| Popis: |
The fragments produced in the reaction between a 14 N beam of various energies and a natural Ag target have been studied. The atomic numbers of the fragments have been identified up to Z = 17 by means of a E - ΔE counter telescope. The cross sections, the kinetic energy distributions as well as the angular distributions have been measured for each atomic number. The kinetic energy distributions show two components: a high-energy component (quasi-elastic), prevailing at angles close to the grazing angles and for atomic numbers close to Z = 7, and a low-energy component (relaxed), at energies close to the Coulomb repulsion energy, present at all angles and for all the Z . A detailed study of the relaxed components of the kinetic energy seems to account for both them means and the widths of these distributions on a purely statistical basis. The cross sections of the relaxed components appear to be quite large at low Z and to decrease rapidly to a fairly constant value in the region of 10 ≦ Z ≦ 17. A marked even-odd alternation in the cross sections is observed. The angular distributions are strongly forward peaked for Z Z > 7 the forward peaking decreases rapidly until, for Z > 13, the limiting form 1/sin θ is attained. Evidence for the existence of a diffusion process along the mass asymmetry coordinate is discussed. |
