A5053229186- Nuclear physics research studies
- Nuclear Physics and Applications
- Astronomical and nuclear sciences
- Atomic and Molecular Physics
- Nuclear reactor physics and engineering
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Neutrino Physics Research
- Radiation Detection and Scintillator Technologies
- Advanced Chemical Physics Studies
- Atomic and Subatomic Physics Research
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced NMR Techniques and Applications
- Rare-earth and actinide compounds
- Nuclear Materials and Properties
- Quantum, superfluid, helium dynamics
- Inorganic Fluorides and Related Compounds
- Astrophysics and Cosmic Phenomena
- Particle Detector Development and Performance
- Spacecraft and Cryogenic Technologies
- Cold Fusion and Nuclear Reactions
- Radioactive contamination and transfer
- Particle accelerators and beam dynamics
- Gamma-ray bursts and supernovae
- Fusion materials and technologies
TRIUMF
2017-2024
National Superconducting Cyclotron Laboratory
2014-2023
Michigan State University
2014-2023
Scottish Universities Physics Alliance
2021-2023
University of the West of Scotland
2011-2022
University of Glasgow
2021
University of Surrey
2011-2019
Universitat de València
2017
Instituto de Física Corpuscular
2017
Consejo Superior de Investigaciones Científicas
2016
With a new detector setup and the high-resolution performance of fragment separator FRS at GSI we discovered 57 isotopes in atomic number range 60$\leq Z \leq 78$: \nuc{159-161}{Nb}, \nuc{160-163}{Pm}, \nuc{163-166}Sm, \nuc{167-168}{Eu}, \nuc{167-171}{Gd}, \nuc{169-171}{Tb}, \nuc{171-174}{Dy}, \nuc{173-176}{Ho}, \nuc{176-178}{Er}, \nuc{178-181}{Tm}, \nuc{183-185}{Yb}, \nuc{187-188}{Lu}, \nuc{191}{Hf}, \nuc{193-194}{Ta}, \nuc{196-197}{W}, \nuc{199-200}{Re}, \nuc{201-203}{Os},...
Heavy neutron-rich nuclei were populated via the fragmentation of a E/A=1 GeV 20882Pb beam. Secondary fragments separated and identified subsequently implanted in passive stopper. By detection delayed γ rays, isomeric decays associated with these have been identified. A total 49 isomers detected, majority them observed for first time. The newly discovered are 204,20580Hg, 201,202,204,20579Au, 197,203,20478Pt, 195,199−20377Ir, 193,197−19976Os, 19675Re, 190,19174W, 18973Ta. Possible level...
The antineutrino spectra measured in recent experiments at reactors are inconsistent with calculations based on the conversion of integral beta recorded ILL reactor. (92)Rb makes dominant contribution to reactor spectrum 5-8 MeV range but its decay properties question. We have studied total absorption spectroscopy. Previously unobserved feeding was seen 4.5-5.5 region and GS found be 87.5(25)%. impact calculated summation method is shown discussed.
Background: Multinucleon transfer reactions (MNT) are a competitive tool to populate exotic neutron-rich nuclei in wide region of nuclei, where other production methods have severe limitations or cannot be used at all.Purpose: Experimental information on the yields MNT comparison with theoretical calculations necessary make predictions for heavy nuclei.It is crucial determine fraction reaction products which surviving neutron emission fission high excitation energy after nucleon...
There is sparse direct experimental evidence that atomic nuclei can exhibit stable "pear" shapes arising from strong octupole correlations. In order to investigate the nature of collectivity in radium isotopes, electric (E3) matrix elements have been determined for transitions ^{222,228}Ra using method sub-barrier, multistep Coulomb excitation. Beams radioactive isotopes were provided by HIE-ISOLDE facility at CERN. The observed pattern E3 different nuclear explained describing ^{222}Ra as...
