In situ SEOP polarised 3He neutron spin filter for incident beam polarisation and polarisation analysis on neutron scattering instruments

• DOI: 10.1016/j.physb.2009.06.039
• Publication Date: 2009-06-14T08:40:30Z
• Authors: S. Boag; E. Babcock; K.H. Andersen; M. Becker; T.R. Charlton; W.C. Chen; R.M. Dalgliesh; S.D. Elmore; C.D. Frost; T.R. Gentile; R. Lopez Anton; S.R. Parnell; A.K. Petoukhov; M.W.A. Skoda; T. Soldner
• Keywords: Analyser; Spallation Neutron Source; Polarizer; Optical Pumping

Abstract We discuss the development and characterisation of a new in situ spin exchange optical pumping (SEOP) based 3 He neutron spin filter polarisation device. We present results from a recent test of the prototype system developed with the Institut Laue-Langevin. The polariser was installed on the polarised reflectometer CRISP at ISIS in the analyser position. The 3 He was pumped continuously in situ on the beamline. The system also integrated a 3 He adiabatic fast passage spin flipper that allowed reversal of the 3 He and therefore neutron polarisation state, allowing for measurement of all four polarisation cross-sections. The system was run for a number of days reaching a 3 He polarisation of 63%.