Exploiting stilbene’s scintillation anisotropy for neutron source localization

Abstract

A technique for neutron source localization that exploits the scintillation anisotropy of stilbene is presented. The light output anisotropy of stilbene and constraints on the direction of recorded scatter events imposed by a threshold were used to estimate the direction of a 252Cf neutron source relative to the crystal axes of a stilbene crystal. The neutron source location was determined via triangulation using source directions estimated from multiple detectors. Two measurements that illustrate the efficacy of the technique are presented. The first measurement was designed with a favorable geometry for triangulation, which resulted in low uncertainties in the estimate of the neutron source location. The second measurement was designed with both favorable and unfavorable geometries for triangulation, which exhibited low and high uncertainties in the estimates of neutron source location, respectively. Pair-wise combinations of three detectors were used to estimate the source location for both measurements. The neutron source was localized with errors of 5.0, 8.9, and 3.9 cm for the first measurement with source detector-distance of 89, 90, and 88 cm for the three detectors. The neutron source was localized with errors of 2.8, 14.2, 6.2 cm for the second measurement with source detector-distances of 233, 123, and 130 cm.