Adiabatic spin rotator for a laser pumped polarized 3He target

Abstract

An adiabatic spin rotator has been constructed for use with the TRIUMF optically pumped polarized 3He target. It consists of two orthogonal pairs of Helmholtz coils allowing adiabatic rotation of the 3He spin into any arbitrary direction. Thus, the target may be polarized alternately in the sideways, longitudinal, and normal directions allowing measurements of complete sets of spin observables in nuclear scattering experiments during a single experimental run. Recently the system was used to measure all parity-allowed spin correlation observables A 00 ij in 3 He( p , p) elastic scattering at 200 and 500 MeV. The system permits reasonably rapid spin reversals (30 s) with minimal polarization losses (< 1×10 −5 per spin reversal). This allows the target spin to be reversed frequently during an experimental run thus reducing systematic uncertainties from variations in the response of other components in the experimental setup.