Related papers: Positron Channeling
Target ionization processes of alkali atoms by Positronium impact are investigated. Calculations are performed in the frame work of model potential formalism using the Coulomb distorted eikonal approximation. Interesting qualitative…
We present the experimental observation of the reduction of multiple scattering of high-energy positively charged particles during channeling in single crystals. According to our measurements the rms angle of multiple scattering in the…
Relativistic antiparticles can be created in high-energy nuclear interactions; thus, detection of antiparticles in an astrophysical source can tell us something remarkable about the underlying high-energy processes and nuclear interactions.…
The process of $\nu \bar{\nu}$ radiation from a relativistic plasma of electrons and positrons is studied within the Random Phase Approximation.
We have calculated all contributions to the energy levels of parapositronium at order $m \alpha^7$ coming from vacuum polarization corrections to processes involving virtual annihilation to two photons. This work is motivated by ongoing…
A possibility to measure the energy and polarization distributions of high intensity gamma-beams is considered. This possibility is based on measurements of the number of electron-pozitron pairs in such media as laser waves and single…
Diagrammatic many-body theory is used to calculate the scattering phase shifts, normalized annihilation rates $Z_{\rm eff}$ and annihilation gamma spectra for positron collisions with the hydrogen-like ions He$^+$, Li$^{2+}$, B$^{4+}$ and…
Positron creation probabilities as well as energy and angular distributions of outgoing positrons in slow collisions of two identical heavy nuclei are obtained within the two-center approach beyond the monopole approximation. The…
Annihilation of the electron-positron pairs in macroscopic polyelectrons is considered. It is shown that very fast collapse of the spatial area occupied by macroscopic polyelectron (or dense electron-positron plasma) produces an instant…
It is shown that the charged particles are refracted and reflected on the boundary of field free and laser field regions in vacuum. Simple and transparent estimates are given which show the possibility of channeling of charged and neutral…
We have recorded channeling patterns produced by 1 to 2 MeV protons aligned with <111> axes in 55 nm thick silicon crystals which exhibit characteristic angular structure for deflection angles up to and beyond the axial critical angle,…
We present simulations of particle beam channeling in carbon nanotubes and evaluate the possibilities for experimental observation of channeling effect in straight and bent nanotubes at IHEP and LNF. Different particle species are…
A model-potential approach has been developed to study positron interactions with molecules. Binding energies and annihilation rates are calculated for positron bound states with a range of alkane molecules, including rings and isomers. The…
A problem to account for the direct electron-positron annihilation in positron-hydrogen scattering above the positronium formation threshold has been resolved within the time independent formalism. The generalization of the optical theorem…
Electron-positron pair annihilation into a single photon is studied when a second free electron is present. Focussing on the relativistic regime, we show that the photon emitted in the three-lepton interaction may exhibit distinct angular…
The process of scattering of fast charged particles in thin crystals is considered in the transitional range of thicknesses, between those at which the channeling phenomenon is not developed and those at which it is realized. The…
Ionization of highly charged relativistic ions by neutral atoms and ions is considered. Numerical results of recently developed computer codes based on the relativistic Born and the equivalent-photon approximations are presented. The…
Calculations of the relaxation energy, contact pair-correlation function, and annihilating-pair momentum density for a single positron immersed in a homogeneous electron gas are presented. We achieve an accurate description of the…
We describe a new sensitive method for the investigation of weakly magnetic films placed inside a tri-layer planar waveguide. Polarized neutrons tunnel into the waveguide through the surface, channel along the layers and are emitted from…
The crystalline undulator is a single crystal with periodically bent crystallographic planes. If ultrarelativistic charged particles channel through such a crystal, they emit hard radiation of undulator type. A crystalline undulator with a…