Koichiro Hirano

Present Status of the Laser Charge Exchange Test Using the 3-MeV Linac in J-PARC

The Accelerator-driven System (ADS) is one of the candidates for transmuting long-lived nuclides, such as minor actinide (MA), produced by nuclear reactors. For efficient transmutation of the MA, a precise prediction of neutronics of ADS is required. In order to obtain the neutronics data for the ADS, the Japan Proton Accelerator Research Complex (J-PARC) has a plan to build the Transmutation Physics Experimental Facility (TEF-P), in which a 400-MeV negative proton (H) beam will be delivered from the J-PARC linac. Since the TEF-P requires a stable proton beam with a power of less than 10 W, a stable and meticulous beam extraction method is required to extract a small amount of the proton beam from the high power beam using 250 kW. To fulfil this requirement, the Laser Charge Exchange (LCE) method has been developed. The LCE strips the electron of the H beam and neutral protons will separate at the bending magnet in the proton beam transport. To demonstrate the charge exchange of the H, a preliminary LCE experiment was conducted using a linac with energy of 3 MeV in JPARC. As a result of the experiment, a charge-exchanged H beam with a power of about 5 W equivalent was obtained under the J-PARC linac beam condition, and this value almost satisfied the power requirement of the proton beam for the TEF-P.

Upgrade and Operation of J-PARC Linac

Kazuo HASEGAWA*, Hidetomo OGURI, Takashi ITO, Etsuji CHISHIRO, Koichiro HIRANO, Takatoshi MORISHITA, Shinichi SHINOZAKI, Hiroyuki AO, Kiyonori OHKOSHI, Yasuhiro KONDO, Jun TAMURA, Saishun YAMAZAKI, Toshihiko HORI, Fumiaki SATO, Yasuo NEMOTO, Isao KOIZUMI, Nobuo OUCHI, Nobuhiro KIKUZAWA, Akira UENO, Akihiko MIURA, Shinpei FUKUTA, Akinobu YOSHII, Koichi SATO, Akira OZONE, Yuki SAWABE, Yusuke KAWANE, Hiroshi IKEDA, Yuichi ITO, Yuko KATO, Kazuo KIKUCHI, Fumio HIROKI, Toshio TAKAYASU, Tsutomu USAMI, Munetoshi YANAI, Kazuhiko TADOKORO, Kenji OHSAWA, Fujio NAITO, Yong LIU, Zhigao FANG, Takashi SUGIMURA, Kenta FUTATSUKAWA, Kiyoshi IKEGAMI, Masato KAWAMURA, Kesao NANMO, Yuji FUKUI, Tomoaki MIYAO, Tomofumi MARUTA and Akira TAKAGI

Generation and acceleration of high brightness electron bunch train at ATF of KEK

Laser Undulator Compact X-ray source (LUCX) is a test bench for compact high brightness X-ray generator at KEK in order to demonstrate the possibility on K-edge digital subtraction angiography, based on the Compton Scattering. For this project, one of the challenging problems is to generate and accelerate high brightness multi-bunch electron beams, compensating the energy difference due to beam loading effect. In this paper, we calculate the transient beam loading voltage and energy gain from RF field in standing wave gun cavity and traveling wave accelerating tube for multi-bunch train, considering the process of propagation, buildup of RF field in them and the special RF pulse shape. We generated and accelerated 100 bunch electron beam train with 50 nC, which beam loading effect was compensated effectively by adjusting the laser injection timing. By BPM and OTR system, we measured the electron beam energy bunch by bunch. The average energy of 100 bunch train is 40.5 MeV and maximum energy difference bunch to bunch is 0.26 MeV, the relative energy spread of single bunch is about 0.13%. The transverse emittance can be optimized roughly to 3.6 pimm.mrad.