Frankfurt 2006 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
A: Atomphysik
A 20: Poster II: Atomare Systeme in starken Laserpulsen und statischen Feldern
A 20.17: Poster
Thursday, March 16, 2006, 16:30–18:30, Labsaal
Effects of weak hyperfine decoupling on metastability exchange optical pumping of 3He — •Marion Batz1, Pierre-Jean Nacher2, Geneviève Tastevin2, and Werner Heil1 — 1Johannes Gutenberg-Universität Mainz, Institut für Physik, Staudingerweg 7, 55099 Mainz, Germany — 2Laboratoire Kastler Brossel, Département de Physique de l’E.N.S., 24 Rue Lhomond, 75231 Paris Cedex 05, France
In order to improve the efficiency of metastability exchange optical pumping of 3He and to obtain a more thorough understanding of the complex relaxation mechanisms in a gas discharge, we set up a 3He optical pumping experiment in magnetic fields up to 30 mT. The gas discharge is the main source of relaxation for the nuclear polarisation of 3He, e.g. due to the emission of circularly polarised fluorescence light in the plasma that is a significant angular momentum loss mechanism. Up to 100 mT, the strong hyperfine coupling in the 23S state and the metastability exchange process are almost unaffected by the applied field. In contrast, above 10 mT electronic and nuclear angular momenta in the excited states involved in the radiative cascade are strongly decoupled and this relaxation mechanism is prevented. We present systematic optical pumping measurements, in which the effects of the magnetic field, of the discharge intensity, of the gas pressure, of the pump laser line and power have been investigated. Our first results indicate that applying a moderate field tends to decrease nuclear relaxation and yields a relative increase in nuclear polarisation by 5-10%.