Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Okumura, Susumu; Miyawaki, Nobumasa; Yuyama, Takahiro; Ishizaka, Tomohisa; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Ishibori, Ikuo; Yuri, Yosuke; Nara, Takayuki; et al.
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.374 - 376, 2011/12
Reduction of the beam changing time is required to increase the available beam time for users. We are developing a technique for reducing the changing time of the magnetic field of the cyclotron, since it takes a long changing time to form the magnetic field for acceleration. Since the deviation of the magnetic field from the desired value for acceleration in the start-up process of the magnetic field dose not decrease in a short time, a correction system of the cyclotron magnetic field with a bipolar power supply and a 5-turn coil was developed. We confirmed that this system enables the magnetic field to be controlled quickly with a pc-based PID controller.
Nomura, Masahiro; Tamura, Fumihiko; Schnase, A.; Yamamoto, Masanobu; Hasegawa, Katsushi*; Shimada, Taihei; Hara, Keigo*; Toda, Makoto*; Omori, Chihiro*; Yoshii, Masahito*
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1263 - 1266, 2011/12
J-PARC 3 GeV RCS and 50 GeV MR employ Magnetic Alloy (MA) loaded RF cavities to achieve a high accelerating voltage. RCS RF cavities employ MA un-cut cores and MR use MA cut cores. We report the impedance measurement results of the RCS RF cavities loaded MA cores without epoxy resin and effectiveness of coating of MR cutting core surface to prevent rusting. We also report the RF systems affected by the great East Japan earthquake.
Harada, Masahide; Iwahashi, Takaaki; Harjo, S.; Strasser, P.*
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.803 - 805, 2011/12
The 2011 off the Pacific coast of Tohoku Earthquake occurred on March 11 in 2011 seriously damaged all J-PARC facilities. In order to restart the beam operation, the alignment work is one of the most important issues. In order to make a plan to re-alignment of devices in MLF, fluctuations of the MLF building and standard points in MLF have been measured with level measurements and traverse measurements. As the results of the level measurements, uneven sinkage of 9 mm in the maximum was found in the MLF building. Large sinkage of about 90 mm and 140 mm was found at two attached buildings. From the measurement after 1.5 month, a sinkage of 1.7 mm in the maximum was found. As the results of the traverse measurements, no large fluctuation in the MLF building was found. However, the attached building was moved away with about 30 mm.
Kashiwagi, Hirotsugu; Miyawaki, Nobumasa; Kurashima, Satoshi; Okumura, Susumu
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.504 - 506, 2011/12
no abstracts in English
Nishimori, Nobuyuki; Nagai, Ryoji; Hajima, Ryoichi; Yamamoto, Masahiro*; Miyajima, Tsukasa*; Honda, Yosuke*; Iijima, Hokuto*; Kuriki, Masao*; Kuwahara, Makoto*; Okumi, Shoji*; et al.
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.20 - 23, 2011/08
no abstracts in English
Sawamura, Masaru; Nagai, Ryoji; Nishimori, Nobuyuki; Hajima, Ryoichi
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1332 - 1335, 2011/08
A spoke cavity has advantages over an elliptical cavity for the ERL accelerating cavity because of short distance between cavities, small frequency vibration due to microphonics and easy field flatness adjustment for strong coupling between cells. The spoke cavity which is more complicated has more parameters to be optimized than the elliptical cavity. Multi-function to be optimized requires multi-objective optimization for cavity design calculation. Multi-object optimization with generic algorithm was carried out and the result will be presented.
