89 research outputs found
Isotopic and velocity distributions of Bi produced in charge-pickup reactions of 208Pb at 1 A GeV
Isotopically resolved cross sections and velocity distributions have been
measured in charge-pickup reactions of 1 A GeV 208Pb with proton, deuterium and
titanium target. The total and partial charge-pickup cross sections in the
reactions 208Pb + 1H and 208Pb + 2H are measured to be the same in the limits
of the error bars. A weak increase in the total charge-pickup cross section is
seen in the reaction of 208Pb with the titanium target. The measured velocity
distributions show different contributions - quasi-elastic scattering and
Delta-resonance excitation - to the charge-pickup production. Data on total and
partial charge-pickup cross sections from these three reactions are compared
with other existing data and also with model calculations based on the coupling
of different intra-nuclear cascade codes and an evaporation code.Comment: 20 pages, 12 figures, background information on
http://www-w2k.gsi.de/kschmidt
Fragmentation of Nuclei at Intermediate and High Energies in Modified Cascade Model
The process of nuclear multifragmentation has been implemented, together with
evaporation and fission channels of the disintegration of excited remnants in
nucleus-nucleus collisions using percolation theory and the intranuclear
cascade model. Colliding nuclei are treated as face--centered--cubic lattices
with nucleons occupying the nodes of the lattice. The site--bond percolation
model is used. The code can be applied for calculation of the fragmentation of
nuclei in spallation and multifragmentation reactions.Comment: 19 pages, 10 figure
Predicting total reaction cross sections for nucleon-nucleus scattering
Nucleon total reaction and neutron total cross sections to 300 MeV for 12C
and 208Pb, and for 65 MeV spanning the mass range, are predicted using
coordinate space optical potentials formed by full folding of effective
nucleon-nucleon interactions with realistic nuclear ground state densities.
Good to excellent agreement is found with existing data.Comment: 10 pages, 4 figure
Measurement of nuclide cross-sections of spallation residues in 1 A GeV 238U + proton collisions
The production of heavy nuclides from the spallation-evaporation reaction of
238U induced by 1 GeV protons was studied in inverse kinematics. The
evaporation residues from tungsten to uranium were identified in-flight in mass
and atomic number. Their production cross-sections and their momentum
distributions were determined. The data are compared with empirical
systematics. A comparison with previous results from the spallation of 208Pb
and 197Au reveals the strong influence of fission in the spallation of 238U.Comment: 20 pages, 10 figures, background information at
http://www-wnt.gsi.de/kschmidt
Spallation Neutron Production by 0.8, 1.2 and 1.6 GeV Protons on various Targets
Spallation neutron production in proton induced reactions on Al, Fe, Zr, W,
Pb and Th targets at 1.2 GeV and on Fe and Pb at 0.8, and 1.6 GeV measured at
the SATURNE accelerator in Saclay is reported. The experimental
double-differential cross-sections are compared with calculations performed
with different intra-nuclear cascade models implemented in high energy
transport codes. The broad angular coverage also allowed the determination of
average neutron multiplicities above 2 MeV. Deficiencies in some of the models
commonly used for applications are pointed out.Comment: 20 pages, 32 figures, revised version, accepted fpr publication in
Phys. Rev.
Measurement of residual nucleus cross sections and recoil energies in p + Fe collisions at 300, 500, 750, 1000 and 1500 MeV
The production of residual nuclei in p + Fe collisions has been measured at GSI on the FRS facility by means of the reverse kinematic techniques at 300, 500, 750, 1000 and 1500 MeV/A. The cross-sections larger than 0.01 mb of all isotopes with Z larger than 8 have been obtained. Velocity distributions were also measured. Comparisons to models describing spallation reactions and some empirical formulae often used in astrophysics are presented. These data are directly used to calculate impurety production and DPAs in a thin window as foreseen in spallation sources or accelerator-driven systems
Evaporation residues produced in spallation of 208Pb by protons at 500A MeV
The production cross sections of fragmentation-evaporation residues in the
reaction Pb+p at 500A MeV have been measured using the inverse-kinematics
method and the FRS spectrometer (GSI). Fragments were identified in nuclear
charge using ionisation chambers. The mass identification was performed
event-by-event using the B-rho - TOF - Delta-E technique. Although
partially-unresolved ionic charge states induced an ambiguity on the mass of
some heavy fragments, production rates could be obtained with a high accuracy
by systematically accounting for the polluting ionic charge states. The
contribution of multiple reactions in the target was subtracted using a new,
partly self-consistent code. The isobaric distributions are found to have a
shape very close to the one observed in experiments at higher energy. Kinematic
properties of the fragments were also measured. The total and the isotopic
cross sections, including charge-pickup cross sections, are in good agreement
with previous measurements. The data are discussed in the light of previous
spallation measurements, especially on lead at 1 GeV
Predictions of total and total reaction cross sections for nucleon-nucleus scattering up to 300 MeV
Total reaction cross sections are predicted for nucleons scattering from various nuclei. Projectile energies to 300 MeV are considered. So also are mass variations of those cross sections at selected energies. All predictions have been obtained from coordinate space optical potentials formed by full folding effective two-nucleon (NN) interactions with one body density matrix elements (OBDME) of the nuclear ground states. Good comparisons with data result when effective NN interactions defined by medium modification of free NN t matrices are used. Coupled with analyses of differential cross sections, these results are sensitive to details of the model ground states used to describe nuclei
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