Polarized 3He ion source based on polarized electron capture

The 3He+ ions which are formed by 3He2+ ions capturing the polarized electrons of the sodium atoms polarized by optical pumping become nuclear polarized beam, as electron polarization shifts to nuclei by ultrafine interaction. When the current of 3He2+ ions was 2 eμA, and the degree of polarization of sodium atoms was 0.30±0.05, the 3He+ beam of nuclear polarization degree 0.0415±0.0061 and beam current 40 nA was obtained. By carrying out the improvement such as the increase of the degree of polarization of sodium or the current of 3He2+, it can be expected to form the polarized beam of current more than 10 μA and degree of polarization close to 30%. The polarization experiment carried out so far was mostly on protons and deuterons, and as for 3He, there was only one polarization experiment. In Research Center for Nuclear Physics, Osaka University, the 3He beam up to 530 MeV can be obtained by using the ring cyclotron, therefore, it was decided to develop the polarized 3He ion source using polarized electron capture. The principle of polarization formation, the experimental equipment consisting of ECR ion source, polarized Na target and 3He nuclear polarization measuring part, and the experimental results are reported. (K.I.)