This is a prototype of an ionisation chamber-based radiation detector for OpenRelief. It is designed around a Nanode but could easily make use of another Arduino-compatible board with Ethernet. The steps involved in its operation are as follows:
- Briefly pull the JFET source low to discharge the chamber wire
- Take a voltage reading
- Take a second voltage reading
- Calculate the voltage drift
Design Files / Code
You can download the design files and the code here:
There are two posts detailing the development of the OpenRelief radiation detector on DesignSpark.
The first is entitled ‘A Treacle Tin Radiation Detector‘ and covers the initial build process. In it Andrew explains that while “the Geiger counter has become synonymous with radiation detection […] there are many ways to achieve this other than using a Geiger-Muller (GM) tube. The ionisation chamber works on similar principles to the GM tube, but is an incredibly simple design that can be constructed from an old tin can and which does not require the use of high voltages and an inert gas and halogen fill.”
The second is entitled ‘An Ionisation Chamber Shield for OpenRelief‘ and details the construction of an inverter to replace the bank of batteries previously used for bias power supply. Andrew explains that “to recap, the bias voltage is applied across the ionisation chamber electrodes, between which tiny currents flow when ionising radiation enters the chamber. Using four PP3 batteries in series provided a bias of 36v, which is possibly suboptimal in addition to not being terribly convenient.”
The radiation detector is licensed it under the Solderpad Hardware License, version 0.51.
The People Behind The Radiation Detector
Andrew is an artist, electronics hacker and open source advocate. He acted as BT’s Open Source Strategist, establishing company-wide open source policy and process and representing them at a number of bodies including The Linux Foundation and ATIS. Andrew co-founded the Electron Club in 2006 — one of the UK’s first hackerspaces, and founded and runs OSHUG, a monthly open source hardware meet-up in and around London, UK.