Channeling of high-energy particles in a multi-wall nanotube

Channeling of high-energy particles in straight and bent multi-wall nanotubes (MWNT) has been studied in computer simulations and compared to the channeling properties of single-wall nanotubes (SWNT) and bent crystal lattices. It is demonstrated that MWNT can efficiently channel positively-charged high-energy particles trapped between the walls of MWNT. Bending dechanneling in MWNT has been computed as a function of the particle momentum to nanotube curvature radius ratio, $pv/R$. It is found that a bent MWNT can steer a particle beam with bending capabilities similar to those of bent silicon crystal lattice and to those of best (i.e. the narrowest) SWNT. In view of channeling applications at particle accelerators, MWNT appear favored as compared to SWNT, because MWNT can be produced quite straight (and in aligned array), while SWNT is typically very curved, thus posing a severe problem for channeling applications. Therefore, we suggest that MWNT provide a better candidate for channeling than SWNT.Comment: 16 pages, 6 figures, to appear in Phys. Lett.

GRBs with optical afterglow and known redshift: a statistical study

We present a correlation between two intrinsic parameters of GRB optical afterglows. These are the isotropic luminosity at the maximum of the light curve (Lpeak) and the time-integrated isotropic energy (Eiso) radiated after the observed maximum. We test the correlation between the logarithms of (Eiso) and (Lpeak) and finally we value the effect of the different samples of GRBs in according with the first optical observation reduced to proper time.Comment: To be published in the proceedings of the conference "SWIFT and GRBs: Unveiling the Relativistic Universe", Venice, June 5-9, 200

The first light of Mini-MegaTORTORA wide-field monitoring system

Here we describe the first light of the novel 9-channel wide-field optical monitoring system with sub-second temporal resolution, Mini-MegaTORTORA, which is being tested now at Special Astrophysical Observatory on Russian Caucasus. The system is able to observe the sky simultaneously in either wide (~900 square degrees) or narrow (~100 square degrees) fields of view, either in clear light or with any combination of color (Johnson B, V or R) polarimetric filters installed, with exposure times ranging from 100 ms to 100 s. The primary goal of the system is the detection of rapid -- with sub-second characteristic time-scales -- optical transients, but it may be also used for studying the variability of the sky objects on longer time scales.Comment: 9 pages, 9 figures, based on the talk presented on "Modern stellar astronomy-2014" (Rostov-on-Don

Negative Particle Planar and Axial Channeling and Channeling Collimation

While information exists on high energy negative particle channeling there has been little study of the challenges of negative particle bending and channeling collimation. Partly this is because negative dechanneling lengths are relatively much shorter. Electrons are not particularly useful for investigating negative particle channeling effects because their material interactions are dominated by channeling radiation. Another important factor is that the current central challenge in channeling collimation is the proton-proton Large Hadron Collider (LHC) where both beams are positive. On the other hand in the future the collimation question might reemerge for electron-positron or muon colliders. Dechanneling lengths increase at higher energies so that part of the negative particle experimental challenge diminishes. In the article different approaches to determining negative dechanneling lengths are reviewed. The more complicated case for axial channeling is also discussed. Muon channeling as a tool to investigate dechanneling is also discussed. While it is now possible to study muon channeling it will probably not illuminate the study of negative dechanneling.Comment: 15 pages, 1 figure, docx fil