A5085554810- Nuclear physics research studies
- Nuclear Physics and Applications
- Astronomical and nuclear sciences
- Quantum Chromodynamics and Particle Interactions
- Atomic and Molecular Physics
- Nuclear reactor physics and engineering
- Particle physics theoretical and experimental studies
- Advanced Chemical Physics Studies
- Advanced NMR Techniques and Applications
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- High-Energy Particle Collisions Research
- Superconducting Materials and Applications
- High-pressure geophysics and materials
- Particle Accelerators and Free-Electron Lasers
- Molecular Spectroscopy and Structure
- Mass Spectrometry Techniques and Applications
- X-ray Diffraction in Crystallography
- Spacecraft and Cryogenic Technologies
- Quantum, superfluid, helium dynamics
- Inorganic Chemistry and Materials
- Radiomics and Machine Learning in Medical Imaging
- Nuclear Materials and Properties
- Middle East and Rwanda Conflicts
- Catalysis and Oxidation Reactions
National Physical Laboratory
2020-2023
University of Surrey
2009-2020
University of Brighton
2012-2019
Université Libre de Bruxelles
2015
Yale University
2009-2012
École Normale Supérieure Paris-Saclay
2009
Technical University of Darmstadt
2009
University of Colorado Boulder
2007
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},...
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 $^{208}\mathrm{Pb}$.
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 half-life of the ${I}^{\ensuremath{\pi}}={6}^{+}$ yrast state at ${E}_{x}=2294$ keV in ${}^{138}$Ce has been measured as ${T}_{1/2}=880(19)$ ps using fast-timing $\ensuremath{\gamma}$-ray coincidence method with a mixed LaBr${}_{3}$(Ce)-HPGe array. excited states have populated by ${}^{130}$Te(${}^{12}\mathrm{C},4n)$ fusion-evaporation reaction an incident beam energy 56 MeV. extracted $B(E2;{6}_{1}^{+}\ensuremath{\rightarrow}{4}_{1}^{+})=0.101(24)$ W.u. value is compared predictions...
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...
Abstract A directional neutron spectrometer named NCT-WES (Neutron Capture Therapy Wide Energy Spectrometer) was developed for quality assurance of the therapeutic beam in Neutron (NCT). operates as a “parallelized” Bonner spheres spectrometer, embedding six semiconductor-based thermal detectors collimated cylindrical moderator. With objective validating simulation model used to derive its response matrix, irradiations reference monoenergetic fields were performed at National Physical...
The single closed-neutron-shell, one proton–hole nucleus 207Tl was populated in deep-inelastic collisions of a 208Pb beam with target. yrast and near-yrast level scheme has been established up to high excitation energy, comprising an octupole phonon state large number core excited states. Based on shell-model calculations, all observed excitations were arise from the breaking N=126 neutron core. While calculations correctly predict ordering these states, their energies are compressed at...
We report on spectroscopic information and lifetime measurements of even-even neutron-rich Te isotopes. Excited states were populated in fast-neutron induced fission $^{238}\mathrm{U}$ at the ALTO facility IJCLab with LICORNE neutron source detected using hybrid $\ensuremath{\nu}$-ball spectrometer. provide first results lifetimes ${6}_{1}^{+}$ state $^{136}\mathrm{Te}$ (${6}_{1}^{+}$), (${4}_{1}^{+}$), (${2}_{1}^{+}$) $^{138}\mathrm{Te}$ discuss context large-scale shell-model calculations....
Neutron-rich nuclei in the lead region, beyond N=126, have been studied at FRS-RISING setup GSI, exploiting fragmentation of a primary uranium beam. Two isomeric states identified 210Hg: 8+ isomer expected from seniority scheme νg9/2 shell and second one low spin excitation energy. The decay strength confirms need effective three-body forces case neutron-rich isotopes. other unexpected low-lying has tentatively assigned as 3− state, although this is contrast with theoretical expectations.
