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Chishiro, Etsuji; Kobayashi, Tetsuya; Suzuki, Hiroyuki; Yamazaki, Masayoshi; Hori, Toshihiko; Fang, Z.*; Fukui, Yuji*; Kawamura, Masato*; Yamaguchi, Seiya*; Anami, Shozo*
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.519 - 521, 2007/00
High power RF sources have been installed in J-PARC linac building. The RF source is defined as the microwave application equipment by the Radio low, and is needed the charge minister's permission to offer the service. To pass the regulation, we sought the leakage point using a search coil and a bilog antenna, and stopped up the leak by contacting the metal connection completely. The result of measuring the microwave at the J-PARC site boundary, we confirmed the field strength which is less than permissible level.
Yuri, Yosuke; Okumura, Susumu; Yuyama, Takahiro; Agematsu, Takashi; Miyawaki, Nobumasa; Ishibori, Ikuo; Ishizaka, Tomohisa
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.607 - 609, 2007/00
The development of the uniform-beam irradiation system using multipole magnets is now in progress at the TIARA AVF cyclotron facility. It is necessary that the transverse intensity distribution of the beam should be initially Gaussian to form a uniform beam. However, the beam extracted from the cyclotron is not always Gaussian but asymmetric. We have, therefore, carried out experiments on the modification of the initial beam profile using a scatterer. The beam was multiply scattered by a thin foil installed at a location of the beam transfer line. The transverse profile was measured by profile monitors, installed in separate positions It is found that the transverse profile is approached toward Gaussian distribution, dependent on the betatron phase advance from the scatterer to the profile monitor.
Schnase, A.; Nomura, Masahiro; Tamura, Fumihiko; Yamamoto, Masanobu; Haga, Koichi; Hasegawa, Katsushi; Yoshii, Masahito*; Omori, Chihiro*; Hara, Keigo*; Toda, Makoto*; et al.
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.212 - 214, 2007/00
Miyawaki, Nobumasa; Okumura, Susumu; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Yuri, Yosuke; Yuyama, Takahiro; Ishibori, Ikuo; Agematsu, Takashi; Ishizaka, Tomohisa; et al.
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.604 - 606, 2007/00
The main probe of the JAEA AVF cyclotron has been modified to measure a beam phase width in the accelerating region without extracting the beam from the cyclotron, which could cause the beam loss at the extraction device. The main probe consists of a carbon block for a beam current measurement and a plastic scintillator for a beam phase measurement. A correlation between the beam phase width and the position of phase slits was confirmed.
Nagai, Ryoji; Hajima, Ryoichi; Nishimori, Nobuyuki; Iijima, Hokuto; Sawamura, Masaru; Kikuzawa, Nobuhiro; Minehara, Eisuke
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.673 - 675, 2007/00
An emittance compensation solenoid magnet is designed for a DC photo-cathode electron gun. The DC gun is now in fabrication at JAEA for an energy-recovery linac (ERL) light-source. The ERL light-source requires very low emittance electron beam to generate coherent X-rays. In order to produce the very low emittance electron beam from the DC gun, a focusing lens is indispensable to compensate the linear emittance growth. A solenoid magnet is employed for the emittance compensation lens. The solenoid magnet consists of a main coil, pure iron yoke, and a backing coil. The compensated emittance is estimated less than 0.6 mm-mrad in the bunch charge of 77 pC by PARMELA simulation.
Nagai, Ryoji; Hajima, Ryoichi; Iijima, Hokuto; Nishimori, Nobuyuki; Sawamura, Masaru; Kikuzawa, Nobuhiro; Minehara, Eisuke
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.676 - 678, 2007/00
A DC electron gun is employed for an electron source of an energy-recovery linac (ERL). The electron beam parameters are fluctuated due to the instability of a high-voltage power supply of the gun. The fluctuations of the electron beam parameters are estimated for the ERL light-source. In the result of the estimation, the bunch length of the electron beam is mainly fluctuated by the instability of the high-voltage power supply. For the bunch length fluctuation of 1% or less, the required high-voltage stability is less than 1
10
. The main part of the instability of the high-voltage is the ripple of the Cockcroft-Walton circuit. The compensation of the ripple utilizing an LC filter is proposed, and the required stability is easily achieved in the preliminary design of the power supply.
