A combined neutron and gamma-ray multiplicity counter based on liquid scintillation detectors

作者：Enqvist Andreas^*; Flaska Marek; Dolan Jennifer L; Chichester David L; Pozzi Sara A

来源：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment , 2011, 652(1): 48-51.

DOI：10.1016/j.nima.2010.10.071

• Nuclear nonproliferation
• Pulse shape discrimination
• Liquid scintillator detectors
• Multiplicity counting
• Coincidences

Multiplicity counters for neutron assay have been extensively used in materials control and accountability for nonproliferation and nuclear safeguards. Typically, neutron coincidence counters are utilized in these fields. In this work, we present a measurement system that makes use not only of neutron (n) multiplicity counting but also of gamma-ray (gamma) multiplicity counting and the combined higher-order multiples containing both neutrons and gamma rays. The benefit of this approach is in using both particle types available from the sample, leading to a reduction in measurement times compared with single-particle measurements. We present measurement results of n, gamma, nn, n gamma, gamma gamma, nnn, nn gamma, n gamma gamma and gamma gamma gamma multiples emitted by Mixed-Oxide (MOX) samples measured at Idaho National Laboratory (INL). The MOX measurement is compared to initial validation of the detection system done using a (252)Cf source. The dual radiation measuring system proposed here uses extra measurables to improve the statistics when compared to a neutron-only system and allows for extended analysis and interpretation of sample parameters. New challenges such as the effect of very high intrinsic gamma-ray sources in the case of MOX samples are discussed. Successful measurements of multiple rates can be performed also when using high-Z shielding.

• 出版日期2011-10-1