J. M. Keatings
A5054474732- Nuclear physics research studies
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Astronomical and nuclear sciences
- Advanced Chemical Physics Studies
- Neutrino Physics Research
- Nuclear reactor physics and engineering
- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Radiation Detection and Scintillator Technologies
- Atomic and Subatomic Physics Research
- Advanced NMR Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Nuclear Materials and Properties
- Muon and positron interactions and applications
- Magnetic Properties of Alloys
- Quantum, superfluid, helium dynamics
- Rare-earth and actinide compounds
- X-ray Diffraction in Crystallography
University of the West of Scotland
2017-2025
Scottish Universities Physics Alliance
2019-2022
University of Glasgow
2021
Daresbury Laboratory
2019
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...
At a fundamental level, the interactions between protons and protons, neutrons, neutrons are not identical. Such isospin nonconserving emerge when comparing excitation energy of analog states in T=1 triplet nuclei. Here, we extend such an analysis to A=78, system-the heaviest system for which complete data exists-and find strong disagreement with contemporary theory. This was achieved by pioneering technique recoil-β-β tagging identify excited ^{78}Zr. We also established ^{78}Zr half-life...
For the N = 50-56 zirconium (Z 40) and molybdenum 42) isotopes, evolution of subshells is evaluated by extracting effective single-particle energies from available particle-transfer data. The extracted systematic neutron systematics excitation energy octupole phonons provide evidence for type-II shape coexistence in Zr isotopes. Employing a simplistic approach, relative are used to estimate whether formation low-lying octupole-isovector excitations possible at proposed energies. results...
The nature of quadrupole and octupole collectivity in $^{222}\mathrm{Rn}$ was investigated by determining the electric-quadrupole ($E2$) ($E3$) matrix elements using subbarrier, multistep Coulomb excitation. radioactive beam, accelerated to 4.23 MeV/u, provided HIE-ISOLDE facility at CERN. Data were collected Miniball $\ensuremath{\gamma}$-ray spectrometer following bombardment two targets, $^{120}\mathrm{Sn}$ $^{60}\mathrm{Ni}$. Transition $E2$ within ground-state bands measured up...
The lifetime of the ${2}_{1}^{+}$ state $^{212}\mathrm{Po}$ was measured in $^{208}\mathrm{Pb}$($^{12}\mathrm{C},^{8}\mathrm{Be}$)$^{212}\mathrm{Po}$ transfer reaction by $\ensuremath{\gamma}$-ray spectroscopy employing recoil distance Doppler shift (RDDS) method. derived absolute $B(E2)$ value 2.6(3) W.u. indicates a low collectivity and contradicts previous claims $\ensuremath{\alpha}$-cluster components structure state. It is demonstrated that consistent description properties...
Low-lying yrast states of $^{204}\mathrm{Po}$ and $^{206}\mathrm{Po}$ were investigated by the $\ensuremath{\gamma}--\ensuremath{\gamma}$ fast timing technique with ${\mathrm{LaBr}}_{3}$(Ce) detectors. Excited these nuclei populated in $^{197}\mathrm{Au}(^{11}\mathrm{B},4n)^{204}\mathrm{Po}$ $^{198}\mathrm{Pt}(^{12}\mathrm{C},4n)^{206}\mathrm{Po}$ fusion-evaporation reactions, respectively. The beams delivered FN-Tandem accelerator at University Cologne. lifetimes ${4}_{1}^{+}$ both...
There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape pear. This phenomenon important for measurements electric-dipole moments atoms, which would indicate CP violation hence probe physics beyond Standard Model particle physics. Isotopes both radon radium have been identified as candidates such measurements. Here, we observed low-lying quantum states in 224Rn 226Rn by accelerating beams these radioactive nuclei. We show isotopes vibrations...
The radioactivity of 76160Os84 and 74156W82 that lie at the two-proton drip line have been measured in an experiment performed Accelerator Laboratory University Jyväskylä. 160Os nuclei were produced using fusion-evaporation reactions induced by a beam 310 MeV 58Ni ions bombarding 106Cd target. separated flight recoil separator MARA implanted into double-sided silicon strip detector, which was used to measure their decays. α decays ground state (Eα = 7092(15) keV, t1/2 97−32+97 μs) its...
We would like to make readers aware that after the publication of this article sort code was updated.This resulted in more gamma-gamma data, particularly for high-spin transitions.By performing additional analysis we confirm energies most states, have identified several new and updated one states incorrectly represented its energy original paper.The figures (Figs. 1234) table (Table 1) are along with their captions.The overall conclusions paper remain unaffected.The data our finding, 224,226...
Newly observed decay schemes of the nuclei $^{137}\mathrm{Sb}$ and $^{138}\mathrm{Sb}$ are reported. The neutron-rich Sb isotopes were produced by in-flight fragmentation a $^{238}\mathrm{U}$ primary beam with an energy 345 MeV/nucleon. Several new excited states $^{137}\mathrm{Te}$ tentatively assigned spin-parities $(5/{2}^{\ensuremath{-}})$, $(9/{2}^{\ensuremath{-}})$, $(7/2)$ have been established which play important role in evolution neutron levels beyond $N=82$. study...
