1　前言γ射线照射量 (防护水平 )标准装置始建于1 976年 ,采用英国标准系列镭源和一套简易移动支架 ,按理想点源和衰变规律推算理论真值 ,检定中有效探测中心和距离测量不准造成的误差较大。 1 994年 ,对整个装置进行了重建性改造 ,根据ＪＪＧ393-85γ辐射防护仪器试行检定规? 1 Introduction γ-ray exposure (protection level) standard device was built in 1976, using the British standard series of laser sources and a simple mobile bracket, according to the ideal point source and decay rule to calculate the true value of the test in the effective detection center and The error caused by inaccurate measurement is larger. In 1994, the entire installation was rebuilt, according to JJG393-85γ radiation protection equipment pilot test regulations?