Optical pumping magnetic resonance in high magnetic fields: Measurement of high field spin exchange cross sections

The polarization of 129Xe gas by spin exchange with optically pumped Rb vapor is examined in high magnetic field. Measurements of the Rb–Xe velocity averaged spin exchange cross section 〈σv̄〉 and the 129Xe relaxation time in the absence of Rb, T1Xe, are discussed. Comparison of these high field results to low field literature values for 〈σv̄〉 show that this parameter is essentially field independent. T1Xe is also found to be significantly longer in high field. On the basis of these observations, it is shown that production of large amounts of spin polarized 129Xe gas can be made more efficient by high field operation.