58 research outputs found
Peculiarities of isotopic temperatures obtained from p+A collisions at 1 GeV
Nuclear temperatures obtained from inclusive measurements of double isotopic
yield ratios of fragments produced in 1 GeV p + A collisions amount to about 4
MeV nearly independent from the target mass.Comment: 4 pages, 4 figures, to be submitted to Eur. Phys. J.
Extrapolation of neutron-rich isotope cross-sections from projectile fragmentation
Using the measured fragmentation cross sections produced from the 48Ca and
64Ni beams at 140 MeV per nucleon on 9Be and 181Ta targets, we find that the
cross sections of unmeasured neutron rich nuclei can be extrapolated using a
systematic trend involving the average binding energy. The extrapolated
cross-sections will be very useful in planning experiments with neutron rich
isotopes produced from projectile fragmentation. The proposed method is general
and could be applied to other fragmentation systems including those used in
other radioactive ion beam facilities.Comment: accepted for publication in Europhysics Letter
Isospin Diffusion and Equilibration for Sn+Sn collisions at E/A=35 MeV
Equilibration and equilibration rates have been measured by colliding Sn
nuclei with different isospin asymmetries at beam energies of E/A=35 MeV. Using
the yields of mirror nuclei of 7Li and 7Be, we have studied the diffusion of
isospin asymmetry by combining data from asymmetric 112Sn+124Sn and 124Sn+112Sn
collisions with that from symmetric 112Sn+112Sn and 124Sn+124Sn collisions. We
use these measurements to probe isospin equilibration in central collisions
where nucleon-nucleon collisions are strongly blocked by the Pauli exclusion
principal. The results are consistent with transport theoretical calculations
that predict a degree of transparency in these collisions, but inconsistent
with the emission of intermediate mass fragments by a single chemically
equilibrated source. Comparisons with ImQMD calculations are consistent with
results obtained at higher incident energies that provide constraints on the
density dependence of the symmetry energy.Comment: 13 pages, 3 figures, submitted to PRC Rapid Communication
Light Nuclides Produced in the Proton-Induced Spallation of 238U at 1 GeV
The production of light and intermediate-mass nuclides formed in the reaction
1H+238U at 1 GeV was measured at the Fragment Separator (FRS) at GSI,
Darmstadt. The experiment was performed in inverse kinematics, shooting a 1 A
GeV 238U beam on a thin liquid-hydrogen target. 254 isotopes of all elements in
the range from Z=7 to Z=37 were unambiguously identified, and the velocity
distributions of the produced nuclides were determined with high precision. The
results show that the nuclides are produced in a very asymmetric binary decay
of heavy nuclei originating from the spallation of uranium. All the features of
the produced nuclides merge with the characteristics of the fission products as
their mass increases.Comment: 40 pages, 16 figures, 3 table
Isotope ratios and isoscaling of spallation products in p(1GeV) + A reactions
An analysis of experimental yields concerning isotopically resolved spallation products from 1GeV-proton nucleus interactions with targets from Fe to Cs is presented. It was found that the yield ratios of isotopes classified by the difference of the neutron numbers are compatible with relations derived in the grand-canonical approach. The independence of isotope temperatures from the target mass was demonstrated for spallation products. The spallation residues exhibit isoscaling behaviour. The high sensitivity of the isoscaling parameters to the nucleonic composition (N/Z) of the disassembling nuclei is analysed. A unified isoscaling for a common description of similar reactions is discussed
Dopant Spin States and Magnetic Interactions in Transition Metal (Fe\u3csup\u3e3+\u3c/sup\u3e)-Doped Semiconductor Nanoparticles: An EMR and Magnetometric Study
In this work, electron magnetic resonance (EMR) spectroscopy and magnetometry studies were employed to investigate the origin of the observed room-temperature ferromagnetism in chemically synthesized Sn1-xFexO2 powders. EMR data clearly established the presence of two different types of signals due to the incorporated Fe ions: paramagnetic spectra due to isolated Fe3+ ions and broad ferromagnetic resonance (FMR) spectra due to magnetically coupled Fe3+ dopantions. EMR data analysis and simulation suggested the presence of high-spin (S = 5/2) Fe3+ ions incorporated into the SnO2 host lattice both at substitutional and at interstitial sites. The FMR signal intensity and the saturation magnetization Ms of the ferromagnetic component increased with increasing Fe concentration. For Sn0.953Fe0.047O2 samples, well-defined EMR spectra revealing FMRs were observed only for samples prepared in the 350–600°C range, whereas for samples prepared at higher annealing temperatures up to 900°C, the FMRs and saturation magnetization were vanished due to diffusion and eventual expulsion of the Fe ions from the nanoparticles, in agreement with data obtained from Raman and X-ray photoelectron spectroscopy
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