Production of intense spin-polarized hydrogen beams using Raman-polarized Cs

We argue that it should be possible to produce multi-ampere nuclear-spin-polarized negative ion beams of hydrogen isotopes by repeated $H-H^-$ charge-transfer collisions with high density spin-polarized Cs vapor. The required spin-polarized alkali-metal densities of 1e14/cc can be attained by off-resonant spontaneous Raman scattering from high-intensity laser light, largely avoiding depolarization by radiation trapping. The transmitted Raman light can be recycled multiple times to produce the meter-scale spin-polarized column of polarized alkali-metal vapor required for production of nuclear-spin-polarized beams. Such beams are of substantial interest for boosting the efficiency of magnetically-confined fusion plasmas.