The Heidelberg compact electron beam ion traps

Micke, P.; Kühn, Steffen; Buchauer, Lisa; Harries, James; Bücking, Thore Mainart; Blaum, Klaus; Cieluch, A.; Egl, Alexander; Hollain, Daniel; Kraemer, Sandro; Pfeifer, Thomas; Schmidt, Piet O.; Schüssler, R. X.; Schweiger, Christoph; Stöhlker, Th.; Sturm, Sven; Wolf, R.; Bernitt, Sven; López‐Urrutia, J. R. Crespo

doi:10.1063/1.5026961

Cited by 70 publications

(59 citation statements)

References 148 publications

(145 reference statements)

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“…Within the radial trapping potential generated by the space charge potential of the electron beam, the cooled ions are more concentrated at the bottom, thus reducing the energy dispersion due to the space charge. The details of this technique are discussed in Beilmann et al (2009Beilmann et al ( , 2010Beilmann et al ( , 2011Shah et al (2016bShah et al ( , 2018; Micke et al (2018). Since the ion trapping parameters were kept constant during the electron beam energy scan, this technique does not introduce any systematic effects on the present measurements.…”

Section: Experimental Techniquementioning

confidence: 99%

Revisiting the Fe xvii Line Emission Problem: Laboratory Measurements of the 3s–2p and 3d–2p Line-formation Channels

Shah

López‐Urrutia

et al. 2019

ApJ

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We determined relative X-ray photon emission cross sections in Fe XVII ions that were mono-energetically excited in an electron beam ion trap. Line formation for the 3s (3s − 2p) and 3d (3d − 2p) transitions of interest proceeds through dielectronic recombination (DR), direct electron-impact excitation (DE), resonant excitation (RE), and radiative cascades. By reducing the electron-energy spread to a sixth of that of previous works and increasing counting statistics by three orders of magnitude, we account for hitherto unresolved contributions from DR and the little-studied RE process to the 3d transitions, and also for cascade population of the 3s line manifold through forbidden states. We found good agreement with state-of-the-art many-body perturbation theory (MBPT) and distorted-wave (DW) method for the 3s transition, while in the 3d transitions known discrepancies were confirmed. Our results show that DW calculations overestimate the 3d line emission due to DE by ∼20%. Inclusion of electron-electron correlation effects through the MBPT method in the DE cross section calculations reduces this disagreement by ∼11%. The remaining ∼9% in 3d and ∼11% in 3s/3d discrepancies are consistent with those found in previous laboratory measurements, solar, and astrophysical observations. Meanwhile, spectral models of opacity, temperature, and turbulence velocity should be adjusted to these experimental cross sections to optimize the accuracy of plasma diagnostics based on these bright soft X-ray lines of Fe XVII.

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Section: Experimental Techniquementioning

confidence: 99%

Revisiting the Fe xvii Line Emission Problem: Laboratory Measurements of the 3s–2p and 3d–2p Line-formation Channels

Shah

López‐Urrutia

et al. 2019

ApJ

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“…The key limitation is the very small production rate, resulting from the combined effect of minute ionization cross sections and the need to stepwise pass through many successive charge states. Typical HCI currents from EBITs are therefore in the range from pA to fA for individual charge states in steady-extraction mode; bunches of 10 2 to 10 7 HCI are standard in pulsed mode (Blessenohl et al, 2018;Currell, 2003;Gillaspy, 2001;Micke et al, 2018).…”

Section: Techniques For Hci Deliverymentioning

confidence: 99%

Highly charged ions: Optical clocks and applications in fundamental physics

et al. 2018

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Recent developments in frequency metrology and optical clocks have been based on electronic transitions in atoms and singly charged ions as references. The control over all relevant degrees of freedom in these atoms has enabled relative frequency uncertainties at a level of a few parts in 10 −18 . This accomplishment not only allows for extremely accurate time and frequency measurements, but also to probe our understanding of fundamental physics, such as a possible variation of fundamental constants, a violation of the local Lorentz invariance, and the existence of forces beyond the Standard Model of Physics. In addition, novel clocks are driving the development of sophisticated technical applications. Crucial for applications of clocks in fundamental physics are a high sensitivity to effects beyond the Standard Model and Einstein's Theory of Relativity and a small frequency uncertainty of the clock. Highly charged ions offer both. They have been proposed as highly accurate clocks, since they possess optical transitions which can be extremely narrow and less sensitive to external perturbations compared to current atomic clock species. The large selection of highly charged ions in different charge states offers narrow transitions that are among the most sensitive ones for a change in the finestructure constant and the electron-to-proton mass ratio, as well as other new physics effects. Recent experimental advances in trapping and sympathetic cooling of highly charged ions will in the future enable advanced quantum logic techniques for controlling motional and internal degrees of freedom and thus enable high accuracy optical spectroscopy. Theoretical progress in calculating the properties of selected highly charged ions has allowed the evaluation of systematic shifts and the prediction of the sensitivity to the "new physics" effects. New theoretical challenges and opportunities emerge from relativistic, quantum electrodynamics, and nuclear size contributions that become comparable with interelectronic correlations. This article reviews the current status of theory and experiment in the field, addresses specific electronic configurations and systems which show the most promising properties for research, their potential limitations, and the techniques for their study.

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“…Compared to [26] our much smaller trap size yields higher secular frequencies, which are required for high-fidelity quantum logic operations [29]. Furthermore, the trap is connected to a low-vibration cryogenic supply line [30] and a compact EBIT producing the desired HCI [31].…”

Section: Introductionmentioning

confidence: 99%

A cryogenic radio-frequency ion trap for quantum logic spectroscopy of highly charged ions

Leopold

King

Micke

et al. 2019

Review of Scientific Instruments

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A cryogenic radio-frequency ion trap system designed for quantum logic spectroscopy of highly charged ions is presented. It includes a segmented linear Paul trap, an in-vacuum imaging lens and a helical resonator. We demonstrate ground state cooling of all three modes of motion of a single 9 Be + ion and determine their heating rates as well as excess axial micromotion. The trap shows one of the lowest levels of electric field noise published to date. We investigate the magnetic-field noise suppression in cryogenic shields made from segmented copper, the resulting magnetic field stability at the ion position and the resulting coherence time. Using this trap in conjunction with an electron beam ion trap and a deceleration beamline, we have been able to trap single highly charged Ar 13+ (Ar XIV) ions concurrently with single Be + ions, a key prerequisite for the first quantum logic spectroscopy of a highly charged ion.

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The Heidelberg compact electron beam ion traps

Cited by 70 publications

References 148 publications

Revisiting the Fe xvii Line Emission Problem: Laboratory Measurements of the 3s–2p and 3d–2p Line-formation Channels

Revisiting the Fe xvii Line Emission Problem: Laboratory Measurements of the 3s–2p and 3d–2p Line-formation Channels

Highly charged ions: Optical clocks and applications in fundamental physics

A cryogenic radio-frequency ion trap for quantum logic spectroscopy of highly charged ions

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