| Project/Area Number |
03402005
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
核・宇宙線・素粒子
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| Research Institution | Osaka University |
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Principal Investigator |
EJIRI Hiroyasu Dept.of Phys., Osaka Univ., Prof., 理学部, 教授 (80013374)
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| Co-Investigator(Kenkyū-buntansha) |
TAKASUGI Eiichi Colledge General Education., Osaka Univ., Prof., 教養部, 教授 (00135633)
TANAKA Junichi Dept.of Phys., Osaka Univ., Research Associate, 理学部, 助手 (70236595)
OHSUMI Hideaki Dept.of Phys., Osaka Univ., Research Associate, 理学部, 助手 (70176882)
OKADA Kenji Kyoto Sangyo Univ., Prof., 理学部, 教授 (90093385)
KISHIMOTO Tadafumi Dept.of Phys., Osaka Univ., Prof., 理学部, 助教授 (90134808)
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| Project Period (FY) |
1991 – 1993
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| Keywords | Nuclear rare decay / Double beta decays / Neutrino / Dark matter / Charge non-conservation / Pauli Principles / Nucleon decay |
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| Research Abstract |
1. Double beta decays and neutrino
(1) Neutrinoless Double beta decays of ^<100>Mo have been measured for studying fundamental properties of neutrino and the validity of electro-weak standard model means of ELEGANT V detector. (2) Double beta decays with two neutrino of ^<100>Mo and ^<116>Cd were studied and the finite half lives for both nuclei were observed. (3) New type drift chambers, which are very sensitive to alpha particles emitted from residual radioactivities, have been installed in the ELEGANTS V detector.
2. Search for dark matter
New particles of dark matter candidates have been searched by means of large NaI with the total mass of 0.76ton in ELEGANTS V detector. NaI detector was found to be very sensitive to spin-coupled dark matter candidates.
3. Test of Conservation Laws of Particle and Nuclear Physics
Electron stability and nucleon stability have been checked by using the electron and nucleon in NaI detector itself in ELEGANTS V detector. These stabilities give one of the highest upperlimits of charge nonconserving decay of electron, breakings of Pauli principle, and mode independent nucleon decays.
4. Ultra-rare Nuclear reactions
ELEGANTS IIIs detector with neutron scatterer was shown to be very sensitive in the search for rare neutron events such as d-d fusion at room temperature. The observed fusion rate was obtained as <1.6・10^<-24> (ddn) fusions/(dd)pair/sec.
5. Radioactivity in Meteorites
Gamma rays from radioactivities in meteorites were measured by means of ELEGANTS IIIs detector. Concentration of ^<26>Al in large meteorites with total mass of several hundred gram can be measured nondestructively in an order of dpm/kg.
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