Search results for " Ring"
showing 10 items of 478 documents
Revising midlatitude summer temperatures back to A.D. 600 based on a wood density network
2015
Annually resolved and millennium-long reconstructions of large-scale temperature variability are primarily composed of tree ring width (TRW) chronologies. Changes in ring width, however, have recently been shown to bias the ratio between low- and high-frequency signals. To overcome limitations in capturing the full spectrum of past temperature variability, we present a network of 15 maximum latewood density (MXD) chronologies distributed across the Northern Hemisphere extratropics. Independent subsets of continental-scale records consistently reveal high MXD before 1580 and after 1910, with below average values between these periods. Reconstructed extratropical summer temperatures reflect n…
First experiments with the heidelberg test storage ring TSR
1989
Abstract The Heidelberg heavy ion test storage ring TSR started operation in May 1988. The lifetimes of the ion beams observed in the first experiments can be explained by interactions with the residual gas. Multiple Coulomb scattering, single Coulomb scattering, electron capture and electron stripping are the relevant processes. Electron cooling of ions as heavy as O 8+ has been observed for the first time. With increasing particle number, the longitudinal Schottky noise spectrum becomes dominated by collective waves for cooled beams, allowing a determination of velocities of sound. After correcting for these coherent distortions fo the Schottky spectrum, the longitudinal beam temperature …
Status and perspectives of atomic physics research at GSI
2003
A short overview on the results of atomic physics research at the storage ring ESR is given followed by a presentation of the envisioned atomic physics program at the planned new GSI facility. The proposed new GSI facility will provide highest intensities of relativistic beams of both stable and unstable heavy nuclei - up to a Lorentz factor of 24. At those relativistic velocities, the energies of optical transitions, such as for lasers.. are boosted into the X-ray region and the high-charge state ions generate electric and magnetic fields of exceptional strength. Together with high beam intensities a range of important experiments can be anticipated, for example electronic transitions in r…
Laser spectroscopy and laser cooling of relativistic stored ion beams
1991
Abstract Experiments with relativistic ions at the test storage ring TSR [P. Baumann et al., Nucl. Instr. and Meth. A268 (1988) 531] demonstrate the potential of the interaction of laser light with energetic stored ions for spectroscopic purposes as well as for manipulation of the ion velocity. Latest results for Li+ ions are reported. At the ion energies available at ESR [B. Franzke, Nucl. Instr. and Meth. B24 B25 (1987) 19] it will become possible to prepare and store bare ions up to U92+. Experiments using these exotic beams are discussed and an outlook to the situation at even higher energies is given.
First radioactive ions charge bred in REXEBIS at the REX-ISOLDE accelerator
2003
REXEBIS is the charge breeder of the REX-ISOLDE post accelerator. The radioactive 1$^{+}$ ions produced at ISOLDE are accumulated, phase-space cooled and bunched in the REXTRAP, and thereafter injected into the EBIS with an energy up to 60 keV. The REXEBIS produced the first charge bred ions in August 2001 and has been running nearly non-stop during September to December 2001. It has delivered stable $^{39}$K$^{10+}$ and $^{23}$Na$^{6+}$ beams generated in the ion source in front of REXTRAP with a Na$^{7+}$ current exceeding 70 pA (6x10$^{7}$ p/s). Stable $^{27}$Al$^{7+}$ and $^{23}$Na$^{6+}$ from ISOLDE and also the first radioactive $^{26}$Na$^{7+}$ and $^{24}$Na$^{7+}$ beams (just 5x10$^…
Mainz/PSI Φ-factory design considerations
1991
Abstract Design considerations for a Φ-factory with a Luminosity of the order of 10 33 cm −2 s −1 lead to the concept of a multi-bunch round beam double storage ring with supercoducting solenoids for micro-beta focusing and beam rotation. Simulations of the beam-beam-interaction indicate, that significantly higher beam-beam-parameters may become possible with round beams. A rough draft design of a round beam Φ-factory is presented.
Laser photodetachment of radioactive $^{128}$I$^−$
2017
International audience; The first experimental investigation of the electron affinity (EA) of a radioactive isotope has been conducted at the CERN-ISOLDE radioactive ion beam facility. The EA of the radioactive iodine isotope (128)I (t (1/2) = 25 min) was determined to be 3.059 052(38) eV. The experiment was conducted using the newly developed Gothenburg ANion Detector for Affinity measurements by Laser PHotodetachment (GANDALPH) apparatus, connected to a CERN-ISOLDE experimental beamline. (128)I was produced in fission induced by 1.4 GeV protons striking a thorium/tantalum foil target and then extracted as singly charged negative ions at a beam energy of 20 keV. Laser photodetachment of th…
Atomic spectroscopy studies of short-lived isotopes and nuclear isomer separation with the ISOLDE RILIS
2002
The Resonance Ionization Laser Ion Source (RILIS) at the ISOLDE on-line isotope separator is based on the selective excitation of atomic transitions by tunable laser radiation. Ion beams of isotopes of 20 elements have been produced using the RILIS setup. Together with the mass separator and a particle detection system it represents a tool for high-sensitive laser spectroscopy of short-lived isotopes. By applying narrow-bandwidth lasers for the RILIS one can study isotope shifts (IS) and hyperfine structure (HFS) of atomic optical transitions. Such measurements are capable of providing data on nuclear charge radii, spins and magnetic moments of exotic nuclides far from stability. Although t…
On-line yields obtained with the ISOLDE RILIS
2003
The ISOLDE resonance ionization laser ion source (RILIS) allows to ionize efficiently and selectively many metallic elements. In recent yield surveys and on-line experiments with the ISOLDE RILIS we observed 23–34 Mg, 26–34 Al, 98–132 Cd, 149 Tb, 155–177 Yb, 179–200 Tl, 183–215 Pb and 188–218 Bi. The obtained yields are presented together with measured release parameters which allow to extrapolate the release efficiency towards more exotic (short-lived) nuclides of the same elements. 2002 Elsevier Science B.V. All rights reserved.
Effect of double frequency heating on the lead afterglow beam currents of an electron cyclotron resonance ion source
2017
International audience; The effect of double frequency heating on the performance of the CERN GTS-LHC 14.5 GHz ElectronCyclotron Resonance (ECR) ion source in afterglow mode is reported. The source of the secondary microwave frequency was operated both in pulsed and continuous wave (CW) modes within the range of 12–18 GHz. The results demonstrate that the addition of the secondary frequency can significantly impact the extracted beam currents and the temporal stability of the beam during the afterglow discharge. For example, up to a factor of 2.6 increase was achieved for 208Pb35+ and a factor of 3.1 for 208Pb37+ compared to single frequency afterglow currents. It is shown that these effect…