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Start Over Author "Hiroyuki Sekiya" Publisher oxford university press (oup)
8 results on '"Hiroyuki Sekiya"'

1. Precise measurement of the scintillation decay constant of the ZnWO4 crystal

Author

Masaru Shibata, Koichi Ichimura, and Hiroyuki Sekiya

Subjects
Physics, Scintillation, Physics - Instrumentation and Detectors, Yield (engineering), FOS: Physical sciences, General Physics and Astronomy, Instrumentation and Detectors (physics.ins-det), High Energy Physics - Experiment, Crystal, High Energy Physics - Experiment (hep-ex), Perpendicular, High Energy Physics::Experiment, Irradiation, Atomic physics, Exponential decay, Anisotropy, Constant (mathematics)
Abstract

The scintillation decay time constant of a ZnWO$_4$ crystal irradiated with $\alpha$-particles from $^{241}$Am was precisely investigated, and was found to depend on the incident direction of the $\alpha$-particles on the crystal. The longest decay time constant ($24.3\pm0.6~\mu$s) was obtained on the surface perpendicular to the b-axis of the crystal (Surface B). On Surfaces A and C, the decay constants were $20.0$ and $21.3\pm0.2~\mu$s, respectively. The scintillation yield of the ZnWO$_4$ was also anisotropic and depended on the incident direction of the heavy particles. The maximum yield was achieved on surface B, suggesting a correlation between the light yield and scintillation decay time constant of ZnWO$_4$ crystals., Comment: 9 pages, 8 figures, Accepted for PTEP

Published
2021

2. Measurements of ν̅ μ and ν̅ μ + ν μ charged-current cross-sections without detected pions or protons on water and hydrocarbon at a mean anti-neutrino energy of 0.86 GeV

