A study of the secondary source phenomenon due to the presence of off-focal radiation in industrial micro-focus cone-beam X-ray computed tomography (XCT) systems and its influence on dimensional measurements is presented. Although off-focal radiation production within X-ray tubes has been studied for medical X-ray imaging systems, its properties and its effects on dimensional measurements in industrial XCT systems have not been discussed prior to this research. The study comprises: evaluation of the geometrical properties of off-focal radiation through a theoretical and experimental study of two-dimensional projection images of the scanned objects, verification of these properties using computer simulations and evaluation of the impact of the secondary source on dimensional measurements using experimental and simulation approaches. In addition, ways to minimise the effects of off-focal radiation are discussed, and reference samples for characterising the properties of off-focal radiation are proposed.

提出了对由于工业微焦点锥束X射线计算机断层扫描（XCT）系统中存在离焦辐射而引起的次要光源现象的研究，以及其对尺寸测量的影响。尽管已经针对医学X射线成像系统研究了X射线管内的离焦辐射产生，但在进行此研究之前，尚未讨论其特性及其对工业XCT系统中尺寸测量的影响。该研究包括：通过对被扫描物体的二维投影图像进行理论和实验研究，评估离焦辐射的几何特性；使用计算机模拟对这些特性进行验证；以及评估次要光源对尺寸测量的影响使用实验和模拟方法。此外，