衰减透射法测量高能X射线能谱

研究了基于衰减透射原理的高能X射线能谱测量与重建。利用蒙特卡罗方法对神龙一号直线感应加速器的X射线源穿过不同厚度铝时的衰减透射过程进行模拟实验。解谱方法采用迭代扰动法，对不同的初始能谱估计和测量噪声水平条件下的能谱重建进行计算分析。结果表明:实验测量不包含噪声时，选择合适的初始能谱可以获得比较准确的能谱重建结果；在实验测量数据包含5.0%高斯随机噪声情况下，X射线能谱重建计算结果仍比较稳定，与真实值偏差相对较小。

High-energy X-ray spectrum estimation by attenuated transmission method

High-energy X-ray spectrum measurement and reconstruction were investigated according to the attenuated transmission principle. Monte Carlo simulation was carried out to demonstrate the attenuation of X-rays, produced by the Dragon-Ⅰ linear induction accelerator, passing through aluminium with different thicknesses. The iterative perturbation method was applied for energy spectrum reconstruction with different initial spectrum estimations and noise levels in the measurement. The calculated results indicate that the reconstructed spectrum can achieve a good accuracy by making a proper estimation of initial spectrum when the transmission data is noise-free. For the measurement containing 5.0% random Gaussian noise, robust reconstructions of X-ray spectrum were also obtained, which showed relatively small discrepancies in comparison with the true spectrum.