Author

M. Barbi, T. Vladisavljevic, A. Longhin, A. Shaykina, M. Lawe, Michelangelo Pari, A. Blanchet, Thorsten Lux, Y. Sonoda, L. Molina Bueno, T. Kikawa, S. Parsa, V. Q. Nguyen, H. W. Sobel, M. Gonin, J. Xia, A. T. Suzuki, A. Dergacheva, C. E. R. Naseby, J. F. Martin, N. Kukita, M. Licciardi, T. Feusels, Y. Tanihara, C. Alt, T. Nakadaira, Shuji Tanaka, R. Shah, J. Lagoda, R. J. Wilson, M. Pavin, S. J. Jenkins, J. R. Wilson, D. Fukuda, L. O'Sullivan, Jochen Steinmann, Xianguo Lu, M. R. Vagins, H. Kikutani, J. G. Walsh, A. Bubak, P. Jonsson, R. A. Owen, P. Novella, K. Iwamoto, K. Niewczas, André Rubbia, Jaroslaw Pasternak, Y. Yoshimoto, M. Batkiewicz-Kwasniak, M. Miura, Marco Laveder, A. Zykova, J. P. Coleman, T. Hayashino, Yuto Ashida, A. J. Finch, R. Fukuda, C. Wret, A. Knox, T. Arihara, T. Sekiguchi, R. Akutsu, J. Morrison, N. McCauley, M. Guigue, A. Pritchard, P. B. Jurj, A. A. Sztuc, J. L. Palomino, G. Zarnecki, Patrick Dunne, P. Paudyal, A. Blondel, T. Koga, B. A. Popov, T. Honjo, A. Rychter, P. Hamacher-Baumann, Oleg Mineev, C. Pistillo, M. Jakkapu, M. Buizza Avanzini, B. Jamieson, G. Christodoulou, K. Nakamura, T. A. Doyle, E. Reinherz-Aronis, Keigo Nakamura, Takaaki Kajita, E. Rondio, B. Quilain, C. J. Densham, K. Yasutome, K. Fusshoeller, Hiroyuki Sekiya, S. L. Cartwright, F. Shaker, W. Uno, C. M. Nantais, F. Nova, K. Porwit, P. F. Denner, R. Fujita, Y. Fukuda, Kendall Mahn, A. K. Ichikawa, V. Paolone, Akitaka Ariga, Ko Okumura, G. Pintaudi, S. Moriyama, Kate Scholberg, D. Cherdack, M. Ziembicki, S. Roth, J. Kameda, J. Zalipska, C. Vilela, S. Kuribayashi, E. S. Pinzon Guerra, Th. A. Mueller, B. Radics, M. Ikeda, A. Zalewska, Federico Sanchez, B. Bourguille, Yousuke Kataoka, Z. Vallari, Y. Takeuchi, K. Wood, R.P. Kurjata, L. F. Thompson, S. Valder, T. Ogawa, T. Golan, M. Hartz, E. D. Zimmerman, C. McGrew, Masayuki Nakahata, C. Pidcott, L. Koch, Y. Asada, A. Gorin, G. A. Fiorentini, A. Knight, A. Shvartsman, N. Teshima, C. Checchia, A. Bravar, Vladimir Volkov, Y. Uchida, Shigeki Aoki, Yuichi Oyama, A. Nakamura, S. Suvorov, R. P. Litchfield, Takatomi Yano, Y. Hayato, C. Andreopoulos, R. A. Wendell, S. Bolognesi, H. M. O'Keeffe, J. Holeczek, S. Hassani, G. Fiorillo, T. Radermacher, Thomas B. Campbell, Yuki Fujii, K. Nakayoshi, D. Bravo Berguño, E. Radicioni, T. Kobata, W. H. Toki, Hiromasa Tanaka, V. A. Matveev, M. B. Smy, T. Towstego, L. Maret, P. N. Ratoff, T. Kutter, Koji Yamamoto, M. McCarthy, M. Zito, Hidekazu Kakuno, Pablo Fernandez, M. O. Wascko, S. Mine, G. Yang, E. Mazzucato, K. Kowalik, Laura Gutermuth Anthony, M. Yu, D. L. Wark, F. Di Lodovico, Yutaka Nakajima, Jan Kisiel, T. Bonus, M. Friend, Teppei Katori, Yanbin Wang, M. Tada, D. J. Payne, K. Abe, T. Okusawa, Jungsang Kim, S. Y. Suzuki, N. Izumi, D. Vargas, J. Dumarchez, N. Chikuma, Vincenzo Berardi, D. Barrow, Etam Noah, C. Bronner, Steven C. Johnson, S. Nakayama, F. J. P. Soler, L. L. Kormos, W. Shorrock, Masaki Ishitsuka, Yoshihiro Suzuki, M. Kuze, T. Tsukamoto, K. Skwarczynski, L. Labarga, A. Eguchi, K. Sakashita, S. M. Oser, L. Berns, S. Yen, M. Hogan, T. Kobayashi, N. C. Hastings, M. Antonova, R. Okada, T. Odagawa, Yoshikazu Yamada, A. N. Khotjantsev, Alan Cosimo Ruggeri, J. Schwehr, D. Karlen, T. Yoshida, Y. Seiya, A. Minamino, Hidetoshi Kubo, A. D. Marino, Hyun-Chul Kim, A. Izmaylov, L. Pickering, Y. Nishimura, S. Manly, S. Ban, S. Bienstock, K. M. Tsui, K. S. McFarland, F. Bench, A. C. Weber, Y. Katayama, G. Vasseur, C. Jesús-Valls, C. Ruggles, G. Santucci, O. Drapier, D. A. Harris, S. Emery-Schrenk, H. K. Tanaka, T. Wachala, T. Ishida, S. P. Kasetti, N. Akhlaq, M. M. Khabibullin, S. L. Liu, M. Posiadala-Zezula, M. G. Catanesi, M. Malek, L. Magaletti, C. Giganti, N. Dokania, S. Berkman, Roberto Spina, A. C. Kaboth, A. Cervera, G. Collazuol, Mark Scott, M. Kabirnezhad, K. Mavrokoridis, J. A. Nowak, A. Chappell, Lars Eklund, T. S. Nonnenmacher, C. Barry, S. Murphy, C. Riccio, C. Mauger, T. Dealtry, E. T. Atkin, M. Cicerchia, Alexei Yu. Smirnov, Yuta Kato, K. Nishikawa, M. Lamoureux, L. N. Machado, J. T. Haigh, S. Zsoldos, V. Palladino, S. B. Boyd, L. Marti-Magro, K. Zaremba, Jan T. Sobczyk, Stephanie Bron, Atsushi Takeda, J. McElwee, D. Sgalaberna, Ahmed Ali, C. Francois, Y. Awataguchi, Xiao-yan Li, W. G. S. Vinning, C. Wilkinson, T. V. Ngoc, C. Yanagisawa, Gareth J. Barker, Yuuki Nakano, D. Coplowe, T. Ishii, A. Hiramoto, T. Hasegawa, Takahiko Matsubara, S. V. Cao, C. Touramanis, M. J. Wilking, M. Jiang, Antonio Ereditato, N. Yershov, T. Maruyama, K. Gameil, J. C. Nugent, G.D. Barr, S. King, F. Iacob, M. Mezzetto, D. R. Hadley, Y. Nagai, W. C. Parker, M. Tani, E. Kearns, G. C. Penn, Masashi Yokoyama, M. Tzanov, C. J. Metelko, Yu.A. Kudenko, A. Dabrowska, K. Matsushita, D. Brailsford, N. T. Hong Van, J. Walker, A. Mefodiev, S. Dolan, T. Lindner, A. Cudd, S. R. Dennis, Tsuyoshi Nakaya, C. M. Schloesser, C. K. Jung, Masato Shiozawa, L. Ludovici, A. Kostin, S. Bhadra, L. Cook, A. Beloshapkin, G. De Rosa, J. Calcutt, A. Shaikhiev, A. Konaka, L. Munteanu, M. Tajima, and Yusuke Koshio

