Performance of Reflectometers on Different Moderators and Target Stations of the ESS Project

Abstract

We have investigated the performance of a reflectometer on an ambient water and liquid hydrogen moderator with different characteristics (coupled, decoupled poisoned, decoupled unpoisoned) on different target stations, which are currently under discussion for the planned European Spallation Source (ESS): 5 MW short pulse at 50 Hz, 1 MW short pulse at 10 Hz and 5 MW long pulse at 16.67 Hz. The Monte-Carlo simulations performed using the software package VITESS show that the performance of a reflectometer is roughly proportional to the power of the source. Therefore, the coupled cold moderator together with the most powerful target station (5 MW short pulse or 5 MW long pulse) is the best choice for reflectometry. The repetition rate and pulse length are of minor importance.