内充气正比计数管系统绝对测量^(135)Xe活度

Absolute Measurement of ^(135)Xe Activity by Using Internal Gas Proportional Counting

1996年9月10日联合国大会通过了全面禁止核试验条约(CTBT),稀有气体氙放射性监测是条约国际监测系统中的重要内容,国内外通常采用平面HPGeγ谱仪系统或β-γ符合系统进行监测样品的测量,如何准确刻度系统的探测效率是放射性氙同位素测量的难点。本文阐述了内充气正比计数管系统绝对测量放射性氙活度的原理和方法,在仔细测试内充气正比计数管系统性能基础上,绝对测量了135Xe活度,测量结果为38.87(1±1.0%)Bq/ml。实验证明用内充气正比计数管测量惰性气体氙的绝对活度是可行的,可为放射性核素实验室探测系统提供准确的绝对刻度标准。

The Comprehensive Nuclear Test Ban Treaty（CTBT）was adopted by the General Assembly of United Nations in 10 september 1996. Noble gas xenon Monitoring is one of important components of CTBT International Monitoring System （IMS）. Monitoring sample is generally measured by HPGe γspectrometer and β-γcoincidence system. How to determine the detect efficiency of the system accurately is a nodes of radioactive Xe measurement. This article introduces the theory and method of activity measurement of radioactive Xe by internal gas proportional counting. The performances of the system are well tested. Then the activity of ^130Xe is measured absolutely by this equipment. The result is 38. 87（1 ± 1. 0 %）Bq/ml. The activity standard of Beijing Radio-Nuclide Laboratory can be provided by this system.