Low-lying states in the odd-$Z$ isotopes $_{\phantom{\rule{3.33333pt}{0ex}}89}^{221}\mathrm{Ac}_{132}$ and $_{\phantom{\rule{3.33333pt}{0ex}}91}^{225}\mathrm{Pa}_{134}$ have been studied using $\ensuremath{\alpha}$-particle $\ensuremath{\alpha}\ensuremath{\gamma}$-coincidence spectroscopy $^{225}\mathrm{Pa}\ensuremath{\rightarrow}^{221}\mathrm{Ac}\ensuremath{\rightarrow}^{217}\mathrm{Fr}$ decay chain. Ground-state spin parity assignments of ${I}^{\ensuremath{\pi}}$ = ${5/2}^{\ensuremath{-}}$...
The first excited level of 96Mo was investigated in a high-statistics experiment using the 95Mo(n, γγ) cold neutron capture reaction. measurements used high flux from research reactor at Institut Laue-Langevin and employed highly-efficient EXILL array to detect γ-ray coincidences. recorded statistics allow identification decay branches with only small relative intensity including E3 decay. With knowledge newly measured branching ratio known transition probability, lifetime determined and,...
The nature of $J^{\pi}=1^-$ levels $^{96}$Zr below the $\beta$-decay $Q_{\beta}$ value $^{96}$Y has been investigated in high-resolution $\gamma$-ray spectroscopy following $\beta$ decay as well a campaign inelastic photon scattering experiments. Branching ratios extracted from allow absolute $E1$ excitation strength to be determined for populated both reactions. combined data represents comprehensive approach wavefunction $1^-$ value, which are theoretical Quasiparticle Phonon Model. This...
The β decay of the semimagic Sn isotopes 136,137,138Sn has been studied at Radioactive Isotope Beam Factory RIKEN Nishina Center. first experimental information on excited states was obtained for 137Sb while, in case 136Sb, established excitation scheme could be extended by ten previously unidentified levels. In most-neutron-rich isotope 138Sn, two γ rays were observed time. new results, combination with state-of-the-art shell-model calculations, provide respect to evolution 0g7/2 and 1d5/2...
An analysis technique has been developed in order to mitigate energy summing due sequential short-lived α decays from nuclei implanted into a silicon detector. Using this technique, α-decay spectroscopy of the N=130 isotones 218Ra (Z=88) and 220Th (Z=90) performed. The energies particles emitted 218Ra→214Rn 220Th→216Ra ground-state-to-ground-state have measured be 8381(4) keV 8818(13) keV, respectively. half-lives ground states 25.99(10) μs 10.4(4) μs, daughters, 214Rn 216Ra, 259(3) ns...
This letter reports lifetime measurements of excited states in the odd-N nucleus 163W using recoil-distance Doppler shift method to probe core polarising effect i13/2 neutron orbital on underlying soft triaxial even-even core. The ratio B(E2:21/2+→17/2+)/B(E2:17/2+→13/2+) is consistent with predictions collective rotational model. deduced B(E2) values provide insights into validity model for heavy transitional nuclei and a geometric origin anomalous ratios observed nearby proposed.
Excited states in the neutron-deficient nuclide <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mmultiscripts><a:mi>Hf</a:mi><a:mprescripts/><a:none/><a:mn>155</a:mn></a:mmultiscripts></a:math> have been investigated experiments performed at Accelerator Laboratory of University Jyväskylä. The <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mmultiscripts><b:mi>Hf</b:mi><b:mprescripts/><b:none/><b:mn>155</b:mn></b:mmultiscripts></b:math> nuclei were produced fusion-evaporation...
Nucleon-transfer sum rules have been assessed via a consistent reanalysis of cross-section data from neutron-adding ($d,p$) and -removing ($d,t$) reactions on well-deformed isotopes Gd, Dy, Er, Yb, W, with $92\ensuremath{\le}N\ensuremath{\le}108$, studied at the Niels Bohr Institute in 1960s 1970s. These are complemented by new measurements cross sections using ($d,p$), ($d,t$), ($p,d$) subset these nuclei. The rules, defined Nilsson-model framework, remarkably consistent. A single overall...
In recent years, a number of both theoretical and experimental investigations have been performed focusing on the zirconium isotopic chain. particular, state-of-the-art Monte Carlo shell-model calculations predict shape coexistence in these isotopes. this context, 94 Zr nucleus, which is believed to possess nearly spherical ground state, particularly interesting since purported deformed structure basedon low-lying 0 2 + making it amenable for detailed study. order provide definitive...
A charge plunger device has been commissioned based on the DPUNS (Taylor et al., 2013) using in-flight mass separator MARA at University of Jyväskylä. The 152Sm(32S,4n)180Pt reaction was used to populate excited states in 180Pt. lifetime measurement 21+ state performed by applying technique, which relies detection state-distribution recoils rather than emitted γ rays. This a good candidate test technique as it known and depopulates through converted transition that competes strongly with...
In this contribution, it is evaluated whether high Q-value β decays from mothers with low ground-state spin are suitable to probe the structure of 1− levels associated pygmy dipole response. A comparison data exemplary 136I →136Xe decay and 136Xe(γ,γ′) reaction reveals that some populated in both reactions but a different pattern. An investigation within microscopic quasiparticle phonon model shows pattern related population parts wave functions these establishing as novel probe.
Projectile Coulomb excitation experiments were performed at HIE-ISOLDE CERN with the radioactive ion beams of 140 Nd and 142 Sm. Ions an energy 4:62 MeV/A impinging on a 1.45 mg/cm 2 thick 208 Pb target. The γ-rays depopulating Coulomb-excited states recorded by HPGe-array MINIBALL scattered particles detected double-sided silicon strip detector. Experimental intensities used for determination electromagnetic transition matrix elements. A preliminary result B(M1; + 3 → 1 ) upper limit case...