利用 MCNP 对阵列电离室电极片电子发射产额的影响研究

摘要

In this paper, by carrying out MCNP simulations on the electron emission yield induced by 1.25 MeV ( rays from electrodes of C, Al, Fe, Cu, Ag, W, Pb in array ionization chamber models, we studied the influ-ence of the electrodes'thickness and material on their gamma ray induced electron emission yields.The calcu-lated results show that, with the increase of the thickness ( over 0.01 mm) and the electron density of the elec-trodes, the yields of the emitted electrons from the array ionization chamber's electrodes decrease apparently, and that the length of the electrodes should be selected with due consideration of the electrodes'material.%本文通过对7种材质（ C、Al、Fe、Cu、Ag、W、Pb）电极片在1．25 MeV入射光子束作用下的电子发射产额进行模拟计算，研究了厚度和材质对阵列电离室电极片电子发射产额的影响关系。研究结果表明：阵列电离室电极片在辐射光子作用下的电子发射产额在电极片厚度较厚时（特别是大于0．01 mm时），随着电极片厚度或电子密度的增大而明显减小。另外，电极片长度的选取需要结合电极的材质适当考虑。