51 research outputs found
Study of the nucleon-induced preequilibrium reactions in terms of the Quantum Molecular Dynamics
The preequilibrium (nucleon-in, nucleon-out) angular distributions of
Al, Ni and Zr have been analyzed in the energy region from
90 to 200 MeV in terms of the Quantum Moleculear Dynamics (QMD) theory. First,
we show that the present approach can reproduce the measured (p,xp') and (p,xn)
angular distributions leading to continuous final states without adjusing any
parameters. Second, we show the results of the detailed study of the
preequilibrium reaction processes; the step-wise contribution to the angular
distribution, comparison with the quantum-mechanical Feshbach-Kerman-Koonin
theory, the effects of momentum distribution and surface refraction/reflection
to the quasifree scattering. Finally, the present method was used to assess the
importance of multiple preequilibrium particle emission as a function of
projectile energy up to 1 GeV.Comment: 22pages, Revex is used, 10 Postscript figures are available by
request from [email protected]
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.
Spallation reactions. A successful interplay between modeling and applications
The spallation reactions are a type of nuclear reaction which occur in space
by interaction of the cosmic rays with interstellar bodies. The first
spallation reactions induced with an accelerator took place in 1947 at the
Berkeley cyclotron (University of California) with 200 MeV deuterons and 400
MeV alpha beams. They highlighted the multiple emission of neutrons and charged
particles and the production of a large number of residual nuclei far different
from the target nuclei. The same year R. Serber describes the reaction in two
steps: a first and fast one with high-energy particle emission leading to an
excited remnant nucleus, and a second one, much slower, the de-excitation of
the remnant. In 2010 IAEA organized a worskhop to present the results of the
most widely used spallation codes within a benchmark of spallation models. If
one of the goals was to understand the deficiencies, if any, in each code, one
remarkable outcome points out the overall high-quality level of some models and
so the great improvements achieved since Serber. Particle transport codes can
then rely on such spallation models to treat the reactions between a light
particle and an atomic nucleus with energies spanning from few tens of MeV up
to some GeV. An overview of the spallation reactions modeling is presented in
order to point out the incomparable contribution of models based on basic
physics to numerous applications where such reactions occur. Validations or
benchmarks, which are necessary steps in the improvement process, are also
addressed, as well as the potential future domains of development. Spallation
reactions modeling is a representative case of continuous studies aiming at
understanding a reaction mechanism and which end up in a powerful tool.Comment: 59 pages, 54 figures, Revie
A LITERATURE SURVEY OF NONELASTIC REACTIONS FOR NUCLEONS AND PIONS INCIDENT ON COMPLEX NUCLEI AT ENERGIES BETWEEN 20 Mev AND 33 Gev
Experimental data on nonelastic reactions of protons, neutrons, pi /sup +/, and pi /sup -/ with complex nuclei at incident energies of 20 Mev to 33 Bev were surveyed. The material is grouped according to the incident particle in the above order. Information on the measured quantity, experimental arrangemert, and the experimental error is included. The 200 publications used in the survey, most of them abstracted for Physics Abstracts, are listed. (D.C.W.
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DESCRIPTION OF PRINTED OUTPUT FROM INTRANUCLEAR CASCADE CALCULATION
ABS>A detailed description of the printed output sheets from the intranuclear cascade calculation described in ORNL3383 is given. The three analysis codes --analysis codes I and II and an evaporation code --that were written to organize the raw data of the output tape are considered. (auth) A tabulation of the neutron total cross section of U/sup 233/ as a function of neutron energy from 0.07 to 10,000 ev, measured with the ORNL fast chopper time- of-flight neutron spectrometer is given. (auth
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