Characterization of a mixed-sinusoid multiplexing scheme with silicon photomultipliers and an inorganic scintillator

Use of silicon photomultipliers (SiPMs) in radiation detection and imaging systems has been dramatically growing, and, because of their small size, the ability to effectively readout multiple SiPMs in a single channel is a critical objective to developing multichannel SiPM-based systems. Therefore, we have developed a relatively simple multiplexing method for SiPMs based on adding a specific sinusoid to the SiPM signal waveform prior to digitization, where the sinusoid serves as the tagging signal. This method has been previously successfully tested with organic scintillators, and this work characterizes its applicability to inorganic scintillators, specifically LYSO crystals with two different SiPMs. The energy and timing resolution is found to be largely unperturbed by this method for appropriate sinusoids, and excellent signal origin reconstruction is obtained. The ideal tagging sinusoids for adding have frequencies greater than 5 MHz and smaller peak-to-peak amplitudes of approximately 50 mV. The potential to use this method with detection systems comprised of both organic and inorganic scintillators is also demonstrated and discussed in detail.