一种新型气体探测器的研制

Development of the New Type of Gas Detector

加速器质谱(accelerator mass spectrometry,AMS)技术因探测对象不同,探测器也应根据需要进行选择。为建立低能量重离子加速器质谱测量技术,本文设计制作一台新型气体探测器并调试应用。该探测器采用厚度50 nm,膜面积8 mm×8 mm的氮化硅膜作为入射窗。采用5.48 MeV的241Am源的α粒子对探测器进行调试,调试后将该探测器安装于中国原子能科学研究院的300 kV小型AMS系统上进行129I粒子测量。经模拟计算以及对探测器的调试、应用,证明该探测器具有较高的能量分辨率,可以很好的实现不同粒子的鉴别,同时测量灵敏度可达到10^-13国际水平,满足低能量重离子的测量要求。

Accelerator mass spectrometry(AMS)technology developed extremely rapidly in the late 1970 s.Since the substances to be detected are different,the detector is selected according to the different needs of the substance to be tested.The design and establishment of the gas detector were report in this paper.In order to establish a low-energy heavy ion AMS measurement technique,a gas detector with a extreme thin entrance window was developed.The detector adopts a silicon nitride film with a thickness of only 50 nm and a membrane area of 8 mm×8 mm as the entrance window.The silicon nitride film has high hardness,thinness and uniformity,so it is an excellent incident window material for the detector.In the early stage,the detector was debugged with the 5.48 MeV 241Am source alpha particle.And then,the detector was placed on a 300 kV small AMS system independently developed by the China Institute of Atomic Energy for 129I particle measurement.Through simulation calculation and debugging and application of the detector.It is proved that the detector has high energy resolution,which can realize the identification of different particles well,and the measurement sensitivity can reach the international level of 10^-13,meeting the measurement requirements of low energy heavy ions.