单能电子半吸收厚度测量中射线吸收强度计算方法研究

在单能电子半吸收厚度测量实验中,现用的取谱方法存在信号区间选择困难、本底扣除不准、主观性太强等问题,导致测量结果误差较大、实验可重复性较差.文中利用蒙特卡罗模拟结合实验验证的方法研究了准单能电子在铝中的输运过程,研究了TPA法、Covell法、Wasson法和半峰净计数法对半吸收厚度计算的影响,结果发现Covell法信号区间选取简单、本底扣除方便、误差最小,适合用于单能电子半吸收厚度计算.

Study on the absorption intensity calculation method in the measurement of the semi-absorbing thickness of mono-energetic electron

In the measurements of the semi absorbing thickness of mono energetic electrons, the spectrum unscrambling methods used are difficult to select the signal interval, deduct the spectral background and contain great subjectivity, so these methods are hard to repeat the experiment and can produce large measurement error. In this paper, the Monte Carlo code MCNP is used to simulate the mono energetic electron transport in aluminum. And the TPA law, Covell law, Wasson law and the existing semi peak net count method are applied to calculate the half absorption thickness. By comparing the calculated results, we find that the Covell law is easy to select the signal interval and has the smallest error in the results, which is suitable to the measurement of the semi absorbing thickness of mono energetic electrons.