Neutron Resonance Radiography for Explosives Detection: Technical Challenges

Conference · Wed Nov 09 00:00:00 EST 2005

DOI:https://doi.org/10.1109/NSSMIC.2005.1596222· OSTI ID:877866

Raas, W L; Blackburn, B; Boyd, E; Hall, J M; Kohse, G; Lanza, R; Rusnak, B; Watterson, J W

Fast Neutron Resonance Radiography (NRR) has recently become a focus of investigation as a supplement to conventional x-ray systems as a non-invasive, non-destructive means of detecting explosive material concealed in checked luggage or cargo containers at airports. Using fast (1-6 MeV) neutrons produced by the D(d,n){sup 3}He reaction, NRR provides both an imaging capability and the ability to determine the chemical composition of materials in baggage or cargo. Elemental discrimination is achieved by exploiting the resonance features of the neutron cross-section for oxygen, nitrogen, carbon, and hydrogen. Simulations have shown the effectiveness of multiple-element NRR through Monte Carlo transport methods; this work is focused on the development of a prototype system that will incorporate an accelerator-based neutron source and a neutron detection and imaging system to demonstrate the realistic capabilities of NRR in distinguishing the elemental components of concealed objects. Preliminary experiments have exposed significant technical difficulties unapparent in simulations, including the presence of image contamination from gamma ray production, the detection of low-fluence fast neutrons in a gamma field, and the mechanical difficulties inherent in the use of thin foil windows for gas cell confinement. To mitigate these concerns, a new gas target has been developed to simultaneously reduce gamma ray production and increase structural integrity in high flux gas targets. Development of a neutron imaging system and neutron counting based on characteristic neutron pulse shapes have been investigated as a means of improving signal to noise ratios, reducing irradiation times, and increasing the accuracy of elemental determination.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 877866
• Report Number(s): UCRL-CONF-217017; TRN: US0601651
• Resource Relation: Journal Volume: 1; Conference: Presented at: IEEE Nuclear Science Symposium and Medical Imaging Conference, Fajardo, PR, United States, Oct 23 - Oct 29, 2005
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
43 PARTICLE ACCELERATORS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
22 GENERAL STUDIES OF NUCLEAR REACTORS
AIRPORTS
CARBON
CARGO
CHEMICAL COMPOSITION
CONFINEMENT
CONTAINERS
CONTAMINATION
DETECTION
EXPLOSIVES
FAST NEUTRONS
HYDROGEN
IRRADIATION
NEUTRON DETECTION
NEUTRON SOURCES
NEUTRONS
NITROGEN
OXYGEN
RESONANCE