A high-pressure polarized 3He gas target for the High Intensity Gamma Source (HIγS) facility at Duke Free Electron Laser Laboratory

A new polarized He-3 target has been developed for nuclear physics experiments utilizing the High Intensity Gamma Source (HI gamma S) at the Duke Free Electron Laser Laboratory (DFELL). This target is designed for a broad program of physics employing high intensity polarized photons and a polarized He-3 target as an effective polarized neutron target. We report the performance of this target based on the technique of spin-exchange optical pumping (SEOP). Due to the significantly larger photon beam size at the HI gamma S facility than that of a typical electron beam at electron accelerator laboratories, the HI gamma S He-3 target contains a larger number of He-3 nuclei than any polarized He-3 targets reported previously. A target polarization on the order of 33-46% has been achieved from both a regular He-3-Rubidium (Rb) target and a hybrid target which contains a mixture of Rb and potassium. The target polarization has been determined within 3% using both the Electron Paramagnetic Resonance (EPR) technique and the NMR-AFP (Adiabatic Fast Passage) technique. (c) 2007 Elsevier B.V. All rights reserved.