Novel standoff explosives detection - Progress in noncontact analysis

Authors:

  • Bernhard Zachhuber
  • Matilda Ågren
  • Markus Nordberg
  • Henric Östmark
  • Mattias Svanqvist
  • Martin Glimtoft
  • Anna Pettersson
  • Andreas Brorsson
  • David Bergström
  • David Gustafsson

Publish date: 2019-02-20

Report number: FOI-R--4695--SE

Pages: 92

Written in: English

Keywords:

  • Raman spectroscopy
  • infrared
  • standoff
  • noncontact detection
  • explosives
  • threat analysis
  • compressive sensing inkjet print
  • energetic material
  • counterterrorism

Abstract

Entitled "Novel standoff explosives detection-Progress in noncontact threat analysis", this report focuses on methods that enable the detection as well as the identification of energetic materials from a distance. It summarises the progress that FOI have made in the field of threat analysis with detectors that minimise the risk to which an operator is subjected when investigating potentially harmful material. The focus here is on methods that avoid direct, mechanical interaction with a sampled material. Scenarios that require noncontact detection favour analysers that apply light or other radiation as their probing medium, since such methods interact with a sample without mechanical contact. One such technique is Raman spectroscopy-a technique that is widespread due to its ability to yield detailed molecule-specific information of a sample after laser excitation. This report describes several concepts that revolve around Raman spectroscopy but also illustrates other methods such as SWIR (shortwave infrared spectroscopy). In this document FOI draw from their practical expertise gained from developing laboratory setups as well as prototypes of the described methodologies. Benefits and drawbacks are stated in this document for different Raman techniques that have been, are, or will be used at FOI. It also serves as a summary of the recent advances FOI have made in the field-with a strong focus on compressive sensing. In addition, a technique is introduced that allows the preparation of solid threat reference samples with high precision: inkjet printing. This work covers the following topics:  FOI's standoff explosive detection concepts and prototypes: A number of different detection concepts are described ranging from standoff Raman detection from large distances, over Raman imaging (visible and UV) of small substance amounts on the surface of items, to the rapid detection of material on moving targets via Raman line-scan. But also methods to determine the content inside containers that are non-transparent to the human eye are introduced alongside infrared detection possibilities.  Capabilities of a newly developed Raman compressive sensing concept are demonstrated.  Production of material samples for noncontact detectors: The development of protocols is described that allow the precise fabrication of solid trace sample that are well-defined not only in mass but also in shape.