| 1. |
- Bergström, I, et al.
(författare)
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High-precision Mass Measurements of Hydrogen-Like 24Mg11+ and 26Mg11+ ions in a Pening Trap
- 2002
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 22:1, s. 41-45
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Tidskriftsartikel (refereegranskat)abstract
- For the determination of the bound-electron g factor in hydrogen-like heavy ions the mass of the ion is needed at a relative uncertainty of at least 1 ppb. With the SMILETRAP Penning trap mass spectrometer at the Manne Siegbahn Laboratory in Stockholm several mass measurements of ions with even-even nuclei at this level of precision have been performed so far, exploiting the fact that the mass precision increases linearly with the ion charge. Measurements of masses of the hydrogen-like ions of the two Mg-isotopes 24Mg and 26Mg are reported. The masses of the hydrogen-like ions are 23.979011054(14) u and 25.976562354(34) u, corresponding to the atomic masses 23.985041690(14) u and 25.982592986(34) u, respectively. The possibility to use these two isotopes for the first observation of an isotope effect in the bound-electron g factor in hydrogen-like heavy ions is discussed.
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| 5. |
- Bläckberg, Lisa, et al.
(författare)
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Measurements of memory effect and resolution for an Al2O3 coated plastic scintillator used for radioxenon detection
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- A cylindrical plastic scintillator cell, used for radioxenon monitoring within the verification regime of the Comprehensive Nuclear-Test-Ban Treaty, has been coated with 425 nm Al2O3 using low temperature Atomic Layer Deposition, and its performance has been evaluated. The motivation is to reduce the memory effect caused by radioxenon diffusing into the plastic scintillator material during measurements, resulting in an elevated detection limit. Measurements of the coated detector show a resolution comparable to uncoated detectors, and a memory effect reduction of a factor of 1000. If these results are reproducible, and the quality of the detector is maintained for a longer period of time, the Al2O3 coating method is believed to be viable solution to the memory effect problem in question.
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| 6. |
- Böhm, Sebastian, et al.
(författare)
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First results from the Stockholm Electron Beam Ion Trap
- 2007
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 58:303, s. 303-306
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Tidskriftsartikel (refereegranskat)abstract
- A new laboratory for highly charged ions is being built up at Stockholm university. An electron beam ion trap (EBIT) (3T magnet,≤30 keV electron beam) was installed. It is used for spectroscopic studies, precision mass measurements, electron ion collisions, and highlycharged ion surface studies. Here we report about a fast ion-extraction scheme from ebit and first results using a time-of-flight detection as well as a labview based operational system of ebit.
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| 11. |
- Fritioff, Tomas, et al.
(författare)
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Precise measurements of ionic masses for QED tests
- 2006
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Ingår i: International Journal of Mass Spectrometry. - : Elsevier BV. - 1387-3806 .- 1873-2798. ; 251:2-3, s. 281-285
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Tidskriftsartikel (refereegranskat)abstract
- The Penning trap mass spectrometer SMILETRAP is designed for precision mass measurements using the merits of highly charged ions. In this paper we describe the feature of SMILETRAP and give examples of mass measurements involving , , and ions. These emphasize the importance of accurate masses of hydrogen-like and lithium-like ions that are required in the evaluation of g-factor measurements of electrons bound to even–even nuclei and test of QED effects. Highly precise mass measurements can also be used for testing atomic structure calculations and determining atomic binding energies. Relevance of such measurements throughout the periodic system is discussed.
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| 12. |
- Fritioff, Tomas, 1971-
(författare)
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Precision Improvements of Penning Trap Mass Measurements Using Highly Charged Ions : Applications to solving current problems in fundamental physics
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In my thesis I describe the improvements of the Penning trap mass spectrometer SMILETRAP. The objective of these improvements have been to increase the reliability and the accuracy with which an atomic mass can be measured using highly charged ions. The improvements have been achieved by stabilizing both the electric and magnetic fields of the trap and by improving the technical performance of the trap system. As a result it has been possible to measure accurately the mass of several atoms ranging from hydrogen to mercury using charge states from 1+ to 52+. It was only possible to use the highest charge states after applying a successful cooling of these ions with Helium during the charge breeding.The technical improvements made a number of interesting accurate mass measurements possible. The measurements of the 3H, 3He, and 4He masses showed that the previously values were wrong. The mass difference between 3H and 3He which is the Q-value of the tritium beta decay has been determined to 18.588(3) keV. The Q-value of the double β-decay of 76Ge was measured at an accuracy of 50 eV. This value is indispensable for the evaluation the Heidelberg-Moscow experiment which aims at finding a possible neutrino-less decay which if present would be a violation of the standard model. The mass ratio of mCs/mp is used to determine the fine structure constant independent of QED calculations. The two decades old anomaly in the mass values of Hg was solved by the mass determination of 198Hg and 204Hg. The mass of 24Mg was measured at an uncertatinty of 0.6 ppb and will be used in the determination of the g-factor of a bound electron in a hydrogen like ions.
