不同晶体时间响应参数对脉冲辐射测量统计涨落影响评估

Effects evaluation of pulsed radiation measurement statistical fluctuation caused by time responses of scintillators

为评估不同时间响应参数的无机晶体所造成的统计涨落对零功率堆瞬发中子时间常数α测量结果的影响,构建数值模型对其进行计算。结果表明:原本为负常数的α曲线,经过不同时间响应参数的晶体卷积后,α值由常数变成曲线;且在时间零点附近急剧变化,甚至出现正数值;晶体时间响应参数越大,偏离α值越多;对于不同的晶体,时间零点附近α值变化区间不一样,慢晶体的变化区间最长。

Different time responses of scintillators result in different fluctuation in pulsed radiation measurement which play great influence on the measurement of time constant α of zero power assembly. Mathematical models are established to evaluate the influence in this paper. Results show that the initial negative constant values of α turns to curves due to convolution of different time responses of scintillators. Values of α changes drastically and there are even positive values of α. The slower the time reoponse is, the more deviation of α. Especially, the time variation section of α changes differently around the zero point of time axis for different scintillators. The time variation section of α is the longest for the slowest time response of scintillators.