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MO: Fachverband Molekülphysik

MO 1: Cold Molecules 1

MO 1.5: Vortrag

Montag, 17. März 2014, 11:45–12:00, BEBEL HS213

Cryogenic buffer-gas cooling: comparison of two different regimes — •Xing Wu, Thomas Gantner, Sotir Chervenkov, Martin Zeppenfeld, and Gerhard Rempe — Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching, Germany

Cryogenic buffer-gas cooling is a promising method for producing bright beams of cold polar molecules [1] for low-temperature collision experiments, chemical reactions, and precision measurements. In combination with the electrostatic guiding technique [2], high-intensity beams of slow and low-field-seeking molecules can be extracted and delivered to further experiments. To optimize the flux of the guided beam, we investigate the performance of buffer-gas cooling in two different regimes, the effusive and the supersonic one. In the effusive regime, molecules with a low peak velocity and a high flux are obtained after the electric guiding. The velocity spread in this case corresponds to the temperature of the cryogenic cell. In the supersonic regime, molecules move at faster forward velocities, but are further cooled in the co-moving frame because of the adiabatic expansion. The output efficiency of the buffer-gas cell is also increased due to the hydrodynamic enhancement. However, the electric guiding of the supersonic beams has only limited performance, most likely because of collisions happening at the entrance of the electric guide, due to the large densities of both buffer gas and molecules in the forward beam.

[1] L.D. van Buuren et al., Phys. Rev. Lett. 102, 033001 (2009)

[2] S.A. Rangwala et al., Phys. Rev. A 67, 043406 (2003)