Development of a light readout based on silicon photomultipliers for a wavelength-shifting fibre gamma camera

A small prototype of 10 SiPMs reading out 10 WSFs was assembled and used to cover a 1 cm2 imaging area with a collimated 57Co source scanned in 1 mm steps, demonstrating the feasibility of applying the SiPMs in a CsI(Na)-WSF gamma camera. Two different algorithms were used for positioning and image reconstruction, obtaining encouraging results operating at 20 °C and with a common bias voltage applied to all SiPMs. The observed dependence of the detection efficiency with temperature indicates that further cooling is necessary in order to achieve better positioning results than previous work using PSPMTs. The development of larger prototypes with detection areas up to 100 cm2 is under way, considering the use of a water cooling system for the SiPMs.