NEWS

26.11.2008

K. Blaum Fellow of the American Physical Society

Prof. Dr. K. Blaum has been elected a fellow of the American Physical Society. Read more

20.11.2008

Paper about hybrid trap published

In this article a novel Penning trap is introduced, which we call the hybrid Penning trap: a combination of cylindrical electrodes and electrodes of non-cylindrical shape, e.g. toroidal or hyperbolic, as opposed to purely cylindrical traps consisting of cylindrical electrodes only. A quasi-Green's function method renders possible the analytical calculation of any hybrid Penning trap allowing for the analytical calculation of the entire electrostatic properties. In a toroidal hybrid trap with the ring electrode made out of ferromagnetic material, the magnetic bottle field is enhanced by more than an order of magnitude which enables the use of the continuous Stern-Gerlach effect for our planned measurement of the proton g-factor. Detailed analytical expressions for the design of a toroidal hybrid Penning trap for are given simplifying the development of such traps for high-precision experiments. Read more

18.08.2008

TRIGA-SPEC: A new facility for high-precision mass and laser spectroscopy experiments at radionuclides

At the Research Reactor TRIGA Mainz currently a setup for high-precision mass measurements and laser spectroscopy on heavy and neutron-rich nuclides is built. A just published article gives a survey of the experimental setup and the physical objective of TRIGA-SPEC (J.Ketelaer et al., Nucl. Instr. Meth. A 594 (2008) 162). At beam tube B of the reactor the Penning trap mass spectrometer TRIGA-TRAP has already been set up and is currently commissioned. Moreover we build a collinear laser spectroscopy beamline and an on-line ion source with a magnetic mass separator as coupling to the reactor.

15.08.2008

First signals from the proton lab

The experiment for the determination of the proton g-factor has been running for a few weeks now. As a first step, we created ion clouds through electron impact ionization and loaded them into a Penning trap where we detected the axial mode non-destructively. The temperature in the trap chamber lies around 5K at a background pressure of better than 1.0E-13 mbar. Further, the ion cloud was cleaned from contaminations by extracting unwanted species from the trap by excitation. Small, pure proton clouds can also be detected via the cyclotron mode. To this end, the particles are excited and thus thrown on different revolution radii, which can be seen from fig. 1.

Fig. 1: Motion of a proton cloud in the cyclotron mode. The excited particles move similar to a planetary motion and are being cooled resistively until they come in thermal equilibrium with the detection circuit.

Since the particles are in resonance with the tank circuit during detection, they are being cooled and reunite to one peak.

26.07.2008

Articles about the elliptical Penning trap published

The theoretical investigation of an ideal elliptical Penning trap and the experimental investigations and simulations of an elliptical Penning trap are described in the two consecutive corresponding articles.
M. Kretzschmar, Int. J. Mass Spectrom. 275, 21–33 (2008):
In this article a complete and rigorous description of the dynamics of the ideal elliptical trap is given. An ideal elliptical Penning trap is an ideal cylindrically symmetric Penning trap with an additional electrostatic quadrupolar potential. M. Kretzschmar also discusses the approximate physical realization of such an elliptical trap by use of a segmented ring electrode and estimates the frequency shifts expected for a real elliptical trap on account of anharmonic potential terms and of image charges by means of classical canonical perturbation theory. Read more

M. Breitenfeldt et al., Int. J. Mass Spectrom. 275, 34–44 (2008):
In this accompanying paper the influence of an additional azimuthal quadrupolar electrostatic field on the eigenfrequencies of ions in a Penning trap has been investigated. This "Elliptical Penning trap" also has been investigated by simulations. For the magnetron motion a shift to smaller frequency values was observed. The experimental results are in agreement with the ion trajectory simulations as well as theoretical predictions (see article of M. Kretzschmar). The described investigations should help to improve the understanding as well as the applicability of ion trapping devices. Read more