Optimization of the pumping laser beam spatial profile in the MEOP experimentperformed at elevated ^{3}He pressures

The efficiency of the metastability exchange optical pumping (MEOP) performed at elevated 3He gas pressures in high magnetic field was improved by modifying the spatial profile of the pumping laser beam in such a way that it matched the nonuniform distribution of plasma in the optical pumping cell. Comparing to a conventional Gaussian profile, at the 3He gas pressure equal to 267 mbar, both the achieved nuclear polarization (equal to 26%) and the total magnetization in the cell (equal to 1.37 sccfp) are 60% higher when the annular laser beam profile is applied.