Subjects
chemistry.chemical_classification, Physics, Particle physics, Muon, Proton, 010308 nuclear & particles physics, General Physics and Astronomy, 01 natural sciences, Hydrocarbon, Pion, chemistry, 0103 physical sciences, 010306 general physics, Nucleon, Energy (signal processing), Charged current, Bar (unit)
Abstract

We report measurements of the flux-integrated ν̅μ and ν̅μ + νμ charged-current cross-sections on water and hydrocarbon targets using the T2K anti-neutrino beam with a mean beam energy of 0.86 GeV. The signal is defined as the (anti-)neutrino charged-current interaction with one induced $\mu^\pm$ and no detected charged pion or proton. These measurements are performed using a new WAGASCI module recently added to the T2K setup in combination with the INGRID Proton Module. The phase space of muons is restricted to the high-detection efficiency region, $p_{\mu}>400~{\rm MeV}/c$ and $\theta_{\mu}200~{\rm MeV}/c$, $\theta_{\pi}600~{\rm MeV}/c$, $\theta_{\rm p}

Published
2021

3. Improved method for measuring low-concentration radium and its application to the Super-Kamiokande Gadolinium project

Author

Y. Takaku, Ko Abe, Masayuki Harada, Hiroyuki Sekiya, M. Ikeda, Hiroshi Ito, Yutaka Nakajima, Yasuhiro Kishimoto, Koichi Ichimura, T. Okada, and Shintaro Ito

Subjects
Physics, Physics - Instrumentation and Detectors, 010308 nuclear & particles physics, Gadolinium, Radiochemistry, Extraction (chemistry), FOS: Physical sciences, General Physics and Astronomy, chemistry.chemical_element, Improved method, Instrumentation and Detectors (physics.ins-det), 010403 inorganic & nuclear chemistry, 01 natural sciences, High Energy Physics - Experiment, 0104 chemical sciences, Semiconductor detector, Radium, High Energy Physics - Experiment (hep-ex), chemistry, 0103 physical sciences, Astrophysics - Instrumentation and Methods for Astrophysics, Super-Kamiokande, Instrumentation and Methods for Astrophysics (astro-ph.IM), Sensitivity (electronics), Volume concentration
Abstract

Chemical extraction using a molecular recognition resin named "Empore Radium Rad Disk" was developed to improve sensitivity for the low concentration of radium (Ra). Compared with the previous method, the extraction process speed was improved by a factor of three and the recovery rate for $^{226}$Ra was also improved from 81$\pm$4% to $>$99.9%. The sensitivity on the 10$^{-1}$ mBq level was achieved using a high purity germanium detector. This improved method was applied to determine $^{226}$Ra in Gd$_2$(SO$_4$)$_3{\cdot}$8H$_2$O which will be used in the Super-Kamiokande Gadolinium project. The improvement and measurement results are reported in this paper., 8 pages, 3 figures

