The production of polarized negative ion beams by ‘‘collisional pumping’’

The production of polarized negative ion beams by ‘‘collisional pumping’’ is described. Collisional pumping utilizes repeated charge changing collisions in a thick electron‐spin‐polarized gas or vapor target to form a polarized fast atom beam. The polarized fast atom beam is then partially converted into a polarized negative ion beam in a vapor target. Analysis is presented for a hydrogen beam passing through either a thick polarized H atom target or a thick polarized alkali target. Large polarizations and large currents may be possible.