| 摘要 |
<p>PROBLEM TO BE SOLVED: To automatically compensate temperature, in a wide range, for a dark current generated when an ion chamber system is coupled with an electric circuit system. SOLUTION: A signal input terminal 5 and a dark current input terminal 6, which are independent from each other with the identical structure, are disposed close to each other, so that the temperatures are equal at always. The currents flowing into minute current measuring circuits 7 and 8 from the terminals are converted into voltages E1 and E2, and then enter a differential amplifier 10 at the next stage. By measuring an output voltage E3 which has been subtracted, a minute current measuring device is realized which is wide- range temperature compensation type, with the effect of temperature changes excluded as possible.</p> |
