He-3 spin filters for a thermal neutron triple axis spectrometer

Type of Work

Article

Date

7-15-2007

Journal Title

Physica B: Condensed Matter

Journal ISSN

0921-4526

Journal Volume

397

Journal Issue

1-2

First Page

168

Last Page

171

DOI

10.1016/j.physb.2007.02.053

Abstract

We have tested two He-3 neutron spin filters (NSF), one for the polarizer and one for the analyzer, in conjunction with a doubly focusing pyrolytic graphite (PG) monochromator on the state-of-the-art BT-7 thermal triple axis spectrometer (TAS) at the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR). This system will provide significantly better neutronic performance for polarization analysis over a conventional TAS with Heusler crystals. We discuss the scheme for employing NSFs on the TAS instrument, including the He-3 cell design, spin-exchange optical pumping (SEOP) of these large He-3 cells, and the holding fields on the spectrometer. Using Rb/K hybrid SEOP, we have produced 75% He-3 polarization for the I I cm diameter cells for TAS in less than two days. (c) 2007 Published by Elsevier B.V.

Hamilton Areas of Study

Physics

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