24 research outputs found
Extraction of the electron mass from factor measurements on light hydrogenlike ions
The determination of the electron mass from Penning-trap measurements with
C ions and from theoretical results for the bound-electron
factor is described in detail. Some recently calculated contributions slightly
shift the extracted mass value. Prospects of a further improvement of the
electron mass are discussed both from the experimental and from the theoretical
point of view. Measurements with He ions will enable a consistency
check of the electron mass value, and in future an improvement of the He
nuclear mass and a determination of the fine-structure constant
High-precision mass spectrometer for light ions
The precise knowledge of the atomic masses of light atomic nuclei, e.g., the proton, deuteron, triton, and helion, is of great importance for several fundamental tests in physics. However, the latest high-precision measurements of these masses carried out at different mass spectrometers indicate an inconsistency of five standard deviations. To determine the masses of the lightest ions with a relative precision of a few parts per trillion and investigate this mass problem, a cryogenic multi-Penning-trap setup, LIONTRAP (Light-Ion Trap), was constructed. This allows an independent and more precise determination of the relevant atomic masses by measuring the cyclotron frequency of single trapped ions in comparison to that of a single carbon ion. In this paper the measurement concept and a doubly compensated cylindrical electrode Penning trap are presented. Moreover, the analysis of the first measurement campaigns of the proton's and oxygen's atomic mass is described in detail, resulting in mp=1.007276466598(33)u and m(16O)=15.99491461937(87)u. The results on these data sets have already been presented by F. Heiße et al. [Phys. Rev. Lett. 119, 033001 (2017)]. For the proton's atomic mass, the uncertainty was improved by a factor of three compared to the 2014 CODATA valu
Image charge shift in high-precision Penning traps
An ion in a Penning trap induces image charges on the surfaces of the trap electrodes. These induced image charges are used to detect the ion's motional frequencies, but they also create an additional electric field, which shifts the free-space cyclotron frequency typically at a relative level of several 10 −11. In various high-precision Penning-trap experiments, systematics and their uncertainties are dominated by this so-called image charge shift (ICS). The ICS is investigated in this work by a finite-element simulation and by a dedicated measurement technique. Theoretical and experimental results are in excellent agreement. The measurement is using singly stored ions alternately measured in the same Penning trap. For the determination of the ion's magnetron frequency with relative precision of better than 10 parts per billion, a Ramsey-like technique has been developed. In addition, numerical calculations are carried out for other Penning traps and agree with older ICS measurements.peerReviewe
High-Precision Measurement of the Proton’s Atomic Mass
We report on the precise measurement of the atomic mass of a single proton
with a purpose-built Penning-trap system. With a precision of 32
parts-per-trillion our result not only improves on the current CODATA
literature value by a factor of three, but also disagrees with it at a level of
about 3 standard deviations
g Factor of Lithiumlike Silicon: New Challenge to Bound-State QED
The recently established agreement between experiment and theory for the
factors of lithiumlike silicon and calcium ions manifests the most stringent
test of the many-electron bound-state quantum electrodynamics (QED) effects in
the presence of a magnetic field. In this Letter, we present a significant
simultaneous improvement of both theoretical and experimental values of the factor of lithiumlike silicon
Si. The theoretical precision now is limited by the
many-electron two-loop contributions of the bound-state QED. The experimental
value is accurate enough to test these contributions on a few percent level.Comment: 5 pages, 1 figur