A5086799881- Atomic and Molecular Physics
- Nuclear physics research studies
- Mass Spectrometry Techniques and Applications
- Nuclear Physics and Applications
- Advanced Chemical Physics Studies
- Astronomical and nuclear sciences
- Particle accelerators and beam dynamics
- Advanced Frequency and Time Standards
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Muon and positron interactions and applications
- Radioactive Decay and Measurement Techniques
- Particle physics theoretical and experimental studies
- X-ray Spectroscopy and Fluorescence Analysis
- Laser-induced spectroscopy and plasma
- Noncommutative and Quantum Gravity Theories
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Electron and X-Ray Spectroscopy Techniques
- Quantum Chromodynamics and Particle Interactions
- Plasma Diagnostics and Applications
- Particle Accelerators and Free-Electron Lasers
- Astro and Planetary Science
- Magnetic confinement fusion research
- Scientific Measurement and Uncertainty Evaluation
University of Manitoba
2015-2025
TRIUMF
2012-2018
University of British Columbia
2012-2016
National Superconducting Cyclotron Laboratory
2012
Simon Fraser University
2012
Michigan State University
2012
Max Planck Institute for Nuclear Physics
2000-2011
Johannes Gutenberg University Mainz
2009-2011
Max Planck Society
2001-2009
Heidelberg University
1999-2002
A precision mass investigation of the neutron-rich titanium isotopes $^{51\ensuremath{-}55}\mathrm{Ti}$ was performed at TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN). The range measurements covers $N=32$ shell closure, overall uncertainties $^{52\ensuremath{-}55}\mathrm{Ti}$ values were significantly reduced. Our results conclusively establish existence weak effect $N=32$, narrowing down abrupt onset this closure. data compared with state-of-the-art ab initio model calculations...
An improved test of time dilation in special relativity has been performed using laser spectroscopy on fast ions at the heavy-ion storage-ring TSR Heidelberg. The Doppler-shifted frequencies a two-level transition 7Li+ v=0.064c have measured forward and backward direction to an accuracy Deltanu/nu=1 x 10(-9) collinear saturation spectroscopy. result confirms relativistic Doppler formula sets new limit 2.2 10(-7) for deviations from factor gamma(SR)=(1-v2/c2)(-1/2).
TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN) constitutes the only high precision mass measurement setup coupled to a rare isotope facility capable of increasing charge state short-lived nuclides prior actual determination in Penning trap. Recent developments around TITAN's breeder, electron beam ion trap, form basis several successful experiments on radioactive isotopes with half-lives as low 65 ms states 22+.
We present the concluding result from an Ives-Stilwell-type time dilation experiment using Li+7 ions confined at a velocity of β=v/c=0.338 in storage ring ESR Darmstadt. A Λ-type three-level system within hyperfine structure Li+7S13→P23 line is driven by two laser beams aligned parallel and antiparallel relative to ion beam. The lasers' Doppler shifted frequencies required for resonance are measured with accuracy <4×10−9 optical-optical double spectroscopy. This allows us verify special...
We review the use of laser cooling and trapping for Standard Model tests, focusing on radioactive isotopes. Experiments with neutral atoms trapped using modern laser-cooling techniques are testing several basic predictions electroweak unification. For nuclear β decay, demonstrated trap include neutrino momentum measurements from beta-recoil coincidences, along methods to produce highly polarized samples. These have set best general constraints non-Standard scalar interactions in first...
Penning trap mass measurements of short-lived nuclides have been performed for the first time with highly charged ions, using TITAN facility at TRIUMF. Compared to singly this provides an improvement in experimental precision that scales charge state q. Neutron-deficient Rb isotopes bred electron beam ion q=8-12+ prior injection into trap. In combination Ramsey excitation scheme, unique setup creating low energy, ions a radioactive opens door unrivaled gains 1-2 orders magnitude. The method...