Tamura, Fumihiko; Schnase, A.; Yamamoto, Masanobu; Omori, Chihiro*; Yoshii, Masahito*; Nomura, Masahiro; Toda, Makoto*; Shimada, Taihei; Hara, Keigo*; Hasegawa, Katsushi*
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.76 - 80, 2011/08
The magnetic-alloy (MA) loaded cavities, which have a wide-band frequency response, are employed the J-PARC RCS. The wake voltage in the wide-band MA cavity consists of not only a component of the fundamental accelerating RF, but also the higher harmonics. We developed a multi-harmonic feedforward compensation system, which handles the most important three harmonics. Adjustments of the amplitude and phase patterns for the cancellation of the wake voltage during the acceleration period are developed. We describe the methodology in the cases without and with driving the accelerating RF. The commissioning of the systems for eleven cavities in the RCS was successful. We describe the commissioning results and the beneficial effects of the feedforward compensation in the beam operation.
Nagai, Ryoji; Hajima, Ryoichi; Nishimori, Nobuyuki
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1174 - 1176, 2011/08
ERL-based next-generation light-sources require an electron beam with an extremely small emittance to generate high brightness, coherent and ultra-short X-rays. In order to satisfy such requirement, the NEA-GaAs photo-cathode DC electron gun has been employed and the development is in progress. It is necessary to take account of so-called magnetic emittance to obtain the electron beam with an extremely small emittance. We have utilized a backing-coil to suppress leakage magnetic field by a solenoid lens on the surface of the cathode. The magnetic emittance correction has been successfully demonstrated in JAEA-250kV photo-cathode electron gun. In this paper, we present details of the magnetic emittance correction with the backing-coil.
Maruta, Tomofumi
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.317 - 319, 2011/08
Suppression of a beam loss is the key issue to operate an accelerator stably for a long term, because the beam loss makes accelerator components radioactivated and a High radioactivation becomes an obstacle for maintenance works by hand. One of the major origins of the beam loss at the J-PARC linac is the scattering process of beam particles (H
for J-PARC Linac) with residual gas inside the beam duct. For the study on the beam loss coming from the H scattering process, I developed a library that can handle H and H
by Geant4 toolkit. I will introduce some parameters, especially for cross sections of H and H, in the library and show some simulation results with the library.
Yoshii, Akinobu; Kikuzawa, Nobuhiro
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.519 - 522, 2011/08
no abstracts in English
Suzuki, Takahiro; Ito, Yuichi; Ishiyama, Tatsuya; Maruta, Tomofumi; Kato, Yuko; Kawase, Masato; Fukuta, Shimpei; Sawabe, Yuki*; Kikuzawa, Nobuhiro
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.527 - 529, 2011/08
no abstracts in English
Oguri, Hidetomo; Ikegami, Kiyoshi*; Okoshi, Kiyonori; Namekawa, Yuya; Ueno, Akira; Takagi, Akira*
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), 3 Pages, 2011/08
The availability of the ion source is directly related to the operation time of the J-PARC accelerator. To evaluate the lifetime of the present ion source, we tried to perform two months beam operation in RUN#36. As the result of the trial operation, 1270 h continuous operation was achieved at the beam current of 16 mA. In RUN#37, the ion source was operated at 25 mA for 217 h at first, then the beam current was decreased to 16 mA. After 1029 h operation, the filament of the ion source was cut off and the beam run was interrupted. By considering the consumption rate of the filament is depended on the beam current, these operation results show the lifetime of the ion source is approximately 1200 h. For another attempt to improve the ion source availability, we tried to decrease the required time for maintenance. By unitizing the replacement parts and keeping them under the vacuum condition until just before the installing, the maintenance time can be decreased from four to two days.
Kawamura, Masato*; Chishiro, Etsuji; Shinozaki, Shinichi; Fang, Z.*; Fukui, Yuji*; Naito, Fujio*; Yamazaki, Masayoshi*; Tsubota, Naoaki; Futatsukawa, Kenta; Sato, Fumiaki; et al.
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), 3 Pages, 2011/08
We will report about status of linac 400 MeV upgrade program and northeast Japan earthquake restoration. On March 11, the linac suffered serious damage as consequence of the earthquake, and was shuttled down for long term. Linac RF group restores the facilities and is accomplishing 400 MeV upgrade at the same time.
