Effects of the longitudinal impedances on non-adiabatic bunch manipulation at flattop of J-PARC MR

Tamura, Fumihiko; Omori, Chihiro*; Yoshii, Masahito*; Tomizawa, Masahito*; Toyama, Takeshi*; Sugiyama, Yasuyuki*; Hasegawa, Katsushi*; Kobayashi, Aine*; Okita, Hidefumi

Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.175 - 178, 2023/01

https://www.pasj.jp/web_publish/pasj2022/proceedings/PDF/FROA/FROA06.pdf

J-PARC MR delivers high intensity proton beams to the neutrino experiment. Eight bunches with high peak currents are extracted from the MR by the extraction kicker, therefore the neutrino beam has the similar structure. Intermediate Water Cherenkov Detector (IWCD) will be installed for the future experiments and the IWCD requires a time structure with low peaks. We consider bunch manipulation at flattop of the MR for reducing the peak current. It should be quickly done to avoid the significant loss of the beam power. The beam gap for the kicker rise time must be kept. We propose a non-adiabatic bunch manipulation using the multiharmonic rf voltage. The longitudinal impedance in the MR can affect the beam stability. The feasibility of the manipulation is discussed by using the longitudinal simulations.

Design and actual performance of J-PARC 3 GeV rapid cycling synchrotron for high-intensity operation

Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.

Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09

https://doi.org/10.1080/00223131.2022.2038301

In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.

Repeatability and reproducibility of measurements of low dissolved radiocesium concentrations in freshwater using different pre-concentration methods

Kurihara, Momo*; Yasutaka, Tetsuo*; Aono, Tatsuo*; Ashikawa, Nobuo*; Ebina, Hiroyuki*; Iijima, Takeshi*; Ishimaru, Kei*; Kanai, Ramon*; Karube, Jinichi*; Konnai, Yae*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 322(2), p.477 - 485, 2019/11

https://doi.org/10.1007/s10967-019-06696-2

We assessed the repeatability and reproducibility of methods for determining low dissolved radiocesium concentrations in freshwater in Fukushima. Twenty-one laboratories pre-concentrated three of 10 L samples by five different pre-concentration methods (prussian-blue-impregnated filter cartridges, coprecipitation with ammonium phosphomolybdate, evaporation, solid-phase extraction disks, and ion-exchange resin columns), and activity of radiocesium was measured. The z-scores for all of the Cs results were within 2, indicating that the methods were accurate. The relative standard deviations (RSDs) indicating the variability in the results from different laboratories were larger than the RSDs indicating the variability in the results from each separate laboratory.

Efficient extreme ultraviolet emission from one-dimensional spherical plasmas produced by multiple lasers

Yoshida, Kensuke*; Fujioka, Shinsuke*; Higashiguchi, Takeshi*; Ugomori, Teruyuki*; Tanaka, Nozomi*; Ohashi, Hayato*; Kawasaki, Masato*; Suzuki, Yuhei*; Suzuki, Chihiro*; Tomita, Kentaro*; et al.

Applied Physics Express, 7(8), p.086202_1 - 086202_4, 2014/08

https://doi.org/10.7567/APEX.7.086202

We demonstrate high conversion efficiency for extreme ultraviolet (EUV) emission at 6.5-6.7 nm from multiple laser beam-produced one-dimensional spherical plasmas. Multiply charged-state ions produce strong resonance emission lines, which combine to yield intense unresolved transition arrays in Gd, Tb, and Mo. The maximum in-band EUV conversion efficiency was observed to be 0.8%, which is one of the highest values ever reported due to the reduction of plasma expansion loss.

Simulation of narrow-band longitudinal noise applied to J-PARC Main Ring

Schnase, A.; Tamura, Fumihiko; Koseki, Tadashi*; Tomizawa, Masahito*; Toyama, Takeshi*; Yoshii, Masahito*; Omori, Chihiro*; Nomura, Masahiro; Yamamoto, Masanobu; Toda, Makoto*; et al.

Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.1079 - 1081, 2010/08

http://www.pasj.jp/web_publish/pasj7/proceedings/P_5PM/P_EH_5PM/THPS095.pdf

Report of ITPA (International Tokamak Physics Activity) meetings, 17

Asakura, Nobuyuki; Kato, Takako*; Nakano, Tomohide; Takamura, Shuichi*; Tanabe, Tetsuo*; Iio, Shunji*; Nakajima, Noriyoshi*; Ono, Yasushi*; Ozeki, Takahisa; Takechi, Manabu; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 82(7), p.448 - 450, 2006/07

http://ci.nii.ac.jp/naid/40007418988

no abstracts in English

Report on ITPA (International Tokamak Physics Activity) meeting, 14

Sakamoto, Yoshiteru; Toi, Kazuo*; Fukuda, Takeshi*; Fukuyama, Atsushi*; Fujita, Takaaki; Ogawa, Yuichi*; Takizuka, Tomonori; Takenaga, Hidenobu; Yagi, Masatoshi*; Yamada, Hiroshi*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 81(8), p.626 - 627, 2005/08

http://www.jspf.or.jp/Journal/PDF_JSPF/jspf2005_08/jspf2005_08-626.pdf

no abstracts in English

The Summary report on engineering design activities in the International Thermonuclear Experimental Reactor (ITER) project

Mori, Masahiro; Shoji, Teruaki; Araki, Masanori; Saito, Keiji*; Senda, Ikuo; Omori, Junji*; Sato, Shinichi*; Inoue, Takashi; Ono, Isamu*; Kataoka, Takahiro*; et al.

Nihon Genshiryoku Gakkai-Shi, 44(1), p.16 - 89, 2002/01

http://ci.nii.ac.jp/naid/10007669933

no abstracts in English

Application for PDT laser therapy based on composite-type optical fiberscope

Oka, Kiyoshi; Seki, Takeshi*; Komori, Yuki

no journal, , 

We developed a new minimally invasive laser device system using a composite-type optical fiberscope. The fiberscope consists of a centrally located 0.1 mm single fiber for laser treatment and its surrounding about 9,000 (5 m/piece) fibers for diagnosis. This system enables transmission of an image and 50 W Yb: fiber laser in parallel. By applying our fiberscope to laser treatment in various medical fields, it enables acquisition of an image, laser treatment, blood flow measurement, estimate of distance only in one fiberscope. By using this device for the PDT treatments applied to such as lung and cervical cancers, we expect to spot the irradiated area selectively while looking at a lesion. In this paper, we present a composition of minimally invasive laser therapy device using 1 mm composite-type optical fiberscope, the basics performance experiment result and an application to PDT therapy.

Magnetic structure of 1D quantum spin system CsCuMoO with - model

Yasui, Yukio*; Fujimura, Akio*; Omori, Kiyoshi*; Igawa, Naoki; Matsukawa, Takeshi*; Yoshida, Yukihiko*; Hoshikawa, Akinori*; Ishigaki, Toru*

no journal, , 

The magnetic structure of CsCuMoO has been studied by using the neutron powder diffraction. Cu spins collinearly ordinate along the axis and we found that this material has ferromagnetic structure in ribbon chains and antiferromagnetic structure between ribbon chains. Those results indicate that the magnetic structure is strongly inflected with ferromagnetic . In this presentation, the detail of magnetic structure of this material will be discussed.