The neutron-rich lead isotopes, up to $^{216}\mathrm{Pb}$, have been studied for the first time, exploiting fragmentation of a primary uranium beam at FRS-RISING setup GSI. observed isomeric states exhibit electromagnetic transition strengths which deviate from state-of-the-art shell-model calculations. It is shown that their complete description demands introduction effective three-body interactions and two-body operators in conventional neutron valence space beyond $^{208}\mathrm{Pb}$.
Many-body nuclear theory utilizing microscopic or chiral potentials has developed to the point that collectivity might be dealt with in an {\it ab initio} framework without use of effective charges; for example proper evolution operators, alternatively, through appropriate and manageable subset particle-hole excitations. We present a precise determination $E2$ strength $^{22}$Mg its mirror $^{22}$Ne by Coulomb excitation, allowing rigorous comparisons theory. No-core symplectic shell-model...
The $\beta$-delayed neutron emission probabilities of rich Hg and Tl nuclei have been measured together with $\beta$-decay half-lives for 20 isotopes Au, Hg, Tl, Pb Bi in the mass region N$\gtrsim$126. These are heaviest species where has observed so far. measurements provide key information to evaluate performance nuclear microscopic phenomenological models reproducing high-energy part strength distribution. In doing so, it provides important constraints global theoretical currently used...
We investigate the decay of $^{87,88}\mathrm{Br}$ and $^{94}\mathrm{Rb}$ using total absorption $\ensuremath{\gamma}$-ray spectroscopy. These important fission products are $\ensuremath{\beta}$-delayed neutron emitters. Our data show considerable $\ensuremath{\beta}\ensuremath{\gamma}$ intensity, so far unobserved in high-resolution spectroscopy, from states at high excitation energy. also find significant differences with $\ensuremath{\beta}$ intensity that can be deduced existing...
Total absorption spectroscopy is used to investigate the β-decay intensity states above neutron separation energy followed by γ-ray emission in (87,88)Br and (94)Rb. Accurate results are obtained thanks a careful control of systematic errors. An unexpectedly large γ observed all three cases extending well beyond excitation region where penetration hindered low energy. The branching as function compared Hauser-Feshbach model calculations. For (87)Br (88)Br reaches 57% 20%, respectively, could...
The elusive β^{-}p^{+} decay was observed in ^{11}Be by directly measuring the emitted protons and their energy distribution for first time with prototype Active Target Time Projection Chamber an experiment performed at ISAC-TRIUMF. measured branching ratio is orders of magnitude larger than any previous theoretical model predicted. This can be explained presence a narrow resonance ^{11}B above proton separation energy.
The beta decays of $^{86}\mathrm{Br}$ and $^{91}\mathrm{Rb}$ have been studied using the total absorption spectroscopy technique. radioactive nuclei were produced at Ion Guide Isotope Separator On-Line facility in Jyv\"askyl\"a further purified JYFLTRAP. are considered to be major contributors decay heat reactors. In addition, was used as a normalization point direct measurements mean gamma energies released fission products by Rudstam et al. assuming that this well known from...
The fragmentation of relativistic uranium projectiles has been exploited at the Gesellschaft f\"ur Schwerionenforschung laboratory to investigate $\ensuremath{\beta}$ decay neutron-rich nuclei just beyond ${}^{208}$Pb. This paper reports on $\ensuremath{\beta}$-delayed $\ensuremath{\gamma}$ decays ${}^{211--213}$Tl, ${}^{215}$Pb, and ${}^{215--219}$Bi de-exciting states in daughters ${}^{211--213}$Pb, ${}^{215}$Bi, ${}^{215--219}$Po. resulting partial level schemes, proposed with help...
The shape of an atomic nucleus is one its most defining characteristics, and the evolution nuclear shapes with nucleon number gives insights into symmetries underlying interactions this many-body quantum system. osmium-platinum region shows a rich set prolate, oblate, axially asymmetric, co-existing shapes. This challenging $\ensuremath{\gamma}$-ray-spectroscopy experiment develops yrast level scheme for ${}^{196}$Os argues that nearly perfectly $\ensuremath{\gamma}$-unstable.