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| 13. |
- Fritioff, Tomas, et al.
(författare)
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Shedding light on the Mercury Mass Discrepancy by weighing Hg52+ ions in a Penning trap
- 2003
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Ingår i: Nuclear Physics A. - : Elsevier Science B.V.. - 0375-9474 .- 1873-1554. ; 723:1-2, s. 3-16
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Tidskriftsartikel (refereegranskat)abstract
- In their nuclear tables Audi and Wapstra have pointed out a serious mass discrepancy between their extrapolated values for the mercury isotopes and those from a direct measurement by the Manitoba group. The values deviate by as much as 85 ppb from each other with claimed uncertainties of about 16 and 7 ppb, respectively. In order to decide which values are correct the masses of the 198Hg and 204Hg isotopes have been measured in the Stockholm Penning trap mass spectrometer SMILETRAP using 52+ ions. This charge state corresponds to a filled Ni electron configuration for which the electron binding energy can be accurately calculated. The mass values obtained are 197.966 768 44(43) u for 198Hg and 203.973 494 10(39) u for 204Hg. These values agree with those measured by the Manitoba group, with a 3 times lower uncertainty. This measurement was made possible through the implementation of a cooling technique of the highly charged mercury ions during charge breeding in the electron beam ion source used for producing the Hg52+ ions.
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| 15. |
- Ringbom, Anders, et al.
(författare)
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Radioxenon measurements at the Shelter Object in the New Safe Confinement at Chernobyl Nuclear Power Plant : Proposed concept and initial investigations
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We discuss a novel method to address the issue of nuclear safety of the Shelter Object in the New Safe Containment at Chernobyl Nuclear Power Plant, using ultra-sensitive radioxenon measurements to monitor the fission activity. The automatic radioxenon measurement system SAUNA QB, originally developed for nuclear explosion monitoring, could be well suited for the proposed method, and theoretical modelling indicates that the radioxenon activity concentration resulting from fission in the fuel containing material might be at detectable levels inside the New Safe Containment. A simplified sampling and measurement method was developed in order to get a first indication of the, still unknown, radioxenon activity concentration levels inside the shelter. Using this system, air was collected close to fuel containing material in the Shelter Object, and the activity of the collected air was measured. No radioxenon could be detected, but the result indicates an upper activity concentration limit of about one Bq/m3, which is inside the dynamic range for the SAUNA QB. Additional measurements are desirable to confirm the result. To further, and more thoroughly, investigate the feasibility of the proposed method, it is necessary to measure for a longer time period using more sensitive equipment, such as the SAUNA QB.
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| 17. |
- Schuch, Reinhold, et al.
(författare)
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Q value related mass determinations using a Penning trap
- 2007
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Ingår i: Hyperfine Interactions. - Nederländerna : Springer. - 0304-3843 .- 1572-9540. ; 173:1-3, s. 73-83
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Tidskriftsartikel (refereegranskat)abstract
- We report here about measurements of reaction and decay Q values by precise determination of pairs of atomic masses. These were performed with the Penning trap mass spectrometer SMILETRAP. Measurements with Penning traps give reliable and accurate masses, in particular Q values, due to the fact that certain systematic errors to a great deal cancel in the mass difference between the two atoms defining the Q value. Some Q values that are of fundamental interest will be discussed here, for example, a new Q value for the 6Li (n,γ) 7Li reaction, for the β-decay of tritium, related to properties of the electron neutrino mass, and for the neutrino-less double β-decay of 76Ge, related to the question of whether the neutrino is a Majorana particle or not. In case of the latter two we report the most accurate Q values, namely 18,589.8(12) eV for the tritium decay and 2,038.997(46) keV for the neutrino-less double β-decay of 76Ge.
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| 18. |
- Suhonen, Markus, 1972-, et al.
(författare)
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High-frequency Ramsey excitation in a Penning trap
- 2007
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Ingår i: Journal of Instrumentation. - England/Italien : IOP, SISSA. - 1748-0221. ; 2:P06003, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- The Ramsey excitation method for high-precision mass-measurements of highly-charged ions has been investigated and benchmarked using H2+ ions in the Penning-trap mass-spectrometer SMILETRAP. The reason for using H2+ ions are their high cyclotron frequency which is typical for the highly-charged ions usually used at SMILETRAP. Two-, three- and four-pulse Ramsey excitation data are analyzed with the help of recent theoretical work and are compared with the previously used single-pulse excitation data. An improvement factor of 2.9 in the statistical uncertainty is achieved. Furthermore the mass of 76Se, included in the previous Q-value measurement of the 76Ge neutrinoless double beta decay, is checked using 76Se25+ ions and a three-pulse Ramsey excitation. The results show a convincing agreement with the measurement when using single-pulse excitation and therefore our Q-value of 2039.006(50) keV, performed with single-pulse excitation, is confirmed.
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