TY  - CONF
AU  - Violini, Nicolo
AU  - Voigt, Jörg
AU  - Brückel, Thomas
AU  - Nemkovskiy, Kirill
AU  - Russina, M.
AU  - Rolfs, K.
AU  - Simeoni, G.
AU  - Lohstroh, W.
AU  - Silvi, L.
AU  - Deen, P.
TI  - Development of a multi-spectral direct geometry chopper spectrometer for the European Spallation Source
M1  - FZJ-2013-00641
PY  - 2012
AB  - Within the ESS Design Update Phase Programme funded by the German Federal ministry of education and research, we investigate the performance of a set of spectrometer concepts at the long pulse source of the ESS, which promises the applicability to a wide manifold of scientific activities of research: strongly correlated electron materials, disordered systems, functional materials, magnetism, soft-matter and biophysics. Here we present the current state-of-the-art in the study of a multispectral wide-band short (50-80m) instrument concept. We describe the main aspects of the instrument conceptual design. The chopper system is a crucial aspect in order to achieve useful resolution for a manifold of scientific purposes, make an efficient use of the flux provided by the source, by means of the Repetition Rate Multiplication and reduce contaminations due to very fast and very slow neutrons. We present the chopper layout under investigation and the method for the RRM implementation, based on the commensurate choppers technique. The useful beam at the sample position is an important figure of merit in the evaluation of the instrument performance and can be a limit to possible scientific applications in several circumstances, when high flux is requested. The problem of the beam transport to the sample is under consideration, in order to transport as much as possible of the phase space density provided by the source, maintaining as low as possible the back-ground contamination coming from the direct view of the pulsed source. A comparison on the estimated performance and application limits of different guide geometries is presented. Special consideration is dedicated to the aim of focusing on very small sample size, down to the mm order of magnitude. The technical implications of the polarization analysis option are discussed. The necessary requirements for the detector development in terms of spatial and time resolution are already evaluated and the implications deriving from technical limitations on this task are discussed. Very preliminary results of virtual experiments performed by means of beam neutron ray-trace simulation packages are presented, in order to show the estimated performance of such a concept, especially focusing on the resolution function evaluation.
T2  - Science and Scientists @ ESS
CY  - 19 Apr 2012 - 20 Apr 2012, Berlin (Germany)
Y2  - 19 Apr 2012 - 20 Apr 2012
M2  - Berlin, Germany
LB  - PUB:(DE-HGF)24
UR  - https://juser.fz-juelich.de/record/129121
ER  -