| 摘要 |
PURPOSE:To enable binary coding conversion to be carried out with high accuracy, by converting an analog signal generated at a high potential level on a micro-channel plate into a binary coded signal after the DC component of the analog signal is corrected by means of two amplifiers having different frequency characteristics. CONSTITUTION:Secondary electrons 5 emitted from sample 6 are selected through an energy analyzer 4 so that only those of high energy may be incident on a micro- channel plate 3 to be boosted there, further to be introduced in a high potential side signal processing circuit 9. Current signals are converted into voltage signals through a Current-voltage conversion circuit 10, one of which is amplified to an optional potential level through a high frequency amplifier 11, while only the DC component of the other of which is amplified to an optional potential level through a low frequency amplifer 12, and a signal waveform including no DC component is obtained by subjecting the above-mentioned signals to subtraction through a high frequency differential amplifier 13. A binary coded signal obtained by inputting the lastly obtained output signal into a pulse formation circuit 14 is transmitted as an optical ON/OFF signal, to a low potential side signal processing circuit 17, via a driver circuit 15, by means of a photoisolator 16.
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