18 research outputs found
Quasi Free 238U (e,e'f)-Cross Section in Macroscopic-Microscopic Approach
We present the result of a theoretical study of inclusive quasi free
electrofission of U. The off-shell cross sections for the quasi free
reaction stage have been calculated within the Plane Wave Impulse Approximation
(PWIA), using a Macroscopic -Microscopic description of the proton and neutron
single particle momentum distributions. Electron wave function distortion
corrections were included using the effective momentum approximation, and the
Final State Interaction (FSI) effects were calculated using an optical
potential. The fissility for the proton single hole excited states of the
residual nucleus Pa was calculated both without and with contributions
of the pre-equilibrium emission of the particles. The fissility for
residual nuclei was calculated within the compound nucleus model.
The cross sections thus obtained were compared with available
experimental data.Comment: 26 pages, 7 figure
Investigation of low energy pion-nucleus interaction using electrofission data for heavy nuclei at the pion threshold
A theoretical approach to describe electro- and photofission
processes at intermediate energies was worked out. Photopion reabsorption
mechanisms by two and three nucleons ( and ) were
incorporated in the calculations. The comparison with electrofission
data for preactinides showed that a substantial component should
be added in the pion absorption to fit the data near photopion
threshold, in accordance with a recent theoretical estimate. It was
also shown that the shape of the fission response curve is sensitive
to detailed aspects of the pion mean free path
Incoherent X-radiation produced by relativistic electrons in crystals
Differential and integral features of incoherent X-radiation, induced by
relativistic electrons in crystals, are studied for observation angles several times greater than , where
is the projectile Lorentz factor. The existence of sharp maxima and a
minimum of the five-folded incoherent differential cross-section as a
function of the final electron angles, and a dip minimum when the cross-section
is taken as a function of the photon energies, is demonstrated. At
near backward observation angles the three-folded cross-section shows a
maximum in the region of several keV photon energies. The obtained results
allow us to optimize the conditions for coincidence experiments, minimizing the
incoherent contribution to the total radiation yield, and helping to analyse
results of finite-size detector experiments with crystal targets
Woods-Saxon potential parametrization at large deformations for plutonium odd isotopes
The structure of single-particle levels in the second minima of Pu was analyzed with the help of an axially-deformed
Woods-Saxon potential. The nuclear shape was parametrized in terms of the
cassinian ovaloids. A parametrization of the spin-orbit part of the
potential was obtained in the region corresponding to large deformations
(second minimum), depending only on the nuclear surface area. With this
parametrization, we were able to reproduce successfully the spin, parity and
energies of the rotational band built on the 8s isomeric state in Pu and, also, a spin assignment for both isomeric states in
Pu and Pu was carried out