Published
2020

4. Anisotropic response measurements of ZnWO4 scintillators to neutrons for developing a direction-sensitive dark matter detector

Author

Juan W. Pedersen, Koichi Ichimura, and Hiroyuki Sekiya

Subjects
Physics, 010308 nuclear & particles physics, business.industry, Detector, Dark matter, General Physics and Astronomy, Scintillator, 01 natural sciences, Optics, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, business, Anisotropy
Abstract

The scintillation yields of ZnWO$_4$ crystals change depending on the incident direction of particles. This property can be used as a direction-sensitive dark matter detector, so we investigated the ZnWO$_4$ light yields ratio of neutron-induced nuclear recoils to gamma-ray-induced electron recoils (quenching factor). Two surfaces almost perpendicular to the crystal axis of ZnWO$_4$ were irradiated with a quasi-monochromatic neutron beam of 0.885 MeV, and the quenching factors of both surfaces for the oxygen-nucleus recoil in the ZnWO$_4$ crystal were measured. The obtained quenching factors of the two surfaces were $0.235 \pm 0.026$ and $0.199 \pm 0.020$, respectively, confirming 15.3% anisotropy.

Published
2020

5. Development of new radon monitoring systems in the Kamioka mine

Author

Shigeki Tasaka, M. Ikeda, Hiroyuki Sekiya, Guillaume Pronost, and T. Nakamura

Subjects
Physics, Physics - Instrumentation and Detectors, 010308 nuclear & particles physics, Detector, chemistry.chemical_element, FOS: Physical sciences, General Physics and Astronomy, Monitoring system, Radon, Instrumentation and Detectors (physics.ins-det), High sensitive, 01 natural sciences, Measure (mathematics), Background level, Nuclear physics, Raspberry pi, Low energy, chemistry, 0103 physical sciences, 010306 general physics
Abstract

Radioactivity from radon is a major threat for high-precision low energy physics experiments like the ones in the Kamioka Mine. We developed a new high sensitive radon monitoring system and conducted systematic radon concentration measurements for the first time in Kamioka. The system consists of portable radon detectors with a capacity of 1 L and new electronics based on Raspberry Pi. These radon detectors measure the radon in air with electro-static collection and a PIN photodiode. We measured the absolute humidity dependence of the 1-L radon detector for air to be $C_{F} (A_{H}) = (12.86 \pm 0.40) - (1.66 \pm 0.19) \sqrt{A_{H}}$ $\mathrm{(counts/day)/(Bq/m^3)}$. The background level of the 1-L radon detector is $0.65\pm0.15$ (stat.) count/day. This corresponds to a detection limit of $\sim0.4$ Bq/m$^3$ in a one-day measurement. Data was collected for a period of more than one year with twenty one 1-L radon detectors in the Kamioka mine. They indicate seasonal and day-night variations in radon concentration within the mine. These results also allow us to confirm the stability of the new Raspberry Pi electronics., Comment: 21 pages, 22 figures, to be published in PTEP Erratum on 2019/03/06: Figures 15 and 16 were corrected, this doesn't change our conclusions

Published
2019

6. Evaluation of radon adsorption efficiency values in xenon with activated carbon fibers

Author

Yuuki Nakano, T. Okada, Hiroyuki Sekiya, Masaki Yamashita, Y. Takeuchi, Koichi Ichimura, Hiroshi Ito, and S. Tasaka

Subjects
Physics, Physics - Instrumentation and Detectors, Argon, Analytical chemistry, General Physics and Astronomy, chemistry.chemical_element, Noble gas, FOS: Physical sciences, Radon, Instrumentation and Detectors (physics.ins-det), Uranium, Xenon, Adsorption, chemistry, Saturation (graph theory), medicine, Activated carbon, medicine.drug
Abstract

