| Project/Area Number |
07454054
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
MITARAI Shiro KYUSHU UNIVERSITY Fac.of Science Research Associate, 理学部, 助手 (00108648)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Hiroyuki KYUSHU UNIVERSITY Fac.of Science Research Associate, 理学部, 助手 (70172434)
KUROYANAGI Tokihiro KYUSHU UNIVERSITY Fac.of Science Emeritus Professor, 理学部, 名誉教授 (70037159)
GONO Yasuyuki KYUSHU UNIVERSITY Fac.of Science Professor, 理学部, 教授 (50016127)
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| Project Period (FY) |
1995 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥7,200,000 (Direct Cost: ¥7,200,000)
Fiscal Year 1997: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1996: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1995: ¥5,600,000 (Direct Cost: ¥5,600,000)
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| Keywords | Recoil Distance Method / Moment / Silicon ball / Plunger / Life-time / Deformed shape / Neutron Wall / Pecoil Distance Doppler Shift / N=Z近傍核 / Recoil Distance Doppler Shift / ブランジャー装置 / Si・ボール / 荷電粒子多重度測定装置 / ドップラー・シフト / ΔE-Si検出器 / 超変形 / N=Z核 |
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| Research Abstract |
In the region of Z=38-44 nuclei, the nuclei with neutron number around N=45 are suited to study the configurations which drive the nucleus away from spherical shape and stabilize the deformed shapes. In heavy-ion fusion reactions at high excitation energy and spin and where the fused system is far from beta-stability line, many reaction channels are open. Silicon ball is a multiplicity filter for charged particles with high ability for reaction channel selection and high detection efficiency. A plunger was used tomeasure lifetimes of excited nuclear levels in the rang from ns to ps by the recoil distance method.
In the heavy ion fusion reaction which many reaction channel open, a combination of two devices makes it possible to measure lifetimes of levels with high acquisition rate and a selection of only those residual nuclei that are of interest.
The Silicon ball (20 detector elements) with 11 pentagonal DELTAE Si detectors in the combination with the plunger system was used for the ^<58>Ni (^<33>S,alpha 2p) ^<85>Zr reaction with three ACS-Ge detectors (37ﾟ ring) of crystal ball. A clean gamma ray spectrum gated by (alpha 2p) can show Doppler-shifted and stopped lines for a gamma ray with enough statistics during a run of one hour. This plunger experiment reveals a transitional character of ^<85>Zr nucleus.
As one of the activities, the search experiments of ^<102>Sn and ^<98>Cd with cross sections around 10 mu barns were successfully performed using Silicon ball together with Neutron Wall at NBI.
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