The near-yrast structure of the near-magic, odd-odd nucleus, ${}_{39}^{88}$Y${}_{49}$, has been studied into high-spin regime. Investigations were performed at Wright Nuclear Structure Laboratory, Yale University, using ${}^{74}$Ge(${}^{18}$O,$p3n$) and ${}^{76}$Ge(${}^{18}$O,$p5n$) fusion-evaporation reactions beam energies 60 90 MeV, respectively. Gamma-ray energy coincidence analyses both double (${\ensuremath{\gamma}}^{2}$) triple (${\ensuremath{\gamma}}^{3}$) fold coincidences, together...
The neutron-rich nucleus $^{200}\mathrm{Pt}$ is investigated via in-beam $\ensuremath{\gamma}$-ray spectroscopy to study the shape evolution in platinum isotopes towards $N=126$ shell closure. two-neutron transfer reaction $^{198}\mathrm{Pt}$($^{82}\mathrm{Se}, ^{80}\mathrm{Se}$)$^{200}\mathrm{Pt}$ used populate excited states of $^{200}\mathrm{Pt}$. Advanced Gamma Ray Tracking Array (AGATA) demonstrator coupled with PRISMA spectrometer detects $\ensuremath{\gamma}$ rays coincident...
The 208Pb region is characterised by the existence of collective octupole states. Here we populated such states in + deep-inelastic reactions. γ-ray angular distribution measurements were used to infer character several E3 transitions. 2318 keV 17− → 14+ 208Pb, 2485 19/2− 13/2+ 207Pb, 2419 15/2− 9/2+ 209Pb and 2465 17/2+ 11/2− 207Tl transitions was demonstrated for first time. In addition, shell model calculations performed using two different sets two-body matrix elements. Their predictions...
The population of isomeric states in the prompt decay fission fragments---so-called yield ratios (IYRs)---is known to be sensitive angular momentum $J$ that fragment emerged with, and may therefore contain valuable information on mechanism behind process. In this work, we investigate how changes fissioning system impact measured IYRs fragments learn more about what parameters affect generation. To enable this, a new technique for measuring is first demonstrated. It based time arrival...
On
The neutron-rich isotopes $^{211,213}\mathrm{Tl}$, beyond the $N=126$ shell closure, have been studied for first time in isomer $\ensuremath{\gamma}$-ray decay, exploiting fragmentation of a primary uranium beam at Fragment Separator-Rare Isotopes Investigation GSI setup. observed isomeric states $^{211,213}\mathrm{Tl}$ show deviation from seniority-like scheme $^{209}\mathrm{Tl}$. possible interpretation data is discussed on basis energy-level systematics and shell-model calculations.
The structure of the neutron-rich bismuth isotope 217Bi has been studied for first time. fragmentation a primary 238U beam at FRS-RISING setup GSI was exploited to perform γ-decay spectroscopy, since μs isomeric states were expected in this nucleus. Gamma rays following decay t1/2=3 isomer observed, allowing one establish low-lying 217Bi. level energies and reduced electric quadrupole transition probability B(E2) from state are compared large-scale shell-model calculations.Received 5 June...
Prompt and delayed $\ensuremath{\gamma}$-ray spectroscopy of the neutron-rich $^{94}\mathrm{Kr}$ was performed, as part fission campaign at ALTO facility IPN Orsay, using fast-neutron-induced reaction $^{238}\mathrm{U}(n,f)$ in combination with $\ensuremath{\nu}$-Ball array, a novel hybrid $\ensuremath{\gamma}$ spectrometer for energy lifetime measurements. Several new yrast nonyrast transitions were observed first time, extending previously known level scheme. Additionally, we report on...
For certain combinations of protons and neutrons, there is a theoretical expectation that the shape nuclei can assume octupole deformation, which would give rise to reflection asymmetry or "pear shape" in intrinsic frame, either dynamically (octupole vibrations) statically (permanent deformation).In this paper, I will briefly review historic evidence for nuclei, describe how recent experiments carried out at REX-ISOLDE are constraining nuclear theory they contribute tests extensions Standard...
The $g$ factor of the ${2}_{1}^{+}$ state $^{172}\mathrm{Hf}$ was measured using perturbed angular correlation technique in a static external magnetic field. result, $g({2}_{1}^{+})=0.25(5)$, is discussed relation to systematics previously reported factors Hf isotopes and compared with predictions several models. An interesting outcome analysis presented this paper agreement between calculated within interacting boson approximation (IBA) results large-scale shell model calculation. This...