Research Fellow: scintillation detectors for aerial surveys (071718)

Development of drone-deployable detector for environmental monitoring

This project will develop a new high resolution gamma and neutron detector for use in drone-based aerial surveys of nuclear materials. This compact and lightweight detector utilises LaBr and GAGG scintillators coupled to a silicon photomultiplier (SiPM), replacing previous CsI/PMT detector technologies. The detector will be able to carry out high resolution gamma surveys, capable of separating 100-300 keV gamma signatures of special nuclear material from NORM U/Th gamma peaks. This project is in partnership with Imitec Ltd, an SME specialising in drone-based surveys of nuclear materials

The aims of the project are to develop a new high resolution lightweight detector that will be suitable for drone-based aerial surveys of nuclear materials. By combining the high gamma resolution of LaBr scintillator, the neutron sensitivity of GAGG, and the low mass SiPM readout technology, the detector will provide significant performance improvements on existing NaI detectors which use traditional PMT readout. The specific objectives of the project are:

To design and construct a LaBr/GAGG scintillator detector suitable for gamma spectroscopy from 100 keV to 1 MeV, and neutron detection. The detector should be sensitive to both SNM and NORM gamma signatures To carry out a laboratory characterisation of the detector performance using a range of laboratory gamma and neutron sources, and NORM samples. At the end of the project, to deliver a prototype detector unit to Imitec for drone-based mapping trials.

The main purpose of the project is to improve on the existing performance of NaI gamma detectors which are currently used by Imitec for drone mapping. NaI detectors show relatively poor energy spectral resolution which prevents clean discrimination of gamma lines from SNM and environmental NORM peaks. Additionally, by replacing the traditional PMT with a SiPM sensor the payload weight is reduced and the drone performance is improved.

Outline Work Program

This project will design, construct, and characterise new scintillation detectors using LaBr and GAGG coupled to SiPM readout. One of the main objectives of the project is to assess the suitability of the detectors for use on a drone for aerial mapping of nuclear materials.

The main tasks for the project are as follows:

Task 1: Design and Construction of SiPM scintillation detectors

The specification and technical performance of the detectors will be agreed, and a detailed design produced. We will purchase the required materials, eg. LaBr and GAGG scintillator material from Epic Crystal (China), and SiPM from SensL (Eire). The detector will be assembled using custom components fabricated using the group’s 3D printer.

Task 2: Laboratory Characterisation of Gamma performance

We will assess the performance of the detectors in terms of gamma ray spectroscopy (detection efficiency and spectral resolution) using a range of laboratory radioisotope sources such as 137Cs, 22Na, 57Co and 60Co. Measurements will also use environmental NORM samples which have been previously obtained by Surrey from the oil industry.

Task 3: Characterisation of Neutron sensitivity

We will assess the performance of the detector’s neutron response using the department’s AmBe neutron source. For GAGG in particular there is a sizable gadolinium cross-section for thermal neutron reactions, and we will assess the performance of GAGG for thermal neutron sensitivity and gamma background rejection.

Project Duration

This project is currently funded for 6 months, from September 2018, however our expectation is that this project will be funded for a total of 12 months. We are currently applying for a further 6 months funding, and this additional funding will be confirmed shortly.

Please note, it is University Policy to offer a starting salary equivalent to Level 3.6 (£31,302) to successful applicants who have been awarded, but are yet to receive, their PhD certificate. Once the original PhD certificate has been submitted to the local HR Department, the salary will be increased to Level 4.1 (£32,236).

Closing Date: 23 Sep 2018
Category: Research & Teaching