Nagai, Ryoji; Hajima, Ryoichi; Sawamura, Masaru; Nishimori, Nobuyuki; Iijima, Hokuto; Kikuzawa, Nobuhiro; Minehara, Eisuke
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.637 - 639, 2007/00
A collaborative project towards an ERL light source has been launched in Japan. In this project, the superconducting cavity is optimized for a high-average current beam. The latest design is a 9-cell cavity of 1.3 GHz with enlarged beam pipes and on-axis HOM absorbers. In this paper, beam breakup instabilities for the newly designed cavity is investigated. Threshold current of beam breakup at a 5-GeV ERL and possible extention to multi-turn configuration is presented.
Nagai, Ryoji; Hajima, Ryoichi; Sawamura, Masaru; Nishimori, Nobuyuki; Kikuzawa, Nobuhiro; Iijima, Hokuto; Minehara, Eisuke
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.16 - 18, 2007/00
We are proposing energy-recovery linac (ERL) based photon sources, which are a next generation X-ray light-source, a 
-ray source for a radioactive waste management, and an EUV-FEL for a next generation lithography. Related R&D is in progress. In this paper, we summarize these proposed ERL photon sources and research activities.
Sato, Kenichiro; Hiroki, Seiji; Lee, S.*; Hayashi, Naoki; Yamamoto, Kazami; Hiramatsu, Shigenori*; Toyama, Takeshi*; Arakawa, Dai*; Igarashi, Zenei*; Saeki, Riuji
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.297 - 299, 2007/00
At the injection and H0 dump line of J-PARC RCS, different beam monitors have been installed. Main purpose of the beam monitors in the injection line is to generate a beam position and profile to adjust the injection trajectory to the RCS ring. To guide the injected beam precisely is, needless to say, required to reduce the beam loss in the ring. Hence the monitor system is one of the most essential to operate the RCS. At the injection point, there are also some beams that are not match the RCS ring, that is negative and neutral proton beam. H0 dump accepts the unsuitable beams through the H0 dump line. The power limitation of the H0 dump is 4 kW. The monitor system in the dump line is to handle the beam and to monitor the dumped beam power. At the conference these monitor systems will be outlined.
Yamazaki, Masayoshi; Chishiro, Etsuji; Kobayashi, Tetsuya; Hori, Toshihiko; Suzuki, Hiroyuki; Anami, Shozo*; Kawamura, Masato*; Fukui, Yuji*; Nammo, Kesao*; Fang, Z.*; et al.
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.516 - 518, 2007/00
no abstracts in English
Okawa, Tomohiro; Ikegami, Masanori*
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.766 - 768, 2007/00
L3BT is a beam transport line from J-PARC (Japan Proton Accelerator Research Complex) linac to the succeeding 3-GeV RCS (Rapid Cycling Synchrotron). The beam commissioning of the L3BT has been started since December 2006. In this paper, we present the results of the beam commissioning of the L3BT to date.
Matsuda, Makoto; Nakanoya, Takamitsu; Kutsukake, Kenichi; Hanashima, Susumu; Takeuchi, Suehiro
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.736 - 738, 2007/00
no abstracts in English
Kobayashi, Tetsuya; Chishiro, Etsuji; Hori, Toshihiko; Suzuki, Hiroyuki; Yamazaki, Masayoshi; Anami, Shozo*; Fang, Z.*; Fukui, Yuji*; Kawamura, Masato*; Michizono, Shinichiro*; et al.
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.510 - 512, 2007/00
High power operation of all the RF systems of J-PARC linac was started for the cavity conditioning in October 2006. Twenty 324-MHz klystrons have supplied the power to the accelerating cavities successfully. The beam commissioning was started in November 2006 then the acceleration to the design energy of 181 MeV was succeeded. The injection to the 3-GeV synchrotron will be started in September 2007. The RF control systems are performing according to the expectation, and the required field stability is satisfied.