We report on a method for determining the absolute nuclear charge radius of high-<a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mi>Z</a:mi></a:mrow></a:math> elements using extreme-ultraviolet spectroscopy highly charged Na-like ions in tandem with accurate atomic structure calculations transition energy differences. The application this has reduced uncertainty <b:math...
The low-energy C IV dielectronic recombination (DR) rate coefficient associated with 2s → 2p Δn = 0 excitations of this lithium-like ion has been measured high-energy resolution at the heavy-ion storage ring TSR Max-Planck-Institut für Kernphysik in Heidelberg, Germany. experimental procedure and especially detection probabilities for high Rydberg states produced by are discussed detail. From data a Maxwellian plasma is derived ±15% systematic uncertainty parameterized ready use...
Radiative recombination (inverse photoionization) is believed to be well understood since the beginning of quantum mechanics. Still, modern experiments consistently reveal excess rates at very low electron-ion center-of-mass energies. In a detailed study on F6+ and C6+ ions with magnetically guided electrons we explored yet unexplained rate enhancement, its dependence magnetic field B, electron density n(e), beam temperatures T( perpendicular) ||). The scales as T(-1/2)( and, surprisingly,...
A new determination of the decay rate negative ion positronium (Ps-), using a beam-foil method and stripping-based detection technique, is reported. The measured result gamma = 2.089(15) ns(-1) factor 6 more precise than previous experimental value 2.09(9) ns(-1), in excellent agreement with theoretical 2.086(6) ns(-1).
Using Triumf's neutral atom trap, Trinat, for nuclear β decay, we have measured the asymmetry with respect to initial spin in ^{37}K be A_{β}=-0.5707(13)_{syst}(13)_{stat}(5)_{pol}, a 0.3% measurement. This is best relative accuracy of any β-asymmetry measurement nucleus or neutron, and agreement standard model prediction -0.5706(7). We compare constraints on physics beyond other β-decay measurements, improve value V_{ud} this mirror by factor 4.
Recombination involving the core excitation of two electrons, which may be termed trielectronic recombination, has been experimentally identified for first time. Using Cl13+ ions circulating in TSR heavy-ion storage ring, we have observed surprisingly strong low-energy recombination resonances, comparable to dielectronic process. At higher electron-ion collision energies, is suppressed due autoionization triply excited intermediate state into final states. The formation depends sensitively...
The neutron-rich mass region around $A\approx100$ presents challenges for modeling the astrophysical $r$-process because of rapid shape transitions. We report on measurements using TITAN Penning trap at TRIUMF-ISAC to attain more reliable theoretical predictions nucleosynthesis paths in this region. A new approach highly charged ($q=15+$) ions has been applied which considerably saves measurement time and preserves accuracy. New $^{94,97,98}$Rb $^{94,97-99}$Sr have uncertainties less than 4...
We have measured the hyperfine splitting of 7P_{1/2} state at 100 ppm level in Fr isotopes (^{206g,206m,207,209,213,221}Fr) near closed neutron shell (N=126 ^{213}Fr). The measurements five and a nuclear isomeric francium, combined with previous determinations 7S_{1/2} splittings, reveal spatial distribution magnetization, i.e., Bohr-Weisskopf effect. compare our results simple model consisting unpaired single valence nucleons orbiting spherical nucleus, find good agreement over range...
High-accuracy mass measurements of neutron-deficient Yb isotopes have been performed at TRIUMF using TITAN's multiple-reflection time-of-flight spectrometer (MR-TOF-MS). For the first time, an MR-TOF-MS was used on line simultaneously as isobar separator and a spectrometer, extending to two further away from stability than otherwise possible. The ground state masses $^{150,153}\mathrm{Yb}$ excitation energy $^{151}{\mathrm{Yb}}^{m}$ were measured for time. As result, persistence $N=82$ shell...
