The influence of anharmonic potentials in calculations of planar channeling radiation from GeV positrons

The frequency of radiation from planar channeled positrons in the GeV region is discussed for realistic planar potentials when the dipolarity condition is not satisfied. It is found that there is a critical beam momentum at which the maximum radiated frequency is practically the same for all channeled positrons. For this momentum a sharp peak in the calculated composite spectrum is to be expected and this could explain the sharp peaking observed in a recent CERN experiment for 5 GeV/c positrons. (orig.)