| 1. |
- Hobein, Matthias, et al.
(författare)
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A compact time-resolving pepperpot emittance meter for low-energy highly charged ions
- 2011
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Ingår i: Physica Scripta. - 0031-8949 .- 1402-4896. ; T144, s. 014062-
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Tidskriftsartikel (refereegranskat)abstract
- An emittance meter for pulsed, low-energy ion beams was developed. Based on the pepperpot method, the device is compact and portable. It has been installed at the S-EBIT Laboratory at AlbaNova, Stockholm University, to measure the emittance of highly charged ions extracted from the electron beam ion trap R-EBIT and the cooling trap of the high-precision Penning trap mass spectrometer SMILETRAP II. Using a fast delay-line anode detector, the emittance and time-of-flight of the extracted ions can be measured simultaneously. In this paper, design and data processing system are described and preliminary results are presented.
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| 2. |
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| 3. |
- Hobein, Matthias, et al.
(författare)
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Evaporative Cooling and Coherent Axial Oscillations of Highly Charged Ions in a Penning Trap
- 2011
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 106:1, s. 013002-
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Tidskriftsartikel (refereegranskat)abstract
- Externally, in an electron beam ion trap, generated Ar16+ ions were retrapped in a Penning trap and evaporatively cooled in their axial motion. The cooling was observed by a novel extraction technique based on the excitation of a coherent axial oscillation which yields short ion bunches of well-defined energies. The initial temperature of the ion cloud was decreased by a factor of more than 140 within 1 s, while the phase-space density of the coldest extracted ion pulses was increased by a factor of up to about 9.
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| 4. |
- Hobein, Matthias, 1981-, et al.
(författare)
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Optimization of the Stockholm R-EBIT for the production and extraction of highly charged ions
- 2010
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 5:C11003
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Tidskriftsartikel (refereegranskat)abstract
- We describe a refrigerated EBIT (R-EBIT) commissioned at the AlbaNova Research Center at Stockholm University. As an innovative solution, the superconducting magnet and the trapping drift tubes of the R-EBIT are cooled to a temperature of 4 K by a set of two cooling heads connected to helium compressors. This dry, i.e. liquid helium and liquid nitrogen free, system is easily operated and creates highly charged ions at a fraction of the cost of traditional liquid-cooled systems. A pulsed and continuous gas injection system was developed to feed neutral particles into the electron beam in the trap region. This improves significantly the highly charged ion production and R-EBIT performance. Fast extraction of ions from the R-EBIT yields very short ( < 100 ns), charge-separated ion bunches which can be either analysed using a straight time-of-flight section or sent to experimental beam lines following selection in a bending magnet. An emittance meter was used to measure the emittance of the ions extracted from the R-EBIT. The extracted ions were also re-trapped in a cylindrical Penning trap and properties of the re-trapped ions have been measured using the emittance meter. Results of these measurements are reported in this publication.
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| 5. |
- Hobein, Matthias, et al.
(författare)
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Re-trapping and cooling of highly-charged
- 2009
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 163, s. 012109-
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Tidskriftsartikel (refereegranskat)abstract
- Presently, a trapping system for cooling highly-charged ions (HCI) is being set up at AlbaNova at Stockholm University. The experiment aims at production of low temperature (emittance) HCI at very low energy. HCI are extracted from the new Stockholm EBIT (S-EBIT) before evaporative cooling is applied in a Penning trap. In the future the cooled ions will be injected into the precision trap of the high-precision mass spectrometer SMILETRAP II. In first tests the emittance of trapped ions was measured and it was shown that highly and low-charged ions could be simultaneously stored
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| 6. |
- Hobein, Matthias, 1981-, et al.
(författare)
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SMILETRAP II
- 2011
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Ingår i: Hyperfine Interactions. - : Springer Netherlands. - 0304-3843 .- 1572-9540. ; 199:1-3, s. 141-150
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Tidskriftsartikel (refereegranskat)abstract
- The new Penning trap mass spectrometer SMILETRAP II has been set up at the AlbaNova Research Center, Stockholm. Based on the former spectrometer SMILETRAP I, it uses the merits of highly-charged ions to achieve high precision in the mass measurements. Various improvements over the SMILETRAP I setup will allow to routinely perform mass measurements with relative uncertainties of 10−10 and below. In this paper we will discuss the limitations of SMILETRAP I and present the corresponding improvements of SMILETRAP II. An overview on the SMILETRAP II setup is given.
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| 7. |
- Hobein, Matthias, 1981-
(författare)
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The Penning trap mass spectrometer SMILETRAP II and evaporative cooling of highly-charged ions
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Accurate mass values have wide-ranging applications in physics and metrology, allowing, for example, to test quantum electrodynamics and fundamental symmetries, to determine fundamental constants, and to establish weight standards. This thesis describes the new high-precision double-Penning trap mass spectrometer SMILETRAP II which aims at relative uncertainties in the mass determination of 10-10 and below. SMILETRAP II exploits the merits of highly-charged ions as the relative precision in the mass determination with Penning traps is directly proportional to the charge state of the ion. The spectrometer was therefore connected to the electron beam ion trap S-EBIT which is designed to produce bare ions of practically any element up to uranium. Technical and experimental developments were realized to overcome limitations that restricted the achievable precision at the former spectrometer SMILETRAP I. The technical developments include, for example, an ion detection setup with close to 100% efficiency and an extremely stable temperature-regulation system. Temperature fluctuations constitute a main limitation for the attainable precision. Cold ions are a prerequisite to reach high precision in experiments with Penning traps. This makes cooling of the ions from the ion sources necessary. Ion temperature measurement and cooling experiments were performed. The transverse temperature of the trapped ions was determined via the emittance of extracted ions. A pepperpot emittance meter was designed to meet the requirements of low-energy, low-intensity beams. To measure the axial temperature and assess the ions’ longitudinal phase-space density, a coherent extraction method was developed. The evaporative cooling technique was successfully implemented. In particular, evaporative cooling of highly-charged ions in a Penning trap could be observed for the first time.
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| 8. |
- Liu, Yuwen, et al.
(författare)
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Improved temperature regulation of Penning trap mass spectrometers
- 2010
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 294:1, s. 28-32
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Tidskriftsartikel (refereegranskat)abstract
- In order to reach relative uncertainties in mass measurements with Penning traps of 10-10 or better, the temperature variation of the trap and surrounding materials must be kept below 10 mK. Temperature variations induce a shift in the measured ion cyclotron frequency because of non-zero, temperature dependent magnetic susceptibilities of the construction materials. In this paper we report of a new temperature regulation system recently installed at SMILETRAP II that manages to keep the temperature fixed at the set point with a standard deviation of only 2.6 mK. −10 or better, the temperature variation of the trap and surrounding.
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| 9. |
- 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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| 10. |
- Schuch, Reinhold, et al.
(författare)
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The new Stockholm Electron Beam Ion Trap (S-EBIT)
- 2010
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Ingår i: Journal of Instrumentation. - 1748-0221 .- 1748-0221. ; 5, s. C12018-
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Tidskriftsartikel (refereegranskat)abstract
- A new laboratory for highly charged ions is being built up at Stockholm University. A fully refrigerated electron beam ion trap (R-EBIT, 3 T magnet, 30 keV electron energy) was installed. It was used for spectroscopic studies, ion cooling experiments, electron ion collisions, and highly-charged ion surface studies. Here we report on an upgrade of this EBIT to a ``Super EBIT'' (S-EBIT, 4 T magnet, 260 keV electron energy). The high-voltage trapping system, the ion injection as well as the extraction scheme of S-EBIT and the LabView based operational system of S-EBIT are described.
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