Study on Preparation Method of ¹³³Ba 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 of ¹³³Ba 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%. The ¹³³Ba 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 distribution ¹³³Ba 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.