| 1. |
- 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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| 2. |
- Lorenz, Ch, et al.
(författare)
-
Quantum-state-selective decay spectroscopy of 213Ra
- 2017
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Ingår i: Physical Review C. - 2469-9985. ; 96:3
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Tidskriftsartikel (refereegranskat)abstract
- An experimental scheme combining the mass resolving power of a Penning trap with contemporary decay spectroscopy has been established at GSI Darmstadt. The Universal Linear Accelerator (UNILAC) at GSI Darmstadt provided a 48Ca beam impinging on a thin 170Er target foil. Subsequent to velocity filtering of reaction products in the Separator for Heavy Ion reaction Products (SHIP), the nuclear ground state of the 5n evaporation channel 213Ra was mass-selected in SHIPTRAP, and the 213Ra ions were finally transferred into an array of silicon strip detectors surrounded by large composite germanium detectors. Based on comprehensive Geant4 simulations and supported by theoretical calculations, the spectroscopic results call for a revision of the decay path of 213Ra, thereby exemplifying the potential of a combination of a mass-selective Penning trap device with a dedicated nuclear decay station and contemporary Geant4 simulations.
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| 3. |
- Droese, C., et al.
(författare)
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High-precision Mass Measurements of 203-207Rn and 213Ra with SHIPTRAP
- 2013
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 49:1, s. 13-19
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Tidskriftsartikel (refereegranskat)abstract
- The masses of the nuclides Rn203-207 and Ra-213 were measured directly for the first time with the Penning-trap mass spectrometer SHIPTRAP at GSI Darmstadt. The results confirm the previously determined mass values. The mass uncertainties for Rn-205 and Ra-213 were significantly reduced. The results are relevant for the investigation of the nuclear shell structure between N = 82 and N = 126. As an indicator of structural changes the two-neutron separation energies S-2n(Z, N) have been studied.
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| 4. |
- Grieser, M., et al.
(författare)
-
Storage ring at HIE-ISOLDE
- 2012
-
Ingår i: European Physical Journal: Special Topics. - : Springer Science and Business Media LLC. - 1951-6401 .- 1951-6355. ; 207:1, s. 1-117
-
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. |
- Au, M., et al.
(författare)
-
In-source and in-trap formation of molecular ions in the actinide mass range at CERN-ISOLDE
- 2023
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Ingår i: Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms. - 0168-583X. ; 541, s. 375-379
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Tidskriftsartikel (refereegranskat)abstract
- The use of radioactive molecules for fundamental physics research is a developing interdisciplinary field limited dominantly by their scarce availability. In this work, radioactive molecular ion beams containing actinide nuclei extracted from uranium carbide targets are produced via the Isotope Separation On-Line technique at the CERN-ISOLDE facility. Two methods of molecular beam production are studied: extraction of molecular ion beams from the ion source, and formation of molecular ions from the mass-separated ion beam in a gas-filled radio-frequency quadrupole ion trap. Ion currents of U+, UO1-3+, UC1-3+, UF1-4+, UF1,2O1,2+ are reported. Metastable tantalum and uranium fluoride molecular ions are identified. Formation of UO1-3+, U(OH)1-3+, UC1-3+, UF1,2O1,2+ from mass-separated beams of U+, UF1,2+ with residual gas is observed in the ion trap. The effect of trapping time on molecular formation is presented.
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| 6. |
- Giacoppo, F., et al.
(författare)
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Recent upgrades of the SHIPTRAP setup : On the finish line towards direct mass spectroscopy of superheavy elements
- 2017
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Ingår i: Acta Physica Polonica B. - 0587-4254. ; 48:3, s. 423-429
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Tidskriftsartikel (refereegranskat)abstract
- With the Penning-trap mass spectrometer SHIPTRAP at GSI, Darmstadt, it is possible to investigate exotic nuclei in the region of the heaviest elements. Few years ago, challenging experiments led to the direct measurements of the masses of neutron-deficient isotopes with Z = 102; 103 around N = 152. Thanks to recent advances in cooling and ion-manipulation techniques, a major technical upgrade of the setup has been recently accomplished to boost its efficiency. At present, the gap to reach more rare and shorter-lived species at the limits of the nuclear landscape has been narrowed.
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| 7. |
- Rodriguez, D., et al.
