Heidelberg 2015 – scientific programme
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A: Fachverband Atomphysik
A 1: Precision spectroscopy of atoms and ions I (with Q)
A 1.1: Talk
Monday, March 23, 2015, 11:30–11:45, C/HSW
The Detection System of the ALPHATRAP Experiment — •Andreas Weigel, Robert Wolf, Sven Sturm, and Klaus Blaum — Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg
The Penning-trap experiment ALPHATRAP is currently being set
up at the Max-Planck-Institut für Kernphysik in Heidelberg. It is the
follow-up to the Mainz g-factor experiment, which has recently succeeded
in the most stringent test of quantum electrodynamics in the
regime of strong fields on hydrogen-like 28Si13+ at the level of 10−11. ALPHATRAP aims
for g-factor measurements on even heavier highly charged ions up to
208Pb81+, with simultaneously improved accuracy. This shall further
contribute to the exploration of the limits of bound-state quantum
electrodynamics.
The determination of the g-factor is based on the non-destructive
determination of the electron spin state inside a magnetic bottle via
the continuous Stern-Gerlach effect. For this purpose the ion eigenfrequencies
have to be measured via the detection of image currents,
which the ion induces into the trap electrodes. These currents are typically on
the order of a few femto-Ampère. Therefore, special highly sensitive detection
electronics consisting of superconducting tank circuits with extremely high Q-factors
followed by ultra-low noise cryogenic amplifiers
will be used. This shall allow for a higher signal-to-noise ratio resulting in an increased measurement precision. The ALPHATRAP detection system
and electronics design will be presented.