| 摘要 |
PROBLEM TO BE SOLVED: To set electron-ray probe current for each magnification, to lessen the time for analysis in low magnification, and to improve sensitivity for X-ray detection, by previously setting plural converging lenses for every magnification of X-ray mapping, and having the size of an electron ray spot watch with a pixel of the X-ray mapping. SOLUTION: Previously stored current values are set by a converging lens control system 14, according to the magnification automatically selected in the time of X-ray mapping, thereby the X-ray sensitivity (signal-to-noise ratio) is improved. That is, the electron ray 3 generated by an electron gun 1 is incident on converging lenses 4a, 4b via a convergence diaphragm 5 and is converged on a sample 12 on the spot. Here, a converging lens control system 14 automatically sets the converging lenses 4a, 4b at previously stored values according to the magnification set by a scanning coil control system 9. Thereby, the diameter of an electron-beam probe at low magnification can be made nearly equal to the area on a sample 12 surface corresponding to one pixel, so that electron-beam probe current can be increased.
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