Liquid scintillators consist of scintillating organic flours in organic solvents, and they have been used in radiation detection for many years. However, there are a number of advantages to using water as a solvent, and R&D of water-based liquid scintillators is becoming popular. Here, we have developed an alternative approach. We use quantum dots, or nano-crystals, as scintillating flours and...
Herein, we study a facile, toxic solvent-free surfactant-dependent mechanochemical synthesis of highly luminescent CsPbBr3 nanocrystals (NCs) and study their scintillation properties. A small amount of surfactant oleylamine (OAM) plays an important role in the two-step ball milling method to control the size and emission properties of the NCs. CsPbBr3 NCs capped with different amounts of...
In recent decades organic electronics have entered mainstream use in consumer electronics found in households around the world. I will present radiation sensors based on organic semiconductor technology, and in particular applications related to detection of hadronic radiation. This includes α, fast and thermal neutron radiation.
Organic semiconductor radiation detectors based on diode-like structures are well established. Here I present preliminary results on the potential for Organic Field Effect Transistors (OFET) as radiation detectors, where the nature of the OFET means that the signal is intrinsically amplified by the device.
Accurate neutron detection can be important for nuclear forensics, safeguards, and nuclear security applications. Organic scintillation detectors are used widely due to their resilience, rapid timing characteristics, and their dual sensitivity to both gamma and fast neutron events. Pulse-shape discrimination (PSD) is often used to separate gamma and neutron events as part of the analysis of...
In various critical applications, the accurate estimation of physical parameters is a necessity for ensuring public safety and effective decision-making. One such critical application where these considerations come into play is source term estimation (STE) in the context of hazardous material releases. The urgency for rapid and precise STE is accentuated by the growing risks of hazardous...
We present a summary of a commercial off the shelf data acquisition project to demonstrate the ability to use a Raspberry Pi as a data acquisition system for a multi channel readout of sensors. The system realised was capable of reading out with a 150ns sampling rate and had a 16 channel capability (expandable to 32 channels) with a touch screen interface. This could be used for radiation...
Detection of nuclear materials remains a matter of utmost importance due to potential security issues. Current detection techniques for neutrons and gammas involve using a combination of a 3He proportional counter, which allows for detection of thermal neutrons, along with a plastic scintillator, which allows for detection of gammas. This in itself creates issues as 3He is a rare and expensive...
Conventional nuclear well-logging detectors employ a neutron source downhole in parallel with a detector tool to monitor interactions of radiation with the surrounding rocks. Chemical radioisotope source replacement is desirable to reduce the number of high activity AmBe and Cf-252 sources in circulation, and replace them with electrical pulsed sources. Deuterium-Tritium (D-T) sources offer...
The safeguarding of nuclear materials and facilities is a global challenge. There are different methods to maintain nuclear safeguarding, with a primary method being the use of cameras. Therefore it is fair to consider the vulnerabilities of the elements of this method of safeguarding. One of these vulnerabilities may be neutron damage to memory cards. This project aims to investigate whether...
NNL entered two teams into the SIGMA data challenge, one internal team and one in collaboration with K.Ward at the University of Lancaster. The internal team utilises the work of K.Ward and his Poisson-FoCuS algorithm, a fast online detection method to identify anomalies. As implemented in the SIGMA data challenge the method provides information on anomalies at a temporal scale but does not...
In the field of nuclear security, safeguard and non-proliferation antineutrino flux profiles have the potential to be used as a verification tool to ensure operations at a nuclear facility are being accurately reported. Due to this potential, there is an interest in performing antineutrino measurements on an operating reactor site, such as the Hartlepool Advanced Gas Reactor. To help assess...
The applications of neutron monitors extend to many critical fields such as leak detection in nuclear power plants, cosmic ray detection for space-weather monitoring, and homeland security in preventing the unauthorised transport of nuclear materials. The industry standard neutron monitor technologies are based on helium-3 but due to the volatile price and scarcity of this rare isotope, the...
We present a novel and condensed imaging technique for thermal neutrons utilizing a fast event mode optical camera (Timepix3) combined with a 6Li:LYSO scintillator. Previous studies have demonstrated the high spatial-resolution imaging capabilities of 6LiF:ZnS scintillators compared to traditional neutron imaging [1]. However, the proposed 6Li:LYSO scintillator exhibits a significantly faster...
Radiation detectors mounted on unmanned aerial vehicles (UAVs) can be utilised to screen freight passing through a seaport for radioactive material that could be used in radiological dispersal or improvised nuclear explosive devices. Payload and battery life restrictions limit the size of the sensor package that can be deployed on a UAV and as a result a low-cost system is likely to deploy...
The Simulation and Optimisation of Position-Sensitive LaBr3 Detectors for Compton Imaging
By Emily Richardson and Dr Fraser Holloway
The University of Liverpool
Abstract: Scintillator-based Compton cameras are a practical choice for nuclear security applications; however, the energy resolution is comparatively poorer than semiconductor-based approaches and accurate...
Brief overview of the SIGMA data challenge, where it came from, who is involved and where it was intended to go.
The Poisson Functional Online Cumulative Sum (Poisson-FOCuS) method is a method for solving the likelihood ratio test of $\text{Poisson}( \lambda)$ null against $\text{Poisson}(\mu \lambda)$ alternative where $\mu > 1$, i.e. searching for an increase in count. This can be thought of as equivalent to testing all possible anomaly start points $\tau \leq T$ at each timestep $T$, giving a...
The threat from nuclear terrorism represents a complex challenge for global governments. Although current systems for detecting threats from illicit materials exist, each have inherent limitations. It is crucial that a system can detect material being transported with malicious intent which is likely to cause health risks and require extensive clean-up operations. One monitoring approach...
In order to reliably detect and identify weak radiological/nuclear sources in real-world environments while maintaining low probabilities of false alarm, it is necessary to employ algorithms that are able to account for temporally and spatially varying backgrounds, exploit the full information content of acquired spectra, and provide interpretable detection metrics.
Over the last several...
Overview of the GROUSE algorithm work done to date by AWE on the SIGMA
Data Challenge data.
Q&A from the Sigma Session, followed by Workshop conclusion