Imaging and Detection of Radioactive Material - Portable Gamma Ray Imaging Spectrometer (PGRIS)

Terrorist threats to the UK take many forms, often abbreviated to CBRNE (Chemical, Biological, Radiological, Nuclear and Explosive). This project will produce a prototype of an advanced type of hand-held radiation detector capable of imaging and accurate spectroscopy, which is relevant to the last three of these areas. Our device can identify precisely and locate radioactive materials that emit gamma rays. Our portable gamma-ray imaging spectrometer will be used to track down and characterise the radiation which has triggered a general purpose portal scanner.
The radiological threat comes from what are sometimes called "dirty bombs" or more generally from any method used to release radioactive material in such a way as to cause a threat to the general public. In order to deal with the radiological threat it is necessary to be able to locate and identify radioactive materials quickly. In addition, in the event that a dirty bomb is exploded, it is vital to be able to monitor the effects by establishing what radiation was emitted and its location.
The nuclear threat comes from nuclear weapons proliferation and in this case the need is to detect special nuclear materials (Uranium and Plutonium). Our device will be able to detect and locate the weak gamma rays emitted by these materials.
Explosives cannot be detected directly by a radiation detector because they normally do not emit gamma rays. However, if they are bombarded by neutrons then they will be activated and will emit characteristic gamma rays, which enable them to be detected and identified. The same technique can be used to search for illegal drugs.
There are already portable radiation detectors, but generally these use scintillators to detect gamma radiation and so the energy resolution is limited which means that gamma rays that are close in energy cannot be distinguished from each other. An alternative is to use Germanium for the detector element. In this case the resolution is very good, but the detector is very expensive and Germanium only operates well as a detector when it is cooled to temperatures around -200C. Our detector uses a semiconductor called Cadmium Zinc Telluride (CZT) which works well as a detector at room temperature. It has much better energy resolution that scintillators and is nearly as good as Germanium. There are a few other portable detectors using CZT detectors, but none which combine this good spectroscopic resolution (for identifying materials by their characteristic gamma-ray energy) with imaging capability to locate the sources of the radioactivity.

The ultimate goal of this proposal is to develop a portable gamma-ray imaging device for use in security applications. This instrument will enable detection and characterisation of radioactive materials entering the UK or in transit or storage within it. There are a number of groups of users who may benefit if this instrument is successfully developed and brought to market:
Instrument manufacturers; UK government and public; Companies needing to run security checks on vehicles or cargo, e.g. port authorities, air freight hubs, police, coastguards, armed forces; Staff tasked with carrying out such security checks; STFC and University of Liverpool; Nuclear industry.
The key impact of this project is that it will de-risk the process of bringing to market a portable directional gamma-radiation detector. Currently there are several hand-held radiation detectors including some with a degree of spectroscopic performance, but most devices are scintillator based (sacrificing resolution performance for lower price) and a few are Germanium based (providing good performance but very expensive). We are not aware of a portable spectroscopic detector on the market with imaging capability.

Instrument Manufacturers:
Two companies have already expressed interest in our concept. We have talked in detail to Kromek and Redlen who confirm that it will be demonstrating performance that can be delivered within the correct price range that is crucial to the success of the concept.
If this instrument is taken into commercial production then the instrument manufacturer who licenses it and completes its development benefits from a novel and improved product to offer. Companies who will gain access to this technology will be able to bring industrially engineered devices to market based on our prototype.
The aim would be a commercial instrument to be marketed at about $20,000, with the expectation that it could capture a good proportion of the NaI(Tl) market, as it will have better energy resolution as well as imaging capability, and some of the Ge market.

The UK government and public:
Detecting radioactive sources attempting to enter the UK, transiting through the UK, or in storage somewhere within the UK will become easier with this device. The increased throughput and easier location capabilities could also facilitate more searches. Increased detection levels have a significant benefit to the government and the public if a radioactive attack is prevented. Awareness of better detection capabilities also deters terrorists from attempting such an attack.

Companies needing to run security checks:
This device will enable companies and agencies to maximise throughput levels at ports, cargo hubs, border crossings etc. and may also result in fewer identifier devices and lower staffing levels.

Staff tasked with carrying out such checks:
Currently once a radioactive source has been found, e.g. in a container of cargo, staff then need to sweep the container with handheld detectors to identify exactly where it is located. Our instrument will greatly speed up the process of locating and characterising the source and so will reduce staff exposure.

STFC and University of Liverpool:
Success of this project is expected to generate licensing opportunities for aspects of the technology developed in the course of the research and prototyping. Success is expected to also lead to further interaction with key players in the security industry and potentially to other collaborations.

Nuclear Industry:
Our detector could be used in the nuclear industry, for instance in mapping the location of radioactive sources in high dose environments, when it is not safe to send a person to do a conventional survey, or in helping to indentify theft of radioactive sources from nuclear sites.