An Interrogation method for radioactive waste by using an ERL-based high-flux -ray source

Kikuzawa, Nobuhiro; Hajima, Ryoichi; Hayakawa, Takehito; Minehara, Eisuke

Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.577 - 579, 2007/00

Laser-Compton-backscattered photons from an energy-recovery linac (ERL) and a high power laser realize a high-efficiency, high-flux and tunable monochromatic -ray source. A non-destructive interrogation method by using nuclear resonance fluorescence (NRF) make possible to measure the discrimination of clearance levels of a concrete solidification radioactive waste. The purpose of our work is to design and evaluation of the NRF-based detection system. For this evaluation, we are developing a GEANT4-based Monte Carlo simulation code. Some simulations have been performed with simple models of a concrete solidification radioactive waste cask and detectors. We present a recent result of the simulation.

Emittance compensation solenoid of a DC photo-cathode electron gun

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.

Estimation of HOM-BBU threshold current for an energy recovery linac

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.

Injection and dump line monitor system of J-PARC RCS

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.

Beam commissioning of the L3BT for J-PARC

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.

Performance of J-PARC LINAC RF system

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.

Development of a unit conversion channel access server for J-PARC LINAC

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.

Tuning of RF amplitude and phase of J-PARC DTL and SDTL

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.

Status of J-PARC ring RF systems

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

Experimental plan for observation of laser intensity dependent Doppler red shift in Thomson scattering

Nishimori, Nobuyuki; Hajima, Ryoichi; Kando, Masaki; Bulanov, S. V.

Proceedings of 4th Annual Meeting of Particle Accelerator Society of Japan and 32nd Linear Accelerator Meeting in Japan (CD-ROM), p.580 - 582, 2007/00

Thomson scattering wavelength between a single photon at wavelength and an electron with velocity c is given by in head-on collision configuration. As the incident laser intensity increases, the scattering wavelength is Doppler red shifted and given by . Here a=eA/mc is the dimensionless laser vector potential. The Doppler red shift is very similar to that in an undulator radiation whose wavelength becomes longer as the undulator gap narrows. The intensity dependent Doppler red shift in Thomson scattering has not been experimentally demonstrated yet to our knowledge. This is in contrast to the undulator radiation whose wavelength can easily be tuned for user experiments. In this paper, an experimental plan for observation of laser intensity dependent Doppler red shift in Thomson scattering is presented.