A5071633876- Nuclear physics research studies
- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Quantum Chromodynamics and Particle Interactions
- Astronomical and nuclear sciences
- Atomic and Molecular Physics
- High-Energy Particle Collisions Research
- X-ray Spectroscopy and Fluorescence Analysis
- Particle accelerators and beam dynamics
- Advanced Chemical Physics Studies
- Theoretical and Computational Physics
- Quantum, superfluid, helium dynamics
- Statistical Mechanics and Entropy
- Superconducting Materials and Applications
- Nuclear Materials and Properties
- Ion-surface interactions and analysis
- Chemical Thermodynamics and Molecular Structure
- Particle physics theoretical and experimental studies
- Atomic and Subatomic Physics Research
- Particle Accelerators and Free-Electron Lasers
- Advanced Thermodynamics and Statistical Mechanics
- Cold Atom Physics and Bose-Einstein Condensates
- Scientific Research and Discoveries
- Astro and Planetary Science
- Radioactive Decay and Measurement Techniques
Lawrence Berkeley National Laboratory
2013-2025
Lawrence Livermore National Laboratory
2007-2013
University of California, Berkeley
1995-2012
Rutgers, The State University of New Jersey
2009
University of Surrey
2009
Hope College
2003
National Superconducting Cyclotron Laboratory
1990-1999
Michigan State University
1990-1999
Multifragment disintegrations following $^{129}\mathrm{Xe}$${+}^{197}$Au collisions at E/A=50 MeV have been studied with a multidetector system covering 88% of 4\ensuremath{\pi} in solid angle. The average number intermediate-mass fragments (Z=3--20) increases strongly as function charged-particle multiplicity and reaches values larger than six for the most violent collisions. results are compared to calculations both dynamical statistical models.
The ^{244}Pu(^{50}Ti,xn)^{294-x}Lv reaction was investigated at Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. experiment aimed the production of a superheavy element with Z≥114 by irradiating an actinide target beam heavier than ^{48}Ca. Produced Lv ions were separated from unwanted and nuclear products using Gas-filled Separator implanted into newly commissioned focal-plane detector system. Two decay chains observed assigned to ^{290}Lv. cross section measured be...
The thermal component of the 8 GeV/c pi+ Au data ISiS Collaboration is shown to follow scaling predicted by Fisher's model when Coulomb energy taken into account. Critical exponents tau and sigma, critical point (p(c),rho(c),T(c)), surface coefficient c(0), enthalpy evaporation DeltaH, compressibility factor C(F)(c) are determined. For first time, experimental phase diagrams, (p,T) (T,rho), describing liquid vapor coexistence finite neutral nuclear matter have been constructed.
Intermediate mass fragment (IMF: $3\ensuremath{\le}Z\ensuremath{\le}20$ emission from necklike structures joining projectilelike and targetlike residues has been observed for peripheral $^{129}\mathrm{Xe}$ + $^{\mathrm{nat}}\mathrm{Cu}$ collisions at $\frac{E}{A}=50$ MeV. These fragments are emitted primarily velocities between those of the residues. Relative to charge distribution evaporated residues, "neck" shows an enhanced with $4\ensuremath{\le}{Z}_{\mathrm{IMF}}\ensuremath{\le}12$....
An analysis of six different sets experimental data indicates that infinite, neutron-proton symmetric, neutral nuclear matter has a critical temperature ${T}_{c}=17.9\ifmmode\pm\else\textpm\fi{}0.4$ MeV, density ${\ensuremath{\rho}}_{c}=0.06\ifmmode\pm\else\textpm\fi{}0.01$ nucleons/fm${}^{3}$, and pressure ${p}_{c}=0.31\ifmmode\pm\else\textpm\fi{}0.07$ MeV/fm${}^{3}$. These values have been obtained by analyzing from reactions studied in three experiments: two ``compound nuclear''...
A new experimental technique is presented using proton-$\ensuremath{\gamma}\mathrm{\text{\ensuremath{-}}}\ensuremath{\gamma}$ correlations from $^{94}\mathrm{Mo}(d,p)^{95}\mathrm{Mo}$ reactions which allows for the model-independent extraction of photon strength function at various excitation energies primary $\ensuremath{\gamma}$-ray decay quasicontinuum to individual low-lying levels. Detected particle provide entrance into residual nucleus while transitions levels specify discrete states...
