Active Interrogation Systems

Research Focus Areas: 2 & 3

(Ph.D. graduate student position available)

Ph.D. Students: C. Meert, A. Jinia

Collaborators: D. Umstadter & S. Chen (Univ. of Nebraska), C.G.R. Geddes & B. Ludewigt (LBNL)


As many special nuclear materials of interest do not produce an easily detectable radiological signature, it is advantageous to probe the material with external radiation. This active interrogation of a material can produce a more identifiable signal than passive detection methods. The external radiation can be produced by accelerators, cyclotrons, isotopic sources, as well as other sources. A variety of methods for creating signatures fall under active interrogation, including radiography, photofission signatures, tomography, and nuclear resonance fluorescence. 

Flux of neutrons created by a 6 MeV photon pencil beam in a sphere of HEU
Flux of neutrons created by a 6 MeV photon pencil    beam in a sphere of HEU
Energy transmission contract for Uranium shielded by a thick steel container/
Energy transmission contract for Uranium shielded by a thick steel container

Our group has performed simulation studies of active systems, and collaborated on measurements for innovative active interrogation systems.  A focus has been on producing quasi-monoenergetic particles, using deuteron reactions to produce neutrons and inverse Compton scattering to produce photons. Collaborations with the University of Nebraska (Umstadter, Chen) and the Lawrence Berkeley National Laboratory (Geddes, Ludewigt) have resulted in promising studies into the applications for quasi-monoenergetic photons for nonproliferation applications.  Signature generation and detection methods can be applied to cargo screening, weapons verification, safeguards, and a variety of other techniques employed for nonproliferation.

Linear accelerator for active interrogation experiments placed in shielding vault
Linear accelerator for active interrogation experiments placed in shielding vault
View of the accelerator from the beam line area
View of the accelerator from the beam line area

Related Journal Articles:

  1. Cheng, A. Di Fulvio, D. Wentzloff, S. D. Clarke, S. A. Pozzi, H. S. Kim “Artificial Neural Network Algorithms for Pulse Shape Discrimination and Recovery of Piled-up Pulses in Organic Scintillators,” Annals of Nuclear Energy, Volume 120, Pages 410-421, October 2018.
  2. Chen, G. Golovin, C. Miller, D. Haden, S. Banerjee, P. Zhang, C. Liu, J. Zhang, B. Zhao, S. Clarke, S.A. Pozzi, D. Umstadter, “Shielded Radiography with a Laser Driven MeV Energy X-ray Source,” Nuclear Instruments & Methods in Physics Research B, vol. 366, pp. 217-223, 2016

Related Conference Proceedings:

  1. A. Meert, T. C. Wu, D. J. Trimas, C. A. Miller, I. Jovanovic, S. D. Clarke, S. A. Pozzi. “Photoneutron detection in a pulsed high-photon field using helium-4 scintillators,” Institute of Electrical and Electronics Engineers Nuclear Science Symposium and Medical Imaging Conference, Boston, MA. October 31 – November 7, 2020.
  2. J. Jinia, T. E. Maurer, K. E. Laferty, S. D. Clarke, H. S. Kim, D. D. Wentzloff, S. A. Pozzi, “Development an Artificial Neural Network for Special Nuclear Material Detection in a Mixed Photon-Neutron Environment,” Institute of Electrical and Electronics Engineers Nuclear Science Symposium and Medical Imaging Conference, Boston, MA. October 31 – November 7, 2020
  3. A. Meert, Y. Li, A.J. Jinia, K.E. Laferty, C.A. Miller, H. Kim, S.D. Clarke, D. D. Wentzloff, S.A. Pozzi, “Neural Network-Based Algorithm for Fast Neutron Detection in a Pulsed High-Photon Field,” Institute of Nuclear Materials Management Annual Meeting, Palm Desert, CA, USA, July 14-18, 2019
  4. A. Meert, C. A. Miller, S. D. Clarke, S. A. Pozzi, “Fast Neutron Detection in a High-Photon Field using Organic Scintillators,” Advances in Nuclear Nonproliferation Technology and Policy Conference (ANTPC), November 11-15, 2018, Orlando, FL, USA
  5. A. Miller, B. Ludewigt, B.J. Quiter, S.A. Pozzi, C.G.R. Geddes, “Assessing Impact of Monoenergetic Photon Sources on Nonproliferation Applications,” Invited Talk, American Nuclear Society, Advances in Nuclear Nonproliferation Technology and Policy Conference (ANTPC), Santa Fe, NM, (Sept. 2016)