用于超灵敏小型迴旋加速器质谱计的微通道板粒子探测器  

A microcbannel-plate detector for high-sensitivity small cyclotron mass spectrometry

作　　者：张映箕[1] 魏永钦[1] 王秋玉 钱文国 张锡麟[1] 陈茂柏[1] 

机构地区：[1]中国科学院上海原子核研究所

出　　处：《核技术》1991年第4期221-227,共7页Nuclear Techniques

基　　金：国家自然科学基金

摘　　要：我们制造并测试了为超灵敏小型通旋加速器质谱计研究设计的单粒子探测系统。探测器由Al_2O_3打拿极、微通道板电子倍增器和阳极三部分组成。入射离子沿80°角方向轰击打拿极,以0.8电子/keV的转换系数产生数目与离子能量成正比的次级电子,每个电子在不同的通道管内单独放大至饱和,阳极收集的电荷数与入射离子能量成正比。用选择甄别阈的方法可以有效地将离子计数与本底分开。从实测数据外推到40keV K或Ar离子时可知:相应于90％计数效率的本底率为10^(-3)/S。探测系统的能量分辨△E=6.5keV,可以用于测量极低能量的重离子谱。A particle detector designed for the high-sensitivity small cyclotron mass spectremetry was made and tested. The detector consists of an Al2O3 conversion dynode, a microchannel-plate e'etron multiplier and an anode. Each ion that strikes the dynode at 80° angle ejects a few tens of secondary electrons, which enter separate channels of the microchanne'-piate and are then independently multiplied to a saturated pulse height. The charge collected by the anode is proportional to the ion energy. This permits a pulse-height discrimination against background. Data taken in an isotope separator are extrapolated and the background rate is found to be lower than 10-3/s at 90% efficiency for 40keV K or Ar ions. The energy resolution of the detector is 6.5keV, suitable for the spectrum measurement of very low energy ions.

关 键 词：微通道板 粒子探测器 质谱计 

分 类 号：TL817.4[核科学技术—核技术及应用]