| Project/Area Number |
06452032
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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 | Faculty of Integrated Arts and Sciences, The University of Tokushima |
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Principal Investigator |
NAKAYAMA Shintaro Faculty of Integrated Arts and Sciences, The University of Tokushima Professor, 総合科学部, 教授 (70116846)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Mamoru Research Center for Nuclear Physics Osaka University Associate Professor, 核物理研究センター, 助教授 (00030031)
KOORI Norihiko Faculty of Integrated Arts and Sciences, The University of Tokushima Professor, 総合科学部, 教授 (20038053)
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| Project Period (FY) |
1994 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥7,300,000 (Direct Cost: ¥7,300,000)
Fiscal Year 1996: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1995: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1994: ¥6,200,000 (Direct Cost: ¥6,200,000)
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| Keywords | charge exchange reaction / isovector resonance / relative spin-strength / effective nuclear interaction / spin-flip transition / non spin-flip transition / スピン-アイソスピン応答 / 巨大共鳴 |
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| Research Abstract |
This project aims at studying isovector giant resonances via the (7Li, 7Be) reaction at intermediate energies. The (7Li, 7Be) reaction has characteristics to separately derive spin-flip (DELTAS=1) and non spin-flip (DELTAS=0) isovector excitations by measuring gamma-rays in coincidence with 7Be-ejectiles. Measurement of both DELTAS=0 and DELTAS=1 spectra under the same kinematical condition is expected to provide direct evidence of isovector resonances with DELTAS=0 and DELTAS=1, their relative strength distribution, and nuclear spin-isospin responses.
A new gamma-detector system "NYMPHS" were developed using 22 pieces of GSO scintillator. Feasibility of the NYMPHS for the 7Be-gamma coincidence was investigated in the (7Li, 7Be) reactions on 12C and 90Zr at 65 AMeV.The multi-segmented detector system showed good performance for the 7Be-gamma coincidence measurement. The 7Be gamma-ray were clearly identified by detecting its Doppler effect.
We investigated nuclear spin-isospin responses in light nuclei. The (7Li, 7Be) reaction was found to predominantly proceed via one-step reaction process. From the H(7Li, 7Be)n reaction, we got an effective nuclear interaction ratio of Vsigmatau/Vtau at 65 AMeV.The ratio is very consistent with the (p, n) data. Using Vsigmatau/Vtau presently observed, we could get relative spin-stregth which reflects nuclear spin-isospin responses.
We conclude that the 7Be-gamma coincidence measurement using the NYMPHS is applicable to the (7Li, 7Be) reaction from light nuclei to medium-heavy nuclei at intermediate energies. This means the (7Li, 7Be) reaction is a unique spin-probe for isovector excitations.
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