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Precision mass measurements: Final limit of SMILETRAP I and the developments of SMILETRAP II
Stockholm University, Faculty of Science, Department of Physics. (Atomfysik)
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The subject of this thesis is high-precision mass-measurements performed with Penning trap mass spectrometers (PTMS). In particular it describes the SMILETRAP I PTMS and the final results obtained with it, the masses of 40Ca and that of the proton. The mass of 40Ca is an indispensible input in the evaluation of measurements of the bound electron g-factor, used to test quantum electrodynamical calculations in strong fields. The value obtained agrees with available literature values but has a ten times higher precision.

The measurement of the proton mass, considered a fundamental physical constant, was performed with the aim of validating other Penning trap results and to test the limit of SMILETRAP I. It was also anticipated that a measurement at a relative precision close to 10-10 would give insight in how to treat certain systematic uncertainties. The result is a value of the proton mass in agreement with earlier measurements and with an unprecedented precision of 1.8×10-10.

Vital for the achieved precision of the proton mass measurement was the use of the Ramsey excitation technique. This technique, how it was implemented at SMILETRAP I and the benefits from it is discussed in the thesis and in one of the included papers.

The second part of the thesis describes the improved SMILETRAP II setup at the S-EBIT laboratory, AlbaNova. All major changes and upgrades compared to SMILETRAP I are discussed. This includes, apart from the Ramsey excitation technique, higher ionic charge states, improved temperature stabilization, longer run times, different reference ions, stronger and more stable magnetic field and a more efficient ion detection. Altogether these changes should reduce the uncertainty in future mass determinations by an order of magnitude, possibly down to 10-11.

Place, publisher, year, edition, pages
Stockholm: Department of Physics, Stockholm University , 2011. , 64 p.
Keyword [en]
SMILETRAP, Precision mass spectrometry, Penning trap, Atomic mass, Highly charged ions, Low energy ion storage, Time of flight ion cyclotron resonance, High frequency, Proton mass, QED, g-factor
National Category
Physical Sciences
Research subject
Physics
Identifiers
URN: urn:nbn:se:su:diva-56777ISBN: 978-91-7447-303-2OAI: oai:DiVA.org:su-56777DiVA: diva2:413035
Public defence
2011-05-26, sal FB53, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 13:00 (English)
Opponent
Supervisors
Note
At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 9: Accepted.Available from: 2011-05-04 Created: 2011-04-27 Last updated: 2011-05-13Bibliographically approved
List of papers
1. Precision mass measurements of 40Ca17+ and 40Ca19+ ions in a Penning trap
Open this publication in new window or tab >>Precision mass measurements of 40Ca17+ and 40Ca19+ ions in a Penning trap
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2006 (English)In: European Physical Journal D: Atomic, Molecular and Optical Physics, ISSN 1434-6060, E-ISSN 1434-6079, Vol. 39, no 1, 1-4 p.Article in journal (Refereed) Published
Abstract [en]

High-precision mass measurements on lithium-like and hydrogen-like 40Ca-ions are reported. The obtained mass of the hydrogen-like and lithium-like ion is 39.952181819(29) u and 39.953272223(24) u, respectively. The corresponding mass of the 40Ca atom is 39.962590858(22) u. This new value has a precision ten times higher than the literature value.

National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-12585 (URN)10.1140/epjd/e2006-00064-8 (DOI)
Available from: 2008-01-15 Created: 2008-01-15 Last updated: 2011-04-27Bibliographically approved
2. Precise measurements of ionic masses for QED tests
Open this publication in new window or tab >>Precise measurements of ionic masses for QED tests
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2006 (English)In: International Journal of Mass Spectrometry, ISSN 1387-3806, Vol. 251, no 2-3, 281-285 p.Article in journal (Refereed) Published
Abstract [en]

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.

