HYSPEC: A crystal time-of-flight hybrid spectrometer for the spallation neutron source with polarization capabilities

The hybrid spectrometer (HYSPEC) is a unique direct geometry inelastic scattering instrument under construction at the spallation neutron source (SNS). It combines the intensity enhancement features of focusing Bragg crystals with time-of-flight energy analysis. It will be located at beam-line 14B, which views a coupled liquid hydrogen moderator. A neutron beam from the moderator will travel along a curved guide, through a Fermi chopper and will then be focused onto a sample in an external building, 39 in from the source. In this configuration the intensity at the sample position is more than an order of magnitude larger than for other planned inelastic instrument. A movable detector bank 4.5 in from the sample will cover all angular range of 60 degrees in the horizontal plane and 15 degrees in the vertical direction. An important feature of HYSPEC is the ability to do neutron polarization analysis experiments. A Heusler crystal, which polarizes the neutron beam, can be used as the focusing crystal and a series of bender analyzers will analyze the polarization of the scattered beam. (c) 2006 Elsevier B.V. All rights reserved.