Neutron detection gamma ray sensitivity criteria

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 654; no. 1; pp. 412 - 416
• Main Authors: Kouzes, Richard T., Ely, James H., Lintereur, Azaree T., Mace, Emily K., Stephens, Daniel L., Woodring, Mitchell L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 21-10-2011
• Subjects: 3He; Accelerators; Alternative neutron detectors; Alternative technology; Criteria; Gamma ray rejection; GARRn; He-3; Helium-3; Homeland security; Meetings; National security; Neutron detection; Neutron detectors; Radiation detection; Rejection; Security; Shortages; 3He; He-3; Gamma ray rejection; GARRn; Homeland security; Helium-3; Radiation detection; National security; Alternative neutron detectors; Neutron detection
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2011.07.030

The shortage of
3He has triggered the search for effective alternative neutron detection technologies for national security and safeguards applications. Any new detection technology must satisfy two basic criteria: (1) it must meet a neutron detection efficiency requirement, and (2) it must be insensitive to gamma-ray interference at a prescribed level, while still meeting the neutron detection requirement. It is the purpose of this paper to define measureable gamma ray sensitivity criteria for neutron detectors. Quantitative requirements are specified for: intrinsic gamma ray detection efficiency and gamma ray absolute rejection. The gamma absolute rejection ratio for neutrons (GARRn) is defined, and it is proposed that the requirement for neutron detection be 0.9<GARRn<1.1 at a 10
mR/h exposure rate. An example of the results from a
3He based neutron detector is provided showing that this technology can meet the stated requirements. Results from tests of some alternative technologies are also reported.