1.1 目的- 本指南包含教程介绍，以使读者熟悉单个非计算机X射线康普顿散射层析成像（CST）固有的操作能力和局限性。还包括对CST的物理和典型硬件配置的简要描述。这种单一技术仍用于少量检查。这并不是涵盖目前用于无损检测和安全屏幕筛选的各种康普顿散射技术的全面指南。 1.2 优势- X射线康普顿散射层析成像（CST）是一种放射无损检测方法，具有以下几个优点: 1.2.1 在不接触检查对象另一侧的情况下进行X射线检查的能力； 1.2.2 X射线束不需要完全穿透检查物体，允许部分检查厚物体。厚的检查物体成为辐射屏蔽的一部分，从而减少辐射危害； 1.2.3 检查和成像物体表面特征的能力，受表面特征的影响最小； 1.2.4 当使用传统的透射光束X射线成像方法时，能够从通常产生低对比度图像的低被摄物对比度材料中获得高对比度图像；和 1.2.5 获取物体特征深度信息的能力，从而提供三个- 尺寸检查。获得深度信息的能力前提是使用具有窄接受角的高度准直探测器系统。 1.3 应用程序- 本指南未规定哪些检查对象适合或不适合CST。与大多数无损检测技术一样，CST具有高度的应用特定性，因此需要首先在应用实验室证明该方法的适用性。本指南不提供CST技术的标准化实践或应用指南。没有提供关于接受或拒绝CST检查对象的指导。 1.4 限制- 与所有无损检测方法一样，CST具有局限性，是对其他无损检测方法的补充。主要的限制是难以在高密度混凝土的厚截面上进行CST- Z 材料。CST最适用于较薄的下部 Z 材料。以下提供了使用160 keV恒电位X射线源时CST适用范围的一般概念: 布料 实际厚度范围 钢 高达约3 mm( 1. / 8. 英寸。） 铝 高达约25毫米（1英寸） 航空航天复合材料 高达约50毫米（2英寸） 聚氨酯泡沫 高达300毫米（12英寸） 该技术的局限性还必须考虑所需的 十、 , Y 和 Z 轴分辨率、成像速度、图像质量以及母材的X射线散射特性和待成像内部特征的差异。 1.5 以英寸-磅和国际单位制表示的数值应单独视为标准。括号中给出的值仅供参考。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 康普顿散射层析成像的主要优点- CST的主要优点是能够执行三维X射线检查，而无需进入检查对象的背面。CST提供了执行任何其他方法都不可能的X射线检查的可能性。 CST子表面切片图像受检查平面外的检查对象特征的影响最小。结果是一个主要包含切片平面信息的射线透视图像。散射辐射限制了正常射线照相和射线透视成像的图像质量。散射辐射对CST没有相同的有害影响，因为散射辐射用于形成图像。事实上，检查对象散射的辐射越多，CST结果越好。常规射线照相和射线透视方法不能很好成像的低受试者对比材料通常是CST的最佳候选材料。CST层析成像具有极高的对比度灵敏度和出色的空间分辨率。 5.2 限制- 与任何无损检测方法一样，CST也有其局限性。该技术适用于较厚的低密度材料。而25毫米（1英寸）铝或50毫米（2英寸）深度在塑性材料中，随着材料密度的增加，检测深度显著降低。正确的图像解读需要使用具有已知内部条件或代表性质量指标（RQI）的标准和检查对象。检查体积通常很小，约为几立方英寸，可能需要几分钟才能成像。因此，使用CST完全检查大型结构需要进行密集的重新测试- 检查量的定位可能很耗时。与其他穿透辐射方法一样，必须适当解决辐射危害。

1.1 Purpose— This guide covers a tutorial introduction to familiarize the reader with the operational capabilities and limitations inherent in a single non-computed X-ray Compton Scatter Tomography (CST). Also included is a brief description of the physics and typical hardware configuration for CST. This single technique is still used for a small number of inspections. This is not meant as comprehensive guide covering the variety of Compton scattering techniques that are now used for non-destructive testing and security screen screening. 1.2 Advantages— X-ray Compton Scatter Tomography (CST) is a radiologic nondestructive examination method with several advantages that include: 1.2.1 The ability to perform X-ray examination without access to the opposite side of the examination object; 1.2.2 The X-ray beam need not completely penetrate the examination object allowing thick objects to be partially examined. Thick examination objects become part of the radiation shielding thereby reducing the radiation hazard; 1.2.3 The ability to examine and image object subsurface features with minimal influence from surface features; 1.2.4 The ability to obtain high-contrast images from low subject contrast materials that normally produce low-contrast images when using traditional transmitted beam X-ray imaging methods; and 1.2.5 The ability to obtain depth information of object features thereby providing a three-dimensional examination. The ability to obtain depth information presupposes the use of a highly collimated detector system having a narrow angle of acceptance. 1.3 Applications— This guide does not specify which examination objects are suitable, or unsuitable, for CST. As with most nondestructive examination techniques, CST is highly application specific thereby requiring the suitability of the method to be first demonstrated in the application laboratory. This guide does not provide guidance in the standardized practice or application of CST techniques. No guidance is provided concerning the acceptance or rejection of examination objects examined with CST. 1.4 Limitations— As with all nondestructive examination methods, CST has limitations and is complementary to other NDE methods. Chief among the limitations is the difficulty in performing CST on thick sections of high- Z materials. CST is best applied to thinner sections of lower Z materials. The following provides a general idea of the range of CST applicability when using a 160 keV constant potential X-ray source: Material Practical Thickness Range Steel Up to about 3 mm ( 1 / 8 in.) Aluminum Up to about 25 mm (1 in.) Aerospace composites Up to about 50 mm (2 in.) Polyurethane Foam Up to about 300 mm (12 in.) The limitations of the technique must also consider the required X , Y , and Z axis resolutions, the speed of image formation, image quality and the difference in the X-ray scattering characteristics of the parent material and the internal features that are to be imaged. 1.5 The values stated in both inch-pound and SI units are to be regarded separately as the standard. The values given in parentheses are for information only. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Principal Advantage of Compton Scatter Tomography— The principal advantage of CST is the ability to perform three-dimensional X-ray examination without the requirement for access to the back side of the examination object. CST offers the possibility to perform X-ray examination that is not possible by any other method. The CST sub-surface slice image is minimally affected by examination object features outside the plane of examination. The result is a radioscopic image that contains information primarily from the slice plane. Scattered radiation limits image quality in normal radiographic and radioscopic imaging. Scatter radiation does not have the same detrimental effect upon CST because scatter radiation is used to form the image. In fact, the more radiation the examination object scatters, the better the CST result. Low subject contrast materials that cannot be imaged well by conventional radiographic and radioscopic means are often excellent candidates for CST. Very high contrast sensitivities and excellent spatial resolution are possible with CST tomography. 5.2 Limitations— As with any nondestructive testing method, CST has its limitations. The technique is useful on reasonably thick sections of low-density materials. While a 25 mm (1 in.) depth in aluminum or 50 mm (2 in.) in plastic is achievable, the examination depth is decreased dramatically as the material density increases. Proper image interpretation requires the use of standards and examination objects with known internal conditions or representative quality indicators (RQIs). The examination volume is typically small, on the order of a few cubic inches and may require a few minutes to image. Therefore, completely examining large structures with CST requires intensive re-positioning of the examination volume that can be time-consuming. As with other penetrating radiation methods, the radiation hazard must be properly addressed.