A5015549894- Nuclear physics research studies
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Astronomical and nuclear sciences
- Quantum Chromodynamics and Particle Interactions
- Advanced Chemical Physics Studies
- Radiation Detection and Scintillator Technologies
- Particle Detector Development and Performance
- Rare-earth and actinide compounds
- Advanced NMR Techniques and Applications
- Nuclear reactor physics and engineering
- Astro and Planetary Science
- Particle physics theoretical and experimental studies
- Quantum, superfluid, helium dynamics
- Particle accelerators and beam dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Quantum chaos and dynamical systems
- Atomic and Subatomic Physics Research
- Scientific Research and Discoveries
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Inorganic Fluorides and Related Compounds
- Medical Imaging Techniques and Applications
- Neutrino Physics Research
- Cold Atom Physics and Bose-Einstein Condensates
Lawrence Berkeley National Laboratory
2014-2023
Indian Institute of Technology Kharagpur
2018
National Superconducting Cyclotron Laboratory
2015
Michigan State University
2015
University of Bonn
2004-2006
University of Toronto
1995-2000
Stony Brook University
1996
McMaster University
1996
University of Liverpool
1996
University of York
1996
The neutron-rich nucleus $^{144}$Ba ($t_{1/2}$=11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers $A$ less than 200. Until now, indirect evidence for such strong has been inferred from observations as enhanced $E1$ transitions and interleaving positive- negative-parity levels in ground-state band. In this experiment, strength was measured directly by sub-barrier, multi-step Coulomb excitation a post-accelerated 650-MeV beam on...
A superdeformed rotational band has been identified in 36Ar, linked to known low-spin states, and observed its high-spin termination at Iπ=16+. Cranked Nilsson-Strutinsky spherical shell model calculations assign the a configuration which four pf-shell orbitals are occupied, leading deformation β2≈0.45. Two major shells active for both protons neutrons, yet valence space remains small enough be confronted with model. This thus provides an ideal case study microscopic structure of collective...
Intermediate-energy Coulomb excitation measurements are performed on the N ≥ 40 neutron-rich nuclei (66,68)Fe and (64)Cr. The reduced transition matrix elements providing a direct measure of quadrupole collectivity B(E2;2(1)(+) → 0(1)(+)) determined for first time in (68)Fe(42) (64)Cr(40) confirm previous recoil distance method lifetime measurement (66)Fe(40). results compared to state-of-the-art large-scale shell-model calculations within full fpgd neutron orbital model space using...
One of the most exotic light neutron-rich nuclei currently accessible for experimental study is 40Mg, which lies at intersection nucleon magic number N=28 and neutron drip line. Low-lying excited states 40Mg have been studied first time following a one-proton removal reaction from 41Al, performed Radioactive Isotope Beam Factory RIKEN Nishina Center with DALI2 γ-ray array ZeroDegree spectrometer. Two transitions were observed, suggesting an excitation spectrum that shows unexpected...
The properties of even-even nuclei with $30\ensuremath{\leqslant}\mathrm{Z}\ensuremath{\leqslant}82$, $\mathrm{A}\ensuremath{\geqslant}60$ have been examined to find examples displaying the characteristics $\mathrm{E}(5)$ critical-point behavior for shape transition from a spherical vibrator triaxially soft rotor. On basis known experimental state energies and $\mathrm{E}2$ strengths, best candidates that were identified are $^{102}\mathrm{Pd}$, $^{106,108}\mathrm{Cd}$, $^{124}\mathrm{Te}$,...
Forty-six decay chains, assigned to the of 288115, were produced using 243Am(48Ca,3n)288115 reaction at Lawrence Berkeley National Laboratory 88-in. cyclotron. The resulting series α decays studied α-photon and α-x-ray spectroscopies. Multiple coincidences observed in element 115 chain members, particularly third- fourth-generation (presumed be 280Rg 276Mt, respectively). Upon combining these data with those from 22 288115 chains a similar experiment, updated level schemes 276Mt 272Bh...
The binding energies of even-even and odd-odd $N=Z$ nuclei are compared. After correcting for the symmetry energy we find that lowest $T=1$ state in is as bound ground neighboring nucleus, thus providing evidence isovector $\mathrm{np}$ pairing. However, $T=0$ states several MeV less than states. We associate this difference with pair gap conclude from analysis differences blocking arguments there no an isoscalar (deuteronlike) condensate nuclei.
A multinucleon transfer reaction between a thin self-supporting Pt 78198 target and an 850MeV Xe 54136 beam has been used to populate study the structure of N=80 isotone Ba 56136. Making use time-correlated γ-ray spectroscopy, evidence for Iπ=(10+) isomeric state found with measured half-life 91±2ns. Prompt-delayed correlations have also enabled tentative measurement near-yrast states which lie above isomer. Shell-model calculations suggest that isomer can be assigned predominantly as...
The lifetime of the 2_+(1) state in 16C has been measured with recoil distance method using 9Be(9Be,2p) fusion-evaporation reaction at a beam energy 40 MeV. mean was to be 11.7(20) ps corresponding B(E2;2_+(1)-->0+) value 4.15(73)e_2 fm_4 [1.73(30) W.u.], consistent other even-even closed shell nuclei. Our result does not support an interpretation for "decoupled" valence neutrons.
