Dr Aled Horner - Evaluating the Suitability of Organic Semiconductor Detectors for Nuclear Security

Wednesday 22 Oct 2025, 13:30 → 15:00 Europe/London

610 (G.O. Jones Bulding)

https://cern.zoom.us/j/68995045975?pwd=fdpw3jZ4ZPU61gbaTtDASbS03qKbf4.1

About the speaker: 

Aled completed his undergraduate integrated Master’s in Physics with Particle Physics at Royal Holloway University of London in 2019, where the 4th year course was intercollegiate, so he attended some lectures here at Queen Mary as well as at UCL. He did a summer placement in 2018 at ISIS Neutron and Muon Source in Oxfordshire, improving existing analysis software for neutron imaging which resulted in his first publication. 

After the Master’s, Aled took a break from studies and worked in pensions in Croydon for almost 2 years before starting his PhD here at Queen Mary in 2021. He initially applied for an ATLAS PhD position working with Ulla but during the interview was asked if he would also like to apply for an unlisted nuclear security project which had only just gotten funding confirmation. Four years later he submitted his thesis on nuclear security last month and is now preparing for his viva on the 11th of November. In the meantime, Aled has begun a 6-month postdoc role with Dr Seth Zenz. Four years after not getting that PhD position he is finally working with ATLAS.

13:30 → 14:00 Biscuits/Coffee/Socialization

14:00 → 15:00 Evaluating the Suitability of Organic Semiconductor Detectors for Nuclear Security

Feasible alternatives for thermal neutron detectors based on 3He have been searched for
over the past near 20 years. These can be used in a wide variety of industries: nuclear
security and safeguarding, the medical industry for neutron therapy beam monitoring,
non-destructive imaging, and as part of nuclear and particle physics experiments. A
number of different alternatives exist to the gas-based 3He detectors, including the
organic semiconducting detectors utilising boron for boron-neutron capture which are
described here. Organic materials allow for high scalability, generally low costs of
manufacture, and excellent tuneability, however a number of drawbacks still remain to
this technology. Low counting efficiencies lead to expensive bespoke read-out equipment
requirements.

In this presentation, work done investigating the suitability of this technology for the specific
context of nuclear security will be given. With reference to two real-life scenarios, the
capability of the detectors fabricated in-house at Queen Mary University of London,
London, UK, will be discussed based on a suite of alpha irradiation data obtained
at Queen Mary and neutron irradiation data at external neutron sources based at
the National Physical Laboratory, Teddington, UK, and at the University of Glasgow,
Glasgow, UK. A number of brief studies are discussed on the improvement on the existing
technology: improvements to the qualities of films are reported, environmental effects
investigated, and gamma blindness from numerous sources considered. A number of
organic materials are used throughout this project. One of the three isomer forms of a
novel material is particularly highlighted, oCbT2-NDI, a polymer in which an icosahedral
carborane (a cluster of boron, carbon, and hydrogen) is included in the monomer backbone.
Here is described the first successful alpha and neutron radiation detection using
this type of material.

This presentation also introduces the findings that a large component of the signal being
read out by these detectors under alpha irradiation in fact originates with ionisation of
air. This phenomenon is discussed in detail as well as suggestions on how to improve
the organic detector technology further when moving to the future with this project.

Convener: Dr Aled Horner (Queen Mary University of London)