Developmental and applicational study of neutron CT-scan measurement

将中子共振吸收光谱（N-RAS）技术与计算机断层成像技术相结合，用于均匀和非均匀块状物体的核素分布分析和测温。这种新方法提供了核素位置或温度在块状物体平面横截面上的二维分布，作为遥感和非破坏性分析的信息。测量是通过记录每个样品物体的方向和中子狭缝位置的光谱来进行的，以包括物体内部的所有空间信息。对狭缝位置和旋转角度的所有组合，利用二维傅里叶变换或最大熵方法进行CT计算，重建的核素位置与实际物体结构一致，重建的温度分布与估计的真实的分布接近。为了证实这种方法的有效性，我们进行了模拟计算。该模拟是在物体具有与实验相同的估计温度分布和统计条件的情况下进行的。实验的模拟正确地再现了结果。为了获得更高的精度，我们需要实现更精细的空间分辨率和更好的N-RAS统计依赖。这种新方法的发展与利用中子进行遥感和非破坏性测温的新工业应用有关，因此可能对各种工业发展有用。

Neutron resonance absorption spectroscopy (N-RAS) associated with computer tomography was applied to nuclide distribution analysis and thermometry for homogeneous and inhomogeneous bulk objects. This new method provides 2-dimensional distributions of nuclide positions or temperatures on the planar cross-section of a bulk object as information from remote-sensing and non-destructive analysis.The study was carried out on the neutron resonance absorption spectrometer DOG installed at KENS at the High Energy Accelerator Research Organization (KEK) in Japan. Measurements were undertaken by recording the spectra for each sample object's direction and neutron slit position to include all the spatial information inside the object. With the spectrum for the all combinations of the slit positions and the rotation angle, the CT calculations were carried out using the 2-dimensional Fourier transformation or maximum entropy methods.The nuclide positions reconstructed by CT agree with the actual object structure, and the reconstructed temperature distribution is close to the estimated real distribution. To confirm the validity of this method we have undertaken simulation calculations. This simulation was carried out as the object had the same estimated temperature distributions and the statistical conditions as the experiment. The simulation of the experiment correctly reproduced the result. For greater accuracy, we need to achieve finer spatial resolution and better statistical reliance on N-RAS. The development of this novel approach has links to new industrial applications utilizing neutrons for remote-sensing and non-destructive thermometry ; thus being potentially useful for various industrial developments.