Design concepts for a supermirror V-cavity based combined beam polarizer and compressor system for the upgraded neutron time-of-flight spectrometer NEAT

Abstract

Abstract Here we present several design concepts for polarization of incoming neutrons based on the use of supermirror optical devices for the application in time-of-flight neutron spectroscopy. The polarization systems, designed for the recently upgraded time-of-flight spectrometer NEAT [1], are using the so-called “V-cavity” approach and provide simultaneous polarization and compression of the neutron beam, due to the geometrical conditions imposed by the instrument layout. Two fundamental design concepts have been explored: hybrid one, which polarizes and compresses simultaneously, and combined one, making the polarization and the compression in two sequential steps. The results are supported by both analytical calculations and simulations by VITESS-package software. The polarizer’s design secures high values of both polarization and transmittance of neutron beam intensity, corresponding to recent state-of-the-arts performances. The comparison of various design concepts and their parameters are presented and discussed.