| 摘要 |
PURPOSE:To measure the rotation of beam section with high precision by measuring the electron beam intensity or intensity distribution of two measuring areas which are isolated from each other, and making a comparison between both measurement signals. CONSTITUTION:An electron beam from an electron gun 1 is projected on a sample or shield 8 through a convergent lens 2, beam section varying device 3, and projection lens 7. An electron beam detector 9 is placed under the sample or shield 8, and the output of the detector 9 is sent to a computer 12 through an amplifier 10 and an A/D converter 11. To a deflector 6, a signal from the computer 12 is sent through a D/A converter 13 and an amplifier 14 to shape a rectangular beam having section of desired size and shape. The detector 9 detects the electron beam intensity or intensity distribution of two measuring areas which are isolated from each other and both detected signals are inputted to the computer 12 to compare the signals with each other, thus measuring the rotation of the beam section. |
