title: VESPA: The vibrational spectrometer for the European Spallation Source.
abstract: VESPA, Vibrational Excitation Spectrometer with Pyrolytic-graphite Analysers, aims to probe molecular excitations via inelastic neutron scattering. It is a thermal high resolution inverted geometry time-of-flight instrument designed to maximise the use of the long pulse of the European Spallation Source. The wavelength frame multiplication technique was applied to provide simultaneously a broad dynamic range (about 0-500 meV) while a system of optical blind choppers allows to trade flux for energy resolution. Thanks to its high flux, VESPA will allow the investigation of dynamical and in situ experiments in physical chemistry. Here we describe the design parameters and the corresponding McStas simulations.
authors.affiliation: Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen Ø, Denmark.
authors.forename: Anna
authors.initials: A
authors.lastname: Fedrigo
authors.affiliation: Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, 50019 Sesto Fiorentino, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Colognesi
authors.affiliation: Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen Ø, Denmark.
authors.forename: Mads
authors.initials: M
authors.lastname: Bertelsen
authors.affiliation: European Spallation Source ESS AB, SE-221 00 Lund, Sweden.
authors.forename: Monika
authors.initials: M
authors.lastname: Hartl
authors.affiliation: Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen Ø, Denmark.
authors.forename: Kim
authors.initials: K
authors.lastname: Lefmann
authors.affiliation: European Spallation Source ESS AB, SE-221 00 Lund, Sweden.
authors.forename: Pascale P
authors.initials: PP
authors.lastname: Deen
authors.affiliation: Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen Ø, Denmark.
authors.forename: Markus
authors.initials: M
authors.lastname: Strobl
authors.affiliation: Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, 50019 Sesto Fiorentino, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Grazzi
authors.affiliation: Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, 50019 Sesto Fiorentino, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Zoppi