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New Mass Value for 7Li
Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
Visa övriga samt affilieringar
2006 (Engelska)Ingår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 96, nr 16, s. 163004-Artikel i tidskrift (Refereegranskat) Published
Ort, förlag, år, upplaga, sidor
2006. Vol. 96, nr 16, s. 163004-
Identifikatorer
URN: urn:nbn:se:su:diva-34862DOI: 10.1103/PhysRevLett.96.163004OAI: oai:DiVA.org:su-34862DiVA, id: diva2:285822
Tillgänglig från: 2010-01-13 Skapad: 2010-01-13 Senast uppdaterad: 2017-12-12Bibliografiskt granskad
Ingår i avhandling
1. New atomic masses related to fundamental physics measured with SMILETRAP
Öppna denna publikation i ny flik eller fönster >>New atomic masses related to fundamental physics measured with SMILETRAP
2005 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

This thesis describes the recent improvements of the SMILETRAP Penning trap mass spectrometer and a number of interesting high precision mass measurements, which have been performed using the improved apparatus, and are relevant in todays fundamental physics problems. The mass of the hydrogen-like 24,26Mg ions as well as the masses of the hydrogen- and lithium-like 40Ca ions are presented in this work that are indispensable input values when evaluating g-factor measurements of the bound electron. In both cases the uncertainty in the masses was improved by one order of magnitude compared to the literature values known so far.

The mass of 7Li has been measured and a new mass value has been obtained with an unprecedented relative uncertainty of 6.3x10-10. A large deviation of 1.1 μu (160ppb) compared to the literature value has been observed. In order to find the reason of this large deviation and to look for possible systematics we have measured the mass of 4He and 6Li and concluded that the 6Li(n,γ)7Li reaction Q-value used in the literature when calculating the 7Li mass is wrong by about 1 keV.

The mass difference between 3He and 3H (Δ m (3H -3He)) is the Q-value of the tritium β-decay. An accurate knowledge of the tritium Q-value is of importance in the search for a finite rest mass of the electron neutrino.

By adding a measurement of the mass of 3He1+ to previous mass measurement of 3H1+ and 3He2+ we have improved our previous Q-value by a factor of 2. At the moment our Q-value is the most accurate and more importantly it is based on the correct atomic mass values.

Ort, förlag, år, upplaga, sidor
Stockholm: Fysikum, 2005. s. 51
Nyckelord
Penning Trap, mass spectrometry
Nationell ämneskategori
Atom- och molekylfysik och optik
Identifikatorer
urn:nbn:se:su:diva-737 (URN)91-7155-166-2 (ISBN)
Disputation
2005-12-19, sal FA32, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 13:00 (Engelska)
Opponent
Handledare
Tillgänglig från: 2005-11-25 Skapad: 2005-11-25 Senast uppdaterad: 2011-04-27Bibliografiskt granskad
2. SMILETRAP I / II: Precision Improvements in Penning-Trap Mass-Spectrometry
Öppna denna publikation i ny flik eller fönster >>SMILETRAP I / II: Precision Improvements in Penning-Trap Mass-Spectrometry
2009 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

This thesis describes the final precision mass measurements with SMILETRAP I, where a relative precision of < 1 ppb (10-9) was reached routinely, and the development of SMILETRAP II, aiming for measurements with < 0.1 ppb relative precision. The emphasis of the thesis is on the implementation of new techniques for achieving this precision improvement with SMILETRAP II. The Ramsey multiple-pulse excitation technique was tested at SMILETRAP I, and a reduction of the statistical uncertainty by factor three could by verified. The technique was applied in the last measurement with SMILETRAP I on H2+ and D+ ions. From these measurements the proton mass was deduced with a relative error of 0.18 ppb. It was found that temperature dependent magnetic field oscillations limited us from reducing the uncertainties further. A technical achievement of reducing the peak to peak temperature oscillation in the trapping region of SMILETRAP II by a factor four is presented, which should give an extended observation time and likewise improved precision. The new SMILETRAP II super-conducting magnet, with a slightly stronger field of 5.8 T compared with the previous of 4.7 T, was installed and adjusted.  A careful field alignment and reduction of inhomogeneities was done for minimizing the disturbances of the cyclotron frequency for improved precision. In that attempt, the localization and control of the trapped ion motion is also important. Thus a new cooling trap was set up. In the spring of 2009 coherent axial motion of a confined ion cloud was discovered in the cooling trap. By observation of the axial oscillations we can see the effects of evaporative cooling in the reduction of the axial energy distribution. Storing the ions up to 1 s in the cooling trap reduces the energy distribution by a factor of five. Other remarkable results of the ion oscillations are also reported.

Ort, förlag, år, upplaga, sidor
Stockholm: Department of Physics, Stockholm University, 2009. s. 78
Nyckelord
Penning trap, Mass spectrometers, Instrumentation and methods for time-of-flight (TOF) spectroscopy, Highly charged ions
Nationell ämneskategori
Atom- och molekylfysik och optik
Forskningsämne
fysik
Identifikatorer
urn:nbn:se:su:diva-29399 (URN)978-91-7155-931-9 (ISBN)
Disputation
2009-09-25, sal FA31, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 10:00 (Engelska)
Opponent
Handledare
Anmärkning
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: In progress. Paper 3: Submitted.Tillgänglig från: 2009-09-03 Skapad: 2009-08-26 Senast uppdaterad: 2010-01-13Bibliografiskt granskad

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