A Kinematically Beamed, Low Energy Pulsed Neutron Source for Active Interrogation

Conference · Thu Oct 07 04:00:00 EDT 2004

DOI:https://doi.org/10.1016/j.nimb.2005.07.139· OSTI ID:15011412

Dietrich, D; Hagmann, C; Kerr, P; Nakae, L; Rowland, M; Snyderman, N; Stoeffl, W; Hamm, R

We are developing a new active interrogation system based on a kinematically focused low energy neutron beam. The key idea is that one of the defining characteristics of SNM (Special Nuclear Materials) is the ability for low energy or thermal neutrons to induce fission. Thus by using low energy neutrons for the interrogation source we can accomplish three goals, (1) Energy discrimination allows us to measure the prompt fast fission neutrons produced while the interrogation beam is on; (2) Neutrons with an energy of approximately 60 to 100 keV do not fission 238U and Thorium, but penetrate bulk material nearly as far as high energy neutrons do and (3) below about 100keV neutrons lose their energy by kinematical collisions rather than via the nuclear (n,2n) or (n,n') processes thus further simplifying the prompt neutron induced background. 60 keV neutrons create a low radiation dose and readily thermal capture in normal materials, thus providing a clean spectroscopic signature of the intervening materials. The kinematically beamed source also eliminates the need for heavy backward and sideway neutron shielding. We have designed and built a very compact pulsed neutron source, based on an RFQ proton accelerator and a lithium target. We are developing fast neutron detectors that are nearly insensitive to the ever-present thermal neutron and neutron capture induced gamma ray background. The detection of only a few high energy fission neutrons in time correlation with the linac pulse will be a clear indication of the presence of SNM.

• Research Organization: Lawrence Livermore National Lab., Livermore, CA (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 15011412
• Report Number(s): UCRL-CONF-207137
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACCELERATORS
FAST FISSION
FAST NEUTRONS
FISSION NEUTRONS
LINEAR ACCELERATORS
LITHIUM
NEUTRON BEAMS
NEUTRON REACTIONS
NEUTRON SOURCES
NEUTRONS
PROMPT NEUTRONS
RADIATION DOSES
THERMAL NEUTRONS
THORIUM