Optimization studies of proton polarization in the TRIUMF optically pumped polarized H− ion source

Abstract

The TRIUMF optically pumped polarized ion source presently produces a 15 μA dc beam of up to 80% polarized H− ions within a calculated normalized emittance of ≲ 0.16 π cm mrad. Extracted beam parameters, after acceleration by the TRIUMF cyclotron to 230 MeV, are ∼ 4 μA with a proton polarization of 75%. The source is based on optical pumping of Rb vapor by Ti:sapphire lasers, resulting in improved polarization compared to previous results using Na as the polarized medium. The instrumentation and results of a detailed study of parameter dependences are reported.