中国散裂中子源快循环同步环形加速器横向准直器上质子束流损失造成的中子场分布

Distribution of Neutron Field Induced by Proton Loss Around the Transverse Collimators on a Rapid Cycling Synchrotron of China Spallation Neutron Source

利用蒙特卡罗模拟软件FLUKA对中国散裂中子源快循环同步环形加速器中主准直器的中子场分布进行计算和分析,得到中子在铁屏蔽体和混凝土屏蔽体表面的总注量率、能谱和时间分布及其他次级粒子能谱。计算结果表明,屏蔽体阻挡和慢化了中子,使中子注量率减小且能谱分布向低能方向转移。从中子的能量和时间分布结果来看,中子场具有明显时间波动性,脉冲周期约为125μs。短周期的脉冲中子场在快响应中子宽谱探测器研发和标定方面具有很好的应用前景。

In this paper,the neutron field distribution of the main collimator in a rapid cycling synchrotron of China Spallation Neutron Source(CSNS RCS)is calculated and analyzed by using the Monte Carlo simulation particle transport code FLUKA.The total fluence rate,energy spectrum,time distribution,and the secondary particle energy spectra of neutrons on the surface of iron shielding and concrete shielding are obtained.The calculation results show that the shielding blocks and slows neutrons,reduces the neutron fluence rate and transfers the energy spectrum distribution to the low energy direction.From the results of neutron energy and time distribution,the neutron field has an obvious time fluctuation,and the pulse period is about 125μs.The short pulse neutron field has a good application prospect in the development and calibration of fast response neutron wide spectrum neutron detectors.