A neutron tomography facility at a low power research reactor
A neutron tomography facility at a low power research reactor
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DOI：
10.1016/s0168-9002(01)00917-2
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发表时间：
2001-09-21
影响因子：
1.4
通讯作者：
Rauch, H
中科院分区：
文献类型：
--
作者：
Koerner, S;Schillinger, B;Rauch, H
中子射线照相（NR）在无损检测领域以及在基础研究中的许多应用中提供了一种非常有效的工具。穿透试样的中子束被试样材料衰减，并由二维成像装置检测。由于中子根据辐射衰减的基本规律衰减，图像包含了样品内部的材料和结构信息。与x射线相反，中子可以被一些轻物质衰减，例如氢和硼，但却能穿透许多重物质。因此，NR可以获得传统方法无法获得的重要信息。然而，结构的许多方面，无论是定量的还是定性的，都无法从二维传输图像中获得。因此，人们对三维中子成像很感兴趣。在奥地利原子能研究所250千瓦的TRIGA Mark II反应堆上安装了中子层析成像设备。该束位置的中子通量为1.3 x 10(5)个中子/cm(2)s，束直径为8 cm。对于样品内部的三维层析重建，需要从不同视角拍摄物体的透射图像。因此，在样品位置安装了一个由步进电机驱动的转台，该转台与计算机运动控制系统相连。同时设计了一种基于中子敏感闪烁屏和ccd相机的电子成像装置。它可以由计算机控制，以同步软件的检测器和转台的目的是自动化的测量。合理的曝光时间可以低至每张图像20秒。这意味着一个样品的完整断层扫描可以在一个工作日内完成。采用滤波反投影算法计算三维体素阵列。(C) 2001年Elsevier Science B.V.出版
Neutron radiography (NR) provides a very efficient tool in the field of non-destructive testing as well as for many applications in fundamental research. A neutron beam penetrating a specimen is attenuated by the sample material and detected by a two-dimensional (2D) imaging device. The image contains information about materials and structure inside the sample because neutrons are attenuated according to the basic law of radiation attenuation. Contrary to Xrays, neutrons can be attenuated by some light materials, as for example, hydrogen and boron, but penetrate many heavy materials. Therefore, NR can yield important information not obtainable by more traditional methods. Nevertheless, there are many aspects of structure, both quantitative and qualitative, that are not accessible from 2D transmission images. Hence, there is an interest in three-dimensional neutron imaging. At the 250 kW TRIGA Mark II reactor of the Atominstitut in Austria a neutron tomography facility has been installed. The neutron flux at this beam position is 1.3 x 10(5) neutrons/cm(2)s and the beam diameter is 8 cm. For a 3D tomographic reconstruction of the sample interior, transmission images of the object taken from different view angles are required. Therefore, a rotary table driven by a step motor connected to a computerized motion control system has been installed at the sample position. In parallel a suitable electronic imaging device based on a neutron sensitive scintillator screen and a CCD-camera has been designed. It can be controlled by a computer in order to synchronize the software of the detector and of the rotary table with the aim of an automation of measurements. Reasonable exposure times can get as low as 20 s per image. This means that a complete tomography of a sample can be performed within one working day. Calculation of the 3D voxel array is made by using the filtered backprojection algorithm. (C) 2001 Published by Elsevier Science B.V.