A5103026866- Nuclear physics research studies
- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Astronomical and nuclear sciences
- Atomic and Molecular Physics
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Cold Fusion and Nuclear Reactions
- Nuclear Materials and Properties
- Particle physics theoretical and experimental studies
- X-ray Spectroscopy and Fluorescence Analysis
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Crystallography and molecular interactions
- Advanced Chemical Physics Studies
- Radioactive Decay and Measurement Techniques
- Atomic and Subatomic Physics Research
- Laser-induced spectroscopy and plasma
- Cold Atom Physics and Bose-Einstein Condensates
- Radiation Therapy and Dosimetry
- Ion-surface interactions and analysis
- Radioactive element chemistry and processing
- Advanced NMR Techniques and Applications
Oregon State University
1995-2020
Hospital Base
2018
National Superconducting Cyclotron Laboratory
2004-2018
Michigan State University
2004-2018
Indiana University Bloomington
1999-2010
Washington University in St. Louis
2007
Australian National University
2005
University of Chile
2000-2002
Indiana University
2002
Uppsala University
1993-2001
Using symmetric $^{112}\mathrm{S}\mathrm{n}+^{112}\mathrm{S}\mathrm{n}$, $^{124}\mathrm{S}\mathrm{n}+^{124}\mathrm{S}\mathrm{n}$ collisions as references, we probe isospin diffusion in peripheral asymmetric $^{112}\mathrm{S}\mathrm{n}+^{124}\mathrm{S}\mathrm{n}$, $^{124}\mathrm{S}\mathrm{n}+^{112}\mathrm{S}\mathrm{n}$ systems at an incident energy of $E/A=50\text{ }\text{ }\mathrm{M}\mathrm{e}\mathrm{V}$. Isoscaling analyses imply that the quasiprojectile and quasitarget these do not achieve...
Isotopic distributions for light particles and intermediate mass fragments have been measured 112Sn+112Sn, 112Sn+124Sn, 124Sn+112Sn, 124Sn+124Sn collisions at E/A = 50 MeV. Isotope, isotone, isobar yield ratios are utilized to estimate the isotopic composition of gas phase freeze-out. Analyses within equilibrium limit imply that is enriched in neutrons relative liquid represented by bound nuclei. These observations suggest neutron diffusion commensurate with or more rapid than fragment production.
The yields of over 200 projectile-like fragments (PLFs) and target-like (TLFs) from the interaction (${E}_{\mathrm{c}.\mathrm{m}.}=450$ MeV) $^{136}\text{Xe}$ with a thick target $^{208}\text{Pb}$ were measured using Gammasphere off-line $\ensuremath{\gamma}$-ray spectroscopy, giving comprehensive picture production cross sections in this reaction. compared to predictions grazing model Zagrebaev Greiner quantitative metric, theory evaluation factor $\mathit{t}ef$. are adequate for describing...
Background: Multi-nucleon transfer reactions have recently attracted attention as a possible path to the synthesis of new neutron-rich heavy nuclei. Purpose: We study involving massive nuclei with intention understanding if semi-classical model GRAZING coupled an evaporation and fission competition can satisfactory reproduce experimental data on in which plays role. Methods: taken computer code added it (GRAZING-F) using our current $\Gamma_n/\Gamma_f$, barriers level densities. Results: The...
Background: The cross section for forming a heavy evaporation residue in fusion reactions depends on the capture section, probability, ${P}_{\mathrm{CN}}$, i.e., probability that projectile-target system will evolve inside fission saddle point to form completely fused rather than reseparating (quasifission), and survival of against fission. ${P}_{\mathrm{CN}}$ is least known these quantities.Purpose: We want determine 101.2 MeV ${}^{18}$O, 147.3 ${}^{26}$Mg, 170.9 ${}^{30}$Si, 195.3...
Symmetric collisions of massive nuclei, such as 238U + 248Cm, have been proposed ways to make new n-rich heavy nuclei via multi-nucleon transfer (MNT) reactions. We measured the yields several projectile-like and target-like fragments from reaction 1360 MeV 204Hg 198Pt. find that current models for this symmetric collision (GRAZING, DNS, ImQMD) significantly underestimate these products, even small transfers.
We have studied the fission-neutron emission competition in highly excited $^{274}$Hs (Z=108) (where fission barrier is due to shell effects) formed by a hot fusion reaction. Matching cross bombardments ($^{26}$Mg + $^{248}$Cm and $^{25}$Mg $^{248}$Cm) were used identify properties of first chance $^{274}$Hs. A Harding-Farley analysis neutrons emitted $^{25,26}$Mg was performed pre- post-scission components neutron multiplicities each system. ($\Gamma$$_{n}$/$\Gamma$$_{t}$) for (E$^{\ast}$ =...
The yields of 42 projectile-like fragments (PLFs) and fission 36 target-like (TLFs) were measured using off-line $\ensuremath{\gamma}$-ray spectroscopy in a thin target experiment involving the $^{136}\mathrm{Xe}+^{198}\mathrm{Pt}$ reaction. center beam energy was 760.5 MeV $({\mathrm{E}}_{\mathrm{c}.\mathrm{m}.}=450$ MeV). reported are compared with those from previous measurements for this reaction predictions GRAZING, di-nuclear systems (DNS), improved quantum molecular dynamics (ImQMD)...
Isotopic yields for light particles and intermediate mass fragments have been measured central $^{112}\mathrm{Sn}+^{112}\mathrm{Sn}$, $^{112}\mathrm{Sn}+^{124}\mathrm{Sn}$, $^{124}\mathrm{Sn}+^{112}\mathrm{Sn}$, $^{124}\mathrm{Sn}+^{124}\mathrm{Sn}$ collisions at $E∕A=50\phantom{\rule{0.3em}{0ex}}\text{MeV}$ compared with predictions of stochastic mean field calculations. These calculations predict a sensitivity the isotopic distributions to density dependence asymmetry term nuclear equation...
