To provide a feeble light detection method capable of multichannel constitution of photodetection part, and detection of both photons even when arrival times of the photons are overlapped.
A pulse signal detection shaping addition circuit 54 has a discrimination information imparting part 56. A pulse current which is a detection signal of a photon detector is converted into a voltage signal by a multichannel amplifier. An output signal PD from the multichannel amplifier is inputted into a comparator 70 constituting a signal conversion part 60 of the discrimination information imparting part 56. The comparator 70 changes an inputted signal into a rectangular wave having a constant voltage and outputs it. The rectangular wave is converted into a signal having a constant pulse width by a waveform shaping part 62 and inputted into a voltage conversion part 64. Resisters R1-R4 constituting the voltage conversion part 64 differentiate the voltage level of an output pulse from the waveform shaping part 62 following a specific ratio, and imparts the discrimination information enabling discrimination of a photon detector outputting the detection signal. A signal to which the discrimination information is imparted is synthesized by an addition part.
KIMURA NORIAKI
YUMII TAKAYOSHI
HAYASHI HIROYOSHI
YOSHIDA TAKUJI
Okubo Misao