If you're using large-diameter scintillators or you want to do coincidence measurements, this 2x2 array board will be very helpful to you. It packs 4 SiPMs total in a 2x2 matrix, resulting in 4 times the active area, but is only marginally larger in size when compared to the standard carrier board.

You can even build yourself a (very) simple gamma camera. Well, considering it's only 4 pixels, it won't be too helpful, but it surely can be an interesting experiment. I'll probably do some testing in this regard and keep you updated.

The Mini SiD is ideal for this kind of use case since you need four different signal channels -- one for each SiPM. You can cut off the excess space on the PCB and make everything pretty compact. If all the digital outputs of the Mini SiDs go into different microcontroller interrupts, you can count pulses on each individual SiPM and do coincidence measurements. That'll greatly reduce total system noise for a single scintillator crystal!

All the hardware files can be found on GitHub: https://github.com/OpenGammaProject/MicroFC-SiPM-Array-Board