Developing a small portable neutron detector for detecting smuggled nuclear material
Illicit nuclear material such as plutonium emits small amounts of fast neutrons which are generally not in the everyday background of ionizing radiation, unlike gamma radiation which is common everywhere. Detection of fast neutrons is therefore a strong indicator of illicit nuclear material when detected at places such as border crossings or other security checkpoints. The main technological challenge of detecting fast neutrons is doing so in a way that distinguishes such detected particles very reliably from detected gamma events, i.e. so-called “gamma blind” radiation detectors. Some technological solutions exist, but are generally either large-scale bulky devices (e.g. using high-pressure gas cylinders) not suitable for hand-held application, or not sufficiently sensitive for real-world use.
A detector approach using wavelength-shifting fibers to extract light from a scintillation material mixture is under development in collaboration between ETH Zurich and the Paul Scherrer Insitute (PSI) which shows great promise in meeting the needs previously described. Signal processing includes readout of a Silicon photomultiplier and identifying bursts of scintillation light which correspond to fast neutrons. First prototypes have been designed and tested, but the signal processing hardware is currently not small-scale or mobile, and is therefore in need of further development in order to find a suitable solution for in-field security applications. This is the purpose of this project. There is interest in this project for example by Labor Spiez (Swiss ABC-protection agency). Due to the nature of silicon photomultipliers, and some particularities of the detector physics involved, a very fast and digital solution is likely to be most suitable, which is why use of FPGA is planned. This preferably has an appropriate user interface, battery power for mobility, and data-logging/communication with a central location for analysis of data from multiple sensors.
Tasks are planned as follows:
- Familiarization with the physics and current signal processing setup of the detector prototype
- Conceptual study of how to meet the needs of the target application in a mobile device (very likely to be FPGA-based solution, although alternative will be considered)
- Design and implementation of a solution, including programing existing microcontroller or FPGA evaluation boards and/or a custom PCB
- Testing of the prototype with gamma and neutron radiation sources at PSI and analysis of results
Status: In Progress
- Lorenz Becker Sander
- 25% Theory
- 50% Implementation
- 25% Testing