Lineshape, linewidth and spectral density of parametric x-radiation at low electron energy in diamond

Abstract

Applying an absorber technique, the experimental shape and width of a parametric x-radiation line has been determined. The 9 keV radiation was produced by bombarding a diamond crystal of 55 μm thickness with electrons of 6.8 MeV. The variance of the spectral line distribution was found to depend on the tilt angle of the crystal and to have a magnitude of σ=51 eV. Simulations based on a Monte Carlo method exhibit that the observed variance is mainly influenced by multiple scattering of electrons passing through the crystal (≈43 eV) and the finite detector opening (≈18 eV), leaving for the intrinsic linewidth a value of the order of 1 eV. The spectral density of the line was found to be J≈10−7 photons/(electron×sr×eV).