Towards a Polarized 3He++ Ion Source at BNL

Because of its single neutron which carries the majority of its nuclear spin, spin-polarized He-3++ ions are a prime candidate to perform neutron spin studies. Here we report on progress made at Brookhaven National Laboratory towards realizing a Metastability-Exchange Optically Pumped (MEOP) polarized helium-3 source for implementation in the Electron Beam Ion Source (EBIS) there. The helium gas will be polarized in the 5T field of the existing EBIS, where it will be ionized and prepared for injection into the Alternating Gradient Synchrotron (AGS). An infrared laser system has been developed for optical pumping and measuring the polarization of the gas within the EBIS field before injection, and an absolute polarimeter will measure the polarization between the EBIS and the AGS. Previous results have demonstrated close to 90% polarization in an "open" cell configuration, with injection and refilling ports valved off. Now, the setup has been moved into an exact copy of the EBIS magnet to take initial measurements before final integration.