Related papers: Positron Channeling
The motion of fast electrons through the crystal during axial channeling could be regular and chaotic. The dynamical chaos in quantum systems manifests itself in both statistical properties of energy spectra and morphology of wave functions…
Channeling and radiation are studied for the relativistic electrons and positrons passing through a Si crystal periodically bent with a small amplitude and a short period. Comprehensive analysis of the channeling process for various bending…
An analytical expression is received for the effective interaction potential of a fast charged particle with the ionic crystal CsCl near the direction of axis <100> as a function of the temperature of the medium. A possibility of positron…
The process of radiation of 120-GeV positrons moving in a channeling regime in (011) plane of a single crystal was considered. At the beginning on the basis of the theory of nonlinear oscillations the trajectory of moving positrons at…
The differential cross-section of the single-photon annihilation of channeled positron on the K-shell electron of one of the crystal atoms is calculated and angular distribution of emitted photons is investigated. It is shown that…
High energy (~GeV) positrons are seen within cosmic rays and observation of a narrow line at 511 keV shows that positrons are annihilating in the galaxy after slowing down to ~keV energies or less. Our state of knowledge of the origin of…
The channeling effect of low energy ions along the crystallographic axes and planes of NaI(Tl) crystals is discussed in the framework of corollary investigations on WIMP Dark Matter candidates. In fact, the modeling of this existing effect…
The energy and momentum conservation laws prohibit positron-electron annihilation in vacuum producing the single photon only. It can produce two photons in vacuum, or the process is possible with a participation of the third body. The…
We present a detailed calculation of channeling radiation of planar-channeled positrons from crystal targets in the framework of our approach, which was proposed recently. In contrast to previous calculations of channeling radiation in…
Two approaches used in the description of the channeling radiation emitted from relativistic positrons are compared with each other. In the first (traditional) case, the probability of the process is proportional to a sum of absolute…
Inhomogeneities can influence the polarisation emerging from a synchrotron source. However, it is shown that the frequency distribution of circular polarisation is only marginally affected, although its magnitude may change substantially.…
Positron scattering and annihilation on noble gas atoms below the positronium formation threshold is studied ab initio using many-body theory methods. The many-body theory provides a near-complete understanding of the…
This paper reports on a comprehensive study of an ultra-relativistic positron beam deflection by an oriented quasi-mosaic crystal. The analysis was carried out for the positron energy of 530 MeV incident on the quasi-mosaic bent Si(111)…
Numerical simulations and `proof of principle' experiments showed clearly the interest of using crystals as photon generators dedicated to intense positron sources for linear colliders. An experimental investigation, using a 10 GeV…
Preliminary results of numerical simulations of electron and positron channeling and emission spectra are reported for straight, uniformly bent and periodically bent silicon crystal. The projectile trajectories are computed using the newly…
Resonant positron annihilation on atomic electrons provides a powerful method to search for light new particles coupled to $e^+e^-$. Reliable estimates of production rates require a detailed characterization of electron momentum…
A brief review is given of recent positron studies of metal and semiconductor nanocrystals. The prospects offered by positron annihilation as a sensitive method to access nanocrystal (NC) properties are described and compared with other…
The two-photon annihilation of a positron with an electron bound in the 1s state of a H-like ion is calculated within the fully relativistic QED framework. The interaction with the nucleus is treated nonperturbatively, thus allowing the…
The electromagnetic radiation generated by ultra-relativistic positrons channelling in a crystalline undulator is discussed. The crystalline undulator is a crystal whose planes are bent periodically with the amplitude much larger than the…
The new method for producing of the polarized relativistic positrons is suggested. A beam of unpolarized positrons accelerated up to a few GeV can be polarized during a head-on collision with an intense circularly polarized lazer wave.…