RESUMO
Interaction cross sections for ^{42-51}Ca on a carbon target at 280 MeV/nucleon have been measured for the first time. The neutron number dependence of derived root-mean-square matter radii shows a significant increase beyond the neutron magic number N=28. Furthermore, this enhancement of matter radii is much larger than that of the previously measured charge radii, indicating a novel growth in neutron skin thickness. A simple examination based on the Fermi-type distribution, and mean field calculations point out that this anomalous enhancement of the nuclear size beyond N=28 results from an enlargement of the core by a sudden increase in the surface diffuseness of the neutron density distribution, which implies the swelling of the bare ^{48}Ca core in Ca isotopes beyond N=28.
RESUMO
The paper presents the results of synthesis and directed modification of structural properties of Zn nanotubes by irradiating with heavy ions. The nanotubes were obtained by electrochemical deposition in pores of template polymer matrices. It was established using SEM, XRD and EDS methods where irradiation with Xe+22 and Kr+14 ions makes it possible to modify the crystal structure of nanotubes. As a result of irradiation with Xe+22 ions, partial destruction of nanotubes is observed, which indicates an increase in the number of defects in the structure and a decrease in strength properties. Change in the crystal structure parameters is observed when irradiation with Kr+14 ions with fluence below 5 × 1011 ion cm-2. That indicates the possibility of using Kr+14 ions for directional modification of nanostructures, while irradiation with Xe+22 ions leads to amorphization and destruction of nanotubes.
