Optically pumped polarized ion sources
- Univ. of Wisconsin, Madison, WI (United States)
Polarized negative hydrogen ions are produced in an optically pumped polarized ion source (OPPIS) as follows. A proton beam is extracted from an ECR ion source, accelerated to an energy of a few kilovolts, and focused into a parallel beam. The proton beam is passed through an optically pumped electron spin polarized alkali vapor target in a large magnetic field where the proton beam is partially neutralized by the pick-up of a polarized electron. The optically pumped alkali vapor target must be in a magnetic field large enough to decouple L and S in the n=2 level of atomic hydrogen so that the radiative decay to the ground level does not result in the loss of electron spin polarization. The large magnetic field also helps avoid radiation trapping limitations on the alkali density. The resulting fast atomic hydrogen beam passes through zero field where Sona transitions convert the electron spin polarization into nuclear spin polarization. The beam then is partially converted into polarized negative hydrogen ions in a sodium vapor target. At the present time the best dc OPPIS (at TRIUMF) produces 120 {mu}A with a polarization of 0.8. The best pulsed OPPIS (at INR in Moscow) produces 400 {mu}A. The use of OPPIS with deuterium has been pioneered at KEK in Japan. There is current research at TRIUMF on the possibility of using multiple spin/charge exchange collisions to increase the available current into the mA range, and there is current research at Osaka in the use of the technique with heavier ions such as helium.
- OSTI ID:
- 375026
- Report Number(s):
- CONF-9304297--
- Journal Information:
- Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 2 Vol. 40; ISSN BAPSA6; ISSN 0003-0503
- Country of Publication:
- United States
- Language:
- English
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Spin-exchange polarization study at the TRIUMF OPPIS
University of Wisconsin, Department of Physics. Technical progress report, February 1, 1981-May 30, 1981