Detection system for forward emitted photons at the Experimental Storage Ring at GSI

Hannen, V.; Anielski, Denis; Geppert, Christopher; Jöhren, Raphael; Kühl, T.; Lochmann, Matthias; López-Coto, R.; Nörtershäuser, W.; Ortjohann, H.-W.; Sánchez, R.; Vollbrecht, Jonas; Weinheimer, C.; Winters, D.

doi:10.1088/1748-0221/8/09/p09018

Cited by 20 publications

(43 citation statements)

References 10 publications

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“…The signal is detected on the opposite side of the storage ring, far away from any stray light of the laser pulse, using specialized mirror systems3031 (inset in Fig. 1), which reflect the fluorescence photons onto photo multiplier tubes.…”

Section: Methodsmentioning

confidence: 99%

High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED

et al. 2017

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Electrons bound in highly charged heavy ions such as hydrogen-like bismuth 209Bi82+ experience electromagnetic fields that are a million times stronger than in light atoms. Measuring the wavelength of light emitted and absorbed by these ions is therefore a sensitive testing ground for quantum electrodynamical (QED) effects and especially the electron–nucleus interaction under such extreme conditions. However, insufficient knowledge of the nuclear structure has prevented a rigorous test of strong-field QED. Here we present a measurement of the so-called specific difference between the hyperfine splittings in hydrogen-like and lithium-like bismuth 209Bi82+,80+ with a precision that is improved by more than an order of magnitude. Even though this quantity is believed to be largely insensitive to nuclear structure and therefore the most decisive test of QED in the strong magnetic field regime, we find a 7-σ discrepancy compared with the theoretical prediction.

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Section: Methodsmentioning

confidence: 99%

High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED

et al. 2017

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“…XUV photons hitting the cathode will produce mostly low energetic (typically a few eV) secondary electrons that will be guided electromagnetically onto a microchannel plate (RoentDek DET40 MCP) which is mounted inside the vacuum. A similar detection system for optical photons, making use of a movable parabolic copper mirror and a photomultiplier outside the vacuum 19 , has already successfully been applied in a measurement of the hyperfine structure splitting in H-like and Li-like bismuth 12,20 . Figure 3, left panel, shows a schematic view of the setup as it was implemented for simulations using the software package SIMION 8.1 21 .…”

Section: Xuv Detection Systemmentioning

confidence: 99%

Laser spectroscopy of the 2S1/2 - 2P1/2, 2P3/2 transitions in stored and cooled relativistic C3+ ions

Winzen

Hannen

Bußmann

et al. 2020

Preprint

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The and 2S1/2 - 2P1/2 and 2S1/2 - 2P3/2 transitions in Li-like carbon ions stored and cooled at a velocity of β ≈ 0.47 in the Experimental Storage Ring (ESR) at the GSI Helmholtz Centre in Darmstadt have been investigated in a laser spectroscopy experiment. Resonance wavelengths have been obtained using a new continuous-wave UV laser system and a novel extreme UV (XUV) detection system used to detect forward emitted fluorescence photons. The results obtained for the two transitions are compared to existing experimental and theoretical data. A discrepancy found in an earlier laser spectroscopy measurement at the ESR with results from plasma spectroscopy and interferometry could be resolved and agreement between experiment and theory is confirmed. Nonetheless, the experimental uncertainty is still smaller than that of state-of-the art theory.

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“…The theoretically predicted lifetime of the F = 5 state in 209 Bi 80+ of about 118 ms [14] at β = 0.71 is even longer and allows us again to detect fluorescence photons opposite to the electron cooler after resonant excitation with the laser. For that purpose a specially developed movable parabolic mirror system [15] (see right part of inset in figure 1) has been used. The need to develop a special detection system for the Li-like transition arises from the low signal rate connected to the long lifetime of the state and the long wavelength of the fluorescence photons that are outside the sensitive range of most PMTs.…”

Section: Libelle Experimentsmentioning

confidence: 99%

Lifetimes and g-factors of the HFS states in H-like and Li-like bismuth

Hannen

Vollbrecht

Andelkovic

et al. 2019

J. Phys. B: At. Mol. Opt. Phys.

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The LIBELLE experiment performed at the experimental storage ring (ESR) at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany, has successfully determined the ground state hyperfine (HFS) splittings in hydrogenlike ( 209 Bi 82+ ) and lithium-like ( 209 Bi 80+ ) bismuth. The study of HFS transitions in highly charged ions enables precision tests of QED in extreme electric and magnetic fields otherwise not attainable in laboratory experiments. Besides the transition wavelengths the time resolved detection of fluorescence photons following the excitation of the ions by a pulsed laser system also allows the extraction of lifetimes of the upper HFS levels and g-factors of the bound 1s and 2s electrons for both charge states. While the lifetime of the upper HFS state in 209 Bi 82+ has already been measured in earlier experiments, an experimental value for lifetime of this state in 209 Bi 80+ is reported for the first time in this work.

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Detection system for forward emitted photons at the Experimental Storage Ring at GSI

Cited by 20 publications

References 10 publications

High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED

High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED

Laser spectroscopy of the 2S1/2 - 2P1/2, 2P3/2 transitions in stored and cooled relativistic C3+ ions

Lifetimes and g-factors of the HFS states in H-like and Li-like bismuth

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