| 摘要 |
PROBLEM TO BE SOLVED: To automatically stop and start negative-feedback control, and automatically make initial setting in starting the negative-feedback control in a beam stabilizer system for a charged particle beam device. SOLUTION: A negative-feedback circuit 18 is provided with an operational amplifier 20 to convert output currents from two electrodes of a detection slit 9 into voltages, and operate difference between them, a subtracter 23 to take output of the operational amplifier 20 to be inputted to one input terminal, an amplifier 24 to amplify output of the subtracter 23 to output a negative- feedback control signal, and a switch 40 connected to an output end of the amplifier 24. When prescribed operation is conducted by an operation display part 1, a control part 3 puts the switch 40 off to stop the negative-feedback control. When the operation is not conducted for a prescribed time after that, the control part 3 takes the output of the operational amplifier 20 through an AD converter 21, and this is outputted to a DA converter 22 to put the switch 40 on. The negative-feedback control is thus favorably restarted. COPYRIGHT: (C)2003,JPO
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