| 1. |
- Aamodt, K., et al.
(författare)
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The ALICE experiment at the CERN LHC
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3:S08002
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Forskningsöversikt (refereegranskat)abstract
- ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries, Its overall dimensions are 16 x 16 x 26 m(3) with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008.
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| 2. |
- Lestinsky, M., et al.
(författare)
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Physics book: CRYRING@ESR
- 2016
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Ingår i: European Physical Journal: Special Topics. - : Springer Science and Business Media LLC. - 1951-6401 .- 1951-6355. ; 225:5, s. 797-882
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Forskningsöversikt (refereegranskat)abstract
- The exploration of the unique properties of stored and cooled beams of highly-charged ions as provided by heavy-ion storage rings has opened novel and fascinating research opportunities in the realm of atomic and nuclear physics research. Since the late 1980s, pioneering work has been performed at the CRYRING at Stockholm (Abrahamsson et al. 1993) and at the Test Storage Ring (TSR) at Heidelberg (Baumann et al. 1988). For the heaviest ions in the highest charge-states, a real quantum jump was achieved in the early 1990s by the commissioning of the Experimental Storage Ring (ESR) at GSI Helmholtzzentrum für Schwerionenforschung (GSI) in Darmstadt (Franzke 1987) where challenging experiments on the electron dynamics in the strong field regime as well as nuclear physics studies on exotic nuclei and at the borderline to atomic physics were performed. Meanwhile also at Lanzhou a heavy-ion storage ring has been taken in operation, exploiting the unique research opportunities in particular for medium-heavy ions and exotic nuclei (Xia et al. 2002).
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| 3. |
- Grieser, M., et al.
(författare)
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Storage ring at HIE-ISOLDE Technical design report
- 2012
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Ingår i: The European Physical Journal Special Topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 207:1, s. 1-117
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Forskningsöversikt (refereegranskat)abstract
- We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to setup the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams that is unique in the world. The envisaged physics programme is rich and varied, spanning from investigations of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR might also be employed for removal of isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. The existing TSR, which is presently in operation at the Max-Planck Institute for Nuclear Physics in Heidelberg, is well-suited and can be employed for this purpose. The physics cases as well as technical details of the existing ring facility and of the beam and infrastructure requirements at HIE-ISOLDE are discussed in the present technical design report.
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| 4. |
- Grieser, M., et al.
(författare)
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Storage ring at HIE-ISOLDE
- 2012
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Ingår i: European Physical Journal: Special Topics. - : Springer Science and Business Media LLC. - 1951-6401 .- 1951-6355. ; 207:1, s. 1-117
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Tidskriftsartikel (refereegranskat)abstract
- We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to setup the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams that is unique in the world. The envisaged physics programme is rich and varied, spanning from investigations of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR might also be employed for removal of isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. The existing TSR, which is presently in operation at the Max-Planck Institute for Nuclear Physics in Heidelberg, is well-suited and can be employed for this purpose. The physics cases as well as technical details of the existing ring facility and of the beam and infrastructure requirements at HIE-ISOLDE are discussed in the present technical design report.
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| 5. |
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| 6. |
- Zhu, B., et al.
(författare)
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X-ray emission associated with radiative recombination for Pb82+ ions at threshold energies
- 2022
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - 2469-9926 .- 2469-9934. ; 105:5
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Tidskriftsartikel (refereegranskat)abstract
- For decelerated bare lead ions at a low beam energy of 10 MeV/u, the x-ray emission associated with radiative recombination (RR) at threshold energies has been studied at the electron cooler of CRYRING@ESR at GSI, Darmstadt. In our experiment, we observed the full x-ray emission pattern by utilizing dedicated x-ray detection chambers installed at 0∘ and 180∘ observation geometry. Most remarkably, no line distortion effects due to delayed emission are present in the well-defined x-ray spectra, spanning a wide range of x-ray energies (from about 5 to 100 keV), which enables us to identify fine-structure resolved Lyman, Balmer, and Paschen x-ray lines along with the RR transitions into the K, L, and M shells of the ions. For comparison with theory, an elaborate theoretical model is established taking into account the initial population distribution via RR for all atomic levels up to Rydberg states with principal quantum number n=165 in combination with time-dependent feeding transitions. Within the statistical accuracy, the experimental data are in very good agreement with the results of rigorous relativistic predictions. Most notably, this comparison sheds light on the contribution of prompt and delayed x-ray emission (up to 70 ns) to the observed x-ray spectra, originating in particular from yrast transitions into inner shells.
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| 7. |
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| 8. |
- Müller, A., et al.
(författare)
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Photoionization of metastable heliumlike C4+ (1s2s S-3(1)) ions : Precision study of intermediate doubly excited states
- 2018
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - 2469-9926 .- 2469-9934. ; 98:3
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Tidskriftsartikel (refereegranskat)abstract
- In a joint experimental and theoretical endeavor, photoionization of metastable C4+ (1s2s S-3(1)) ions via intermediate levels with hollow, double-K-vacancy configurations 2s2p, 2s3p, 2p3s, 2p3d, 2s4p, 2p4s, and 2p4d has been investigated. High-resolution photon-ion merged-beams measurements were carried out with the resolving power reaching up to 25 800 which is sufficient to separate the leading fine-structure components of the 2s2p P-3 term. Many-body perturbation theory was employed to determine level-to-level cross sections for K-shell excitation with subsequent autoionization. The resonance energies were calculated with inclusion of electron correlation and radiative contributions. Their uncertainties are estimated to be below +/- 1 meV. Detailed balance confirms the present photoionization cross-section results by comparison with previous dielectronic-recombination measurements. The high accuracy of the theoretical transition energies together with the present experimental results qualify photoabsorption resonances in heliumlike ions as new, greatly improved energy-reference standards at synchrotron radiation facilities.
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| 9. |
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| 10. |
- Böhm, S, et al.
(författare)
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Enhancement of dielectronic recombination by external electromagnetic fields
- 2003
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Ingår i: Hyperfine Interactions. - 0304-3843. ; 146-147:1-4, s. 23-27
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Tidskriftsartikel (refereegranskat)abstract
- The enhancement of the dielectronic recombination rate of lithiumlike Ne7+ and O5+ ions by external electromagnetic fields has been measured at the storage ring CRYRING. The energy range covered all 1s(2)2pnl dielectronic recombination resonances attached to the 2s --> 2p core excitation. Electric fields up to 1436 V/cm were applied in the Ne7+ experiment and the saturation of the enhancement with increasing electric field could clearly be seen. In the O5+ experiment the enhancement was studied as a function of the Rydberg quantum number n.
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