The influence of defects on magnetic properties of fcc-Pu

The influence of vacancies and interstitial atoms on magnetism in Pu has been considered in frames of the Density Functional Theory (DFT). The relaxation of crystal structure arising due to different types of defects was calculated using the molecular dynamic method with modified embedded atom model (MEAM). The LDA+U+SO (Local Density Approximation with explicit inclusion of Coulomb and spin-orbital interactions) method in matrix invariant form was applied to describe correlation effects in Pu with these types of defects. The calculations show that both vacancies and interstitials give rise to local moments in $f$-shell of Pu in good agreement with experimental data for annealed Pu. Magnetism appears due to destroying of delicate balance between spin-orbital and exchange interactions.Comment: 13 pages, 4 figure

Design concepts for the Cherenkov Telescope Array CTA: an advanced facility for ground-based high-energy gamma-ray astronomy

Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA