We report on first laser cooling studies of bunched beams of triply charged carbon ions stored at... more We report on first laser cooling studies of bunched beams of triply charged carbon ions stored at an energy of 1.46 GeV at the ESR (GSI). Despite for the high beam energy and charge state laser cooling provided a reduction of the momentum spread of one order of magnitude in spacecharge dominated bunches as compared to electron cooling. For ion currents exceeding 10 µA intrabeam-scattering losses could not be compensated by the narrow band laser system presently in use. Yet, no unexpected problems occurred encouraging the envisaged extension of the laser cooling to highly relativistic beams. At ESR, especially the combination with modest electron cooling provided three-dimensionally cold beams in the plasma parameter range of unity, where ordering effects can be expected and a still unexplained signal reduction of the Schottky signal is observed.
Journal of Physics B: Atomic, Molecular and Optical Physics, 2000
Dielectronic recombination(DR) of lithium-like Ti 19+ (1s 2 2s) ions via 2s → 2p core excitations... more Dielectronic recombination(DR) of lithium-like Ti 19+ (1s 2 2s) ions via 2s → 2p core excitations has been measured at the Heidelberg heavy ion storage ring TSR. We find that not only external electric fields (0 ≤ E y ≤ 280 V/cm) but also crossed magnetic fields (30 mT≤ B z ≤ 80 mT) influence the DR via high-n 2p j nℓ-Rydberg resonances. This result confirms our previous finding for isoelectronic Cl 14+ ions [Bartsch T et al, Phys. Rev. Lett. 82, 3779 (1999)] that experimentally established the sensitivity of DR to E × B fields. In the present investigation the larger 2p 1/2 − 2p 3/2 fine structure splitting of Ti 19+ allowed us to study separately the influence of external fields via the two series of Rydberg DR resonances attached to the 2s → 2p 1/2 and 2s → 2p 3/2 excitations of the Li-like core, extracting initial slopes and saturation fields of the enhancement. We find that for E y 80 V/cm the field induced enhancement is about 1.8 times stronger for the 2p 3/2 series than for the 2p 1/2 series.
We present the concluding result from an Ives-Stilwell-type time dilation experiment using 7Li+ i... more We present the concluding result from an Ives-Stilwell-type time dilation experiment using 7Li+ ions confined at a velocity of β=v/c=0.338 in the storage ring ESR at Darmstadt. A Λ-type three-level system within the hyperfine structure of the 7Li+3S1 →3P2 line is driven by two laser beams aligned parallel and antiparallel relative to the ion beam. The lasers' Doppler shifted frequencies required for resonance are measured with an accuracy of <4×10(-9) using optical-optical double resonance spectroscopy. This allows us to verify the special relativity relation between the time dilation factor γ and the velocity β, γ√1-β2=1 to within ±2.3×10(-9) at this velocity. The result, which is singled out by a high boost velocity β, is also interpreted within Lorentz invariance violating test theories.
Journal of Physics B: Atomic, Molecular and Optical Physics, 2005
The electric dipole intercombination decay rate of the 2s2p 3Po1 level in the Be-like ions N3+ an... more The electric dipole intercombination decay rate of the 2s2p 3Po1 level in the Be-like ions N3+ and O4+ has been measured with ions circulating in a heavy-ion storage ring. The observation employed three devices in parallel, two different VUV photon detectors and a residual gas recoil ion detector. The measured transition probabilities of (578 ± 3.3) s-1 for N3+ (level lifetime tau = 1.73 ± 0.01 ms) and of (2315 ± 50) s-1 for O4+ (tau = 0.432 ± 0.009 ms), corroborate the results of recent calculations and improve the precision with which the isoelectronic trend can be established.
Dielectronic recombination(DR) of lithium-like Ti 19+ (1s 2 2s) ions via 2s → 2p core excitations... more Dielectronic recombination(DR) of lithium-like Ti 19+ (1s 2 2s) ions via 2s → 2p core excitations has been measured at the Heidelberg heavy ion storage ring TSR. We find that not only external electric fields (0 ≤ E y ≤ 280 V/cm) but also crossed magnetic fields (30 mT≤ B z ≤ 80 mT) influence the DR via high-n 2p j nℓ-Rydberg resonances. This result confirms our previous finding for isoelectronic Cl 14+ ions [Bartsch T et al, Phys. Rev. Lett. 82, 3779 (1999)] that experimentally established the sensitivity of DR to E × B fields. In the present investigation the larger 2p 1/2 − 2p 3/2 fine structure splitting of Ti 19+ allowed us to study separately the influence of external fields via the two series of Rydberg DR resonances attached to the 2s → 2p 1/2 and 2s → 2p 3/2 excitations of the Li-like core, extracting initial slopes and saturation fields of the enhancement. We find that for E y 80 V/cm the field induced enhancement is about 1.8 times stronger for the 2p 3/2 series than for the 2p 1/2 series.
Time dilation is one of the most fascinating aspects of special relativity as it abolishes the no... more Time dilation is one of the most fascinating aspects of special relativity as it abolishes the notion of absolute time. It was first observed experimentally by Ives and Stilwell in 1938 using the Doppler effect. Here we report on a method, based on fast optical atomic clocks with large, but ...
