Spectrometer for inelastic-ally scattered slow neutrons at the ''FAKEL'' accelerator

The time-of-flight spectrometer installed at the ''Fakel'' electron linac is developed for investigation of excitation spectra in condensated media by the method of slow neutron inelastic scattering. The spectrometer has two similar sectors, each of them comprises eight independent crystals-monochromators istalled around the sample. The beryllium filter-collimator and neutron detector are placed under each crystal. Crystals of pyrolitic graphite of approximately 90% reflection are used as monochromators. The filter is a lattice cadmium collimator filled with metallic beryllium. The filter is located in the cryostat for improvement of cold neutron transmission. 3He-counters placed inside the unit of borated polyethylene are used as neutron detectors. The spectrometer has small sample to detector flight distance equal 0.41 m. The developed spectrometer permits simultaneous measurement of 16 neutron inelastic scattering spectra within 15-165 deg angles. Energy resolution of the spectrometer in the range of energy transfer from 0.5 to 1 eV constituted 3-5%. The results of measurement of neutron inelastic scattering with excitation of optical oscillations of hydrogen in the lattice of zirconium hydride are presented as an illustration of the spectrometer operation