Lefmann, Kim5; Klenø, Kaspar H.5; Birk, Jonas Okkels6; Hansen, Britt Rosendahl1; Holm, Sonja L.7; Bergbäck Knudsen, Erik8; Lieutenant, Klaus9; von Moos, Lars3; Sales, Morten7; Willendrup, Peter Kjær1; Andersen, Ken H.7
1 Department of Physics, Technical University of Denmark2 Neutrons and X-rays for Materials Physics, Department of Physics, Technical University of Denmark3 Department of Energy Conversion and Storage, Technical University of Denmark4 Electrofunctional materials, Department of Energy Conversion and Storage, Technical University of Denmark5 University of Copenhagen6 École Polytechnique Fédérale de Lausanne7 European Spallation Source ESS AB8 National Space Institute, Technical University of Denmark9 Institute for Energy Technology
We here describe the result of simulations of 15 generic neutron instruments for the long-pulsed European Spallation Source. All instruments have been simulated for 20 different settings of the source time structure, corresponding to pulse lengths between 1 ms and 2 ms; and repetition frequencies between 10 Hz and 25 Hz. The relative change in performance with time structure is given for each instrument, and an unweighted average is calculated. The performance of the instrument suite is proportional to (a) the peak flux and (b) the duty cycle to a power of approximately 0.3. This information is an important input to determining the best accelerator parameters. In addition, we find that in our simple guide systems, most neutrons reaching the sample originate from the central 3-5 cm of the moderator. This result can be used as an input in later optimization of the moderator design. We discuss the relevance and validity of defining a single figure-of-merit for a full facility and compare with evaluations of the individual instrument classes.
Review of Scientific Instruments, 2013, Vol 84, Issue 5