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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
Hajima, Ryoichi; Nagai, Ryoji; Iijima, Hokuto; Nishimori, Nobuyuki; Honda, Yosuke*; Muto, Toshiya*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.607 - 609, 2008/00
We review R&D status of the high-brightness electron gun for future ERL light sources.
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.
Morishita, Takatoshi
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.81 - 83, 2008/00
The beam commissioning of J-PARC linac has been started since November 2006. After the scheduled shutdown in summer 2007, the beam is successfully delivered from the linac to the RCS. Since then, nine beam commissioning runs are conducted, in which a stable beam provision to RCS is focused. During these commissioning, the stability of the ion source, RF system, and cavities are improved steadily. Commissioning schedule of the J-PARC linac is summarized in this proceeding together with the operating experiences, and the demonstrations for higher power operations and the residual radiation level of the accelerator are discussed.
Sakanaka, Shogo*; Kobayashi, Yukinori*; Sato, Kotaro*; Kasuga, Toshio*; Kawata, Hiroshi*; Hajima, Ryoichi; Nakamura, Norio*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.225 - 227, 2008/00
Collaborative research efforts towards future ERL-based light sources are carried out. We present the R&D status of an electron gun and superconducting cavities, updated design study on the test facility (Compact ERL).
Hirano, Koichiro; Ao, Hiroyuki; Morishita, Takatoshi; Asano, Hiroyuki; Hori, Toshihiko; Yamazaki, Masayoshi; Kobayashi, Tetsuya; Kubota, Chikashi*; Yamazaki, Yoshishige
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.497 - 499, 2008/00
An ACS (Annular Coupled Structure) module has been developing for the 190-MeV to 400-MeV part of the J-PARC Linac. We have conducted the high power test of the first ACS module which consists of two accelerating tanks with 17 cells and a bridge tank with 9 cells. This paper describes results of the high power RF tests. The module achieved an average axial accelerating gradient of E0 = 4.5 MV/m at 1.8 MW RF input power, 0.6 ms pulse width, and 50 Hz repetition rate.
Sawamura, Masaru; Umemori, Kensei*; Furuya, Takaaki*; Sakanaka, Shogo*; Takahashi, Takeshi*; Sakai, Hiroshi*; Shinoe, Kenji*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.610 - 612, 2008/00
Damping higher-order-modes is important for superconducting main accelerators to suppress beam breakup and to increase the beam current. Our strategy for HOM damping is (1) large beam pipe, (2) optimization of cell shapes and (3) eccentric fluted beam pipe. Two single-cell cavities and one 9-cell cavity of niobium were made to check the performance of the new design cavity. The two single-cell cavities showed the good results of vertical test of 2 K. The vertical test of 9-cell cavity will be done soon.
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
Iijima, Hokuto; Nagai, Ryoji; Nishimori, Nobuyuki; Hajima, Ryoichi
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.604 - 606, 2008/00
We report an experimental result of measuring a mid-infrared FEL optical pulse by means of frequency-resolved optical gating (FROG) and a comparison with a numerical simulation result. The measurement was performed at JAEA ERL-FEL with the perfect synchronism condition. The FEL optical pulse was measured to be 0.6 ps of the pulse duration and 4.6 THz of the bandwidth. The simulation results were 0.5 ps and 4.4 THz, respectively. The measurement result was good agreement with the simulation result within a measurement error. The chirp in frequency domain followed a cubic function. This behavior is the so-called "self-chirp", which is not caused by a dispersive material but relation of electron-bunch parameters and FEL-undulator parameters.
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
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
Sugimoto, Hiroshi*; Okamoto, Hiromi*; Wei, J.*; Yuri, Yosuke; Sessler, A. M.*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.436 - 438, 2008/00
no abstracts in English
Yamazaki, Masayoshi; Chishiro, Etsuji; Kobayashi, Tetsuya; Hori, Toshihiko; Suzuki, Hiroyuki; Anami, Shozo*; Kawamura, Masato*; Fukui, Yuji*; Nammo, Kesao*; Fang, Z.*; et al.
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.485 - 487, 2008/00
no abstracts in English
