Düsseldorf 2007 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 5: Precision spectroscopy II
A 5.6: Vortrag
Montag, 19. März 2007, 17:45–18:00, 6G
Progress towards a direct measurement of the proton g-factor in a double Penning trap — •Susanne Kreim1, Klaus Blaum1,2, Holger Kracke1, Wolfgang Quint2, Stefan Stahl4, Stefan Ulmer1,3, and Jochen Walz1 — 1Institut für Physik, Universität Mainz, 55099 Mainz — 2GSI, 64291 Darmstadt — 3Ruprecht-Karls-Universität, 69047 Heidelberg — 4Stahl-Electronics, 67582 Mettenheim, Germany
Determining the g-factor of a single, isolated proton in a double Penning trap setup results from an accurate measurement of its cyclotron and spin precession frequency. The latter can be determined by inducing radio frequency transitions between the two spin states in the homogeneous magnetic field region of the first, precision Penning trap. The resulting spin state is detected in another region, namely the magnetic bottle field of the analysis trap. There, the spin direction is monitored by measuring the respective axial frequency via the continuous Stern-Gerlach effect. This experiment is performed in a 4K cryogenic environment providing an ultra-high vacuum as well as long storage times of the particle. These surroundings bear great challenges for the electronics needed to non-destructively detect the trapped proton. However, it leads to a low Johnson noise of the detection electronics. Together with the use of superconducting alloys, which lead to a high Q-value of the resonant coil, the signal-to-noise ratio can be improved by some orders of magnitude enabling measurements with a very low uncertainty. The sealed system also calls for an in-trap creation of protons with a newly developed cryogenic electron gun.