电流模式下微型裂变电离室参数对探测性能的影响

裂变电离室在工作时,其内部气体中持续地发生着电离和复合过程。为了进一步了解这些过程对探测性能的影响,需要从等离子体物理的角度来研究裂变电离室。借助BOLSIG+以及电流模式下微型裂变电离室的基本理论模型,计算了电极的几何尺寸、裂变率以及气体电离度等参数对探测器饱和区电压范围的影响,并对结果进行了讨论。此外,根据不同电离度情况下的计算结果,对高温导致探测器饱和区电压范围变小这一现象给出了一种可能的解释。

Influence of parameters of micro fission chamber operated in current mode upon the detection performance

Background: When a fission chamber is operating for neutron detection, the ionization and recombination processes occur continually in its inner gas. Its detection performance correlates with these processes. Purpose: This study aims to further understand the influence of these processes and parameters of micro fission chamber on the detection performance from the aspect of plasma physics.Methods: BOLSIG+ software and basic theory model of fission micro chamber are applied for the simulation of the detection performance in current mode. The voltage range of saturation zone is taken as function of parameters such as geometry dimension of the electrode size, fissile rate and gas ionization degree.Results:The voltage range of saturation zone increases with the sensitive length, but decreases with fission rate and gas ionization degree. An optimal geometric electrode size exists for maximum voltage saturation zone.Conclusion: According to the computation results at different gas ionization degrees, one possible reason for the reduction of the voltage range of saturation zone at high temperature is explained.