A laser-driven target of high-density nuclear polarized hydrogen gas
  We report the best figure-of-merit achieved for an internal nuclear polarized hydrogen gas target and a Monte Carlo simulation of spin-exchange optical pumping. The dimensions of the apparatus were optimized using the simulation and the experimental results were in good agreement with the simulation. The best result achieved for this target was 50.5% polarization with 58.2% degree of dissociation of the sample beam exiting the storage cell at a hydrogen flow rate of $1.1\times 10^{18}$ atoms/s. 
B. Clasie, C. Crawford, J. Seely, W. Xu, D. Dutta, H. Gao