Optimization study for small angle neutron scattering spectrometer at the ET-RR-1 reactor

The design principle of a Small Angle Neutron Scattering (SANS) spectrometer is based on producing monochromatic neutron bursts using two phased rotors with curved slots. An optimization study of their number and shape to achieve the highly available intensity of monoenergetic neutrons at the required resolution is given. The study was applied to the improvement of the performance of the pulsed monochromatic double rotor system at ET-RR-1 to operate as SANS spectrometer. It is shown that for rotors having 19 slots each with radius of curvature 96.8 cm, the intensity gain factor is 13. The proposed SANS spectrometer could cover the neutron wavelength range from 2 Å up to 6 Å through small angles of scattering from 5 × 10 ^-3 rad to 0.1 rad, i.e., the scattering wavevector transfer between 0.6 Å ^-1 and 0.01 Å ^-1. The maximum neutron intensity on the specimen is 2 × 10 ⁶ n s ^-1.