12 research outputs found
Coherent pair production in deformed crystals with a complex base
We investigate the coherent electron-positron pair creation by high-energy
photons in a periodically deformed single crystal with a complex base. The
formula for the corresponding differential cross-section is derived for an
arbitrary deformation field. The conditions are specified under which the
influence of the deformation is considerable. The case is considered in detail
when the photon enters into the crystal at small angles with respect to a
crystallographic axis. The results of the numerical calculations are presented
for single crystal and Moliere parametrization of the
screened atomic potentials in the case of the deformation field generated by
the acoustic wave of type. In dependence of the parameters, the presence of
deformation can either enhance or reduce the pair creation cross-section. This
can be used to control the parameters of the positron sources for storage rings
and colliders.Comment: 10 pages, 4 figures, misprint in the numerical coefficients in figure
captions is correcte
Coherent bremsstrahlung in periodically deformed crystals with a complex base
In the present paper we investigate coherent bremsstrahlung of high energy
electrons moving in a periodically deformed single crystal with a complex base.
The formula for corresponding differential cross-section is derived for an
arbitrary deformation field. The conditions are discussed under which the
influence of the deformation is important. The case is considered in detail
when the electron enters into the crystal at small angles with respect to a
crystallographic axis. It is shown that in dependence of the parameters, the
presence of the deformation can either enhance or reduce the bremsstrahlung
cross-section.Comment: 10 pages, 2 figure
Angular distribution of positrons in coherent pair production in deformed crystals
We investigate the angular distribution of positrons in the coherent process
electronpositron pair creation process by high-energy photons in a periodically
deformed single crystal with a complex base. The formula for the corresponding
differential cross-section is derived for an arbitrary deformation field. The
case is considered in detail when the photon enters into the crystal at small
angles with respect to a crystallographic axis. The results of the numerical
calculations are presented for and diamond single crystals
and Moliere parameterization of the screened atomic potentials in the case of
the deformation field generated by the acoustic wave of S-type.Comment: 11 pages, 4 figures, figures and references adde