X射线管焦点是影响影象质量的重要因素,一般用单次针孔成象法测试其有效焦点.1992年我厂进口了两个PhilipsMCN165型金属陶瓷X射线管,采用两次针孔成象新方法测试其焦点形状和尺寸.1 测试原理焦点尺寸主要取决于X射线管阴极灯丝的形状和大小.阳极靶被电子撞击的部分叫做实际焦点;实际焦点在射线窗口的投影称为有效焦点,如图1.假设电子束近似平行地射向阳极,然后利用小孔成 X-ray tube focus is an important factor affecting the image quality, usually with a single pinhole imaging method to test the effective focus 1992 I plant imported two PhilipsMCN165-type cermet X-ray tube, using two pinhole imaging The new method to test its focus shape and size.1 The principle of the test Focus size depends on the shape and size of the cathode filament of the X-ray tube The part of the anode target impacted by the electrons is called the actual focus; the projection of the actual focus on the ray window is called the effective focus, As shown in Figure 1. It is assumed that the electron beam is directed approximately parallel to the anode and then made with small holes