Recent progress on HYSPEC, and its polarization analysis capabilities

Barry Winn, Uwe Filges, V. Ovidiu Garlea, Melissa Graves-Brook, Mark Hagen, Chenyang Jiang, Michel Kenzelmann, Larry Passell, Stephen M. Shapiro, Xin Tong, Igor Zaliznyak

Research output: Contribution to journalConference articlepeer-review

57 Scopus citations

Abstract

HYSPEC is a high-intensity, direct-geometry time-of-flight spectrometer at the Spallation Neutron Source, optimized for measurement of excitations in small single-crystal specimens with optional polarization analysis capabilities. The incident neutron beam is monochromated using a Fermi chopper with short, straight blades, and is then vertically focused by Bragg scattering onto the sample position by either a highly oriented pyrolitic graphite (unpolarized) or a Heusler (polarized) crystal array. Neutrons are detected by a bank of 3He tubes that can be positioned over a wide range of scattering angles about the sample axis. HYSPEC entered the user program in February 2013 for unpolarized experiments, and is already experiencing a vibrant research program. Polarization analysis will be accomplished by using the Heusler crystal array to polarize the incident beam, and either a 3He spin filter or a supermirror wide-angle polarization analyser to analyse the scattered beam. The 3He spin filter employs the spin-exchange optical pumping technique. A 60- wide angle 3He cell that matches the detector coverage will be used for polarization analysis. The polarized gas in the post-sample wide angle cell is designed to be periodically and automatically refreshed with an adjustable pressure of polarized gas, optically pumped in a separate cell and then transferred to the wide angle cell. The supermirror analyser has 960 supermirror polarizers distributed over 60-, and has been characterized at the Swiss Spallation Neutron Source. The current status of the instrument and the development of its polarization analysis capabilities are presented.

Original languageEnglish
Article number03017
JournalEPJ Web of Conferences
Volume83
DOIs
StatePublished - Jan 23 2015
Event11th International Conference on Quasielastic Neutron Scattering, QENS 2014 and 6th International Workshop on Inelastic Neutron Spectrometers, WINS 2014 - Autrans, France
Duration: May 11 2014May 16 2014

Fingerprint

Dive into the research topics of 'Recent progress on HYSPEC, and its polarization analysis capabilities'. Together they form a unique fingerprint.

Cite this