| 摘要 |
PURPOSE:To realize a long service life of the titled detector by connecting both opening parts of a secondary electron multiplier glass thin tube, when an electric discharge has occurred between both of them, and preventing the subsequent discharge. CONSTITUTION:A plate 17, an anode 19 and an intermediate electrode 18, of a multi-channel plate detector 15 in a vacuum container are led out to the outside through a seal mechanism and connected to a protective device 20. A voltage between the plate 17 and the intermediate electrode 18 is compared with a setting signal for discriminating a signal component of a charged particle and a discharge signal component, by a comparator 24, and by a comparing signal being larger than a set level, an FF circuit 25 is set to a set state, by which the plate is short-circuited to a ground point by operating a switching element 23. In such a way, the discharge generated by deterioration of the degree of vacuum becomes only one creeping discharge, therefore, a long service life of the titled detector can be realized.
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