A three-dimensional integrated gamma-ray imaging and vision system

Supervisor: Dr Andrew Boston

A comprehensive understanding of the nature of legacy waste is an essential part of the nuclear decommissioning process. This studentship targets the process of locating and identifying the nature of the gamma-ray emitting radioisotopes present in legacy nuclear waste. The ability to locate, characterise and correctly partition the waste into intermediate, low and free release level categories is key to this strategy.

The fusion of three-dimensional spectroscopic gamma-ray images with three‐dimensional stereoscopic optical images offers the potential for a step change in the performance of gamma-ray imaging systems. The ability to locate, identify and measure the dose of gamma-ray emitting radioactive material is of crucial importance to the sectors of Energy, Security and Environmental monitoring. Existing technology falls short of the desired performance characteristics.

This collaborative knowledge exchange project will develop a field capable imaging gamma-ray sensor, couple it with an existing 3-D vision system and provide control software and reconstruction algorithms for real time image fusion. The ability to locate and identify radioactive material to high precision with this system will lead to reliable quantification of waste into low/intermediate level brackets, with the potential to significantly reduce the cost and time of decommissioning.

The University of Liverpool Nuclear Physics group has pioneered the development of near field‐of-view (FOV) semiconductor-based Compton Gamma-ray imaging systems for potential use in security, medical and nuclear decommissioning applications. Standard gamma imaging devices (such as the Radscan 800) utilise scintillator based detector technology, which offers a relatively poor energy resolution. They derive their position resolution from a collimator system, which limits the sensitivity and field of view of the camera.

A Compton camera instead relies on electronic collimation derived from the kinematics of the gamma-ray interaction with the sensors. This innovation offers a much more compact and less weighty camera head, yielding the future potential for a lightweight, portable device. The systems offer a large field of view (typically 180 degrees) and full three-dimensional imaging sensitivity, which eliminates the need for raster scanning. Combined, these advantages offer the ability to image with much higher efficiency and/or a real time imagining capability. Crucially they also offer higher resolution spectroscopy and the ability to image gamma‐radiation up to relatively high energy (~ MeV) – something impossible with a collimator based system.

The studentship will:

(1) Optimise existing high-sensitivity imaging-capable semiconductor-based gamma-ray sensors for in-situ wide field of view imaging applications.
(2) Fuse optical stereoscopic and 3D gamma-ray images over a wide field of view and provide an appropriate visualisation interface.
(3) Deliver an image reconstruction solution that provides a fully calibrated environmental intensity map.

For more details contact Dr Andrew Boston (ajboston@liverpool.ac.uk)

To apply, please complete the online application form that is available at http://www.liv.ac.uk/physics/postgraduate/postgraduate-research/physics-mphil-phd/applying/