J. Smallcombe
A5037399374- Nuclear physics research studies
- Nuclear Physics and Applications
- Astronomical and nuclear sciences
- Atomic and Molecular Physics
- Nuclear reactor physics and engineering
- Quantum Chromodynamics and Particle Interactions
- Advanced NMR Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Radiation Detection and Scintillator Technologies
- Rare-earth and actinide compounds
- Neutrino Physics Research
- Particle physics theoretical and experimental studies
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Astro and Planetary Science
- Scientific Research and Discoveries
- Advanced Chemical Physics Studies
- Radiopharmaceutical Chemistry and Applications
- Particle Detector Development and Performance
- Particle accelerators and beam dynamics
- Radiation Effects in Electronics
- Radiation Therapy and Dosimetry
- Physics of Superconductivity and Magnetism
- Ionosphere and magnetosphere dynamics
- Crystallography and Radiation Phenomena
Japan Atomic Energy Agency
2015-2024
Advanced Science Research Center
2015-2024
University of Liverpool
2019-2024
TRIUMF
2015-2023
McMaster University
2021
University of Surrey
2018-2019
Simon Fraser University
2017
University of York
2014-2016
Fission-fragment mass distributions were measured for ^{237-240}U, ^{239-242}Np, and ^{241-244}Pu populated in the excitation-energy range from 10 to 60 MeV by multinucleon transfer channels reaction ^{18}O+^{238}U at Japan Atomic Energy Agency tandem facility. Among them, data ^{240}U ^{240,241,242}Np observed first time. It was found that all studied nuclides maintain a double-humped shape up highest energy contrast expectations of predominantly symmetric fission due washing out nuclear...
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...
It is shown that the multinucleon transfer reactions a powerful tool to study fission of exotic neutron-rich actinide nuclei, which cannot be accessed by particle-capture or heavy-ion fusion reactions. In this work, channels 18O + 232Th reaction are used fourteen nuclei 231,232,233,234Th, 232,233,234,235,236Pa, and 234,235,236,237,238U. Identification fissioning their excitation energy performed on an event-by-event basis, through measurement outgoing ejectile particle in coincidence with...
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...
Gamma-ray spectroscopy and lifetime measurements using the Doppler shift attenuation method (DSAM) were performed on nucleus $^{28}\mathrm{Mg}$ near $N=20$ ``island of inversion,'' which was populated a $^{12}\mathrm{C}(^{18}\mathrm{O},2\mathrm{p})^{28}\mathrm{Mg}$ fusion-evaporation reaction to investigate impact shell evolution its high-lying structure. Three new levels identified at 7203(3), 7747(2), 7929.3(12) keV along with several gamma rays. A newly extracted...
The $\beta$-decay half-lives of $^{128\text{--}130}$Cd have been measured with the newly commissioned GRIFFIN $\gamma$-ray spectrometer at TRIUMF-ISAC facility. time structures most intense $\gamma$-rays emitted following were used to determine $^{128}$Cd and $^{130}$Cd be $T_{1/2}= 246.2(21)$ ms 126(4)$ ms, respectively. 3/2$^+$ 11/2$^-$ states $^{129}$Cd $T_{1/2}(3/2^+)= 157(8)$ $T_{1/2}(11/2^-)= 147(3)$ ms. Cd isotopes around $N=82$ shell closure are an important ingredient in...
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...
A search for superallowed $\ensuremath{\alpha}$ decay of $N=Z$ nuclei $^{104}\mathrm{Te}$ and $^{108}\mathrm{Xe}$ was carried out using a novel recoil-decay scintillator detector at the tandem accelerator facility Japan Atomic Energy Agency (JAEA). Inorganic crystal scintillation material YAP:Ce (yttrium aluminum perovskite) coupled to position-sensitive photomultiplier tube (PSPMT) implemented first time in radioactive experiment. Residues from fusion-evaporation reaction...
A measurement of proton inelastic scattering 8He at 8.25A MeV TRIUMF shows a resonance 3.54(6) with width 0.89(11) MeV. The energy the state is in good agreement coupled cluster and no-core shell model continuum calculations, latter successfully describing measured as well. Its differential cross section analyzed phenomenological collective excitation form factor microscopic reaction channels framework consistently reveals large deformation parameter β2 = 0.40(3), consistent predictions...
Background: Electric-quadrupole (E2) strengths relate to the underlying quadrupole deformation of a nucleus and present challenge for many nuclear theories. Mirror nuclei in vicinity line N=Z represent convenient laboratory testing deficiencies such models, making use isospin symmetry systems. Purpose: Uncertainties associated with literature E2 23Mg are some largest Tz=∣∣12∣∣ sd shell. The purpose paper is improve precision which these values known, enable better comparison theoretical...
