The Effect of Anharmonic Potential on the Planar Channeling Radiation of Positrons in the Disordered fcc Single Crystals

Planar channeling radiation characteristics like, transition energies and
transition probabilities were investigated against the planar channeling potential
with higher anharmonic terms. The calculations have been performed, by using
first-order perturbation theory, to fcc single crystals the lattices and disordered
lattices by dumb-bell configuration (DBC) or by body-centered interstitial
(BCI) , and has been executed for relativistic positrons at energies (10 - 500)
MeV channeled in copper single crystal in the planar direction (100). It has
been found that, by using higher anharmonic terms in the channeling potential,
a new transition line at Δ n = ± 5. has been detected. In addition, the
calculations showed that, the effect of higher anharmonic terms on channeling
radiation characteristics is very significant for transitions at higher bound states,
and the significance decreases for transitions at lower bound states.