摘要
为优化中子多重性探测器设计、指导多重性实验的正确实施,论述了利用蒙特卡罗程序获取中子时间脉冲序列链进行多重性随机模拟的方法。提出了一种新的三均分算法计算中子衰减时间常数,解决了生成时间序列链超大矩阵排序问题。基于大空腔探测系统,利用无死时间的时间序列链经过数据解谱,分析利用252 Cf中子源标定的参数在钚样品多重性测量过程中的匹配问题,考察了探测效率的差异和二阶矩三阶矩的门份额的适用性,并提出了移位寄存器(MSR)处理过程中门宽的优化选取原则。模拟了大量不同质量的钚样品,建立了大空腔探测系统的质量相对标准偏差(RSD)曲线。结果表明:252 Cf源标定的探测效率比Pu样品的效率差3%左右,比值法与公式法计算的门份额完全一致,大空腔探测系统对公斤级的金属钚在1000s时间内的质量测量RSD约为4%。
For optimization design of a neutron multiplicity counter and forming a guidance of the experiment,we describe a detailed method using Monte Carlo codes to generate neutron time pulse chain for stochastic simulation.A new fitting algorithm to calculate the die-away time was proposed.The applicability of calibrated parameters using 252Cf to plutonium samples was evaluated on the big cavity detection system,and the detection efficiency bias was calculated.Using the optimizing principle,the gate width in MSR algorithm was given for several plutonium samples.The curve of expected assay precision （RSD） vs 240 Pu effective mass was given.The simulation results showed that the difference of detection efficiency between 252Cf and Plutonium was 3％.No difference was observed in gate fraction between using ratio method and formula method.With a measure time of 1000 s,the big cavity detection system had a RSD of about 4％ for kg level plutonium metal.Those results will play an important role in determining necessary measurement time in plutonium measurement.
出处
《强激光与粒子束》
EI
CAS
CSCD
北大核心
2014年第1期216-221,共6页
High Power Laser and Particle Beams
基金
国家自然科学基金项目(11175164)
关键词
中子多重性
随机模拟
钚部件
质量测量
参数计算
neutron multiplicity
stochastic simulations
plutonium sample
mass measurement
parameter calculation
