Design of array switching circuit for multiplex nuclear pulse signal

Commercial multi-channel energy spectrometers have good performance, they have multiple input signal channels and multi-channel analyzers, which can simultaneously acquire the energy spectrum of multiple nuclear pulse signals. But the input signal channel of this general multi-channel energy spectrometer cannot be switched between the internal multi-channel analyzers, and an input signal channel can only be fixed to the corresponding multi-channel analyzers. Hence, to resolve this issue, this paper designed a nuclear pulse signal array switching circuit. The core of the array switching circuit is a switch array chip with low internal resistance and high bandwidth, which controls the signal connection between the input signal channel with the multi-channel analyzers. Using 137Cs and uranium ore as radioactive sources, the energy spectrum test and spectrum data analysis were carried out using a NaI detector, respectively, when the nuclear pulse signal passed through and did not pass through the array switching circuit. The results showed that the circuit demonstrates little effect on the energy resolution and linearity of the multi-channel analyzers but causes a small drift of the high-energy photopeak, and improve the reliability of the circuit by energy spectrum data accumulation. This circuit can make the application of a multi-channel energy spectrometers more flexible and reliable.