Context

Characterisation of the gamma radiation field is essential for accurate dosimetry. Indeed, physical dosimeters can show a strong energy-dependent response. Knowledge of the radiation spectrum and its spatial distribution enables the implementation of energy corrections. Computational dosimetry directly depends on the accuracy of radiation field characteristics to define the source terms. This is especially important for working environments where complex gammas fields are encountered. For example, multiple sources, sometimes mixed, can be present in facilities being decommissioned, resulting in spatially heterogenous fields; while, in interventional radiology rooms, the x-ray source settings and position are frequently adapted during a procedure, resulting in rapid changes in energy and position.

The cadmium zinc telluride (CdZnTe or CZT) spectrometers have received increased attention over the last years for their promising properties. CZT spectrometers have good energy resolution, are lightweight and relatively inexpensive compared to existing gamma spectrometers.

Objectives

This project aims to characterize a specific CZT spectrometer for supporting computational dosimetry research in the field of decommissioning and interventional radiology.

The main project objectives are:

• Characterising the CZT spectrometer response in (i) reference laboratory conditions, and conditions illustrative of (ii) decommissioning and (iii) interventional radiology.
• Determining the spectrometer efficiency by comparing laboratory measurements to Monte Carlo simulations for (i) reference laboratory conditions, and conditions illustrative of (ii) decommissioning and (iii) interventional radiology.

Tasks

To achieve these objectives, the candidate will have to:

• Plan, prepare and perform measurements in various environments.
• Develop a Monte Carlo model of the spectrometer and simulate its response in various environments.
• Analyse, report and compare the results of measurement and simulations.