Development of a 3He nuclear spin flip system on an in-situ SEOP 3He spin filter and demonstration for a neutron reflectometer and magnetic imaging technique

摘要

Wehavebeendevelopinga3Heneutronspinfilter(NSF)usingthespinexchangeopticalpumping(SEOP)technique.The3HeNSFprovidesahigh-energypolarizedneutronbeamwithlargebeamsize.Moreoverthe3HeNSFcanworkasaπ-flipperforapolarizedneutronbeambyflippingthe3Henuclearspinusinganuclearmagneticresonance(NMR)technique.ForNMRwiththein-situSEOPtechnique,thepolarizationofthelasermustbereversedsimultaneouslybecauseanon-reversedlaserreducesthepolarizationofthespin-flipped3He.Tochangethepolarityofthelaser,ahalf-wavelengthplatewasinstalled.Therotationangleofthehalf-wavelengthplatewasoptimized,andapolarizationof97%wasobtainedforthecircularlypolarizedlaser.The3Hepolarizationreached70%andwasstableoveroneweek.Ademonstrationofthe3HenuclearspinflipsystemwasperformedatthepolarizedneutronreflectometerSHARAKU(BL17)andNOBORU(BL10)atJ-PARC.Off-specularmeasurementfromamagneticFe/CrthinfilmandmagneticimagingofamagneticsteelsheetwereperformedatBL17andBL10,respectively...