1992 Fiscal Year Final Research Report Summary
Excitation-Energy and Spin Dependence of High-Energy Gamma-Rays
| Project/Area Number |
03640264
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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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 | Tokyo Institute of Technology |
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Principal Investigator |
MURAKAMI Takeshi Tokyo Inst.Tech., Dept.Phys., Res.Ass., 理学部, 助手 (20166250)
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| Co-Investigator(Kenkyū-buntansha) |
KASAGI Jirohta Tohoku Univ., Dept.Phys., Prof., 理学部, 教授 (10016181)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Heavy-ion reactions / High-energy gamma rays / Excitation energy / Angular momentum |
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| Research Abstract |
1. Spectra of high-energy gamma-rays from the ^<100>Mo+^<32>S reaction were measured as a function of gamma-ray multiplicities at the beam energies of 150,180, and 210 MeV. The GDR on the excited states were observed for the nuclei with an excitation energy of 80 MeV or higher, where the data had been scarce.
2. The GDR energy showed slight variance with increasing gamma multiplicities. The width increased rapidly with increasing thermal energies.
3. Since the gamma-ray multiplicities correlate with the thermal energies, it is not appropriate to attribute the reason of the increasing width to the angular momentum.
4. The following problems were understood: (1)multiplicity resolution was not enough to resolve each value of the angular momentum. (2)The yield of the high-energy gamma-rays not originating in the compound nuclei were larger than that was expected.
5. In order to solve the problem (1), the 4-pi detector was developed.
6. Production cross section of compound nuclei were measured for the ^<116>Sn+^<40>Ar reaction in order to investigate the reaction mechanism. The large cross section was obtained at an incident energy of 37MeV/u, which seemed too high to produce the heavy compound nuclei. Coincidence measurements between neutrons, charged particles, gamma-rays and compound nuclei have been carried out.
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