title: A laser driven pulsed X-ray backscatter technique for enhanced penetrative imaging.
abstract: X-ray backscatter imaging can be used for a wide range of imaging applications, in particular for industrial inspection and portal security. Currently, the application of this imaging technique to the detection of landmines is limited due to the surrounding sand or soil strongly attenuating the 10s to 100s of keV X-rays required for backscatter imaging. Here, we introduce a new approach involving a 140 MeV short-pulse (< 100 fs) electron beam generated by laser wakefield acceleration to probe the sample, which produces Bremsstrahlung X-rays within the sample enabling greater depths to be imaged. A variety of detector and scintillator configurations are examined, with the best time response seen from an absorptive coated BaF2 scintillator with a bandpass filter to remove the slow scintillation emission components. An X-ray backscatter image of an array of different density and atomic number items is demonstrated. The use of a compact laser wakefield accelerator to generate the electron source, combined with the rapid development of more compact, efficient and higher repetition rate high power laser systems will make this system feasible for applications in the field. Content includes material subject to Dstl (c) Crown copyright (2014). Licensed under the terms of the Open Government Licence except where otherwise stated. To view this licence, visit http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@ nationalarchives.gsi.gov.uk.
authors.affiliation: Security Sciences Department, DSTL, Fort Halstead, Sevenoaks, Kent, UK.
authors.forename: R M
authors.initials: RM
authors.lastname: Deas
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK.
authors.forename: L A
authors.initials: LA
authors.lastname: Wilson
authors.affiliation: SUPA Department of Physics, University of Strathclyde, Glasgow, UK.
authors.forename: D
authors.initials: D
authors.lastname: Rusby
authors.affiliation: Department of Physics and Astronomy, Queens University of Belfast, Belfast, UK.
authors.forename: A
authors.initials: A
authors.lastname: Alejo
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK.
authors.forename: R
authors.initials: R
authors.lastname: Allott
authors.affiliation: Security Sciences Department, DSTL, Fort Halstead, Sevenoaks, Kent, UK.
authors.forename: P P
authors.initials: PP
authors.lastname: Black
authors.affiliation: Security Sciences Department, DSTL, Fort Halstead, Sevenoaks, Kent, UK.
authors.forename: S E
authors.initials: SE
authors.lastname: Black
authors.affiliation: Department of Physics and Astronomy, Queens University of Belfast, Belfast, UK.
authors.forename: M
authors.initials: M
authors.lastname: Borghesi
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK.
authors.forename: C M
authors.initials: CM
authors.lastname: Brenner
authors.affiliation: Blackett Laboratory, Imperial College London, London, UK.
authors.forename: J
authors.initials: J
authors.lastname: Bryant
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK.
authors.forename: R J
authors.initials: RJ
authors.lastname: Clarke
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK.
authors.forename: J C
authors.initials: JC
authors.lastname: Collier
authors.affiliation: Innovations, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, UK.
authors.forename: B
authors.initials: B
authors.lastname: Edwards
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK.
authors.forename: P
authors.initials: P
authors.lastname: Foster
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK.
authors.forename: J
authors.initials: J
authors.lastname: Greenhalgh
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK.
authors.forename: C
authors.initials: C
authors.lastname: Hernandez-Gomez
authors.affiliation: Department of Physics and Astronomy, Queens University of Belfast, Belfast, UK.
authors.forename: S
authors.initials: S
authors.lastname: Kar
authors.affiliation: Security Sciences Department, DSTL, Fort Halstead, Sevenoaks, Kent, UK.
authors.forename: D
authors.initials: D
authors.lastname: Lockley
authors.affiliation: Security Sciences Department, DSTL, Fort Halstead, Sevenoaks, Kent, UK.|Department of Medical Physics and Biomedical Engineering, University College London, London, UK.
authors.forename: R M
authors.initials: RM
authors.lastname: Moss
authors.affiliation: Blackett Laboratory, Imperial College London, London, UK.
authors.forename: Z
authors.initials: Z
authors.lastname: Najmudin
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK.
authors.forename: R
authors.initials: R
authors.lastname: Pattathil
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK.
authors.forename: D
authors.initials: D
authors.lastname: Symes
authors.affiliation: Security Sciences Department, DSTL, Fort Halstead, Sevenoaks, Kent, UK.
authors.forename: M D
authors.initials: MD
authors.lastname: Whittle
authors.affiliation: Blackett Laboratory, Imperial College London, London, UK.
authors.forename: J C
authors.initials: JC
authors.lastname: Wood
authors.affiliation: SUPA Department of Physics, University of Strathclyde, Glasgow, UK.
authors.forename: P
authors.initials: P
authors.lastname: McKenna
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK.|SUPA Department of Physics, University of Strathclyde, Glasgow, UK.
authors.forename: D
authors.initials: D
authors.lastname: Neely
mesh_terms: D054042:Bombs / Q000145:classification*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement / Q000295:instrumentation*; D012542:Scattering, Radiation; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*; D014857:Warfare; D014965:X-Rays
keywords: X-ray; X-ray backscatter; X-ray imaging systems; X-ray radar; detection