Development of a 4pi position-sensitive detectors and a study on the measurement of nuclear-reaction cross sections induced by polarized neutrons in the energy region around MeV

点击翻译按钮获取中文摘要

In the present research, a charged particle counter-telescope system with wide angular acceptance has been developed for the investigation of the double differential cross section of neutron-induced nuclear reactions. The counter-telescope system is capable of identification of particle sorts, measurement of the total energy and ray-tracing of the passing path.As a part of this counter-telescope system, a two-dimensional position-sensitive gas counter was newly designed and constructed. In this gas counter, two-dimensional position sensing is achieved with a combination of two different methods for each axis ; one is the charge division method with a backgammon-shaped electrode and the other method is besed on the measurement of electron drift time. The sensitive area is about 100x100 mm^2 and the inherent position resolution has been estimated at 0.75 mm in FWHM.This position-sensitive gas counter has transmission capability. Therefore, angle determination of passing particles is available by the ray-tracing when several such detectors are stacked.A SSD,48x48 mm^2 sensitive area and 300 mum thickness, was put behind the ray-tracing system to measure the total energy of incident charged particles. A personal-computer based data-acquisition system has been developed with CAMAC electronics. On-line data analysis is possible in this data-acquisition system.Finally, the practicability of this counter-telescope system was successfully demonstrated at the Tandem Accelerator facility of Kyushu university using about 9 MeV protons which were elastically scattered from a polyethylene target by the neutron beam.