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通过数值模拟手段研究了源强对Rossi-α测量的影响。为了定量研究中子源强对Rossi-α测量的影响,基于MCNP软件;开发了用于计算Rossi-α分布的数值模拟工具。反应堆模型和加速器驱动次临界系统的示意模型的数值模拟结果被用于展示瞬发中子衰减常数与源强之间的关联。数值模拟结果表明,入射源强源中子强度对Rossi-α测量结果有显著影响。对于处于次临界状态的反应堆和加速器驱动次临界系统模型,在入射源强较小时,Rossi-α方法可以正确给出反应堆中子衰减常数,但当入射源强较大时,测量不能给出正确的中子衰减常数。通过研究源强和测量结果的关系,可以找到能够给出正确测量结果的最大可用源强。通过选择一个可用源强范围内的较强中子源,可以减少测量所需时间。
The effect of source intensity on the Rossi-α measurement was studied by means of numerical simulation. In order to quantitatively study the effect of neutron source intensity on Rossi-α measurement, MCNP software was developed and a numerical simulation tool for calculating Rossi-α distribution was developed. Numerical simulations of schematic models of reactor models and accelerator-driven subcritical systems were used to show the correlation between instantaneous neutron decay constants and source intensities. Numerical simulation results show that the intensity of neutron source with incident source has a significant effect on the Rossi-α measurement results. For subcritical reactors and accelerator-driven subcritical systems, the Rossi-α method gives the correct neutron decay constant at low incident source intensities but can not give correct measurements when the source intensity is large Neutron decay constant. By studying the relationship between source intensity and measurement results, one can find the maximum available source intensity that gives the correct measurement result. By choosing a stronger source of neutrons within the available source range, the time required for the measurement can be reduced.