The Canadian Penning Trap (CPT) mass spectrometer at the Argonne National Laboratory makes precise mass measurements of both stable and unstable nuclides. To date, more than 60 radioactive isotopes having half-lives as short as one second have been measured with the CPT with a mass precision approaching 10 ppb. This thesis will present measurements made of nuclides along the rp-process path, which describes a process resulting from a series of rapid proton-capture reactions in an astrophysical environment. One possible site for the rp-process mechanism is an x-ray burst which results from the rapid accretion of hydrogen and helium from one star onto the surface of its neutron star binary companion. Mass measurements are required as key inputs to network calculations used to describe the rp-process in terms of the abundances of the nuclides produced, the light-curve profile of the x-ray bursts, and the energy produced. This thesis will describe the CPT apparatus, explain the method used to make precise mass measurements, and present the masses of the "waiting-point" nuclides ⁶⁸Se and ⁶⁴Ge. The mass measurement results, when used in x-ray burst models, confirm both ⁶⁸Se and ⁶⁴Ge as waiting-point nuclides which delay the rp-process by approximately 30 s and 7 s respectively.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (p. 210-216).

A position-sensitive microchannel plate (MCP) detector has been installed at the Canadian Penning Trap (CPT) mass spectrometer located at the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) facility at Argonne National Laboratory in order to carry out Phase-Imaging Ion Cyclotron Resonance (PI-ICR) measurements. With this new measurement method, proof-of-principle mass measurements of five nuclei were made to a precision of $\delta m/m \approx 10^{-7}$. The PI-ICR results are found to be consistent with previous Time-of-Flight Ion Cyclotron Resonance (ToF-ICR) measurements. The content of this thesis covers the entire mass measurement process beginning with beam production at CARIBU through to ion detection at the CPT and a comparison of the ToF-ICR and PI-ICR measurement methods. The future of mass measurements at the CPT with this new technique will also be discussed. / May 2016

This thesis addresses the issue of the time variability of the fine structure constant, alpha. Recent claims of a varying alpha are set against the established standards of quantum electrodynamical theory and experiments. A study of the feasibility of extracting data on the time dependence of alpha using particles in Penning traps is compared to the results obtained by existing methods, including those using astrophysical data and those obtained in atomic clock experiments. Suggestions are made on the nature of trapped particles and the trapping fields.

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. / 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.

The precision of mass measurements in a Penning trap is directly proportional to an ion's charge state and can be increased by using highly charged ions (HCI) from an Electron Beam Ion Trap (EBIT). By bombarding the injected and trapped singly charged ions with an intense electron beam, the charge state of the ions is rapidly increased. To use this method for short-lived isotopes, very high electron beam current densities are required of the TITAN EBIT, built and commissioned at the Max-Planck-Institute for Nuclear Physics in Heidelberg, Germany and transported to TRIUMF for the TITAN on-line facility. This EBIT has produced charge states as high as Kr34+ and Ba54+ with electron beams of up to 500 mA and 27 keV. Once the EBIT is operational at full capacity (5 A, 60 keV), most species can be bred into a He-like configuration within tens of ms. / October 2006

A single electron in a quantum cyclotron provides the most precise measurement of the electron magnetic moment, given in units of the Bohr magneton by g/2 = 1.001 159 652 180 73 (28) [0.28 ppt]. The most precise determination of the fine structure constant comes from combining this measurement with Standard Model theory, yielding \(\alpha^{-1} = 137.035 999 173 (34)\) [0.25 ppb], limited by the experimental uncertainty of the electron g-value. The most stringent test of CPT symmetry in leptons comes from comparing the electron and positron magnetic moments, limited by the positron uncertainty at 4.2 ppt. A new high-stability apparatus has been built and commissioned for improved measurements of the electron and positron magnetic moments, a greatly improved test of lepton CPT symmetry, and an improved determination of the fine structure constant. These new measurements require robust positron loading from a retractable radioactive source that is small enough to avoid compromising the high-precision environment of our experiment. The design and implementation of such a scheme is a central focus of this work. Robust positron loading at a rate of \(1-2 e^+/min\) from a \(6.5 \mu Ci^{22}Na\) source has been demonstrated. / Physics

The precision of mass measurements in a Penning trap is directly proportional to an ion's charge state and can be increased by using highly charged ions (HCI) from an Electron Beam Ion Trap (EBIT). By bombarding the injected and trapped singly charged ions with an intense electron beam, the charge state of the ions is rapidly increased. To use this method for short-lived isotopes, very high electron beam current densities are required of the TITAN EBIT, built and commissioned at the Max-Planck-Institute for Nuclear Physics in Heidelberg, Germany and transported to TRIUMF for the TITAN on-line facility. This EBIT has produced charge states as high as Kr34+ and Ba54+ with electron beams of up to 500 mA and 27 keV. Once the EBIT is operational at full capacity (5 A, 60 keV), most species can be bred into a He-like configuration within tens of ms.

The precision of mass measurements in a Penning trap is directly proportional to an ion's charge state and can be increased by using highly charged ions (HCI) from an Electron Beam Ion Trap (EBIT). By bombarding the injected and trapped singly charged ions with an intense electron beam, the charge state of the ions is rapidly increased. To use this method for short-lived isotopes, very high electron beam current densities are required of the TITAN EBIT, built and commissioned at the Max-Planck-Institute for Nuclear Physics in Heidelberg, Germany and transported to TRIUMF for the TITAN on-line facility. This EBIT has produced charge states as high as Kr34+ and Ba54+ with electron beams of up to 500 mA and 27 keV. Once the EBIT is operational at full capacity (5 A, 60 keV), most species can be bred into a He-like configuration within tens of ms.

With only two ingredients, atomic nuclei exhibit a rich structure depending on the ordering of the different proton- and neutron-occupied states. This ordering can give rise to excited states with exceptionally long half-lives, also known as isomers, especially near shell closures. On-line mass spectrometry can often be compromised by the existence of such states that may even be produced in higher proportion than the ground state. This thesis presents the first results obtained from a nuclear spectroscopy setup coupled with the high-resolution Penning-trap mass spectrometer ISOLTRAP, at CERN’s radioactive ion beam facility ISOLDE. The isomerism in the neutron-deficient thallium isotopes was investigated. The data on 184,190,193−195 Tl allow an improvement of existing mass values as well as a mass-spin-state assignment in 190,193,194 Tl. Due to the presence of the ground and isomeric state for 194 Tl the excitation energy of the latter was determined for the first time experimentally. Systematic trends in the vicinity of the Z = 82 shell closure have been discussed.