Tim Kuhlbusch's BetaBoard Is a Pocket-Sized, Raspberry Pi RP2040-Powered Particles Physics Lab
Built using a modular design, this business card-sized tool is made for accessible education in particle physics.
Physicist, electrical engineer, and radio ham Tim "DJ8TK" Kuhlbusch wants to put a particle physics lab in your pocket with the BetaBoard, a low-cost particle detector in the footprint of a business card — and which can be produced in small quantities for less than $10 each.
"This project is a cheap semiconductor particle detector for educational purposes," Kuhlbusch explains of the BetaBoard. "I was inspired by the CERN DIY particle detector, but wanted to make it more accessible and simpler to use. Apart from the educational purposes, I've noticed this is quite a nice business card for me: it represents my physics background, electrical engineering skills, and also my interest in sharing knowledge. All while matching the form-factor of a business card."
The BetaBoard builds atop a home-made particle detector designed by Oliver Keller while at CERN, and serves the same purpose: to detect and distinguish particles and electrons and measure their energies between 33keV and 8MeV. Kuhlbusch's take on the project, though, aims for a lower cost while also reducing noise levels, and makes the move to the popular and low-cost Raspberry Pi RP2040 microcontroller as its driving device.
The latest revision of the BetaBoard design uses a stack of four PCBs, with the electronics housed in the lowest of the four. The next two layers act as a shield for the analog electronics, which include amplified PIN diodes acting as alpha and beta particle detectors, with a top layer for protection hosting a schematic showcasing the device's operating principle. By covering the windows over the particle sensors with electrical tape, light is excluded — and the diodes can react to the target particles instead.
"As an example for the experiments possible with this small detector I've measured the rate of a 15g package of potassium carbonate," Kuhlbusch writes of the BetaBoard's testing. "Due to the low activity we only get a few recorded pulses per minute. Therefore each data point in the figure [pictured] took 23 minutes. It is clearly visible that the rate drops with increasing distance."
The project is documented in full on Hackaday.io, with hardware design files and source code published to GitHub under the permissive BSD 2-Clause license.