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

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 < or ∼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. (orig.)