OPTIMIZATION OF THE CHANNELING RADIATION SOURCE CRYSTAL TO PRODUCE INTENSE QUASI-MONOCHROMATIC X-RAYS

Channeling radiation is a source of intense, tunable, quasimonochromatic x rays produced by electrons traveling along a direction of symmetry through a crystal. We analyze the effect of the channeling source crystal, through both its composition and lattice structure, on the number of photons emitted per electron, the linewidths of the radiation, and the maximum sustainable currents to identify the crystal which will yield the most photons in a bandwidth of less than 10% full width at half maximum (FWHM). Although high atomic number (Z) crystals produce a greater number of photons per electron, given their poor thermal properties these crystals cannot sustain as high average currents as lower Z crystals. The linewidths of the channeling radiation emitted from high Z crystals are as large as 50% FWHM, and electrons are dechanneled more quickly in these crystals, limiting their use as a quasimonochromatic x-ray source. Given its exceptional thermal conductivity and narrow linewidths, diamond is the optimal source crystal for the production of intense, quasimonochromatic x rays using channeling radiation.