内充气正比计数管测量37Ar活度中壁效应的理论研究

通过分析³⁷Ar衰变产生的X射线和俄歇电子在内充气正比计数管灵敏体积中的逃逸及计数管在³⁷Ar活度测量中的壁效应，得出X射线在正比计数管中的逃逸是产生壁效应的主要原因，提出了压力指数外推方法。使用MCNP模拟X射线和俄歇电子在内充气正比计数管中的输运，模拟结果与理论分析结论一致。比较模拟得出的壁效应值与实验测量的壁效应值可知，实验给出的壁效应值是可信的。本工作的研究结果为37Ar测量方法提供了理论支持。

Wall Effect of Internal Gas Proportional Counter in 37 Ar Activity Measurement

By analyzing the escape of X-ray and Auger electron generated by 37Ar, wall effect of internal gas proportional counter in 37Ar activity measurement was studied theoretically. Escape of X-ray is the main reason for wall effect of internal gas proportional counter in 37Ar activity measurement. Thus, the exponential extrapolation method of pressure was proved correctly. X-ray and electron transport in proportional counter was simulated by MCNP, and the simulation result accords with theory analytic result. The value of the wall effect was calculated by MCNP, and it is close to experimental result. This work offers theory support for 37Ar detection.