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Impact case study

HALO X-ray Technologies Ltd: Commercialisation of High-energy X-ray Diffraction Imaging Innovations for Next Generation Security Screening

Unit(s) of assessment: General Engineering

Research theme: Safety and Security of Citizens and Society

School: School of Science and Technology


(Header image courtesy Vanderlande and Halo X-Ray)

A major problem for aviation security is that the current generation of X-ray scanners is limited fundamentally in their ability to discriminate between benign and threat materials in luggage being placed on-board aircraft. For example, while such technologies may be able to detect well-engineered military or commercial grade explosives they cannot reliably identify homemade explosives. This is because the transmitted X-rays, which form a spatial image, do not contain sufficient information to provide a definitive “fingerprint”. This is true of all transmission X-ray imaging techniques, including state-of-the-art (spectroscopic) computed tomography (CT).

Collaborative research led by NTU has resulted in patented X-ray diffraction techniques to identify explosives and other threats as well as illicit drugs and contraband items in scans of luggage and cargo. Unique, hollow-beam ‘molecular fingerprinting’ underpins the unprecedented capability of HALO’s technology to discriminate between benign and threat materials at operational speeds. These innovations have led to the creation of HALO X-ray Technologies Ltd, based in Nottingham, to commercialise a range of security X-ray scanners (HXT132, HXT264, HXT364 and HXT464 product series) through assigned IP assets and a pipeline agreement. HALO product development has been funded during the period by significant investment of $3.6 million from the U.S. Department of Homeland Security and VC investment in 2019. A HXT264 scanner has also been installed at the U.S. Transportation Security Laboratory’s William J. Hughes Technical Center at Atlantic City International Airport.

Research background

Historically, capability weaknesses are exploited, by chance or by design, by terrorists. The increasing ingenuity applied to homemade explosives by terrorists is therefore a major and globally pressing concern. One possible countermeasure would be to broaden the classification of threat signatures via software in currently deployed X-ray systems. However, this would lead inevitably to increases in false-alarm rates and hand-searches of luggage. The potential consequences for the travelling public would be profound with ever increasing delays at travel hubs and spiralling security costs. To ensure the continued safety and security of the travelling public a step change in technology was required.

The U.S. and U.K. governments have pursued bilateral research programmes to initiate a disruptive advance to reduce false alarms and increase threat detection rates. One potential approach is to employ the measurement of scattered or diffracted X-rays from luggage. Such “XRD” measurements, employed routinely in laboratory diffractometers, are the ‘gold standard’ for material phase identification. However, the translation of laboratory instrument technology – capable only of penetrating a fraction of a mm into a carefully prepared sample – into a viable luggage screening modality was severely hampered by fundamental scientific and technological limitations. Despite strenuous efforts by the industry, over two decades, no commercially viable XRD security luggage scanner ever emerged.

Professor Paul Evans led a collaboration with Rogers at Cranfield to combine X-ray radiography and X-ray diffraction as the basis for a “threat tuneable” futureproof solution. Initially, Evans led work on scatter enhanced 3D imaging combining diffraction and absorption imaging by exploring novel multiple X-ray beams for 3D scatter collection. In parallel with this multiple beam method Evans originated a radical new idea, which he developed in close collaboration with Rogers. Namely, the invention of hollow or shell-beam X-ray probes, termed focal construct technology. The probe shape concentrates diffracted X-rays from a sample/threat onto a detector to improve greatly the diffraction signal, by orders of magnitude. This method provides high-speed – fraction of a second– operation with commercial-off-the-shelf source/sensor components to enable cost-effective high-energy XRD screening. This new invention from the NTU led collaborative research was patented, and subsequently developed and tested for the first time with funding under CONTEST the UK’s counter terrorism strategy. This work was sponsored by: U.K. Home Office; U.K. Dept for Transport; U.K. Centre for the Protection of National Infrastructure; U.K. Metropolitan Police Service, and the U.S. Dept. of Homeland Security. Thus, a completely new high-energy XRD method was demonstrated together with sophisticated tomographic – diffraction and absorption – approaches to provide high-speed materials identification capability. This work provided the scientific and IP underpinning for further research in security, process control and diagnostic medical imaging


A spin-out, HALO X-ray Technologies Ltd, has been created to commercialise patented new technologies from NTU’s collaborative research, established its viability, creating jobs, and generating revenue

HALO X-ray Technologies Ltd. (HALO) is commercialising novel tools and technologies invented through the ground-breaking research carried out by Professor Paul Evans’ team at Nottingham Trent University in collaboration with Professor Keith Rogers’ team at Cranfield University. Professor Evans at NTU led the formation of this Nottingham based spinout company, Evans was the Founder on 4 April 2012, Director and CTO up until significant Venture Capital investment in 2019. HALO’s CEO (who is also current Company Director) completed a PhD in Evans’ Group in 2015. HALO’s Science Lead was a Senior Research Fellow in Evans’ Group for eight years having previously obtained his PhD at Cranfield University with Evans (at NTU) as a supervisor and lead on the sponsoring EPSRC grant with Rogers.

