274 - 276, 2008/00
no abstracts in English
Suzuki, Takahiro; Yoshikawa, Hiroshi; Sakaki, Hironao; Takahashi, Hiroki; Ito, Yuichi; Kato, Yuko; Kawase, Masato; Ishiyama, Tatsuya; Fukuta, Shimpei*; Watanabe, Kazuhiko*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.84 - 86, 2008/00
no abstracts in English
Takayanagi, Tomohiro; Harada, Hiroyuki*; Ueno, Tomoaki; Irie, Yoshiro*; Kinsho, Michikazu; Yoshimoto, Masahiro; Kamiya, Junichiro; Watanabe, Masao; Sato, Kenichiro*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.352 - 354, 2008/00
The examination of the painting injection of the 3-GeV RCS in J-PARC has been performed. The gap of the shift bump magnet was adjusted by the insulator thin sheets that thickness was decided by the experimental results and the analysis results. The integrated magnetic field will be zero and the displacement of the beam orbit was less than 1mm, which was confirmed by the beam examination of the response characteristic. Furthermore, the balance adjustment the exciting current revel and the magnetic field level that is the horizontal paint bump magnets were confirmed. So the positive proof of the beam control for the beam painting has been obtained.
Sato, Susumu; Igarashi, Zenei*; Tomisawa, Tetsuo; Miura, Akihiko; Ueno, Akira; Sako, Hiroyuki; Morishita, Takatoshi; Kondo, Yasuhiro; Shen, G.; Akikawa, Hisashi*; et al.
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.500 - 502, 2008/00
no abstracts in English
Yuyama, Takahiro; Nara, Takayuki; Ishibori, Ikuo; Kurashima, Satoshi; Yoshida, Kenichi; Ishizaka, Tomohisa; Okumura, Susumu; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yuri, Yosuke; et al.
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.259 - 261, 2008/00
no abstracts in English
Kashiwagi, Hirotsugu; Okamura, Masahiro*; Tamura, Jun*; Kanesue, Takeshi*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.509 - 511, 2008/00
no abstracts in English
Shiraga, Takashi*; Nakamura, Norio*; Harada, Kentaro*; Shimada, Miho*; Sakanaka, Shogo*; Kobayashi, Yukinori*; Hajima, Ryoichi
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.589 - 591, 2008/00
An energy recovery linac (ERL) is expected to be the next generation synchrotron radiation source that can provide synchrotron radiation of higher brilliance, shorter pulse and higher coherence than the existing third-generation synchrotron light sources. The compact ERL is planned to be constructed in order to solve some problems in achievement of such synchrotron radiation and to confirm advantages of ERLs. We studied and optimized the compact ERL optics to achieve subpico-second bunch generation and efficient energy recovery and to transport the beam to the beam dump without serious beam loss. The design study of the compact ERL optics was done by using the simulation code Elegant. As a result, we succeeded in obtaining a 40-fs bunch with a charge of 77 pC just after the first TBA cell. Furthermore we could suppress the maximum beam size to less than 8.5 mm even after deceleration.
Sakai, Hiroshi*; Shinoe, Kenji*; Ishii, Atsushi*; Umemori, Kensei*; Sakanaka, Shogo*; Takahashi, Takeshi*; Furuya, Takaaki*; Sawamura, Masaru
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.592 - 594, 2008/00
We are developing a input coupler for the 1.3GHz 9-cell superconducting cavities to realize the ERL. Estimated input power is about 20kW for 20MV/m ERL operation. This coupler is based on the STF-BL input coupler, which adopts the TRISTAN type coaxial coupler, and some modifications are applied for the CW 20kW power operation. Now we are developing the high power coupler test stand to carry out the components test of the ceramic windows and bellows by using a 30kW IOT. In this paper, we report the design strategy of the input power coupler for ERL main linac and the recent status of the high power coupler test stand.
Yuri, Yosuke; Ishizaka, Tomohisa; Yuyama, Takahiro; Okumura, Susumu; Ishibori, Ikuo
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.397 - 399, 2008/00
no abstracts in English
Yamamoto, Yasuchika*; Hayano, Hitoshi*; Kako, Eiji*; Noguchi, Shuichi*; Sato, Masato*; Shishido, Toshio*; Umemori, Kensei*; Watanabe, Ken*; Sakai, Hiroshi*; Shinoe, Kenji*; et al.
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.888 - 891, 2008/00
In KEK, the new Superconducting RF Test Facility(STF) is being constructed, including the electro-polish system (EP), the high pressure rinsing system (HPR), the clean-room, the refrigerator system, the high power RF source system, and the vertical test system. The cavity is generally measured in the vertical cryostat for the performance test. The new vertical test facility was constructed since the last year, and completed at the beginning of March. The first test was done for the total system check at the beginning of July.