We report on first laser cooling studies of bunched beams of triply charged carbon ions stored at... more We report on first laser cooling studies of bunched beams of triply charged carbon ions stored at an energy of 1.46 GeV at the ESR (GSI). Despite for the high beam energy and charge state laser cooling provided a reduction of the momentum spread of one order of magnitude in spacecharge dominated bunches as compared to electron cooling. For ion currents exceeding 10 µA intrabeam-scattering losses could not be compensated by the narrow band laser system presently in use. Yet, no unexpected problems occurred encouraging the envisaged extension of the laser cooling to highly relativistic beams. At ESR, especially the combination with modest electron cooling provided three-dimensionally cold beams in the plasma parameter range of unity, where ordering effects can be expected and a still unexplained signal reduction of the Schottky signal is observed.
Journal of Physics B: Atomic, Molecular and Optical Physics, 2000
Dielectronic recombination(DR) of lithium-like Ti 19+ (1s 2 2s) ions via 2s → 2p core excitations... more Dielectronic recombination(DR) of lithium-like Ti 19+ (1s 2 2s) ions via 2s → 2p core excitations has been measured at the Heidelberg heavy ion storage ring TSR. We find that not only external electric fields (0 ≤ E y ≤ 280 V/cm) but also crossed magnetic fields (30 mT≤ B z ≤ 80 mT) influence the DR via high-n 2p j nℓ-Rydberg resonances. This result confirms our previous finding for isoelectronic Cl 14+ ions [Bartsch T et al, Phys. Rev. Lett. 82, 3779 (1999)] that experimentally established the sensitivity of DR to E × B fields. In the present investigation the larger 2p 1/2 − 2p 3/2 fine structure splitting of Ti 19+ allowed us to study separately the influence of external fields via the two series of Rydberg DR resonances attached to the 2s → 2p 1/2 and 2s → 2p 3/2 excitations of the Li-like core, extracting initial slopes and saturation fields of the enhancement. We find that for E y 80 V/cm the field induced enhancement is about 1.8 times stronger for the 2p 3/2 series than for the 2p 1/2 series.
We present the concluding result from an Ives-Stilwell-type time dilation experiment using 7Li+ i... more We present the concluding result from an Ives-Stilwell-type time dilation experiment using 7Li+ ions confined at a velocity of β=v/c=0.338 in the storage ring ESR at Darmstadt. A Λ-type three-level system within the hyperfine structure of the 7Li+3S1 →3P2 line is driven by two laser beams aligned parallel and antiparallel relative to the ion beam. The lasers' Doppler shifted frequencies required for resonance are measured with an accuracy of <4×10(-9) using optical-optical double resonance spectroscopy. This allows us to verify the special relativity relation between the time dilation factor γ and the velocity β, γ√1-β2=1 to within ±2.3×10(-9) at this velocity. The result, which is singled out by a high boost velocity β, is also interpreted within Lorentz invariance violating test theories.
Journal of Physics B: Atomic, Molecular and Optical Physics, 2005
The electric dipole intercombination decay rate of the 2s2p 3Po1 level in the Be-like ions N3+ an... more The electric dipole intercombination decay rate of the 2s2p 3Po1 level in the Be-like ions N3+ and O4+ has been measured with ions circulating in a heavy-ion storage ring. The observation employed three devices in parallel, two different VUV photon detectors and a residual gas recoil ion detector. The measured transition probabilities of (578 ± 3.3) s-1 for N3+ (level lifetime tau = 1.73 ± 0.01 ms) and of (2315 ± 50) s-1 for O4+ (tau = 0.432 ± 0.009 ms), corroborate the results of recent calculations and improve the precision with which the isoelectronic trend can be established.
Dielectronic recombination(DR) of lithium-like Ti 19+ (1s 2 2s) ions via 2s → 2p core excitations... more Dielectronic recombination(DR) of lithium-like Ti 19+ (1s 2 2s) ions via 2s → 2p core excitations has been measured at the Heidelberg heavy ion storage ring TSR. We find that not only external electric fields (0 ≤ E y ≤ 280 V/cm) but also crossed magnetic fields (30 mT≤ B z ≤ 80 mT) influence the DR via high-n 2p j nℓ-Rydberg resonances. This result confirms our previous finding for isoelectronic Cl 14+ ions [Bartsch T et al, Phys. Rev. Lett. 82, 3779 (1999)] that experimentally established the sensitivity of DR to E × B fields. In the present investigation the larger 2p 1/2 − 2p 3/2 fine structure splitting of Ti 19+ allowed us to study separately the influence of external fields via the two series of Rydberg DR resonances attached to the 2s → 2p 1/2 and 2s → 2p 3/2 excitations of the Li-like core, extracting initial slopes and saturation fields of the enhancement. We find that for E y 80 V/cm the field induced enhancement is about 1.8 times stronger for the 2p 3/2 series than for the 2p 1/2 series.
Time dilation is one of the most fascinating aspects of special relativity as it abolishes the no... more Time dilation is one of the most fascinating aspects of special relativity as it abolishes the notion of absolute time. It was first observed experimentally by Ives and Stilwell in 1938 using the Doppler effect. Here we report on a method, based on fast optical atomic clocks with large, but ...
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Papers by Guido Saathoff