Experimental data are presented from three different heavy-ion storage rings (ASTRID in Aarhus, CRYRING Stockholm, and TSR Heidelberg) to assess the reliability of this experimental tool for extraction absolute rate coefficients cross sections dissociative recombination (DR). The DR reaction between ${\mathrm{HD}}^{+}$ electrons has been studied 0 30 eV on a dense energy grid. displays two characteristic local maxima around 9 16 eV. These influence analysis at smaller collision energies. We...
Electron-ion recombination spectra of the Li-like ion ${\mathrm{F}}^{6+}$ in energy range $0.0\ensuremath{-}0.6 \mathrm{eV}$ from two different storage rings are presented, showing excellent agreement. The experimental results compared with a calculated spectrum, obtained by combination relativistic many-body methods and complex rotation, agreement is found to be very good. spectrum studied region determined ${2p}_{j}6{\mathcal{l}}_{{j}^{\ensuremath{'}}}^{\ensuremath{'}}$ dielectronic...
We have measured resonance strengths and energies for dielectronic recombination (DR) of beryllium-like Fe XXIII forming boron-like XXII via N = 2 → N' 3 core excitations. All measurements were carried out using the heavy-ion Test Storage Ring at Max Planck Institute Nuclear Physics (MPI-K) in Heidelberg, Germany. also calculated these three independent, perturbative, state-of-the-art theoretical techniques: multiconfiguration Breit-Pauli (MCBP) method, Dirac-Fock (MCDF) Flexible Atomic Code...
We demonstrate sub-Doppler laser spectroscopy with a beam of ${^{7}\text{L}\text{i}}^{+}$ ions stored at 33.8% the speed light in experimental storage ring GSI. Using two lasers, one copropagating and other counterpropagating, respect to ion beam, fluorescence line is observed via optical-optical double-resonance on $\ensuremath{\Lambda}$-type level configuration. A linewidth $\ensuremath{\approx}114\text{ }\text{MHz}$ found, which 12 times narrower than Doppler broadening due momentum...
A measurement of the α-β-ν[over ¯] angular correlation in Gamow-Teller decay (8)Li→(8)Be(*)+ν[over ¯]+β, (8)Be(*)→α+α has been performed using ions confined a linear Paul trap surrounded by silicon detectors. The energy difference spectrum α particles emitted along and opposite direction β particle is consistent with standard model prediction places limit 3.1% (95.5% confidence level) on any tensor contribution to decay. From this result, amplitude component C(T) relative that dominant...
We performed the first direct mass measurements of neutron-rich vanadium V52–55 isotopes passing N=32 neutron shell closure with TRIUMF's Ion Trap for Atomic and Nuclear science. The new confirm all previous indirect results. Through a reduced uncertainty V55 we quenching in vanadium. discuss evolution between K Cr show similar signatures half-life surface when studied along isotopic chains.Received 2 June 2018DOI:https://doi.org/10.1103/PhysRevC.98.024310©2018 American Physical...
A new series of neutron-rich indium mass measurements is reported from the TITAN multiple-reflection time-of-flight spectrometer (MR-TOF-MS). These cover $^{125\ensuremath{-}134}\mathrm{In}$ ($N=76--85$) and include ground states as well isomeric states. The masses nuclei in this region are known to be great importance for accurately modeling $r$-process nucleosynthesis, significance discussed context. Results compared with earlier experimental data where available theoretical models. here...
Absolute total electron-ion recombination rate coefficients of argonlike ${\mathrm{Sc}}^{3+}{(3s}^{2}{3p}^{6})$ ions have been measured for relative energies between electrons and ranging from 0 to 45 eV. This energy range comprises all dielectronic resonances attached $3\stackrel{\ensuremath{\rightarrow}}{p}3d$ $3\stackrel{\ensuremath{\rightarrow}}{p}4s$ excitations. A broad resonance with an experimental width $0.89\ifmmode\pm\else\textpm\fi{}0.07 \mathrm{eV}$ due the...