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Your search keyword '"Tokiyasu, Atsushi"' showing total 7 results
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7 results on '"Tokiyasu, Atsushi"'

1. Performance evaluation of electron multiplier tubes as a high-intensity muon beam monitor of accelerator neutrino experiments

Author

Honjo, Takashi, Ashida, Yosuke, Auersperg-Castell, Oderich F., Friend, Megan, Heitkamp, Ian, Ichikawa, Atsuko K., Ishitsuka, Masaki, Izumi, Nao, Kasama, Sohei, Kashiwagi, Shigeru, Kawamura, Yuma, Kikawa, Tatsuya, Kobata, Takuya, Matsubara, Tsunayuki, Miyabe, Manabu, Nakamura, Kiseki D., Nakamura, Hina, Sato, Yukine, Sakashita, Ken, Seiya, Yoshihiro, Takifuji, Kouchi, Tokiyasu, Atsushi, Yamamoto, Tatsuya, Yamamoto, Kazuhiro, and Yasutome, Kenji

Subjects
Physics - Instrumentation and Detectors
Abstract

Upgrade work towards increasing the beam intensity of the neutrino beamline at J- PARC is underway. Monitoring tertiary muon beams is essential for stable operation of the beamline. Accordingly, we plan to replace the present muon monitor sensors with electron multiplier tubes (EMTs). We investigated the radiation tolerance and linearity response of EMTs using a 90 MeV electron beam. An EMTs was irradiated with electrons up to 470 nC. EMTs show higher radiation tolerance than the Si sensors which are presently used as one of the muon monitor detectors for the T2K long-baseline neutrino experiment at J-PARC. The integrated charge yield decrease is found to be less than 8% after a beam irradiation equivalent to 132 days of operation at the future J-PARC beam power of 1.3 MW. The EMTs show linearity better than $\pm$5% up to the future beam intensity. The observed yield decrease is likely due to dynode deterioration based on the detailed investigation. The studies described here confirm that EMTs can be used as a high-intensity muon beam monitor. From the reported results, we are proceeding with the installation in the J-PARC neutrino beamline., Comment: 20 pages,19 figures

Published
2024
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3. Measurement of KN scattering below the KN mass threshold

Author

Noumi Hiroyuki, Inoue Kentaro, Kawasaki Shingo, Aikawa Shuu, Ajimura Shuhei, Akaishi Takaya, Asano Hidemitsu, Beer George, Berucci Carolina, Bragadireau Mario, Buehler Paul Alois, Busso Luigi, Cargnelli Michael, Choi Seonho, Curceanu Catalina, Enomoto Shun, Fujioka Hiroyuki, Fujiwara Yuya, Fukuda Tomokazu, Guaraldo Carlo, Hashimoto Tadashi, Hayano Ryugo S., Hiraiwa Toshihiko, Iio Masami, Iliescu Mihai, Ishiguro Yusuke, Ishimoto Shigeru, Ishikawa Takashi, Ithashi Kenta, Iwai Massaki, Iwasaki Masahiko, Kanno Koki, Kato Kazuma, kato Yuko, Kienle Paul, Komatsu Yusuke, Kou Hiroshi, Ma Yue, Marton Johann, Matsuda Yasuyuki, MIzoi Yutaka, Morra Ombretta, Murayama Rie, Nagae To-mofumi, Ohnishi Hiroaki, Okada Shinji, Omar Zhadyra, Outa Haruhiko, Piscicchia Kristian, Sada Yuta, Sakaguchi Atsushi, Sakuma Fuminori, Sato Masaharu, Scordo Alessadro, Sekimoto Michiko, Shi Hexi, Shirotori Kotaro, Sirghi Diana, Sirghi Florin, Suzuki Ken, Suzuki Shoji, Suzuki Takatoshi, Tanida Kiyoshi, Tatsuno Hideyuki, Tokiyasu Atsushi O., Tokuda Makoto, Tomono Dai, Toyoda Akihisa, Tsukada Kyo, Vazquez-Doce Oton, Widmann Eberhard, Yamaga Takumi, Yamazaki Toshimitsu, Yim Heejoong, Zhang Qi, and Zmeskal Johannes

Subjects
Physics, QC1-999
Abstract

Abstract. We measured πE invariant mass spectra below and above the K¯N mass threshold in the K−d → NπE reaction in order to study the K¯N interaction and the Λ(1405) resonance. This reaction can be described by the two-step process: (i) K¯N1 → K¯N followed by (ii) K¯N2 → πΣ, where N1 and N2 are nucleons bound in the deuteron. We deduced the S -wave scattering amplitude of K¯N →K¯N in the framework of the K¯N πΣ coupled channel so as to reproduce the observed πΣ spectra in the I = 0 channel. We found a resonance pole at 1417.7-7.4+6.0 (fitting error)-1.0+1.1 (systematic error) - i[26.9-7.9+6.0 (fitting error)-2.0+1.7 (systematic error)]MeV/c2.

