Proton-Rich Nuclei Studied by Multi-Nucleon Transfer Reactions

Research Project

Project/Area Number	08640345
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	素粒子・核・宇宙線
Research Institution	Yamagata University
Principal Investigator	KATO Seigo Yamagata University, Department of Physics, Professor, 理学部, 教授 (70013422)
Co-Investigator(Kenkyū-buntansha)	YOSHIDA Hiroshi Yamagata University, Department of Physcs, Lecturer, 理学部, 講師 (80241727) SHIMIZU Hajime Yamagata University, Department of Physics, Professor, 理学部, 教授 (20178982)
Project Period (FY)	1996 – 1997
Project Status	Completed (Fiscal Year 1997)
Budget Amount *help	¥2,200,000 (Direct Cost: ¥2,200,000) Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000) Fiscal Year 1996: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords	proton-rich nuclei / transfer reactions / detectors / BSO crystal / CsI crystal / PWO crystal / light guide / photo-multiplier / ガンマ線検出器 / シンチレーター / エネルギー分解能 / 位置分解能
Research Abstract	The aim of this research is to study the structure of proton-rich nuclei by mutli-nucleon transfer reactions. The information will be useful for the understanding of the rapidproton process which occurs in stellar environments and of the evolution of chemical elements in the universe. For the experimental study of the above-mentioned reactions, the development of counter system with high performance of particle identification is essential because the cross section of the expected reaction is very small compared to the huge background ones. We studied the characteristics of the BSO crystal as a scintilator for particle and gamma detection. In 1996, we ordered a company to fabricate a large BSO crystal. The size was as large as 30mm x 30mm x 200mm which is the largest crystal ever made in the world. This crystal can easily be extended to a counter system which covers full solid angle for gamma detection by adding several identical sets. In 1997, after adding a light guide and a photo-multiplier, an offline test to investigate the performance of the counter was made with a gamma source. Further, an extensive study was made by using an electron beam from the electron synchrotron of High Energy Accelerator Research Organization at Tanashi. We could obtain position and energy resolutions as expected. As a related study, the performances of the CsI and the PWO crystals were also investigated using electron beams from the same accelerator. The former is widely used in the low-energy region, and the latter in the high-energy one. The BSO can be regarded as being located between them.