The $T_z$~=~$-\frac{3}{2}$ nucleus ${}^{21}$Mg has been studied by Coulomb excitation on ${}^{196}$Pt and ${}^{110}$Pd targets. A 205.6(1)-keV $\gamma$-ray transition resulting from the of $\frac{5}{2}^+$ ground state to first excited $\frac{1}{2}^+$ in was observed for time. cross-section measurements with both targets a measurement half-life yield an adopted value $B(E2;\frac{5}{2}^+\rightarrow\frac{1}{2}^+)$~=~13.3(4)~W.u. new at 1672(1)~keV tentative $\frac{9}{2}^+$ assignment also...
Background: There have been measurements on roughly 230 nuclei that are $\ensuremath{\beta}$-delayed neutron emitters. They range from $^{8}\mathrm{He}$ up to $^{150}\mathrm{La}$. Apart $^{210}\mathrm{Tl}$, with a branching ratio of only 0.007%, no other emitter has measured beyond $A=150$. Therefore, new data needed, particularly in the region heavy around $N=126$, order guide theoretical models and help understand formation third $r$-process peak at $A\ensuremath{\sim}195$.Purpose: To...
There is significant evidence supporting the existence of deformed ground states within neutron-rich $N\ensuremath{\approx}20$ neon, sodium, and magnesium isotopes that make up what commonly called ``island inversion.'' However, rotational band structures, which are a characteristic fingerprint rigid nonspherical shape, have yet to be observed. In this work, we report on measurement analysis yrast (lowest lying) in $^{32}\mathrm{Mg}$ spin $I={6}^{+}$ produced two-step projectile...
The reduced transition probabilities $B(E2;{0}_{\mathrm{g}.\mathrm{s}.}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})$ of the $^{46}\mathrm{Ar}$ and $^{44}\mathrm{Ca}$ nuclei were studied using Coulomb excitation technique at intermediate energy LISE/GANIL facility. in-flight $\ensuremath{\gamma}$ rays, emitted after their first ${2}^{+}$ states, detected in an array $64{\mathrm{BaF}}_{2}$ crystals. present $\text{B}(\mathrm{E}2\ensuremath{\uparrow})$ value for $^{44}\mathrm{Ca}$, 475(36)...
Lifetimes of $2^+_1$ and $4^+_1$ states, as well some negative-parity non-yrast in $^{188-200}$Hg were measured using $\gamma-\gamma$ electronic fast timing techniques with the LaBr$_3$(Ce) detector array GRIFFIN spectrometer. The excited states populated $\epsilon/\beta^+$-decay $J^\pi =7^+/2^-$ $^{188-200}$Tl produced at TRIUMF-ISAC facility. deduced B(E2) values are compared to different interacting boson model predictions. precision achieved this work over previous ones allows for a...
The half-life of the yrast ${I}^{\ensuremath{\pi}}={2}^{+}$ state in neutron-rich nucleus ${}^{188}$W has been measured using fast-timing techniques with HPGe and LaBr${}_{3}$:Ce array at National Institute Physics Nuclear Engineering, Bucharest. resulting value ${t}_{1/2}=0.87(12)$ ns is equivalent to a reduced transition probability $B(E2;{2}_{1}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})=85(12)$ W.u. for this transition. $B(E2;{2}_{1}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})$ compared...
Isomeric ratios have been determined for 23 metastable states identified in $A\ensuremath{\approx}200$ nuclei from Pt to Rn near the valley of stability following fragmentation ${}^{238}$U. This includes high-spin with angular momenta ranging (39/2)$\ensuremath{\hbar}$ 25$\ensuremath{\hbar}$. The experimental results are discussed together those similar experiments performed this mass region. compared theoretical predictions where momentum fragment arises purely due nucleons removed...