HIGH-EFFICIENCY NEUTRON SPECTROMETER

The possibility for increasing the small effect detection efficiency i n neutron time-of-flight investigations performed under a high backgro und which is independent of the neutron source is considered. It is sh own that even small changes in Eight path length and/or neutron source intensity result in considerable variations in efficiency. A new neut ron spectrometer with half the flight path length and triple neutron i ntensity of those of the spectrometer used earlier is described. The n eutron capture cross section of the Hf-178m2 isomer has been measured by both spectrometers. The results obtained show that the efficiency o f the new spectrometer is similar to 400 times higher. (C) 1998 Elsevi er Science B.V. All rights reserved.