Optimization of a Neutron Detector System for the Fourier RTOF-Diffractometer Facility at the ETRR-1 Reactor

The present work deals with the optimization of a detector system for use with the Fourier reverse time of flight (RTOF) diffractometer facility recently installed at the ETRR-1 reactor. The detector system of the diffractometer is designed for detecting neutrons scattered from the sample at an angle 20-90 degree and consists of 4 independent scintillation detector elements; arranged according to the time focusing geometry in order to increase the luminosity of the diffractometer for the given resolution. Each of the detector elements is made of 1 mm thick 6Li-glass scintillator (NE-912) whose surface area is 200 200 mm2. The present detector system ensures reliable identification and separation of thermal neutron pulses from those due to fast neutrons and gamma-quanta. It has been found from measurements with a diamond powder sample, that it is possible to obtain a neutron diffraction pattern within 30 minutes using the present detector system and with resolution approx 0.54%