Fragments produced in binary splits of an excited projectile-like fragment (PLF${}^{*}$) formed the reactions ${}^{124}$Xe $+$ ${}^{112,124}$Sn at incident energy 50 MeV/$A$ are examined. The dependence isotopic composition light fragments ($4\ensuremath{\leqslant}{Z}_{L}\ensuremath{\leqslant}8$) on rotation angle allows one to explore changes $N/Z$ time scale rotational period PLF${}^{*}$. Changes persist for times as long 2--3 zs (600--900 fm/$c$). two-component nature...
Aligned fragment emission associated with peripheral and midperipheral dissipative collisions of $^{124}\mathrm{Xe}$$+$$^{124}\mathrm{Sn}$ at $E/A=50$ MeV is examined. Binary decay the excited projectile-like (PLF${}^{*}$) correlated significant velocity damping from projectile velocity. Both a forward component, attributed to standard statistical emission, backward component are observed. The arises both dynamical processes. This manifests strong alignment direction PLF${}^{*}$ found depend...
Background: ${}^{11}$Li is one of the most studied halo nuclei. The fusion with ${}^{208}$Pb subject a number theoretical studies widely differing predictions, ranging over four orders magnitude, for excitation function.Purpose: purpose was to measure function $+$ reaction.Methods: A stacked foil and degrader assembly targets irradiated beam producing center-of-target energies from above-barrier near-barrier (40--29 MeV). intensity (chopped) 1250 particles/s on-target time 34 h....
The defining characteristics of fragment emission resulting from the noncentral collision ${}^{114}\mathrm{Cd}$ ions with ${}^{92}\mathrm{Mo}$ target nuclei at $E/A=50 \mathrm{MeV}$ are presented. Charge correlations and average relative velocities for midvelocity exhibit significant differences when compared to standard statistical decay. These associated similar velocity dissipation indicative influence entrance channel dynamics on production process.
The total kinetic energy release in the neutron induced fission of $^{235}$U was measured (using white spectrum neutrons from LANSCE) for energies E$_{n}$ = 3.2 to 50 MeV. In this range average post-neutron drops 167.4 $\pm$ 0.7 162.1 0.8 MeV, exhibiting a local dip near second chance threshold. values and slope TKE vs. agree with previous measurements but do disagree (in magnitude) systematics. variances distributions are larger than expected apart structure threshold, invariant 11 We also...
We measured the fusion-fission excitation functions for ${}^{32}$S+${}^{181}$Ta reaction and ${}^{38}$S+${}^{181}$Ta reaction. (The radioactive ${}^{38}$S beam was produced by projectile fragmentation.) The thresholds were to be 137.5$\ifmmode\pm\else\textpm\fi{}$1.0 130.7$\ifmmode\pm\else\textpm\fi{}$2.0 MeV ${}^{32}$S ${}^{38}$S-induced reactions, respectively. This result agrees with systematics of fusion may significant in synthesis new heavy nuclei.
We measured the capture-fission excitation functions for ${}^{32}\mathrm{S}{+}^{181}\mathrm{Ta}$ reaction and ${}^{38}\mathrm{S}{+}^{181}\mathrm{Ta}$ reaction. (The radioactive ${}^{38}\mathrm{S}$ beam was produced by projectile fragmentation.) In ${}^{32}\mathrm{S}$-induced reaction, an incomplete fusion component observed at high energies, with average linear momentum transfer corresponding to escape of $\ensuremath{\alpha}$ particle. The deduced interaction barrier heights were...
The characteristics of intermediate mass fragments (IMFs: 3<=Z<=20) produced in mid-peripheral and central collisions are compared. We compare IMFs detected at mid-velocity with those evaporated from the excited projectile-like fragment (PLF*). On average, larger atomic number, exhibit broader transverse velocity distributions, more neutron-rich as compared to PLF*. In contrast, comparison associated reveals that their remarkably similar despite difference impact parameter. consistent...
We have measured the capture-fission excitation functions for reaction of stable $^{39}\mathrm{K}$ and radioactive $^{46}\mathrm{K}$ with $^{181}\mathrm{Ta}$ using ReA3 facility at National Superconducting Cyclotron Laboratory. In addition function $^{39}\mathrm{K}+^{181}\mathrm{Ta}$ was Australian University . The capture cross sections $^{46}\mathrm{K}+^{181}\mathrm{Ta}$ are larger than those induced reactions in near barrier region although reduced two do not indicate any fundamental...
The capture-fission cross section for the $^{36}\mathrm{S}+^{208}\mathrm{Pb}$ reaction was measured seven center-of-mass energies ranging from 147.5 to 210.2 MeV. A comparison of deduced interaction barriers ``distribution barriers'' measurements and simple $1/{E}_{\mathrm{c}.\mathrm{m}.}$ plots 13 well-characterized systems shows validity latter approach deducing barriers, especially involving radioactive beams where former are not currently feasible. Application plot technique gives an...
Particle correlation functions from central $^{129}\mathrm{Xe}+^{197}\mathrm{Au}$ collisions at $50A\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$ have been measured with a large area $\text{silicon}\text{\penalty1000-\hskip0pt}\text{strip}∕\mathrm{Cs}\mathrm{I}$ detector array. A new technique of spin determination particle is proposed. Two examples are studied. The the first excited level $^{8}\mathrm{B}$ $0.774\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$ determined as $J=1$.