Advanced Scintillator Material for High Energy X-ray Imaging.

Lead Research Organisation: University of Bristol
Department Name: Physics


The overarching project aims to develop a revolutionary analysis technique with a particular focus on monitoring of nuclear waste drums as a collaborative project between the Interface Analysis Center (IAC), Sellafield, Queen's University Belfast (QUB) and the STFC Central Laser Facility (CLF). By firing an extremely high-energy laser for a very short duration, an intense spot of x-ray radiation is generated and projected towards detector plates. In a similar manner to medical x-rays, any object placed between the bright source of x-rays and either photographic film, or digital image plates, is captured in detail. However, because a very high energy source is used, imaging of uranium waste, one of the densest materials on earth, is possible.

Since 1952 Sellafield has been responsible for safe storage and reprocessing of all the UK's nuclear waste. Decades of research and development have resulted in more manageable forms of nuclear waste. However, a whole host of problems remain, particularly with the ageing nuclear waste that has been stockpiled since the 1960's. Before long term storage in a geological disposal facility is considered, the composition and degradation state of the waste material and containment vessel needs to be established. Due to the radioactivity and dangerous corrosion products formed during storage, a destructive investigation of the waste containers is considered too hazardous to be performed. Therefore, a non-destructive evaluation of the containers is proposed.

For a visual inspection of the waste, high-energy x-rays are desired to create an image of the sample in storage. Typical means of producing x-rays do not achieve both the resolution required to identify corrosion products nor the energy needed to penetrate through the large, dense, waste containers. Therefore, it has been proposed that the Vulcan laser at the central laser facility (CLF) is utilised to generate the necessary high-energy x-rays required for this analysis.

This particular research proposal focuses on the development of the detection methods used to capture the x-ray images of nuclear waste containers. Specifically, we aim to deploy a novel transparent scintillator (referred to as an acronym of its elemental constituents as GLO - gadolinium lutetium oxide) capable of converting the high-energy x-rays into visible light for imaging. The key property of the high-energy x-rays that we require is the ability to travel through objects unimpeded. However, the advantage they present is also the reason why it is difficult to collect an image from them - they pass through most detector materials too easily! Therefore, the use of a high density, high atomic number material (which is the GLO scintillator) greatly increases the probability that x-rays will interact and convert to visible light photons. These are then captured on low-light CCD cameras providing a picture of the container contents.

The final stage of the overarching project involves replacing the single-shot Vulcan laser with a rapid-fire DiPOLE laser capable of 10 shots a second (or more). This, combined with our proposed new detector arrangement, will enable far better image acquisition and even 3D tomography (like a medical CT scan) if the drums are rotated during acquisition.


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Description DASA - Manufacture of GLO Scintillator material for high-energy imaging applications
Amount £250,000 (GBP)
Organisation Defence Science & Technology Laboratory (DSTL) 
Sector Public
Country United Kingdom
Start 01/2021 
End 07/2022
Description Industry Fellowship
Amount £90,000 (GBP)
Organisation Royal Academy of Engineering 
Sector Charity/Non Profit
Country United Kingdom
Start 09/2021 
End 09/2023
Description Professorial Research Fellowships Scheme
Amount £625,000 (GBP)
Organisation Royal Academy of Engineering 
Sector Charity/Non Profit
Country United Kingdom
Start 03/2021 
End 02/2026
Description William Penney Fellowship
Amount £120,000 (GBP)
Organisation Atomic Weapons Establishment 
Sector Private
Country United Kingdom
Start 05/2022 
End 05/2025
Description AWE high energy imaging partnership 
Organisation Atomic Weapons Establishment
Department National Nuclear Security Programme
Country United Kingdom 
Sector Public 
PI Contribution For the AWE we have been providing expertise on laser-driven gamma and neutron pulses as well as novel fast neutron imaging technologies using Diamond with a scintillation backing material. We are also supporting them in the establishment of a national high energy imaging facility.
Collaborator Contribution The AWE have co-funded a Royal Academy of Engineering professorial fellowship for me to run for 5 years until February 2021. This is a financial contribution of £50,000 per year, plus additional funding specifically for projects and secondments of members of my team.
Impact Outputs have inlcuded: - A modelling study report on the use of diamond for fast neutron imaging - Conducting a joint experiment at the LANSCE neutron facility in the USA to test deuterium infused diamond with a scintillator backing material as a fast neutron imaging material. - Undertaking a deuterium infusion study of diamond (at the AWE) to determine the deuterium (H-2) solubility as a function of pressure and temperature. The collaboration is ongoing and we will conduct further experiments in the next 12 months.
Start Year 2017
Description Collaboration with CLF, Harwell 
Organisation Rutherford Appleton Laboratory
Department Central Laser Facility
Country United Kingdom 
Sector Academic/University 
PI Contribution We worked with the CLF to conduct some 'proof of principle' experiments (May 2015) using the Vulcan Laser to demonstrate the possibility of using laser driven gamma-ray projection radiography and neutron flash measurements to examine nuclear waste packages.
Collaborator Contribution The CLF team provided access to Vulcan and led in conducting the experiments with us. They also assisted with data processing and their contracts team drew up and filed a joint patent.
Impact We have a research paper (not yet published), a patent (filed November 2015: P143188GB00) and are awaiting the outcome of an STFC IPS grant proposal for furthering the gamma scanning technology.
Start Year 2014
Description Henri Royce Institute - User Access on GLO development 
Organisation Henry Royce Institute
Department Henry Royce Institute – University of Sheffield Facilities
Country United Kingdom 
Sector Academic/University 
PI Contribution We have utilised a core funded postdoc and PhD student to conduct research into the fabrication of GLO material. We have conducted analysis on GLO powder (precursor to the imaging plate material) and prepared it for Hot Isostatic Pressing (HIP). We have also begun to work with UCL towards a second phase of work related to manufacture of nano-powder precursor GLO using hydrothermal synthesis.
Collaborator Contribution This has been the contribution of funding from the AWE towards this project - triggered by HRI access to do HIP and SPS testing for GLO material
Impact No outcomes as yet
Start Year 2019
Description Waste inspection partnership with Sellafield Ltd 
Organisation Sellafield Ltd
Country United Kingdom 
Sector Private 
PI Contribution We have been developing feasibility data and a business case towards proving the use of petawatt lasers for generating multi-modal gamma-ray and neutron beams to conduct nuclear waste package inspection. We have been developing a series of test samples in partnership with the CLF and Sellafield for testing with the Vulcan laser system at the CLF.
Collaborator Contribution Sellafield have been assisting in development of our understanding of the application for the technology at Sellafield site. Sellafield have also been assisting with the provision of some test samples (10 years old) to be shipped from Springfields to Bristol to then subsequently be examined using Vulcan.
Impact In addition to having published the initial feasibility work we have also filed a joint patent (GB 1519758.5) .
Start Year 2016