Huang P H, Kase K R, Bjärngard B E
Med Phys. 1981 May-Jun;8(3):368-74. doi: 10.1118/1.594959.
The "quality of radiation" for a high energy x-ray beam can be specified by its attenuation curve in a selected material. The inverse Laplace transform of the attenuation curve can be used as an approximate indication of the energy spectrum of the beam. Existing mathematical procedures for this purpose have been evaluated and were found to poorly represent measured transmission data for 4 MV x-rays from a linear accelerator. The transmission data between 1 and 0.002 could be fitted within the experimental uncertainty by expressing the logarithmic transmission as a second order polynomial of attenuator thickness. The inverse Laplace transform them becomes a Gaussian function of the attenuation coefficient. This new version of "attenuation analysis" provides a practical method for specification of the quality of the radiation in this energy range.
高能X射线束的“辐射质量”可通过其在选定材料中的衰减曲线来指定。衰减曲线的拉普拉斯逆变换可用于近似指示束的能谱。已对为此目的的现有数学程序进行了评估，发现其不能很好地表示来自直线加速器的4MV X射线的测量透射数据。通过将对数透射率表示为衰减器厚度的二阶多项式，可在实验不确定度范围内拟合1至0.002之间的透射数据。然后，拉普拉斯逆变换就变成了衰减系数的高斯函数。这种新版本的“衰减分析”提供了一种实用方法，用于指定该能量范围内辐射的质量。
