DEVELOPMENT OF HIGH ENRGY RESOLUTION SPECTROMETER FOR NEUTRONS WITH PROPORTIONAL COUNTER Si DETECTOR TELESCOPE TYPE

Research Project

Project/Area Number	08458132
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Research Field	Nuclear fusion studies
Research Institution	NAGOYA UNIVERSITY
Principal Investigator	MORI Chizuo NAGOYA UNIVERSITY,SCHOOL OF ENGINEERING,PROFESSOR, 工学研究科, 教授 (80023068)
Co-Investigator(Kenkyū-buntansha)	SASAO Mamiko NATIONAL INSTITUTE FOR FUSION SCIENCE,DEPARTMENT OF ASSOCIATE LARGE HELICAL DEVI, 大型ヘリカル研究部, 助教授 (00144171) URITANI Akira NAGOYA UNIVERSITY,SCHOOL OF ENGINEERING,ASSISTANT PROFESSOR, 工学研究科, 助手 (10213521)
Project Period (FY)	1996 – 1997
Project Status	Completed (Fiscal Year 1997)
Budget Amount *help	¥4,600,000 (Direct Cost: ¥4,600,000) Fiscal Year 1997: ¥1,300,000 (Direct Cost: ¥1,300,000) Fiscal Year 1996: ¥3,300,000 (Direct Cost: ¥3,300,000)
Keywords	FAST NEUTRON / ENERGY SPECTROMETOR / COUNTER TELESCOPE / NUCLEAR FUSION / PROPORTIONAL COUNTER / Si SEMI-CONDUCTOR DETECTOR / RECOIL PROTON / HIGH RESOLUTION / エネルギースペクトル / プラズマ温度 / エネルギー分解能 / スペクトロメータ / 半導体検出器
Research Abstract	A new type of fast neutron spectrometer composed of a CH_4 proportional counter and a Si semiconductor detector was constructed for plasma-temperature diagnostics. There are many types of fast neutron spectrometers for this purpose, including natural diamond detector. When they adopt recoil-proton telescope type spectrometer, the energy loss of protons in the neutron-proton converter deteriorates the energy resolution for neutrons if they do not measure and compensate the loss. We adopted proportional counter gas as a converter with which we can measure the energy loss dE1, with good energy resolution, of a recoil-proton in the gas. The proton loses the energy dE2 in the dead space of CH_4 gas between the proportional counter part and Si-detector, and the remaining energy Er in the Si-detector which is off-centered by a distance to avoid radiation damage by direct neutron irradiation. The energy Ep of a recoil-proton is expressed by the sum of the above three energy loses : Ep=dE1+dE2+Er. The neutron energy En is then obtained by En=Ep/cos^2rheta.where rhetais a recoil-proton angle which can be determined by knowing the geometrical distance L corresponding to the observed energy loss dE1 as follows : L=^<de1>_{1/(dE/dx)}dE.The loss dE2 is also calculated by knowing dE1. We reported the energy resolution to be 2.1% before, which has been greately improved by setting the narrow collimator arrangement. The energy resolution and the detection efficiency for 14.1MeV neutrons were 1.7% and 0.810^<-6>, respectively. The resolution is the best value reported so far.