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Nagai, Ryoji; Hajima, Ryoichi; Mori, Michiaki; Shizuma, Toshiyuki; Akagi, Tomoya*; Araki, Sakae*; Honda, Yosuke*; Kosuge, Atsushi*; Terunuma, Nobuhiro*; Urakawa, Junji*
Proceedings of 6th International Particle Accelerator Conference (IPAC '15) (Internet), p.1607 - 1609, 2015/06
Accelerator and laser technologies required for laser Compton scattering (LCS) photon source based on an energy-recovery linac (ERL) have been developed at the Compact ERL (cERL) facility. A high-flux, energy tunable, and monochromatic photon source such as the ERL-based LCS photon source is necessary for nondestructive assay of nuclear materials. For the demonstration of the ERL-based LCS photon generation, a laser enhancement cavity was installed at the recirculation loop of the cERL. The electron beam energy, the laser wavelength, and the collision angle are 20 MeV, 1064 nm, and 18 deg., respectively. The calculated maximum energy of the LCS photons is about 7 keV. A silicon drift detector (SDD) with active area of 17 mm
placed 16.6 m from the collision point was used for observation of the LCS photons. As a result of the measurement, the flux on the detector, central energy, and energy width of the LCS photons were obtained as 1200 /s, 6.91 keV, and 81 eV, respectively.
Nagai, Ryoji; Hajima, Ryoichi; Mori, Michiaki; Shizuma, Toshiyuki; Akagi, Tomoya*; Kosuge, Atsushi*; Honda, Yosuke*; Urakawa, Junji*
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1328 - 1331, 2014/10
A high intensity 
-ray source from the laser Compton scattering (LCS) by an electron beam in an energy-recovery linac (ERL) is a key technology for a nondestructive assay system to identify nuclear materials. In order to demonstrate accelerator and laser technologies required for a LCS photon generation, a LCS photon source is under construction at the Compact ERL (cERL). The LCS photon source consists of a mode-locked fiber laser and a laser enhancement cavity. A beamline and an experimental hatch are also under construction. The commissioning of the LCS photon source will be started in February 2015 and LCS photon generation is scheduled in March 2015.
Nagai, Ryoji; Hajima, Ryoichi; Mori, Michiaki; Shizuma, Toshiyuki; Akagi, Tomoya*; Kosuge, Atsushi*; Honda, Yosuke*; Urakawa, Junji*
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.839 - 842, 2014/10
In order to demonstrate accelerator and laser technologies required for a laser Compton scattering (LCS) photon generation, a LCS photon source is under construction at the Compact ERL (cERL). We considered the flux monitors for the adjustment LCS photon source. A thin scintillator detector and a silicon drift detector are employed as flux monitors and are installed at the upstream part of the LCS beamline. The background signal level due to the bremsstrahlung of the electron beam was measured by a CsI(pure) scintillator. In the result of the measurement, the background signal is acceptable level for the flux monitors.
Nagai, Ryoji; Sawamura, Masaru; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki; Nishitani, Tomohiro; Minehara, Eisuke
Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.376 - 378, 2005/07
no abstracts in English
Hajima, Ryoichi; Suwada, Tsuyoshi*
Hoshako, 18(3), p.200 - 201, 2005/05
no abstracts in English
Sawamura, Masaru; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Minehara, Eisuke; Nagai, Ryoji; Nishimori, Nobuyuki
Proceedings of 9th European Particle Accelerator Conference (EPAC 2004) (CD-ROM), p.1723 - 1725, 2004/07
After the success of energy recovery linac (ERL) for the superconducting free-electron laser (FEL) in the Japan Atomic Energy Research Institute (JAERI), the JAERI ERL-FEL has been upgrading for high-power and long-pulse operation. The new RF sources of CW mode for higher power for non-energy-recovery parts have been installed and tested for long-pulse operation. The properties of the superconducting linac required for the long-pulse operation were measured such as pressure in the cryomodule, vibration of frequency and piezo tuner response. The RF control systems have been also upgraded to reduce the fluctuation to less than 0.1% for amplitude and 0.1 deg for phase.
Hajima, Ryoichi; Sawamura, Masaru; Nagai, Ryoji; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki; Minehara, Eisuke
Dai-14-Kai Kasokuki Kagaku Kenkyu Happyokai Hokokushu, p.696 - 698, 2003/11
An energy-recovery linac (ERL) for a high-power free-electron laser (FEL) is under development in JAERI. We completed the construction of the ERL, and demonstrated the first energy-recover operation and FEL lasing in 2002. For realizing FEL lasing in 5-10kW average power, further upgrade of the ERL is carrying on, which includes reinforcement of the injector, replacement of the RF control system and so on. As future plans, we present possible quantum control of chemical reaction dynamics through a self-chirped FEL pulse, application of ERL technologies to high-flux photon sources in a wide range of photon energy from THz radiation to -ray.
