Kevin J. Haskell

Photofission-Based, Nuclear Material Detection: Technology Demonstration

The Idaho National Engineering and Environmental Laboratory (INEEL), the Los Alamos National Laboratory (LANL), and the Advanced Research and Applications Corporation (ARACOR) [Sunnyvale, California] performed a photonuclear technology demonstration for shielded nuclear material detection during August 21–22, 2002, at the LANL TA-18 facility. The demonstration used the Pulsed Photonuclear Assessment Technique (PPAT) that focused on the application of a photofission-based, nuclear material detection method as a viable complement to the ARACOR Eagle inspection platform. The Eagle is a mobile and fully operational truck and cargo inspection system that uses a 6-MeV electron accelerator to perform real-time radiography. This imaging is performed using an approved “radiation-safe” or “cabinet safe” operation relative to the operators, inspectors, and any stowaways within the inspected vehicles. While the PPAT has been primarily developed for active interrogation, its neutron detection system also maintains a complete and effective passive detection capability.

Active nuclear material detection and imaging

An experimental evaluation has been conducted to assess the operational performance of a coded-aperture, thermal neutron imaging system and its detection and imaging capability for shielded nuclear material in pulsed photonuclear environments. This evaluation used an imaging system developed by Brookhaven National Laboratory. The active photonuclear environment was produced by an operationally-flexible, Idaho National Laboratory (INL) pulsed electron accelerator. The neutron environments were monitored using INL photonuclear neutron detectors. Results include experimental images, operational imaging system assessments and recommendations that would enhance nuclear material detection and imaging performance.

ARACOR Eagle-matched Operations and Neutron Detector Performance Tests

A test campaign was undertaken during April 16-19 in LaHonda, California to match the operational performance of the Idaho National Engineering and Environmental Laboratory (INEEL)Varitron accelerator to that of an ARACOR Eagle accelerator. This Eagle-matched condition, with the INEEL Varitron, will be used during a concept demonstration test at Los Alamos National Laboratory (LANL). This operational characterization involved the use of similar electron beam energies, similar production of photoneutrons from selected non-nuclear materials, and similar production of photofissionbased, delayed neutrons from an INEEL-provided, depleted uranium sample. Then using the matched operation, the Varitron was used to define detector performances for several INEEL and LANL detectors using the depleted uranium target and Eagle-like, bremsstrahlung collimation. This summary report provides neutron measurements using the INEEL detectors. All delayed neutron data are acquired in the time interval ranging from 4.95 to 19.9 ms after each accelerator pulse. All prompt neutron data are acquired during 0.156 to 4.91 ms after each accelerator pulse. Prompt and delayed neutron counting acquisition intervals can still be optimized.