SiPM Pocket Scintillation Detector

This device uses a Broadcom AFBR-S4N66C013 SiPM and a 16×30 mm² NaI(Tl) scintillator to make an extremely portable and powerful handheld scintillation detector.

The SiPM carrier board and the driver board are developed by NuclearPhoenix on GitHub. Huge thanks to him for his help and his projects that try to make SiPMs available for a broad range of detector enthusiasts.

While discussing on a Forum I noticed that many tend to use another type of SiPM that is easier to solder. Due to shortages in supplies of that common SiPM I decided to use the much cheaper but harder to solder AFBR SiPM. I could not find anyone on the internet that wrote something about the usability of that chip in a scintillation detector.

Using a hot air soldering station the chips BGA is soldered carefully and slowly to the carrier board. That carrier board has a filter circuit on the backside. It is then hooked up to the driver board and the surface of the SiPM is attached to the NaI(Tl) crystal window.

The Bias Voltage is adjusted to about 30V before hooking the SiPM to the driver board.

Everything is hooked to up a Raspberry Pi Pico (USB C Version) and a OLED. The treshold can now be adjusted on the driver board so we detect enough pulses but no noise.

The case was designed so that all seen above parts fit inside and also a 400mAh Li-Ion Battery with charge regulator fits below the lage driver board. (Battery and Regulator are not in the picture below) By the way, the pico does not need a separate switch mode power supply to decrease the battery voltage because it has an integrated buck-boost supply.

Keeping in mind that this detector registers about 2000 impulses per minute and works around 20 hours on a full battery, this is a beast of a miniature detector and beats every other detector that size I own.

Next I will do is optimize the user interface and integrate a buzzer.