College Park, Maryland June 6 - 10 , 2004
TP40: VISION: A Neutron Vibrational Spectrometer for SNS
J.Z. Larese (Chemistry Dept., Univ. of Tennessee; Oak Ridge National Laboratory), L.L. Daemen, P.A. Seeger (Los Alamos Neutron Science Center, Los Alamos National Laboratory), B.S. Hudson (Chemistry Dept., Syracuse Univ.), J. Eckert (Los Alamos Neutron Science Center, Los Alamos National Laboratory)
There is a need in the United States for a state-of-the-art neutron scattering instrument for vibrational spectroscopy to investigate the structure and dynamics of condensed matter systems by the simultaneous use of elastic diffraction and moderate resolution (1-2% DE/E) inelastic scattering over a broad energy transfer range. The use of neutron vibrational spectroscopy (NVS) is growing at a significant rate in Europe thanks to the second-generation instrument TOSCA at ISIS, the spallation neutron source at the Rutherford-Appleton Laboratory in England.
We will outline our proposal to design a next generation, time of flight (TOF) spectrometer named, VISION, which is not an acronym, to investigate a vast array of molecular dynamics and structure. Under optimal conditions this instrument will
- have a throughput two orders of magnitude greater than TOSCA
- currently the best instrument in the field;
- cover an energy transfer range of 0-500 meV (0-4000 cm-1 );
- have a 1-2% energy resolution while simultaneously enabling diffraction studies for structural characterization;
- offer a wide range of sample environments (low temperature, high-pressure, flow cell, thermal analysis, etc).
Our approach will incorporate neutron techniques developed during the decade since TFXA and TOSCA were first designed and built. This includes improved supermirror technology, parametrically matched crystal analyzer–helium gas detectors, efficient electronics for high rate data acquisition, high-performance data analysis algorithms, novel moderator concepts, and well-developed Monte Carlo software for neutron optics and instrument design and optimization. This new design combined with the flux available at SNS will enable time-resolved vibrational measurements for the first time at a neutron source.
Proposals to form an Instrument Design Team (IDT) and a subsequent proposal describing the scientific background for VISION have been presented to the Spallation Neutron Source (SNS) Experimental Facilities Advisory Committee (EFAC) and have been positively received. (EFAC has enthusiastically endorsed the science case presented by the IDT and a beamline position for installation and construction of VISION has been identified by SNS.)
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