Yamamoto, Kazami; Yamazaki, Yoshio; Yoshimoto, Masahiro; Kamiya, Junichiro; Harada, Hiroyuki; Saha, P. K.; Hotchi, Hideaki; Kinsho, Michikazu; Kato, Shinichi*
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.312 - 316, 2011/08
In the J-PARC RCS, the significant losses were observed at the branch of H0 dump line and the Beam Position Monitor which was put at the downstream of the H0 dump branch duct. From the beam study, we were certain that these losses were caused by the scattering of the injection and circulating beam at the charge exchange injection foil. In order to mitigate these losses, we started to develop a new collimation system in the H0 branch duct. We present latest study results and overview of this new collimation system.
Kato, Shinichi*; Yamamoto, Kazami; Yamazaki, Yoshio; Yoshimoto, Masahiro; Kamiya, Junichiro; Harada, Hiroyuki; Kinsho, Michikazu
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.296 - 300, 2011/08
In the J-PARC RCS, the significant losses were observed at the branch of H0 dump line and the Beam Position Monitor which was put at the downstream of the H0 dump branch duct. These losses were caused by the large angle scattering of the injection and circulating beam at the charge exchange foil. To realize high power operation, we have to mitigate these losses. So, we started to develop a new collimation system in the H0 branch duct. In order to optimize this system efficiently, we primarily focused on the relative angle of collimator block from scattering particles. We simulated behavior of particles scattered by foil and produced by collimator block and researched most optimized position and angle of the collimator block. These simulation were performed by SAD and GEANT4. We present simulation results and anticipated performance of this new collimation system.
Yamada, Keisuke; Nara, Takayuki; Ishibori, Ikuo; Kurashima, Satoshi; Yoshida, Kenichi; Yuyama, Takahiro; Ishizaka, Tomohisa; Agematsu, Takashi; Uno, Sadanori; Chiba, Atsuya; et al.
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), 3 Pages, 2011/08
no abstracts in English
Schnase, A.; Sato, Kenichiro*; Tomizawa, Masahito*; Toyama, Takeshi*; Uota, Masahiko*; Yoshii, Masahito*
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.338 - 342, 2011/08
J-PARC Center, Accelerator Division
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), 5 Pages, 2011/08
The operation status and progress of the J-PARC accelerators are reported. The accelerators have delivered beam to the user facilities at about 95 % availability in JFY 2010. The beam power to the MLF users has been upgraded from 100 to 200 kW since November. The efficiency of the slow extracted beam from the MR has been recorded to 99.5 % and 3 to 3.6 kW beam was delivered to the Hadron experimental facility. The beam power to the neutrino experiments has been steadily increasing up to 145 kW. The great earthquake in March 11, however, suspended all the J-PARC activities and intensive restoration work is underway.
Sakaki, Hironao; Kanasaki, Masato; Hori, Toshihiko*; Fukuda, Yuji; Yogo, Akifumi; Nishiuchi, Mamiko; Katagiri, Masaki*; Niita, Koji*
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.667 - 669, 2011/08
In JAEA, we develop the small size high energy particle source that based on the laser-driven ion accelerator. Laser-driven acceleration systems have generated beams with energies up to tens-MeV ions1) from laser-plasma interaction. These ions are combined with X-ray and high energy electrons. The diagnostic most using for these ion beams is the Thomson parabola with CR-39 detector that has a characteristic of an effective way for ions detection under these conditions. However, CR-39 is necessary the etching process, and cannot obtain Thomson parabola's data online. So we challenge the development of an online Thomson parabola spectrometor with CCD camera and fluorescence film.
Hayashi, Naoki
Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.434 - 436, 2011/08
Under linear lattice assumption, average position resolution of BPM (Beam Position Monitor) could be estimated by using 3-BPM method. However, this determined resolution is average value of these BPM, it is no individual characteristics. It would not be a problem, if these three BPMs have the same characteristics. In this paper, the 3-BPM method is extended to determine the individual resolution and this new method is applied for the J-PARC RCS BPM systems.
