Impact of oscilloscope connections and bandwidth on signal formation from a SiPM coupled to a LYSO scintillator for gamma spectroscopy

This article explores the signal produced by a silicon photomultiplier (SiPM) coupled to a LYSO scintillator in gamma spectroscopy using time and frequency-domain measurements with an oscilloscop. Analyses were performed to address the influence of coaxial cables and oscilloscope probes in the measurements. Limitations of the oscilloscopes bandwidth on the extracted pulses were studied, as well as investigation of the effect of the ambient disturbances, using the two types of cable connections. The analytic Fourier transform of the pulse is analyzed, to indentify the parameters correlating both time and frequency domain. Since there are no further additional amplifiers or signal conditioning stages after the sensor, the results represent the unfiltered signal shape collected by the oscilloscope input impedance. Conclusions are presented as guidelines and design trade-offs concerning the instrumentation and pre-amplifier design.