U.S. Government contract funding investment in HALO ($3.6 million BAA funding and ‘Opioid Detection Challenge’) has underpinned development and testing of novel scanners

$3.5 million U.S. Department of Homeland Security product development contracts: The Broad Agency Announcement (BAA) is a funding call tool used by the United States Department of Homeland Security Science and Technology Directorate to solicit proposals from outside groups “to quickly and efficiently execute research and development to deliver practical solutions to critical first responder problems”. The award of major BAA contracts to HALO X-ray Technologies Ltd. ($3.5 million spent by HALO in REF period, $1.6m as major subcontractor and $1.9m as Prime contractor, detailed below), is highly significant and important because the U.S. Government is the world’s largest customer for X-ray security screening systems.

Award of $100k to HALO as a finalist in the US Government ‘Opioid Detection Challenge’: The US Government ‘Opioid Detection Challenge’ (2019) was a Department of Homeland Security Science and Technology Directorate led collaboration with U.S. Customs and Border Protection, the Office of National Drug Control Policy and the U.S. Postal Inspection Service to seek new tools and technologies to detect deadly opioids in parcels to combat large-scale drug trafficking into the U.S via international mail. HALO won $100k in the Challenge, one of only 8 finalists from 83 submissions.

£0.5 million U.K. and U.S. Government DASA product development contracts: HALO has received a total of £502k, during 2019-20, product development funding from the Defence and Security Accelerator (DASA) under the Future Aviation Security Solutions (FASS) Programme courtesy of the U.K. Department for Transport and U.K. Home Office as well as the U.S. Department for Homeland Security. The FASS programme forms part of the Strategic Defence and Security Review (SDSR) published in 2015 and set out the U.K. Government’s National Security Strategy for the coming five years. HALO has received income of £218k for the development of an ‘Alarm Registration Capability (ARC)’ for the HXT264 series, under contract ACC6008370; and received an additional income of £285k to develop ‘HEROS: High Energy Resolver for Cargo Screening’ (HXT2108) for the screening of cargo, bulk mail, and hold/checked bags, under contract ACC6007509.

Venture Capital investment has been raised by HALO which has supported expansion and the establishment of a US Office.  The successful delivery of the BAA contracts enabled HALO, in March 2019, to secure significant VC investment from venture capital firm Midven Ltd and the Midlands Engine Investment Fund.

HALO has developed products, is funded by international industrial product development collaborations, and has generated revenue from product sales.  development collaborations, and has generated revenue from product sales HALO X-ray Technologies Ltd. has created a new range of scanner technologies, HXT132, HXT264, HXT364, and HXT464 XRD. The HALO CEO wrote, “together with high-energy hold and cargo screening variants, which incorporate Evans’ and Rogers’ Patented focal construct X-ray diffraction and absorption techniques. HALO are integrating, combining and co-tuning these technologies with a range of different scanners produced by globally leading security scanner manufacturers.

These collaborations have or are funding the combination of HALO’s HXT264 technology”, with: Rapiscan’s 620DV to form a HXT364 system (under DoHS contract 70RSAT18CB0000038); Leidos Clearscan CT scanner, to form a HXT464 system (Department of Homeland Security Contract HSHQDC15CB0036); and Integrated Defence and Security Solutions (IDSS) DETECT1000 CT system to form a HXT464 system (projecting beyond the REF period, $3.7 million total under DoHS contract 70RSAT20CB0000025, 29 Sept 2020 to 28 June 2023). These development programmes allow liquids and laptops to remain in the bag. Such industrial product development collaborations are essential in the highly regulated aviation security sector to enable HALO scanners to obtain ECAC Standard 3 approved and U.S. Transportation Security Administration certified explosives detection system status.


  • Evans, P.; Rogers K.; Chan J.; Rogers J.; Dicken, A.; Title: High intensity x-ray diffraction in transmission mode employing an analog of Poisson’s spot; (2010); Applied Physics Letters; Vol. 97, 20, p204101;
  • Dicken, A., Evans, J.P.O., Rogers, K.D., Greenwood, C., Godber, S.X. (HALO Ltd), Prokopiou, D., Stone, N., Clement, J.G., Lyburn, I., Martin, R.M., Zioupos, P., 2015. Energy-dispersive X-ray diffraction using an annular beam. Optics Express, 23 (10), pp. 13443- 13454. ISSN 1094-4087
  • Dicken, A., Evans, J.P.O., Rogers, K.D., Prokopiou, D., Goder, S.X. (HALO Ltd), Wilson, M. (STFC), 2017. Depth resolved snapshot energy-dispersive X-ray diffraction using a conical shell beam. Optics Express, 25 (18), pp. 21321-21328. ISSN 1094-4087
  • Evans, P.; Rogers, K.; Dicken, A.; Godber, S. (HALO Ltd); Prokopiou, D; X-ray diffraction tomography employing an annular beam; (2014); Optics Express; 22(10) 11930-11944; DOI
  • Elarnaut, F; Evans, J.P.O.; Downes, D.; Dicken, A.J.; Godber, S.X. (HALO Ltd); Rogers, K. D.; Sporadic absorption tomography using a conical shell X-ray beam; (2017); Optics Express; 25(26) 33029-33042;
  • Dicken, A., Evans, J.P.O., Rogers, K.D., Prokopiou, D., Goder, S.X. (HALO Ltd), Elarnaut, F., Shevchuk, A., Downes, D., Wilson, M. (STFC), 2019. Confocal energy-dispersive X-ray diffraction tomography employing a conical shell beam. Optics Express, 27 (14), pp. 19834-19841. ISSN 1094-4087