The radioactive noble gas radon-222 ($\mathrm{^{222}Rn}$, or Rn) produced in the uranium series is a crucial background source in many underground experiments. We have estimated the adsorption property of Rn with Activated Carbon Fibers (ACFs) in air (Air), argon (Ar), and xenon (Xe) gas. In this study, we evaluated six ACFs, named A-7, A-10, A-15, A-20, A-25, and S-25, provided from UNITIKA Ltd. We measured intrinsic radioactivity of these ACF samples, and found A-20's radioactivity of the uranium series is $, 17 pages, 9 figures

Published
2020

7. Improved search for two-neutrino double electron capture on 124-Xe and 126-Xe using particle identification in XMASS-I

Author

N. Oka, H. Takiya, G. Kanzaki, K. Nishijima, Yoshitaka Itow, O. Takachio, Lee Min-Kie, K. Hosokawa, Shogo Nakamura, Masaki Yamashita, K. Martens, M. Miyasaka, Yasuhiro Kishimoto, Shigeki Tasaka, Nam Young Kim, Atsushi Takeda, K. Kobayashi, Hiroshi Ogawa, T. Norita, Katsuhiko Sato, Shigetaka Moriyama, Hiroyuki Sekiya, Katsuki Hiraide, Kimiaki Masuda, Ken-Ichi Fushimi, Y. Fukuda, Motoki Kobayashi, Y. Takeuchi, Koichi Ichimura, Y. D. Kim, Yong Hamb Kim, Kentaro Miuchi, K.B. Lee, K. Kanzawa, R. Fujita, R. Kegasa, B. D. Xu, Masayuki Nakahata, Yoshihiro Suzuki, B. S. Yang, and Ko Abe

Subjects
Physics, Physics - Instrumentation and Detectors, 010308 nuclear & particles physics, Electron capture, General Physics and Astronomy, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), 01 natural sciences, Particle identification, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, Neutrino, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment
Abstract

We conducted an improved search for the simultaneous capture of two $K$-shell electrons on the $^{124}$Xe and $^{126}$Xe nuclei with emission of two neutrinos using 800.0 days of data from the XMASS-I detector. A novel method to discriminate $\gamma$-ray/$X$-ray or double electron capture signals from $\beta$-ray background using scintillation time profiles was developed for this search. No significant signal was found when fitting the observed energy spectra with the expected signal and background. Therefore, we set the most stringent lower limits on the half-lives at $2.1 \times 10^{22}$ and $1.9 \times 10^{22}$ years for $^{124}$Xe and $^{126}$Xe, respectively, with 90% confidence level. These limits improve upon previously reported values by a factor of 4.5., Comment: 17 pages, 9 figures, accepted for publication in PTEP

Published
2018

8. Direction-sensitive dark matter search with gaseous tracking detector NEWAGE-0.3b'

Author

K. Nakamura, Takashi Hashimoto, Joseph D. Parker, Y. Mizumura, Kentaro Miuchi, Atsushi Takada, Yushiro Yamaguchi, H. Nishimura, S. Komura, Atsushi Takeda, Tetsuya Mizumoto, Hiroyuki Sekiya, Hidetoshi Kubo, Y. Matsuoka, Tatsuya Sawano, and Toru Tanimori

Subjects
Nuclear physics, Physics, WIMP, Observatory, Weakly interacting massive particles, Detector, Dark matter, General Physics and Astronomy, Tracking (particle physics)
Abstract

Direction-sensitive dark matter search with gaseous tracking detector NEWAGE-0.3b’ Kiseki Nakamura1,∗, Kentaro Miuchi2, Toru Tanimori1, Hidetoshi Kubo1, Atsushi Takada1, Joseph D. Parker1, Tetsuya Mizumoto1, Yoshitaka Mizumura1, Hironobu Nishimura1, Hiroyuki Sekiya3, Atsushi Takeda3, Tatsuya Sawano1, Yoshihiro Matsuoka1, Shotaro Komura1, Yushiro Yamaguchi2 and Takashi Hashimoto2 1Department of Physics, Kyoto University, Oiwakecho, Sakyo-ku Kyoto-shi, Kyoto, 606-8502, Japan 2Department of Physics, Kobe University, Rokodai, Nada-ku Kobe-shi, Hyogo, 657-8501, Japan 3Kamioka Observatory, ICRR, The University of Tokyo, Gifu, 506-1205 Japan ∗E-mail: nakamura@cr.scphys.kyoto-u.ac.jp

Published
2015

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