Hajima, Ryoichi
Dai-14-Kai Kasokuki Kagaku Kenkyu Happyokai Hokokushu, p.401 - 403, 2003/11
We propose a novel approach to the analysis of the coherent synchrotron radiation (CSR) effect on beam dynamics in energy-recovery linacs (ERL). Since an ERL return-arc consists of a large number of dipole and quadrupole magnets, it is not a practical way to search an optimum design by time-consuming particle simulations. We show that a first-order transfer matrix can be applied to calculate the emittance growth due to the CSR in the linear regime, weak CSR limit. The optimum design of ERL arcs such as triple-bend achromat lattice is easily obtained by matrix calculation. As an example, optimization of a 3GeV ERL arc is presented.
Hajima, Ryoichi; Sawamura, Masaru; Nagai, Ryoji; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki; Minehara, Eisuke
Proceedings of 28th Linear Accelerator Meeting in Japan, p.390 - 392, 2003/08
no abstracts in English
Hajima, Ryoichi; Shizuma, Toshiyuki; Sawamura, Masaru; Nagai, Ryoji; Nishimori, Nobuyuki; Kikuzawa, Nobuhiro; Minehara, Eisuke
Nuclear Instruments and Methods in Physics Research A, 507(1-2), p.115 - 119, 2003/07
Times Cited Count：24 Percentile：81.86(Instruments & Instrumentation)An energy-recovery linac (ERL) for a high-power FEL has been designed and constructed at JAERI (Japan Atomic Energy Research Institute). The construction of the ERL was completed and the first energy-recovery operation was demonstrated at February, 2002. The parameters of the ERL are : injection energy of 2.5MeV, recirculating energy of 17MeV, average current of 5mA, bunch repetition of 10MHz, RF frequency of 500MHz, and so on. The injector will be reinforced to generate 40mA beam current for 10kW FEL. We present the design overview and the performance of the JAERI-ERL. Future plans towards 10kW FEL are also presented.
Sawamura, Masaru; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Minehara, Eisuke; Nagai, Ryoji; Nishimori, Nobuyuki
Proceedings of 2003 Particle Accelerator Conference (PAC 2003) (CD-ROM), p.3446 - 3448, 2003/00
no abstracts in English
Sawamura, Masaru; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Minehara, Eisuke; Nagai, Ryoji; Nishimori, Nobuyuki
Proceedings of 2003 Particle Accelerator Conference (PAC 2003) (CD-ROM), p.3449 - 3451, 2003/00
no abstracts in English
Nagai, Ryoji; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Minehara, Eisuke; Nishimori, Nobuyuki; Sawamura, Masaru
Proceedings of 2003 Particle Accelerator Conference (PAC 2003) (CD-ROM), p.3443 - 3445, 2003/00
no abstracts in English
Ikeda, Yoshitaka; Kasugai, Atsushi; Moriyama, Shinichi; Kajiwara, Ken*; Seki, Masami; Tsuneoka, Masaki*; Takahashi, Koji; Anno, Katsuto; Hamamatsu, Kiyotaka; Hiranai, Shinichi; et al.
Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.435 - 451, 2002/09
Times Cited Count：26 Percentile：82.31(Nuclear Science & Technology)no abstracts in English
Hajima, Ryoichi; Minehara, Eisuke
Proceedings of 27th Linear Accelerator Meeting in Japan, p.169 - 171, 2002/08
We propose a full-DC injector for a future ERL light source. The injector consists of a DC accelerator (Dynamitron type), a magnetic merger and a buncher-booster. We have found that the injector can generate electron bunches required for ERL light sources and RF coupler power of the buncher booster is also decreased by partial energy-recovery.
Hajima, Ryoichi; Sawamura, Masaru; Nagai, Ryoji; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki; Shizuma, Toshiyuki; Minehara, Eisuke
Proceedings of 27th Linear Accelerator Meeting in Japan, p.97 - 99, 2002/08
An energy-recovery linac (ERL) has been developed at the JAERI superconducting FEL. Whole the ERL system has been completed and the beam comitioning and FEL experiments are ongoing, now. We report recent results of our study on the ERL, and future R&D plans towards a 10kW FE based on the ERL technologies.
Sawamura, Masaru; Hajima, Ryoichi; Iwashita, Yoshihisa*; Nagai, Ryoji; Nishimori, Nobuyuki; Kikuzawa, Nobuhiro; Minehara, Eisuke
Proceedings of 27th Linear Accelerator Meeting in Japan, p.275 - 277, 2002/08
no abstracts in English
Shizuma, Toshiyuki; Hajima, Ryoichi; Minehara, Eisuke
Nuclear Instruments and Methods in Physics Research A, 475(1-3), p.569 - 573, 2001/12
Times Cited Count：1 Percentile：12.96(Instruments & Instrumentation)no abstracts in English
Hajima, Ryoichi
Hoshako, 14(5), p.323 - 330, 2001/11
no abstracts in English
Hajima, Ryoichi; Shizuma, Toshiyuki; Sawamura, Masaru; Nagai, Ryoji; Nishimori, Nobuyuki; Kikuzawa, Nobuhiro; Minehara, Eisuke
Proceedings of 26th Linear Accelerator Meeting in Japan, p.61 - 63, 2001/08
The superconducting linac at JAERI-FEL is under modification into an energy-recovery configuration for further increasing FEL power. The linac was almost completely disassembled and rearranged in accordance with the newly designed beam transport line. We present the design concept of the energy-recovery system briefly. We also report the status of the construction of the energy-recovery linac and the results of initial beam test.
