TY - JOUR
T1 - Recent progress on HYSPEC, and its polarization analysis capabilities
AU - Winn, Barry
AU - Filges, Uwe
AU - Garlea, V. Ovidiu
AU - Graves-Brook, Melissa
AU - Hagen, Mark
AU - Jiang, Chenyang
AU - Kenzelmann, Michel
AU - Passell, Larry
AU - Shapiro, Stephen M.
AU - Tong, Xin
AU - Zaliznyak, Igor
N1 - Publisher Copyright:
© 2015 Owned by the authors, published by EDP Sciences.
PY - 2015/1/23
Y1 - 2015/1/23
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84921733288&partnerID=8YFLogxK
U2 - 10.1051/epjconf/20158303017
DO - 10.1051/epjconf/20158303017
M3 - Conference article
AN - SCOPUS:84921733288
SN - 2101-6275
VL - 83
JO - EPJ Web of Conferences
JF - EPJ Web of Conferences
M1 - 03017
T2 - 11th International Conference on Quasielastic Neutron Scattering, QENS 2014 and 6th International Workshop on Inelastic Neutron Spectrometers, WINS 2014
Y2 - 11 May 2014 through 16 May 2014
ER -