Low-Power Charge Division Circuits for Wireless Applications Based on Silicon Photomultipliers

In this paper, we present a dedicated charge division circuit (CDC) as readout system for wireless detectors based on silicon photomultiplier (SiPM) arrays coupled to scintillators. In the proposed readout circuit, the SiPM output current is split into two symmetric signals by a pair of diodes, so it was called diode coupled symmetric charge division (DCSCD). The circuit was investigated using LTSPICE, fabricated as a printed circuit board and characterized. Its performances were compared with that of the traditional discrete positioning circuit (DPC) scheme. Testing the two CDC networks on a $16\times 28$ array of SiPMs, we found that image reconstruction is significantly compromised when the DPC configuration is connected to few SiPMs, while the diode-based CDC configuration presents a very high-quality image histogram independently on the number of the connected photosensors. The proposed electronics features very low-power consumption when compared with commercial solutions and it is, therefore, suitable for battery-operated device, which requires a power-efficient design. Indeed, the DCSCD electronics requires less than 10 mW of static power to read out the $16\times 28$ array of SiPMs, demonstrating the efficacy of the proposed diode-based CDC as passive readout circuitry and opening the route for the development of wireless gamma camera systems.