1992 Fiscal Year Final Research Report Summary
Detection of High Energy Cosmic Neutrino in the Deep Ocean
| Project/Area Number |
03044036
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | University of Tokyo |
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Principal Investigator |
OHASHI Yozo University of Tokyo, 宇宙線研究所, 助教授 (80022599)
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| Co-Investigator(Kenkyū-buntansha) |
J LEARNED ハワイ大学高エネルギー物理グループ, 教授
UEHARA Sadaharu National Laboratory for High Energy Physics, 助手 (70176626)
HAYASHINO Tomoki Tohoku University, 理学部, 助手 (10167596)
YAMAGUCHI Akira Tohoku University, 理学部, 助教授 (60004470)
TANAKA Sho Tohoku University, 理学部, 教授 (70004306)
KITAMURA Takashi Kinki University, 理工学総合研究所, 教授 (10013426)
KOBAYAKAWA Keizo Kobe University, 発達科学部, 教授 (00031287)
MITSUI Kiyomi University of Tokyo, 宇宙線研究所, 助手 (80013340)
OKADA Atsushi University of Tokyo, 宇宙線研究所, 助手 (90013341)
LEARNED John University of Hawaii
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| Project Period (FY) |
1991 – 1992
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| Keywords | Cosmic Neutrino / Deep Sea / Optical Detector / Bioluminescence |
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| Research Abstract |
This research is an international project organized by scientists from Japan, USA and Europe, and Japanese group are responsible to prepare optical modules for the deep sea water Cerenkov detector. The international collaboration meeting is held four times a year, one of which was held in Japan in 1992. The schedule has been decided to start the construction of the detector off the Big Island of Hawaii from 1993 October.
1). The components of the optical modules have been prepared for two strings. Characteristics of PMTs have been measured, the pattern of the circuit board was revised, and the software to control the circuit was changed to the universal OS-9. Running tests have been done with circuit boards in the temperature programmable chamber. Mechanical tests of the optical modules have been done by oscillating the sample module at *2g. The assembled modules have been sent to Ull, and calibrated there using a water tank.
2). Workshop on High Energy Neutrino Astrophysics was held March 1992 at UH, Honolulu, where the expected energy spectrum and its flux of neutrinos originated from AGN was widely discussed. Following the above results the sensitivity of the DUMAND array to neutrinos from AGNs was simulated. Capability to detect cascades induced by HE neutrinos from AGN was examined. Sensitivity of the array to neutralino cold dark matter was also examined.
3). Background light due to organisms was investigated using a highly sensitive video camera. Images of biolight were recorded at depths of 4500, 3500, and 2500m near DUMAND site and at depths of 5000, 4000 and 3000m off Ibosaki of the Japan Island. Light intensity largely fluctuates time to time, and its mean value decreases with the depth. Comparison of the data at both sites shows that the light intensity at DUMAND site is a factor of (*10) smaller.
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