Novel active interrogation system for Special Nuclear Material (SNM), leveraging a compact fusion neutron source in conjunction with particle detectors

Novel active interrogation system for Special Nuclear Material (SNM), leveraging a compact fusion neutron source in conjunction with particle detectors.

Supervisors: Dr Mahmoud Bakr and Professor Tom Scott

The project is available through the Nuclear Threat Reduction Network (NTR-Net) Centre for Doctoral Partnership. NTR-Net is a new research and innovation network that will enhance the activities of the UK’s NTR Programme and create a pipeline of skilled people to support our national capability and preparedness. The initiative is hosted at the University of Bristol and supported by AWE, the Ministry of Defence and the Home Office.

Project importance:

Detecting illicit materials used for chemical, biological, radiological, nuclear, and explosive weapons, known as CBRNE threats, is crucial for global counter-terrorism efforts. While portable/transportable devices and stationary devices have been deployed for on-site nondestructive inspection at ports of entry, there has been a gap in addressing special nuclear materials (SNMs) like Pu-239 and U-235. Breakthroughs are pressing to support mobile applications that detect SNMs hidden in cargo containers or suspicious unattended bags.

Introduction:

Detecting materials employed in chemical, biological, radiological, nuclear, and explosive weapons, collectively termed CBRNE threats, is pivotal for global counter-terrorism endeavours. Interrogation of nuclear threats is a crucial topic for nuclear security to prevent terrorist threats and the illicit smuggling of special nuclear materials (SNM) at ports and seaports. For decades, nuclear security has predominantly focused on investigating SNMs, particularly Pu-239 and U-235. Numerous passive and active interrogation methods have been developed and implemented worldwide. Passive detection systems, which seek emitted neutrons and/or photons, prove effective for investigating nuclear threats such as Co or Cs, with a distinct spontaneous fission signature. However, these methods prove insufficient for detecting Pu-239 and U-235 concealed within a container due to their weak spontaneous fission signature. Conversely, active interrogation systems utilise probing neutrons and/or photons and subsequently analyse secondary emissions to investigate SNM. These systems hold promise for detecting concealed threats within shielded and unshielded containers. Nevertheless, the induced fission signature resulting from probing neutrons or photons can be challenging to distinguish due to ambiguity in neutrons’ energy and intensity, making differentiation between probing and fission neutrons difficult.

The project focus:

This PhD project focuses on developing and applying a nondestructive inspection technique based on the active interrogation of SNM. The technique employs the threshold energy neutron analysis (TENA) method and utilises a compact neutron source and particle detectors. The TENA method is a recently developed technique by the group at Kyoto University for detecting neutrons based on the neutron-in-neutron-out method. To enable using the TENA method, a compact neutron source based on the inertial electrostatic fusion device (IECF) is used as a probing neutron source. The secondary neutron from the fission through the SNM is detected using the centrifugally tensioned metastable fluid detector (CTMFD). The primary experiment

for the method and tools has been conducted, and the preliminary results are promising. An introductory paper for the technique has been accepted for publication in the Journal of Nuclear Sciences and Techniques.

The student will undertake experimental and simulation activities to optimise the parameters controlling the detection of the SNM, such as the neutron flux, neutron energy, irradiation time, number of detectors, detector operating conditions, etc. The student will also partially conduct some experimental work with our colleagues at Kyoto University, Japan.

Candidate requirements:

A master’s degree in physics, Nuclear Engineering, or a related field is typically required.

Completing relevant coursework in physics, nuclear physics, experimental methods, and simulation modelling is essential. Courses in particle physics, nuclear engineering, and detection techniques would be advantageous.

Skills: Proficiency in experimental techniques, data analysis, and simulation modelling is essential.

Being familiar with relevant software tools for simulation and data analysis, such as MATLAB, COMSOL Multiphysics, Geant4, MCNP, or similar programs, is desirable.

Strong mathematical skills, including proficiency in calculus, differential equations, and statistical methods, are necessary.

A well-written statement of purpose outlining the candidate’s research interests, motivation for pursuing a PhD, and career goals in experimental and simulation modelling physics for nuclear materials detection is required.

Interview: will be conducted for the shortlisted candidates

The application process may include a successful interview with faculty members or the admissions committee. This interview may assess the candidate’s research interests, academic background, and suitability for the program.

Funding:

This fully funded project covers tuition fees and provides a tax-free stipend (depending on circumstances) based on the UKRI rate (£19,237 for 2024/25). Due to the terms and conditions of the NTR-Net funding, candidates shall generally be required to meet special nationality rules.

We encourage you to make informal enquiries to Dr Mahmoud Bakr ([email protected]) if you have any queries or would like to discuss the project details.

How do I apply?

(1) CV, (2) a Personal Statement, which is a one- to two-page document introducing yourself and outlining your motivation for PhD research, and (3) a transcript of any qualifying degrees (completed and/or underway).

(2) Deadline to apply is 16 June 2024