(författare)
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MATS and LaSpec : High-precision experiments using ion traps and lasers at FAIR
- 2010
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Ingår i: The European physical journal. Special topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 183, s. 1-123
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Forskningsöversikt (refereegranskat)abstract
- Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. The mass and its inherent connection with the nuclear binding energy is a fundamental property of a nuclide, a unique ""fingerprint"". Thus, precise mass values are important for a variety of applications, ranging from nuclear-structure studies like the investigation of shell closures and the onset of deformation, tests of nuclear mass models and mass formulas, to tests of the weak interaction and of the Standard Model. The required relative accuracy ranges from 10(-5) to below 10(-8) for radionuclides, which most often have half-lives well below 1 s. Substantial progress in Penning trap mass spectrometry has made this method a prime choice for precision measurements on rare isotopes. The technique has the potential to provide high accuracy and sensitivity even for very short-lived nuclides. Furthermore, ion traps can be used for precision decay studies and offer advantages over existing methods. With MATS (Precision Measurements of very short-lived nuclei using an Advanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10(-9) can be reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique on single stored ions. This accuracy limit is important for fundamental interaction tests, but also allows for the study of the fine structure of the nuclear mass surface with unprecedented accuracy, whenever required. The use of the FT-ICR technique provides true single ion sensitivity. This is essential to access isotopes that are produced with minimum rates which are very often the most interesting ones. Instead of pushing for highest accuracy, the high charge state of the ions can also be used to reduce the storage time of the ions, hence making measurements on even shorter-lived isotopes possible. Decay studies in ion traps will become possible with MATS. Novel spectroscopic tools for in-trap high-resolution conversion-electron and charged-particle spectroscopy from carrier-free sources will be developed, aiming e. g. at the measurements of quadrupole moments and E0 strengths. With the possibility of both high-accuracy mass measurements of the shortest-lived isotopes and decay studies, the high sensitivity and accuracy potential of MATS is ideally suited for the study of very exotic nuclides that will only be produced at the FAIR facility. Laser spectroscopy of radioactive isotopes and isomers is an efficient and model-independent approach for the determination of nuclear ground and isomeric state properties. Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessible information on the nuclear spin, magnetic dipole and electric quadrupole moments as well as root-mean-square charge radii. The dependencies of the hyperfine splitting and isotope shift on the nuclear moments and mean square nuclear charge radii are well known and the theoretical framework for the extraction of nuclear parameters is well established. These extracted parameters provide fundamental information on the structure of nuclei at the limits of stability. Vital information on both bulk and valence nuclear properties are derived and an exceptional sensitivity to changes in nuclear deformation is achieved. Laser spectroscopy provides the only mechanism for such studies in exotic systems and uniquely facilitates these studies in a model-independent manner. The accuracy of laser-spectroscopic-determined nuclear properties is very high. Requirements concerning production rates are moderate; collinear spectroscopy has been performed with production rates as few as 100 ions per second and laser-desorption resonance ionization mass spectroscopy (combined with beta-delayed neutron detection) has been achieved with rates of only a few atoms per second. This Technical Design Report describes a new Penning trap mass spectrometry setup as well as a number of complementary experimental devices for laser spectroscopy, which will provide a complete system with respect to the physics and isotopes that can be studied. Since MATS and LaSpec require high-quality low-energy beams, the two collaborations have a common beamline to stop the radioactive beam of in-flight produced isotopes and prepare them in a suitable way for transfer to the MATS and LaSpec setups, respectively.
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| 8. |
- Hansen, Klavs, 1958, et al.
(författare)
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Dissociation energies of gold clusters Au+N, N=7-27
- 2006
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Ingår i: Phys. Rev. A. - 1050-2947. ; 73
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Tidskriftsartikel (refereegranskat)abstract
- Unimolecular decay rates and monomer-dimer branching ratios of gold clusters Au (N=7–27) have been measured as a function of excitation energy in photodissociation experiments on size-selected clusters stored in a Penning trap. Part of the data set has previously been used to extract model-free values of dissociation energies [Vogel et al., Phys. Rev. Lett. 87, 013401 (2001)]. Other parts of the data set do not allow this analysis. We use these data to extract tentative dissociation energies, based on the systematics of deviations between an Arrhenius analysis and the model-free values. The observed systematics also allows an estimate of the true frequency factor which often is much higher than the Arrhenius value but in good agreement with the expected detailed balance value. The data are also reanalyzed including radiative cooling which may explain part of the discrepancy between model-free and Arrhenius dissociation-energy values.
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| 9. |
- Hansen, Klavs, 1958, et al.
(författare)
-
The dissociation energy of V13+ and the consequences for radiative cooling
- 2005
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Ingår i: Eur. Phys. J. D. - : Springer Science and Business Media LLC. - 1434-6060. ; 34, s. 67-71
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Tidskriftsartikel (refereegranskat)abstract
- The dissociation energy of V13+ has been determined by comparison of the rates of sequential fragmentation, V13+→V 12+→V 11+, and single-step fragmentation of the first fragment, V12+→V 11+. The dissociation-energy value obtained as D=4.35(13) eV has implications for the amount of radiative cooling of the cluster derived form the data presented earlier [C. Walther et al., Phys. Rev. Lett. 83, 3816 (1999)] and is used to analyze additional results.
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| 10. |
- Schweikhard, L., et al.
(författare)
-
Cluster studies in ion traps
- 2005
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Ingår i: Proceedings of ISACC 2003. - 1860944957 ; , s. 85-95
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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