A new frontier of discrete-line $\ensuremath{\gamma}$-ray spectroscopy at ultrahigh spin has been opened in the rare-earth nuclei $^{157,158}\mathrm{Er}$. Four rotational structures, displaying high moments inertia, have identified, which extend up to $\ensuremath{\sim}65\ensuremath{\hbar}$ and bypass band-terminating states these occur $\ensuremath{\sim}45\ensuremath{\hbar}$. Cranked Nilsson-Strutinsky calculations suggest that structures arise from well-deformed triaxial configurations lie...
Two isomers decaying by electromagnetic transitions with half-lives of 4.7(1.1) and $247(73)\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$ have been discovered in the heavy $^{254}\mathrm{Rf}$ nucleus. The observation shorter-lived isomer was made possible a novel application digital data acquisition system. were interpreted as ${K}^{\ensuremath{\pi}}={8}^{\ensuremath{-}}$, ${\ensuremath{\nu}}^{2}(7/{2}^{+}[624],9/{2}^{\ensuremath{-}}[734])$ two-quasineutron ${K}^{\ensuremath{\pi}}=1{6}^{+}$,...
Lifetimes of states in a rotational-like $M1$ band ${}^{110}\mathrm{Cd}$ have been determined through Doppler-shift attenuation method measurement performed with the Gammasphere array. The deduced $B(M1)$ values, which agree well predictions tilted axis cranking model, clearly confirm that it has character shears band. Using semiclassical scheme coupling two long $j$ vectors we deduce information on strength and form effective interaction between constituent nucleons. These results are first...
Lifetimes of high-spin states in two $\ensuremath{\Delta}I=1$ bands and one $\ensuremath{\Delta}I=2$ band ${}^{109}\mathrm{Cd}$ have been measured using the Doppler shift attenuation method an experiment performed ${}^{96}\mathrm{Zr}{(}^{18}\mathrm{O},5n)$ reaction with GAMMASPHERE array. Experimental total angular momenta reduced transition strengths for both were compared tilted axis cranking (shears mechanism) predictions principal predictions, based on configurations involving proton...
Lifetimes have been measured in a superdeformed rotational band recently identified the $N=Z$ nucleus ${}^{36}\mathrm{Ar}.$ A large low-spin quadrupole deformation $({\ensuremath{\beta}}_{2}=0.46\ifmmode\pm\else\textpm\fi{}0.03)$ is confirmed and decrease collectivity observed as high-spin termination at ${I}^{\ensuremath{\pi}}{=16}^{+}$ approached. Detailed comparisons of experimental $B(E2)$ values with results cranked Nilsson-Strutinsky large-scale...
Lifetimes of states in the lowest lying positive parity band 106Cd have been measured using Doppler shift attenuation method. The deduced B(E2) transition rates show a marked decrease with increasing spin. Cranking and semiclassical model calculations suggest that structure has character shears-type resulting from coupling g(9/2) proton holes to aligned pairs h(11/2) g(7/2) neutron particles. This is first clear evidence for phenomenon "antimagnetic" rotation nuclei.
We have searched even-even nuclei with $Z>~20,$ $N>~20$ to find examples displaying the predicted characteristics of X(5) critical point behavior. On basis yrast state energies and intraband transition strengths, best candidates are ${}^{126}\mathrm{Ba},$ ${}^{130}\mathrm{Ce},$ previously suggested $N=90$ isotones Nd, Sm, Gd, Dy.
We have deduced the cross section for $^{237}\mathrm{U}$($n,f$) over an equivalent neutron energy range from 0 to 20 MeV using surrogate ratio method. A 55 $^{4}\mathrm{He}$ beam 88 inch cyclotron at Lawrence Berkeley National Laboratory was used induce fission in following reactions: $^{238}\mathrm{U}$$(\ensuremath{\alpha},{\ensuremath{\alpha}}^{\ensuremath{'}}f)$ and $^{236}\mathrm{U}$$(\ensuremath{\alpha},{\ensuremath{\alpha}}^{\ensuremath{'}}f)$. The $^{238}\mathrm{U}$ reaction a...
Excited states in 256Rf were populated via the 208Pb(50Ti,2n) fusion–evaporation reaction. Delayed γ-ray and electron decay spectroscopy was performed three isomeric have been identified. A fourth low-energy nonyrast state identified from of one higher lying isomers. The are interpreted as multi-quasiparticle excitations.Received 7 December 2007DOI:https://doi.org/10.1103/PhysRevC.79.031303©2009 American Physical Society
Excited states in the neutron-rich $N=38$, 36 nuclei $^{60}\mathrm{Ti}$ and $^{58}\mathrm{Ti}$ were populated nucleon-removal reactions from $^{61}\mathrm{V}$ projectiles at $90\text{ }\text{ }\mathrm{MeV}/\text{nucleon}$. The $\ensuremath{\gamma}$-ray transitions such these Ti isotopes detected with advanced tracking array GRETINA corrected event by for large Doppler shifts ($v/c\ensuremath{\sim}0.4$) using interaction points deduced online signal decomposition. new data indicate that a...