Published
2024
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5. A spectroscopic study of 𝚵10Li hypernucleus via the 10B(K−,K+)X reaction

Author

Tokiyasu Atsushi

Subjects
Physics, QC1-999
Abstract

We are planning a 10ΞLi production experiment using the 10B(K−,K+)X reaction at the J-PARC, K1.8 beamline. We perform spectroscopy of missing masses using the S − 2S spectrometer, which can achieve high resolution. Since the cross section of Ξ-hypernuclei is very small, we would like to use a thick target. To ensure the missing mass resolution, we propose a semiinclusive method using a tracking device to detect the decay particles from Ξ-hypernuclei.

Published
2022
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6. Strangeness physics programs by S-2S at J-PARC

Author

Gogami Toshiyuki, Achenbach Patrick, Ahn Jung Keun, Androić Darko, Aoki Kanae, Asaturyan Arshak, Botta Elena, Bukhari Masroor. H., Camsonne Alexandre, Covrig Silviu. C., Ebata Kengo, Ekawa Hiroyuki, Evtoukhovitch Petr, Feliciello Alessandro, Fujioka Hiroyuki, Fujita Manami, Garibaldi Franco, Harada Takeshi. K., Hasegawa Shoichi, Hasegawa Tomoyuki, Hayakawa Shuhei. H., Hirose Erina, Honda Ryotaro, Hosomi Kenji, Ichikawa Yudai, Imai Kenichi, Ishige Tatsuhiro, Jung Wooseung, Kamada Kento, Kanatsuki Shunsuke, Kato Seigo, Kim Shinhyung. H., Kobori Takumi, Marcello Simonetta, Markowitz Pete, Miwa Koji, Mkrtchyan Arthur, Mkrtchyan Hamlet, Moritsu Manabu, Nagae Tomofumi, Nagao Sho, Nakagawa Manami, Nakamura Satoshi. N., Nanamura Takuya, Naruki Megumi, Negishi Ryosuke, Okuyama Kazuki, Oura Fumiya, Pandey Bishnu, Pochodzalla Josef, Sakaguchi Atsushi, Sakao Tamao, Sako Hiroyuki, Samanta Chhanda, Sato Susumu, Shabestari Mitra. H., Shahinyan Albert, Shirotori Kotaro, Širca Simon, Son C., Sugimura Hitoshi, Takahashi Hitoshi, Takahashi Shuji, Takahashi Tomonori, Takahashi Toshiyuki, Tamura Hirokazu, Tanida Kiyoshi, Tokiyasu Atsushi, Tsamalaidze Zviadi, Uchida Makoto, Ukai Mifuyu, Une Chiaki, Urciuoli Guido. M., and Yamamoto Takeshi. O.

Subjects
Physics, QC1-999
Abstract

In the K1.8 beam-line at Hadron Experimental Facility of J-PARC, a new magnetic spectrometer S-2S is being installed. S-2S was designed to achieve a high momentum resolution of Δp/p = 6 × 10−4 in FWHM. Several strangeness-physics programs which require the high resolution will be realized by S-2S. The present article introduces J-PARC E70 (missing-mass spectroscopy of Ξ12Be) and E94 (missing-mass spectroscopy of Λ7Li, Λ10B, and Λ12C) experiments.

Published
2022
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7. The Role of Collision Ionization of K-Shell Ions in Nonequilibrium Plasmas Produced by the Action of Super Strong, Ultrashort PW-Class Laser Pulses on Micron-Scale Argon Clusters with Intensity up to 5 × 10 21 W/cm 2.

Author

Skobelev, Igor Yu., Ryazantsev, Sergey N., Kulikov, Roman K., Sedov, Maksim V., Filippov, Evgeny D., Pikuz, Sergey A., Asai, Takafumi, Kanasaki, Masato, Yamauchi, Tomoya, Jinno, Satoshi, Ota, Masato, Egashira, Syunsuke, Sakai, Kentaro, Minami, Takumi, Abe, Yuki, Tokiyasu, Atsushi, Kohri, Hideki, Kuramitsu, Yasuhiro, Sakawa, Youichi, and Miyasaka, Yasuhiro

Subjects
ULTRASHORT laser pulses, ULTRA-short pulsed lasers, LASER plasmas, NONEQUILIBRIUM plasmas, ELECTRON-ion collisions, ARGON, IONS
Abstract

The generation of highly charged ions in laser plasmas is usually associated with collisional ionization processes that occur in electron–ion collisions. An alternative ionization channel caused by tunnel ionization in an optical field is also capable of effectively producing highly charged ions with ionization potentials of several kiloelectronvolts when the laser intensity q > 1020 W/cm2. It is challenging to clearly distinguish the impacts of the optical field and collisional ionizations on the evolution of the charge state of a nonequilibrium plasma produced by the interaction of high-intensity, ultrashort PW-class laser pulses with dense matter. In the present work, it is shown that the answer to this question can be obtained in some cases by observing the X-ray spectral lines caused by the transition of an electron into the K-shell of highly charged ions. The time-dependent calculations of plasma kinetics show that this is possible, for example, if sufficiently small clusters targets with low-density background gas are irradiated. In the case of Ar plasma, the limit of the cluster radius was estimated to be R0 = 0.1 μm. The calculation results for argon ions were compared with the results of the experiment at the J-KAREN-P laser facility at QST-KPSI. [ABSTRACT FROM AUTHOR]

Published
2023
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