Background: Stellar carbon synthesis occurs exclusively via the 3α process, in which three α particles fuse to form C12 excited Hoyle state, followed by electromagnetic decay ground state. The state is above threshold, and rate of stellar production depends on radiative width this cannot be measured directly, must instead deduced combining separately quantities. One these quantities E0 branching ratio current 10% uncertainty stems mainly from ratio. process an important input parameter...
A study of Sm154 through γ-ray and internal conversion electron coincidence measurements was performed using the Silicon And GErmanium spectrometer (SAGE). An upper limit for ρ2(E0;22+→21+) measurement ρ2(E0;42+→41+) monopole transitions strengths were determined. The extracted transition strength each is significantly lower than that predicted by either Bohr Mottelson β-vibration description or interacting boson model. Hence, long standing interpretation these states as a collective band...
A model experiment of magnetic field amplification (MFA) via the Richtmyer-Meshkov instability (RMI) in supernova remnants (SNRs) was performed using a high-power laser. In order to account for very-fast acceleration cosmic rays observed SNRs, it is considered that has be amplified by orders magnitude from its background level. possible mechanism MFA SNRs stretching and mixing RMI when shock waves pass through dense molecular clouds interstellar media. astrophysical phenomenon laboratories,...
The $E0$ transition strength in the $2^+_2 \rightarrow 2^+_1$ transitions of $^{58,60,62}$Ni have been determined for first time following a series measurements at Australian National University (ANU) and Kentucky (UK). CAESAR Compton-suppressed HPGe array Super-e solenoid ANU were used to measure $δ(E2/M1)$ mixing ratio internal conversion coefficient each inelastic proton scattering. Level half-lives, ratios $γ$-ray branching measured UK neutron new spectroscopic information was determine...
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...
In the selenium isotopes various shape phenomena are present, in particular, emergence of a dominant oblate deformation most neutron-deficient has been observed. The scenario coexisting and prolate bands proposed across isotopic chain, with crossing point such being located near <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mmultiscripts><a:mi>Se</a:mi><a:mprescripts/><a:none/><a:mn>70</a:mn></a:mmultiscripts></a:math>, where no coexistence yet identified. To determine presence or...
Excited states in $^{58,60,62}\mathrm{Ni}$ were populated via inelastic proton scattering at the Australian National University as well neutron of Kentucky Accelerator Laboratory. The Super-e electron spectrometer and CAESAR Compton-suppressed HPGe array used complementary experiments to measure conversion coefficients $\ensuremath{\delta}(E2/M1)$ mixing ratios, respectively, for a number ${2}^{+}\ensuremath{\rightarrow}{2}^{+}$ transitions. data obtained combined with lifetimes branching...
The "Island of Inversion" for neutron-rich nuclei in the vicinity N=20 has become testing ground par excellence our understanding and modelling shell evolution with isospin. In this context, structure transitional nucleus 29Mg is critical. first quantitative measurements single particle are reported, using data from d(28Mg,p gamma)29Mg reaction. Two key states carrying significant ell=3 (f-wave) strength were identified at 2.40 +/- 0.10 (Jpi = 5/2-) 4.28 0.04 MeV (7/2-). New state-of-the-art...
We have developed a set up to measure fission properties of excited compound nuclei populated by multi-nucleon transfer reactions. This approach has an advantage that we can study neutron-rich which cannot be accessed particle or charged-particle capture Unique feature in our setup is produce data for many depending on different channels. Also wide excitation energy range covered this up, allowing us the dependence properties. Preliminary obtained 18O + 238U reaction will presented.
Three three-quasiparticle isomers, one at an excitation energy of 2.3 MeV with ${T}_{1/2}=0.48(4)\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{s}$, and two shorter-lived unknown half-lives slightly lower energies have been identified in $^{129}\mathrm{Nd}$ using the MARA $+$ JUROGAM 3 setup recoil tagging technique. All three isomers present decay patterns characteristic high-$K$ isomers. The known 6.7 s $\ensuremath{\beta}$-decaying isomer previously assigned to $5/{2}^{+}$ level is now...
The selenium isotopes lie at the heart of a tumultuous region nuclear chart where shape coexistence effects grapple with neutron-proton pairing correlations, triaxiality, and impending proton drip line. In this work, study $^{72}\mathrm{Se}$ by internal conversion electron $\ensuremath{\gamma}$-ray spectroscopy was undertaken SPICE TIGRESS arrays. New measurements branching ratio lifetime ${0}_{2}{}^{+}$ state were performed, yielding determination...