Intermediate mass fragment (IMF: 3\ensuremath{\le}Z\ensuremath{\le}20) emission for the $^{36}\mathrm{Ar}$${+}^{197}$Au reaction at E/A=35 MeV has been studied with a low-threshold 4\ensuremath{\pi} charged-particle detector array covering angular range of 16\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}${\mathrm{\ensuremath{\theta}}}_{\mathrm{lab}}$\ensuremath{\le}160\ifmmode^\circ\else\textdegree\fi{}. While most IMF's are emitted in central collisions characterized by large...
The relationship between observed intermediate mass fragment and total charged particle multiplicities has been measured for Kr84 + Au197 collisions at energies E/A=35 400 MeV. Fragment are greatest central or near-central collisions. For these collisions, production increases up to E/A≊100 MeV, then decreases higher energies.Received 14 January 1994DOI:https://doi.org/10.1103/PhysRevC.49.R2271©1994 American Physical Society
Velocity distributions and fragment-fragment correlation functions have been measured as a function of charged particle multiplicity for $^{129}\mathrm{Xe}$${+}^{\mathrm{nat}}$Cu collisions at E/A=50 MeV. With increasing multiplicity, the velocity evolve from pattern exhibiting targetlike projectilelike sources to an anisotropic distribution centered near projectile-target center-of-mass velocity. Emission times extracted are consistent with decay source in low collisions, but time scale...
Two-fragment (Be-Be, B-B, and C-C) correlation functions were measured at small relative momenta for noncompound fragment emission in $^{36}\mathrm{Ar}$${+}^{197}$Au collisions E/A=35 MeV. Interpretation of the experimental terms final-state Coulomb-interaction models indicate average fragment-emission times about 100--200 fm/c.
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.
An experiment was performed at Lawrence Berkeley National Laboratory's 88-in. Cyclotron to determine the mass number of a superheavy element. The measurement resulted in observation two α-decay chains, produced via Am243(Ca48,xn)291−xMc reaction, that were separated by mass-to-charge ratio (A/q) and identified combined BGS+FIONA apparatus. One event occurred A/q=284 assigned Nh284 (Z=113), daughter Mc288 (Z=115), while second A/q=288 Mc288. This represents first direct measurements numbers...
The potential of particle therapy due to focused dose deposition in the Bragg peak has not yet been fully realized inaccuracies range verification. purpose this work was correlate location with target structure, by overlaying onto a standard ultrasound image. Pulsed delivery 50 MeV protons accomplished fast chopper installed between ion source and cyclotron inflector. limited train bunches so that 2 Gy were delivered . pulse generated thermoacoustic pulses detected cardiac array, which also...
The g factors of ${2}_{1}^{+},$ ${4}_{1}^{+},$ and ${2}_{2}^{+}$ states in the stable ${}^{130,132,134,136}\mathrm{Xe}$ isotopes have been measured via projectile Coulomb excitation inverse kinematics combination with transient field technique. results show a steady decrease ${g(2}_{1}^{+})$ as number neutron holes increases lighter nuclei below closed $N=82$ shell. ${4}_{1}^{+}$ ${}^{132,134}\mathrm{Xe}$ are consistently larger than ${2}_{1}^{+}$ states, characteristic proton excitation....
Charge and transverse energy distributions for intermediate mass fragments have been extracted central 84Kr+197Au collisions at E/A=35−400 MeV. The slopes of the measured fragment charge decrease monotonically with incident energy, consistent expectations highly charged systems, but not recent critical exponent analyses. Statistical model calculations, which reproduce experimental trends, suggest that post-breakup secondary decays alter significantly observed distributions. Radial expansion...
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...
Element distributions and fragment multiplicity have been measured for E/A=50 MeV $^{129}\mathrm{Xe}$${+}^{12}$C, $^{27}\mathrm{Al}$, $^{51}\mathrm{V}$, $^{\mathrm{nat}}\mathrm{Cu}$, $^{89}\mathrm{Y}$, $^{197}\mathrm{Au}$ reactions using a low threshold 4\ensuremath{\pi} detector. Both show strong correlation with the detected charged particle large degree of target independence. The are compared hybrid model calculations which incorporate important dynamical aspects in both preequilibrium...
The surrogate nuclear reaction method can be used to determine neutron-induced cross sections from measured decay properties of a compound nucleus created using different and calculated formation sections. reliability $(n,\ensuremath{\gamma})$ determined the Weisskopf-Ewing ratio approximations are explored for $^{155,157}\mathrm{Gd}$$(n,\ensuremath{\gamma})$ reactions. Enriched gadolinium targets were bombarded with 22-MeV protons $\ensuremath{\gamma}$ rays detected in coincidence scattered...