METHOD AND APPARATUS FOR MONITORING ASTIGMATISM AND FOCUS IN ELECTRON MICROSCOPE

There are disclosed a method and an apparatus for monitoring astigmatism and the condition of the focus in a transmission electron microscope. The apparatus includes a TV camera for converting the specimen image taken by the electron microscope into a video signal, which is sent to a control unit. An image monitor, a graph monitor and image memory are connected with the control unit, as well as the TV camera. The control unit superimposes radial cursor lines on the image of a specimen displayed on the image monitor, and reads data about the pixels lying on the cursor lines from the image memory. The control unit then creates graphs showing the distributions of data about the pixels existing on the cursor lines from the data read from the memory. An array of the graphs is displayed on the graph monitor.