title: Simulation of a suite of generic long-pulse neutron instruments to optimize the time structure of the European Spallation Source.
abstract: 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.
authors.affiliation: Nanoscience and eScience Centers, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
authors.forename: Kim
authors.initials: K
authors.lastname: Lefmann
authors.forename: Kaspar H
authors.initials: KH
authors.lastname: Klenø
authors.forename: Jonas Okkels
authors.initials: JO
authors.lastname: Birk
authors.forename: Britt R
authors.initials: BR
authors.lastname: Hansen
authors.forename: Sonja L
authors.initials: SL
authors.lastname: Holm
authors.forename: Erik
authors.initials: E
authors.lastname: Knudsen
authors.forename: Klaus
authors.initials: K
authors.lastname: Lieutenant
authors.forename: Lars
authors.initials: L
authors.lastname: von Moos
authors.forename: Morten
authors.initials: M
authors.lastname: Sales
authors.forename: Peter K
authors.initials: PK
authors.lastname: Willendrup
authors.forename: Ken H
authors.initials: KH
authors.lastname: Andersen