公开(公告)号：JPS5821578A

公开(公告)日：1983-02-08

申请号：JP12085181

申请日：1981-07-31

Applicant: SHIMADZU CORP

Inventor： AKUTAGAWA TETSUO ,  HIRAOKA MASARU

IPC: H01J47/08 ,  G01T1/18

Abstract: PURPOSE:To achieve earier measurement starting time while preventing damage to a meter by discharging charged electric charge quickly through a clamp circuit while clamping overvoltage therewith. CONSTITUTION:Ionization current generated from an ionization chamber 1 is amplified with an arithmetic amplifier 2 and a negative output current is generated to deflect a pointer of a meter 3. On the other hand, the arithmetic amplifier 2 is connected to the ground on the negative side of a power source 4 thereof via a series circuit of a variable resistance 5 and a diode 6 and two diodes 7 and 8 are connected to an output terminal thereof. When output voltage V0 of the arithmetic amplifier 2 is V0>V2-(VR+V1), it is clamped to V2-(VR+V1). When it is V0