Performances of a method for reconstructing the energy of neutrons detected by a double scattering spectrometer

A neutron spectrometer based on the double scattering technique has been designed and built at the Laboratorio Tecnologico of INFN-Turin (Italy) for cold fusion experiments. The operating principle for the reconstruction of the energy can be applied to various fields (neutron emission from sources, fission and fusion) and is described together with the tests performed. A resolution of less than +or-280 keV has been obtained for neutrons of 2.45 MeV, in a typical running configuration. The technique for measuring the energy of neutrons emitted without an associated detectable particle has been realized in an experiment dedicated to the detection of neutrons at low rate. The performance of the measurement technique has been studied with the help of a suitable Monte Carlo program by means of which the crucial role of the precision in the time of flight and (mainly) of the angle measurement has been stressed. The spreading effect due to the multiple scattering of the neutrons in the same slab has also been investigated. >