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Precision Measurements with Noble Gases : Magnetometry and EDM Searches

Mercredi 15 juin 2016 11:00 - Duree : 1 heure
Lieu : ILL 4, Seminar Room, 71 avenue des Martyrs - Grenoble

Orateur : Skyler DEGENKOLB (Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI 48109-1040, USA)

Hyperpolarized diamagnetic atoms have been a key technological element in searches for a permanent electric dipole moment. Their small spin-flip cross-sections and long coherence times are advantageous for co-magnetometry, and in several nuclear species we expect large Schiff moment enhancements that substantially increase sensitivity to an underlying EDM. I will discuss these systems in two contexts : (1) a SQUID-based search for the 129Xe nuclear EDM, presently underway at FRM-II ; and (2) prospects for extending the domain of optical magnetometry to include such species of interest as 129Xe and 223Rn.

(1) The 129Xe EDM is sensitive to the nuclear Schiff moment and the tensor electron-nucleon interaction ; in this sense it is complementary to octupole-deformed systems such as 225Ra or 223Rn (where the enhanced Schiff moment is expected to dominate), and to the neutron (in which the main contributions are purely hadronic). The FRM-II experiment relies on a high-performance magnetically shielded room, simultaneous spin-exchange polarization of 129Xe and the 3He co-magnetometer, LTc SQUID magnetometry, and novel vapor cells with silicon electrodes bonded to GE180 glass. We have observed T2* > 2700s for both species in such cells, with applied voltages of 10kV across a 2.5cm electrode gap.

(2) Optical magnetometry with diamagnetic systems is mainly limited by the high excitation energies for electronic states in closed-shell atoms ; the longest-wavelength E1 transition in 129Xe is at 147nm, well outside the reach of conventional light sources. This limitation can be relaxed by exploiting longer-wavelength nonlinear processes, especially two-photon transitions : 223Rn and 129Xe have multiple two-photon resonances at wavelengths longer than 250nm, which are available from both continuous-wave and pulsed lasers. I will discuss laser systems for driving these transitions, model experiments in similar atoms, and novel features such as spatial resolution that arise from this approach.

Contact : tellier@ill.fr

Discipline évènement : (Physique)
Entité organisatrice : (ILL)
Nature évènement : (Séminaire)
Evènement répétitif : (General ILL Seminar - College 3)
Site de l'évènement : Polygone scientifique

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