Characteristics of the 2012 model lithium-6 time-analyzer neutron detector (LiTA12) system as a high efficiency detector for resonance absorption imaging

Neutron resonance absorption imaging, being used to visualize a spatial distribution of elements and/or temperature within a sample, is one of the important applications of an intense short-pulse neutron source. Two-dimensional time-analyzer neutron detectors are indispensable to perform neutron energy dependent imaging by means of the time-of-flight technique. Some state-of-the-art time-analyzer neutron detectors have been developed for thermal or cold neutrons. However the detection efficiencies of such neutron detectors are not sufficient for neutron resonance absorption imaging which utilizes neutrons in the energy region from eV to keV. The 2012 model lithium-6 time-analyzer neutron detector (LiTA12) system, based on a lithium glass scintillator and multi-anode photomultiplier tube, has the highest neutron efficiency among the detectors for pulsed neutron imaging together with the flexibility to tune the efficiency by changing the thickness of the lithium glass. The authors estimated performances of the detector at resonance neutron energies finding that 0.7 mm width line pairs made by 3 μm thick gold could be resolved at 4.9 eV and the maximum count rate of 8 Mcps was achieved at 1 keV.