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Title: Plutonium Detection with Straw Neutron Detectors

A kilogram of weapons grade plutonium gives off about 56,000 neutrons per second of which 55,000 neutrons come from spontaneous fission of 240Pu (~6% by weight of the total plutonium). Actually, all even numbered isotopes (238Pu, 240Pu, and 242Pu) produce copious spontaneous fission neutrons. These neutrons induce fission in the surrounding fissile 239Pu with an approximate multiplication of a factor of ~1.9. This multiplication depends on the shape of the fissile materials and the surrounding material. These neutrons (typically of energy 2 MeV and air scattering mean free path >100 meters) can be detected 100 meters away from the source by vehicle-portable neutron detectors. [1] In our current studies on neutron detection techniques, without using 3He gas proportional counters, we designed and developed a portable high-efficiency neutron multiplicity counter using 10B-coated thin tubes called straws. The detector was designed to perform like commercially available fission meters (manufactured by Ortec Corp.) except instead of using 3He gas as a neutron conversion material, we used a thin coating of 10B.
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Publication Date:
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Report Number(s):
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Resource Relation:
Conference: ANS Plutonium Futures - the Science 2014 Renaissance Hotel; Las Vegas, September 7-12, 2014
Research Org:
Nevada Test Site/National Security Technologies, LLC (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
plutonium, neutron, straw