main results:
|
We developed an original formalism to study the photonuclear
reactions in the intermediate energies. With this formalism, we can analyse
the photo and electrofission cross sections to get information on the photon-nucleus
and pion-nucleus interactions and observe the nucleus characteristics in
different steps of the photoabsorption process: thermalization, composite
nucleus formation, evaporation and fission. We study the behaviour of the
nucleus composite energy in function of the incident photon energy. We
show that it is possible to verify pion characteristics it the nucleus
in the low kinetic energy region, in particular its mean free path in the
nuclear matter and the number of nucleons participating of the pion reabsorption.
A sub-product of this work was an original unfolding method of photoexcitation
sections cross of nuclear from the electrofission section of cross, simpler
and more practical than the traditionally used methods. The results
of this work had motivated other groups to carry through detailed measured
of photofission cross section in the region of the pions threshold in many
laboratories, as the Saskatoon Laboratory (Canada) and the TJNAF (U.S.A.). |
