Quantitative Method of Measuring Spot Size of Microfocus X-ray Generator

Microfocus X-ray generators have been extensively used for magnification radiography. In these applications, the sharpness of an image depends on the X-ray source size. Therefore, it is important to evaluate and optimize the X-ray spot quantitatively. Although several methods have been devised to date, some require complicated systems whereas others are not fully quantitative. Here, we introduce a simple, practical, and quantitative method that makes use of the penumbra of a knife edge. Because the method is very simple, it can be readily integrated as an auto focusing system of a focal spot.