Thermal Chopper Spectrometer for the European Spallation Source

Abstract

One of the instruments being considered for the ESS is a thermal chopper spectrometer, intended for the study of lattice vibrations and magnetic excitations. However, as the ESS will be a long pulsed source, we propose a very long instrument (180 m -300 m). We here present a guide system that can achieve a flux of 3.47×10 8 n/s/cm 2 and a resolution of dE/E = 5.3% for 1 Å neutrons on the sample with a transport efficiency of 80%. Furthermore, we demonstrate the efficiency of the instrument using a virtual experiment measuring an elastic line width.

Optimization of Performance, Price, and Background of Long Neutron Guides for European Spallation Source

“…In fact, 8 of the first 15 instruments selected for ESS are placed at this distance [4], which is about twice as long as the longest instruments currently in use [7]. For this reason, a dedicated guide simulation effort has been coordinated by ESS and performed by several groups during the last decade [5,6,[8][9][10][11][12][13]. The results from these works are that long neutron guides are indeed feasible, when ballistic guide concepts [14,15] are used.…”