0000000000023731
AUTHOR
T. Valenzuela
Determination of the g-Factor of Single Hydrogen-Like Ions by Mode Coupling in a Penning Trap
A method has been developed and applied for the determination of the electronic g-factor of single hydrogen-like ions stored in a Penning trap. The method is based on mode coupling of the ion trapping motions and is conceptionally advantageous as compared to previously used methods. It has been applied to hydrogen-like oxygen 16O7+ and yields a value for the gJ-factor which is in agreement with previously determined values. Experimental requirements and possibilities of the new method are discussed.
The magnetic moment anomaly of the electron bound in hydrogen-like oxygen16O7
The measurement of the g-factor of the electron bound in a hydrogen-like ion is a high-accuracy test of the theory of quantum electrodynamics (QED) in strong fields. Here we report on the measurement of the g-factor of the bound electron in hydrogen-like oxygen (16O7+). In our experiment a single highly charged ion is stored in a Penning trap. The electronic spin state of the ion is monitored via the continuous Stern?Gerlach effect in a quantum non-demolition measurement. Quantum jumps between the two spin states (spin up and spin down) are induced by a microwave field at the spin precession frequency of the bound electron. The g-factor of the bound electron is obtained by varying the micro…
Double Penning trap technique for precise g factor determinations in highly charged ions
We present a detailed description of an experiment to determine the magnetic moment of an electron bound in hydrogen-like carbon. This forms a high-accuracy test of bound-state quantum electrodynamics. Special emphasis is given to the discussion of systematic uncertainties which limit our present accuracy. The described experimental setup may also be used for the determination of g factors in other highly charged ions.
Individual and center-of-mass resonances in the motional spectrum of an electron cloud in a Penning trap
We have examined experimentally the motional spectrum of an electron cloud confined in a Penning trap. When the axial oscillation is excited by a radio frequency field the resonance exhibits a double structure. Both components depend differently on the number of trapped electrons and have different shape and width. We conclude that one of them corresponds to the excitation of the individual electrons while the other is the center-of-mass mode of the cloud. The threshold behaviour of the center-of-mass resonance suggests that it is a parametric instability of a Mathieu type equation of motion.
Instabilities of an electron cloud in a Penning trap
We have measured the storage instabilities of electrons in a Penning trap at low magnetic fields. These measurements are carried out as a function of the trapping voltage, for different magnetic fields. It is seen that these instabilities occur at the same positions when the trapping voltage is expressed as a percentage of the maximum voltage, given by the stability limit. The characteristic frequencies at which these instabilities occur, obey a relation that is given by n zω z + n +ω + + n -ω - = 0, where ω z, ω + and ω - are the axial, perturbed cyclotron and the magnetron frequencies of the trapped electrons respectively, and the n's are integers. The reason for these instabilities are a…
HITRAP: A Facility for Experiments with Trapped Highly Charged Ions
HITRAP is a planned ion trap facility for capturing and cooling of highly charged ions produced at GSI in the heavy-ion complex of the UNILAC-SIS accelerators and the ESR storage ring. In this facility heavy highly charged ions up to uranium will be available as bare nuclei, hydrogenlike ions or few-electron systems at low temperatures. The trap for receiving and studying these ions is designed for operation at extremely high vacuum by cooling to cryogenic temperatures. The stored highly charged ions can be investigated in the trap itself or can be extracted from the trap at energies up to about 10 keV/q. The proposed physics experiments are collision studies with highly charged ions at wel…
A Possible New Value for the Electron Mass from g-Factor Measurements on Hydrogen-Like Ions
The mass of the electron in atomic units (m e) represents the largest error contribution in an experiment to determine the g-factor of the electron bound in hydrogen-like carbon. Recent progress in the calculation reduces the uncertainty of the theoretical value to such a low value that m e can be determined from a comparison of experimental and theoretical g-factors. The present preliminary value of the electron mass agrees with the accepted value but reduces the uncertainty by about a factor 2.
Continuous Stern–Gerlach effect and the magnetic moment of the antiproton
Abstract The measurement of the magnetic moment (or g-factor ) of the antiproton and of the proton is a sensitive test of CPT invariance. We discuss the possibility of applying the continuous Stern–Gerlach effect to detect quantum jumps between the two spin states (spin up and spin down) of the antiproton. The measurement will be performed on a single antiproton stored in a Penning trap. The g -factor of the antiproton is determined by measuring its cyclotron frequency and its spin precession frequency in the magnetic field of the trap. With the double Penning trap method the g -factor of the antiproton can be determined with an accuracy of 1 ppb.
Electron and positron cooling of highly charged ions in a cooler Penning trap
Abstract Electron cooling is a well-established technique to increase the phase space density of particle beams in storage rings. In this paper, we discuss the feasibility of electron and positron cooling of ions in a Penning trap. We calculate the cooling times for the cases of trapped bare ions with nuclear charge Z =1 (protons), Z =36 (krypton) and Z =92 (uranium) with the Spitzer formula. Our calculations show that for typical experimental conditions the time for cooling from initial energies of 10 keV per charge down to rest is in the order of a second. We investigate the dependence of the cooling time on the number of ions and electrons, and their charge and mass.
Measurement of the g Factor of the Bound Electron in Hydrogen-like Oxygen 16O7+
The measurement of the g factor of the electron bound in a hydrogen-like ion is a high- accuracy test of the theory of Quantum Electrodynamics (QED) in strong fields. Here we report on the measurement of the g factor of the bound electron in hydrogen-like oxygen 16O7+. In our experiment a single 16O7+ ion is stored in a Penning trap. Quantum jumps between the two spin states (spin up and spin down) are induced by a microwave field at the spin precession frequency of the bound electron. The g factor of the bound electron is obtained by varying the microwave frequency and counting the number of spin flips. Our experimental value for the g factor of the bound electron is gexp(16O7+) = 2.000 04…
Precision studies in traps: Measurement of fundamental constants and tests of fundamental theories
Experiments on single atomic particles confined in Penning ion traps have contributed significantly to the improvements of fundamental constants and to tests of the theory of Quantum Electrodynamics for free and bound electrons. The most precise value of the fine structure constant as well as the electron mass have been derived from trap experiments. Numerous atomic masses of interest for fundamental questions have been determined with precisions of 10 � 9 or below. Further progress is envisaged in the near future.
ElectronicgFactor of Hydrogenlike OxygenO7+16
We present an experimental value for the $g$ factor of the electron bound in hydrogenlike oxygen, which is found to be ${g}_{\mathrm{e}\mathrm{x}\mathrm{p}\mathrm{t}}=2.000\text{ }047\text{ }025\text{ }4\text{ }(15)(44)$. The experiment was performed on a single $^{16}\mathrm{O}^{7+}$ ion stored in a Penning trap. For the first time, the expected line shape of the $g$-factor resonance is calculated which is essential for minimizing the systematic uncertainties. The measurement agrees within $1.1\text{ }\ensuremath{\sigma}$ with the predicted theoretical value ${g}_{\mathrm{t}\mathrm{h}\mathrm{e}\mathrm{o}\mathrm{r}\mathrm{y}}=2.000\text{ }047\text{ }020\text{ }2\text{ }(6)$. It represents a…