Fang, Z.*; Anami, Shozo*; Michizono, Shinichiro*; Yamaguchi, Seiya*; Kobayashi, Tetsuya; Suzuki, Hiroyuki
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.507 - 509, 2007/00
The J-PARC 181-MeV proton linear accelerator (LINAC) was commissioned in October 2006. The RF sources of the LINAC consist of 4 solid-state amplifiers and 20 klystrons. In each RF source, the RF fields are controlled by a digital RF feedback (FB) system installed in a compact PCI (cPCI) in order to realize an accelerating field stability of 
1% in amplitude and 1 degree in phase. In this paper, the performance of the RF feedback control systems will be reported in detail.
Sako, Hiroyuki
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.402 - 403, 2007/00
A unit conversion server has been developed for magnet power supplies at J-PARC LINAC. The server is a separated system from the control system. The server application is written as a Portable Channel Access Server in C++. The conversion function is defined as a 3rd order polynomial functions with 3 ranges in the current so that it can fit well with magnet field measurements and calculations reasonably while the inverse conversion can be solved analytically. The parameters for the polynomial functions and boundary current values, lower and upper limits, and fudge factors are defined as a configuration file which is maintained and automatically generated from a database. The server is applied to about 200 power supplies of quadrupole, steering dipole magnets, and bending magnets of LINAC. During beam commissioning since November 2006, it has been working stably.
Sako, Hiroyuki; Shen, G.; Ueno, Akira; Okawa, Tomohiro; Akikawa, Hisashi*; Ikegami, Masanori*
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.598 - 600, 2007/00
Transverse matching has been performed at J-PARC LINAC for matching sections at DTL-SDTL, S01A-S03B, MEBT2-ACS, and L3BT. Each matching section consists of 4 wire scanners and upstream 4 quadrupole magnets. From r.m.s. of beam profiles measured at 4 wire scanners, transverse Twiss parameters and emittance are fitted with Newton method based on an online model. Field of quadrupole magnets with matching conditions is calculated based on the model. At beam current of 5 mA and 25 mA, matching factors of within 4% were achieved.
Shen, G.; Sako, Hiroyuki; Sato, Susumu; Ikegami, Masanori*
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.522 - 524, 2007/00
An accurate tuning has been performed for the RF amplitude and phase of J-PARC (Japan Proton Accelerator Research Complex) LINAC during the beam commissioning. The tuning has been performed using a phase-scan method for all RF cavities, including buncher, debuncher, DTL (Drift Tube LINAC), and SDTL (Separate-type DTL). An adequate set-point is determined with satisfied accuracy, which is within 1
; for phase and 1% for amplitude, by matching measured absolute beam energy with those from a modeling. This paper presents detail procedures of RF tuning.
Shen, G.
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.525 - 527, 2007/00
The RF power source of J-PARC LINAC is required to maintain a correct accelerating field within 1% for amplitude and 1 for phase. To monitor the RF waveform stability, a commercial oscilloscope is used for each RF modules. An EPICS IOC is developed to control the oscilloscope, which is embedded inside the oscilloscope. This paper describes the detail realization and the current status of monitor system of RF waveform stability.
Shen, G.; Sako, Hiroyuki; Sato, Susumu
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.595 - 597, 2007/00
During the beam commissioning of J-PARC LINAC, a conventional beam-based alignment method is performed to find a relative alignment offset of a quadrupole magnet to a nearby beam-position monitor. This method involves varying quadrupole magnet field and upstream steering magnet strength. The responses of downstream BPMs are measured, and the offset of magnetic center is measured by analyzing the deviation of beam orbit. The measurement has been performed for all singlet quadrupole magnets. Accuracy within a few 10 micrometers has been achieved. This paper describes a detail procedure and the measurement results.
Hori, Toshihiko; Yamazaki, Masayoshi; Chishiro, Etsuji; Suzuki, Hiroyuki; Ao, Hiroyuki; Hirano, Koichiro; Hasegawa, Kazuo
Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.425 - 427, 2007/00
The temperature rise of 972 MHz Klystron RF Window was measured using an infrared thermometer with a pulse width of 600 us, and a repetition rate of 50 pps, and a peak power of 2.6 MW. In this data, the estimated temperature rise at the full RF Power (3 MW) would be about 70 degree, which is lager than design value of 30 degree.