Thermal Chopper Spectrometer for the European Spallation Source

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 3.47x10(8) n/s/cm(2) and a resolution of dE/E = 5.3% for 1 angstrom 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.