Development of Polarized 3He⁺⁺ion source at BNL

We are also developing a high intensity (2. 10¹¹ions per pulse) 3He⁺⁺ polarized ion source for the future Electron Ion Collider (EIC). The polarized 3He⁺⁺ ion beam help us to understand the spin structure of the neutron beam. This source will use a new technique which is based on the polarization of accumulated ultra-pure 3He gas in a high magnetic field by metastability-exchange optical pumping. Polarized gas will be ionized by the electron beam of the existing Electron Beam Ion Source (EBIS). An infrared laser system for pumping and measurement in the high field of EBIS has been developed. In the test setup, polarization of 80-85% has been achieved for ultra-pure 3He gas in the "Open" cell configuration with refilling valve tube inlet and isolation valve closed. The development of the spin-rotator and 3He-4He absolute nuclear polarimeter at 6 MeV 3He⁺⁺ beam energy is also presented.