APPARATUS FOR DETECTING LUMINOUS ENERGY

摘要

The current signal from the anode (12) of a photomultiplier tube (10) is converted into a voltage signal (V1) by a current-to-voltage converter (30), and the voltage signal (V1) is compared with a reference signal (V0) by a comparator (50). When the received luminous energy is smaller than a predetermined quantity, the comparator (50) judges that the voltage signal (V1) is smaller than the reference voltage (V0), and a power source (60) applies a constant voltage to the photomultiplier tube (10). A signal processor (80) calculates the received luminous energy based on the voltage signal (V1). When the received luminous energy is greater than a predetermined quantity, the comparator (50) judges that the voltage signal (V1) is greater than the reference voltage (V0), and the power source (60) applies such a voltage to the photomultiplier tube (10) that the voltage signal (V1) approaches the reference voltage (V0). A buffer (70) amplifies the output signal from the comparator (50), and the signal processor (80) calculates the received luminous energy based on the voltage signal (V2) output from the buffer.