DEVELOPMENT OF A 3He/Xe GAS SCINTILLATION COUNTER TO MEASURE THE 3He(n,p)T CROSS SECTION IN THE INTERMEDIATE ENERGY RANGE

DEVELOPMENT OF A ³He/Xe GAS SCINTILLATION COUNTER TO MEASURE THE ³He(n,p)T CROSS SECTION IN THE INTERMEDIATE ENERGY RANGE

J.W. Behrens, O.A. Wasson, A.D. Carlson and Ma Hongchang

National Bureau of Standards, Ionizing Radiation Division
Gaithersburg, Maryland 20899 USA

A ³He/Xe gas scintillation counter has been developed for measuring the neutron energy range from thermal to 3 MeV. Great effort was concentrated on improving the detector design to optimize light production and collection to improve the energy resolution which is primarily controlled by photon statistics. The detectors were tested using a ²³⁸Pu alpha-particle source, a thermal neutron beam from the NBS reactor, and the white-neutron spectrum from the NBS linac. The detector measures an energy resolution of 17% (FWHM) for the ³He(n,p)T reaction at 2.0 MeV which is sufficient for cross section measurement.

KEYWORDS: counter, cross section, helium-3 gas, neutron, scintillation