X射线质量厚度测量研究

拟合了能量在200 keV以下的中低能光子质量减弱系数的实验数据,发现基于光电效应,瑞利散射和康普顿散射的半经验公式能够精确地模拟光子质量减弱系数的实验数据.计算了X射线管发出的连续能谱X射线经过吸收片过滤后的能谱分布,发现能谱呈峰形.将它用作物质的透射模拟实验,发现在一定厚度范围内,它与某单能光子的强度减弱规律相同而等效.利用拟合求得的减弱系数半经验公式,求出并讨论了这一等效能量的数值和规律.讨论了X射线束的光电流和光子计数两种探测方式,计算发现经过低能过滤后的X射线,两者都能够反映强度减弱规律.进行了吸收实验,证明低能过滤X射线束的能量探测的确可以用来进行物质的质量厚度测量.

Research of mass thickness measurement utilizing X-ray

The data of X-ray attenuation coefficients under 200 keV were fitted using a semi-experiential formula based on photoelectric effect, Compton and Rayleigh scattering. It was found that the semi- experiential formula accorded with the data accurately. A series of spectra of X-ray generated from the cathode ray tube passing through a nickel steel absorber and aluminum samples of different thicknesses were simulated. It was found that these spectra exhibited peak distributions. Simulative experiments were done and it was found in a certain range of mass thickness, the attenuation rule of X-ray was like that of the single energy gamma ray. Based on the semi-experimental expression, an equivalent energy was advanced. Detection methods for photon electric current and for photons counting were discussed and it was found that low energy part of X-ray after absorbing was like the attenuation rule of a single energy X- ray in both detection methods. An absorption experiment was finished. It was proved that mass thickness could be measured utilizing X-ray attenuation.