Theoretical Description And Experimental Detection Of The Interference Between Parametric X Radiation And Coherent Bremsstrahlung

Parametric X radiation (PXR) produced by electrons with an energy of E-0 = 4 MeV interacting with the atoms in the (220) plane of a 20-mu m silicon and a 55-mu m diamond crystal and observed at an angle of 44 degrees by a Si(Li) detector has been investigated with respect to the interference with coherent bremsstrahlung (CB) that originates in the same interaction process between the incoming relativistic electron and the crystal. Since the energy of PXR and CB is identical, contributions of both types of radiation are indistinguishable. The newly derived analytical expressions describe the radiation which consists of a coherent superposition of PXR and CB. For the comparison of the experimental results with the theoretical predictions a Monte Carlo simulation taking into account all effects accompanying the radiation process has been performed. The comparison shows very good agreement between experiment and theory.