Hamburg 2009 – scientific programme
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A: Fachverband Atomphysik
A 3: Precision Spectroscopy of Atoms and Ions I
A 3.5: Talk
Monday, March 2, 2009, 15:30–15:45, VMP 6 HS-B
Preparation of a single proton in a Penning trap experiment for the determination of the g-factor of the proton — •Cricia Rodegheri1, Klaus Blaum2,3, Holger Kracke1, Susanne Kreim1, Andreas Mooser1, Christian Mrozik1, Wolfgang Quint4, Stefan Ulmer1,2,4, and Jochen Walz1 — 1Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz — 2Max-Planck-Institut für Kernphysik, 69117 Heidelberg — 3Ruprecht-Karls-Universität, 69047 Heidelberg — 4GSI, 64291 Darmstadt
The determination of the proton g-factor results from the accurate measurement of two frequencies of the stored particle in a double Penning trap setup, as it can be calculated as g=2νL/νc. The free cyclotron frequency νc is determined in the homogeneous magnetic field of the precision trap. The Larmor frequency νL will be measured by means of the continuos Stern-Gerlach effect in the analysis trap. The preparation of a single proton from a particle cloud loaded in the precision trap is presented. The undesired species, products of the in-trap ion creation process, are removed by applying a strong dipolar excitation at the axial frequency of the ions and lowering the trap potential. The resulting proton cloud is successively reduced up to one single proton by exciting the cyclotron motion in a detuned trap. In an anharmonic potential the frequency of the ion depends on its energy. Thus, with a broad band excitation one can spread the ion cloud and then remove the protons individually with a stronger discrete excitation. Due to the extremely low background pressure inside the trap chamber the storage time of the isolated proton is longer than several weeks.