257 research outputs found
Doppler-tuned Bragg Spectroscopy of Excited Levels in He-Like Uranium: a discussion of the uncertainty contributions
We present the uncertainty discussion of a recent experiment performed at the
GSI storage ring ESR for the accurate energy measurement of the He-like uranium
1s2p3P2- 1s2s3S1 intra-shell transition. For this propose we used a Johann-type
Bragg spectrometer that enables to obtain a relative energy measurement between
the He-like uranium transition, about 4.51 keV, and a calibration x-ray source.
As reference, we used the Ka fluorescence lines of zinc and the Li-like uranium
1s22p2P3/2 - 1 s22s 2S1/2 intra-shell transition from fast ions stored in the
ESR. A comparison of the two different references, i.e., stationary and moving
x-ray source, and a discussion of the experimental uncertainties is presented
Doppler-tuned Bragg Spectroscopy of Excited Levels in He-Like Uranium: a discussion of the uncertainty contributions
We present the uncertainty discussion of a recent experiment performed at the
GSI storage ring ESR for the accurate energy measurement of the He-like uranium
1s2p3P2- 1s2s3S1 intra-shell transition. For this propose we used a Johann-type
Bragg spectrometer that enables to obtain a relative energy measurement between
the He-like uranium transition, about 4.51 keV, and a calibration x-ray source.
As reference, we used the Ka fluorescence lines of zinc and the Li-like uranium
1s22p2P3/2 - 1 s22s 2S1/2 intra-shell transition from fast ions stored in the
ESR. A comparison of the two different references, i.e., stationary and moving
x-ray source, and a discussion of the experimental uncertainties is presented
Doppler-tuned Bragg Spectroscopy of Excited Levels in He-Like Uranium: a discussion of the uncertainty contributions
We present the uncertainty discussion of a recent experiment performed at the
GSI storage ring ESR for the accurate energy measurement of the He-like uranium
1s2p3P2- 1s2s3S1 intra-shell transition. For this propose we used a Johann-type
Bragg spectrometer that enables to obtain a relative energy measurement between
the He-like uranium transition, about 4.51 keV, and a calibration x-ray source.
As reference, we used the Ka fluorescence lines of zinc and the Li-like uranium
1s22p2P3/2 - 1 s22s 2S1/2 intra-shell transition from fast ions stored in the
ESR. A comparison of the two different references, i.e., stationary and moving
x-ray source, and a discussion of the experimental uncertainties is presented
Radiative recombination of bare Bi83+: Experiment versus theory
Electron-ion recombination of completely stripped Bi83+ was investigated at
the Experimental Storage Ring (ESR) of the GSI in Darmstadt. It was the first
experiment of this kind with a bare ion heavier than argon. Absolute
recombination rate coefficients have been measured for relative energies
between ions and electrons from 0 up to about 125 eV. In the energy range from
15 meV to 125 eV a very good agreement is found between the experimental result
and theory for radiative recombination (RR). However, below 15 meV the
experimental rate increasingly exceeds the RR calculation and at Erel = 0 eV it
is a factor of 5.2 above the expected value. For further investigation of this
enhancement phenomenon the electron density in the interaction region was set
to 1.6E6/cm3, 3.2E6/cm3 and 4.7E6/cm3. This variation had no significant
influence on the recombination rate. An additional variation of the magnetic
guiding field of the electrons from 70 mT to 150 mT in steps of 1 mT resulted
in periodic oscillations of the rate which are accompanied by considerable
changes of the transverse electron temperature.Comment: 12 pages, 14 figures, to be published in Phys. Rev. A, see also
http://www.gsi.de/ap/ and http://www.strz.uni-giessen.de/~k
Relativistic quantum dynamics in strong fields: Photon emission from heavy, few-electron ions
Recent progress in the study of the photon emission from highly-charged heavy
ions is reviewed. These investigations show that high- ions provide a unique
tool for improving the understanding of the electron-electron and
electron-photon interaction in the presence of strong fields. Apart from the
bound-state transitions, which are accurately described in the framework of
Quantum Electrodynamics, much information has been obtained also from the
radiative capture of (quasi-) free electrons by high- ions. Many features in
the observed spectra hereby confirm the inherently relativistic behavior of
even the simplest compound quantum systems in Nature.Comment: Version 18/11/0
Enhancing the energy resolution of resonant coherent excitation using the cooled U 89+ beam extracted from the ESR
Synopsis We report on the resonant coherent excitation (RCE) of the 2 s -2 p 3/2 transition in Li-like U 89+ with an enhanced energy resolution, which was achieved by reducing the projectiles momentum spread. The kinetic temperature of the beam was decreased by electron cooling in the ESR, and the collisional momentum broadening in the target was suppressed by the use of thin crystal (1.0 and 2.5 ÎŒm-thick). The resonance width was observed to be âŒ1.4 eV in FWHM, which is three-times narrower than that from the previous work
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