Polarized 3He++ Ion Source for RHIC and an EIC

Abstract

The capability of accelerating a polarized $^3$He ion beam in RHIC would demonstrate an effective polarized neutron beam for the study of new high-energy QCD studies of nucleon structure. This development would be particularly beneficial for the future plans of an Electron Ion Collider (EIC), which could use a polarized $^3$He ion beam to probe the spin structure of the neutron. The proposed polarized $^3$He ion source is based on the Electron Beam Ion Source (EBIS) currently in operation at Brookhaven National Laboratory (BNL). $^3$He gas would be polarized within the 5 T field of the EBIS solenoid via Metastability Exchange Optical Pumping (MEOP) and then pulsed into the EBIS vacuum and drift tube system where the $^3$He will be ionized by the 10 Amp electron beam. The goal of the polarized $^3$He ion source is to achieve $2.5 \times 10^{11}$ $^3$He$^{++}$/pulse at 70\% polarization. An upgrade of the EBIS is currently underway at BNL. The EBIS capability to produce polarized $^{3}$He$^{++}$ is being developed through a collaboration between BNL and MIT.