This device uses an open-air ionization chamber with a simple amplifier circuit. It is based on the brilliant work by Charles Wenzel & Alan Yates (http://www.techlib.com/science/ion.html & http://www.vk2zay.net/category/30) among others.
The main innovation when compared to existing meters is the novel ion chamber design, made with PCB technology and standard low-cost components.
This is an experimental design, at the moment IT MUST NOT BE USED IN CRITICAL APPLICATIONS. The author(s) of this project are not liable for any damage or responsibility derived from the use or misuse of the Open Radiation Detector.
The project started as a personal challenge to build a true low cost radiation detector. For this we needed to tackle the following problems:
- Decide the detection method among all the options (see log entry 1).
- Design prototypes and test them to assess performance (see log entry 4).
- There were problems with electrostatic affecting the measurements. See how we solved it in entry 6.
- Thorough the whole project, optimize the design for pick-and-place manufacture with the least components possible.
List of specifications and how they will be met
- It must tell if an object is substantially radioactive. There is a lack of low cost options to measure alpha radiation (see log entry 1: introduction to radiation detectors). We decided to go for a ionization chamber design for the following reasons: as opposed to other detectors, ion chambers are simple and don’t require high voltages, any vacuum tubes nor delicate mica windows. Still, they are really good at detecting alpha radiation (see log entry 2: DIY ion chambers).
- The Open Radiation Detector must be small and low cost. We have already gone through many prototypes and iterations: a spark detector, and many different shapes of ionization chambers (see the log entries).
- It must use standard, modern components. Existing DIY designs that can be found online are great, but they rely upon old transistor models that are difficult to find. For this project we have studied more up-to-date options (see log entry 5).
- Preference goes to facilitating pick-and-place assembly. Existing DIY projects use recycled tin cans and hand-made parts. We have designed an ion chamber that is built with low cost SMD components and can be assembled with pick-and-place machines. These components originally had completely different purposes, but we arranged them to work as an effective ion chamber (see log entry 4).
- It must be open source. We don’t believe in patents, specially in the field of safety. The on-line maker community is the best place to share this design and ensure that it reaches the places and applications that may benefit from the Open Radiation Detector.
Will it be world changing?
The goal of this project is to facilitate the identification of radioactive hazards by creating a low cost & mass-producible detector.
Read more: Open Radiation Detector