Investigation of the Nonstationary Energy Distribution of an Atomic Collision Cascade

In this paper, we derive a nonstationary distribution function describing the energy distribution of the cascade of moving atoms taking into account their multiplication. The function was derived by solving the Boltzmann kinetic equation. The development of the cascade was considered for the materials consisting of atoms of the same type without taking into account the binding energy of atoms at the crystal lattice sites. The scattering of moving atoms is assumed to be elastic and spherically symmetrical in a center-of-inertia system, and the interaction cross-section is assumed to be constant. The use of these assumptions allows us to derive simple analytic formulas for the nonstationary energy distribution function for the cascade and analyze its main distinctive features. The results obtained allow evaluating the accuracy of various approximate solutions.

Incorporation of Ion Post Stripper in the APAPES Experimental Setup

A new accelerator beam line dedicated to atomic collision physics has been constructed as part of the APAPES project that is being carried out at the TANDEM of the NCSR “Demokritos”. Interest in various charge states resulted in the design of a second stripping point after acceleration that was added to the main part of the TANDEM accelerator after the analyzing magnet. In addition, the charge-state analysis program named TARDIS was implemented in C# code to assist in the optimal charge selection.

Экспериментальное наблюдение эффекта ограничения каскада столкновений при распылении пористого кремния

Results of investigation of the mass spectra of secondary ions sputtered from bulk (continuous) and porous silicon targets with various characteristic core particle dimensions are presented. It has been established that the sputtering of nanostructured Si samples leads to a significant increase in the relative yield of massive cluster ions. This effect is especially pronounced when the characteristic nanoparticle size approaches the range of bombarding ions in the Si target. The obtained results are explained taking into account the confinement of atomic collision cascades.