133Ba活性炭滤盒源制备方法研究

¹³³Ba（T_1/2=10.51 y）因与¹³¹I（T_1/2=8.02 d）谱形相似，常作为替代核素用于碘监测仪探测效率传递标准源的制备。本文采用旋转蒸发方式制备均匀分布¹³³Ba活性炭滤盒源，经测量，各滤盒之间单位质量活性炭的净计数率相对标准偏差小于1%，符合均匀性要求。6个月稳定性结果与衰变时间修正后的活度偏差≤1%，满足稳定性要求。活度测量结果与标准溶液加入量在约1%范围内一致。采用滤纸平面源制备了指数分布状态的¹³³Ba活性炭滤盒源，对不同分布滤盒源探测效率进行测量和模拟计算，两者在3.3%范围内符合，但均匀分布与指数分布¹³³Ba滤盒源探测效率相差≥13%，建议采用多个传递标准源的方式测得碘监测仪对几种典型分布滤盒源的探测效率，以方便用户使用。

Study on Preparation Method of133Ba Activated Carbon Filter Cartridge Source

¹³³Ba（T_1/2=10.51 y）,with a similar gamma spectrum as ¹³¹I（T_1/2=8.02 d）, is often used as a substitute nuclides for the preparation of standard sources of detection efficiency for iodine monitors. In this paper, the uniform distribution of¹³³Ba activated carbon filter cartridge was prepared by rotary evaporation. The measured uniformity was better than 1%, the stability at 6 months was better than 1%, and the activity measurement was consistent with the standard solution in the range of about 1%. The¹³³Ba activated carbon filter cartridge with exponential distribution was prepared by using the filter paper. The detection efficiency of different distribution filter cartridge was measured and simulated, which was consistent in the range of 3.3%, but the detection efficiency of uniform distribution and the exponential distribution¹³³Ba filter cartridges were different, about 13% or higher. It is recommended to use multiple transfer standard sources to measure the detection efficiency of iodine monitors for several typical distribution filter cartridge sources for user convenience.