High-efficiency neutron spectrometer

The possibility for increasing the small effect detection efficiency in neutron time-of-flight investigations performed under a high background which is independent of the neutron source is considered. It is shown that even small changes in flight path length and/or neutron source intensity result in considerable variations in efficiency. A new neutron spectrometer with half the flight path length and triple neutron intensity of those of the spectrometer used earlier is described. The neutron capture cross section of the 178m2Hf isomer has been measured by both spectrometers. The results obtained show that the efficiency of the new spectrometer is ∼ 400 times higher.