| Project/Area Number |
04452025
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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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 | NIIGATA UNIVERSITY |
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Principal Investigator |
OHYA Susumu NIIGATA UNIV., FACULTY OF SCIENCE,PROFESSOR, 理学部, 教授 (90092676)
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| Co-Investigator(Kenkyū-buntansha) |
OHTSUBO Takasi NIIGATA UNIV., FACULTY OF SCIENCE,RESEARCH ASSOCIATE, 理学部, 助手 (70262425)
FURUSAWA Akira NIIGATA UNIV., FACULTY OF SCIENCE,ASSOCIATE PROFESSOR, 理学部, 助教授 (10018260)
DANJO Atsunori NIIGATA UNIV., FACULTY OF SCIENCE,PROFESSOR, 理学部, 教授 (40018669)
平口 和彦 旭町地区放射性同位元素共同利用施設, 助手 (30212195)
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| Project Period (FY) |
1992 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1993: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1992: ¥4,000,000 (Direct Cost: ¥4,000,000)
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| Keywords | LOW-TEMPERATURE NUCLEAR ORIENTATION / gamma DECAY / TIME-REVERSAL INVARIANCE / 核崩壊 |
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| Research Abstract |
Time-reversal invariance in the gamma transitions were investigated by observing the angular distribution of the linear polarization of the mixed (E2, M1) gamma transitions in ^<192>Pt from a source of ^<192>IrFe polarized at a low temperature of 9.3 (1) mK.As the polarimeters, four thin disk-type (two 44mmPHIx15mm, two 51mmPHIx20mm) detectors were used. The linear polarization could be detected in single gamma-ray measurements by these detectors. By this method it is possible to measure the linear polarization with high energy resolution without troubles of coincidence circuits. They were placed at the symmetric positions each other and at the angles of 54.7 and 125.3 degree with respect to the spin direction. The asymmetries of the 308-, 484- and 604-ke Vgamma rays were measured. Values of phase angles of sin (eta+xi) were obtained to be 1(14) x10^<-3>,0 (30) x10^<-3> and 2.1 (53) x10^<-3> for the 308-, 484- and 604-ke Vgamma transitions, respectively. These results are consistent with time reversal invariance.
In order to improve the polarization sensitivity we employed more thinner detectors (two 51mmPHIx7mm) . The measurements were performed for about 35 days. Now the result of the value ofsin (eta+xi) for the 604-keV transition were tentatively obtainde ; -26 (25) x10^<-4>, -80 (74) x10^<-4>, -30 (28) x10^<-4>,90 (94) x10^<-4> for the detector Nos.1-4 respectively. Detailed analyzes are now in progress.
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