Hidex 300SL液闪装置测量低水平氚水活度的参数优化

Hidex 300SL是基于三管符合计数/两管符合计数(TDCR)方法绝对测量低水平氚水活度的液闪装置。本工作基于该装置对标准非淬灭氚水样品进行测量研究,明确了系统的探测效率与TDCR的关系;讨论了该装置的测量模式、符合时间等参数对计数率、衰变率和TDCR的影响;并对仪器的运行参数进行选择优化,在"H-3"测量模式及35ns的符合时间窗下,系统对3 H的探测效率达73.2%,衰变率稳定性好于0.47%;最后对空气本底样品进行测量,评估了该装置对氚水样品的探测下限,为后续环境低水平样品的精确测量提供有益参考。

Parameters Optimization of Hidex 300SL Liquid Scintillation Counter for Measuring Activity of Low Level Tritium Water

Hidex 300SL is the liquid scintillation device based on triple-to-double coincidence ratio(TDCR)method for absolutely measuring the activity of low level tritium water.The relationship between the detection efficiency of the system and the TDCR was established by an unquenched standard tritium water sample measurements.The influences of counting rate,disintegrations rate and TDCR were also discussed.Additionally,a detailed optimiza-tion study of the instrument operation parameters was carried out.The system detection efficiency of 73. 2% and the stability better than 0. 47% were obtained with "H-3"measure-ment model and 35 ns coincidence gate.Finally,the detection limits were evaluated by an air background sample measurements,which can provide useful references for the accurate determination of tritium concentration in environmental water.