Keyword
g-Factor; Penning trap; Lamor precision frequency; Isotopes; QED
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-12596 (URN)10.1016/j.ijms.2006.02.008 (DOI)
Available from: 2008-01-15 Created: 2008-01-15 Last updated: 2011-04-27Bibliographically approved
3. Q value related mass determinations using a Penning trap
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2007 (English)In: Hyperfine Interactions, ISSN 0304-3843, E-ISSN 1572-9540, Vol. 173, no 1-3, 73-83 p.Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
Nederländerna: Springer, 2007
Keyword
Penning trap, Precision mass determinations, Q value, SMILETRAP
National Category
Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-29375 (URN)10.1007/s10751-007-9545-0 (DOI)
Available from: 2009-08-25 Created: 2009-08-25 Last updated: 2011-04-27Bibliographically approved
4. High-frequency Ramsey excitation in a Penning trap
Open this publication in new window or tab >>High-frequency Ramsey excitation in a Penning trap
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2007 (English)In: Journal of instrumentation, ISSN 1748-0221, Vol. 2, no P06003, 1-14 p.Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
England/Italien: IOP, SISSA, 2007
Keyword
Mass spectrometers, Instrumentation and methods for time-of-flight (TOF) spectroscopy, Analysis and statistical methods
National Category
Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-29366 (URN)10.1088/1748-0221/2/06/P06003 (DOI)000253651600003 ()
Available from: 2009-08-25 Created: 2009-08-25 Last updated: 2011-04-27Bibliographically approved
5. Determination of the proton mass from a measurement of the cyclotron frequencies of D+ and H2+ in a Penning trap
Open this publication in new window or tab >>Determination of the proton mass from a measurement of the cyclotron frequencies of D+ and H2+ in a Penning trap
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2008 (English)In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 78, no 1, 2514-2520 p.Article in journal (Refereed) Published
Abstract [en]

We determine the cyclotron frequency ratio of H2+ and D+, applying the two-pulse Ramsey-excitation technique in the Penning-trap mass spectrometer SMILETRAP. The final result, based on probing more than 100 000 ions, is a frequency ratio of 0.999 231 659 33(17). Using a value of the D+ mass recently measured by the Seattle group, we obtain so far the most precise experimental H2+ mass value of 2.015 101 497 16(34) u. From this value a proton mass value of 1.007 276 466 95(18) u (0.18 ppb relative uncertainty) could be derived, in good agreement with the value of 1.007 276 466 89(14) u published by Van Dyck et al.

Place, publisher, year, edition, pages
Maryland, USA: American Physical Society, 2008
Keyword
atomic mass, deuterium, hydrogen ions, mass spectra, mass spectroscopy, particle traps, protons
National Category
Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-29381 (URN)10.1103/PhysRevA.78.012514 (DOI)000258180300118 ()
Available from: 2009-08-26 Created: 2009-08-26 Last updated: 2011-04-27Bibliographically approved
6. Re-trapping and cooling of highly-charged
Open this publication in new window or tab >>Re-trapping and cooling of highly-charged
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2009 (English)In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 163, 012109- p.Article in journal (Refereed) Published
Abstract [en]

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

National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-56737 (URN)10.1088/1742-6596/163/1/012109 (DOI)
Available from: 2011-04-27 Created: 2011-04-26 Last updated: 2011-04-27Bibliographically approved
7. Improved temperature regulation of Penning trap mass spectrometers
Open this publication in new window or tab >>Improved temperature regulation of Penning trap mass spectrometers
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2010 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, Vol. 294, no 1, 28-32 p.Article in journal (Refereed) Published
Abstract [en]

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.

Keyword
Penning trap, Magnetic field, Stabilization, Precision mass spectrometry, Temperature regulation
National Category
Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-29382 (URN)10.1016/j.ijms.2010.04.008 (DOI)000279462700005 ()
Available from: 2009-08-26 Created: 2009-08-26 Last updated: 2011-11-23Bibliographically approved
8. Evaporative Cooling and Coherent Axial Oscillations of Highly Charged Ions in a Penning Trap
Open this publication in new window or tab >>Evaporative Cooling and Coherent Axial Oscillations of Highly Charged Ions in a Penning Trap
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2011 (English)In: Physical Review Letters, ISSN 0031-9007, Vol. 106, no 1, 013002- p.Article in journal (Refereed) Published
Abstract [en]

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.

National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:su:diva-56739 (URN)10.1103/PhysRevLett.106.013002 (DOI)000286749900008 ()
Available from: 2011-04-27 Created: 2011-04-26 Last updated: 2012-01-25Bibliographically approved
9. A compact time-resolving pepperpot emittance meter for low energy highly-charged ions
Open this publication in new window or tab >>A compact time-resolving pepperpot emittance meter for low energy highly-charged ions
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(English)In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896Article in journal (Refereed) Accepted
National Category
Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-56741 (URN)
Available from: 2011-04-27 Created: 2011-04-26 Last updated: 2011-05-20Bibliographically approved

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