Optimization of the pumping laser beam spatial profile in the MEOP experiment performed at elevated ³He pressures

¹ M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland
² Physics Department, Agricultural University, Al. Mickiewicza 21, 31-120 Kraków, Poland
³ Laboratoire Kastler Brossel, École Normale Supérieure, 24 rue Lhomond, 75005 Paris, France
⁴ Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland

^a e-mail: msuchanek@ar.krakow.pl

Received: 7 December 2010
Accepted: 2 March 2011
Published online: 18 May 2011

Abstract

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.