Design and realization of a measurement system of cold neutron speeds by TOF method

Neutrons of low kinetic energy (cold neutrons) are frequently used in spectrometers for the condensed matter investigation like neutron diffractometers or small angle neutron scattering spectrometers. The accurate knowledge of the speed of the incident neutron beam on the sample is essential for the correct interpretation of experimental data. Besides being used in a large variety of neutron scattering experiments, the time-of-flight (TOF) technique stands as a relatively simple and accurate for measuring the energy of cold neutrons if a time-modulated beam of sufficient intensity is available. In this paper we present a system for measuring the absolute energy of cold neutrons at the Small angle scattering facility of the NUR reactor and the neutron diffraction facility at the Es-Salam reactor using the time-of-flight technique.