[en] Motivated by the need for establishing a reliable database useful for the application of X-ray spectroscopic tools for the diagnostic of very high temperature plasmas, high-resolution crystal spectrometer measurements have been performed investigating the characteristic K-shell radiation of highly charged krypton and xenon. The measurements, which have been performed at the Electron-Beam-Ion-Trap facility of the Lawrence Livermore National Laboratory, include the investigation of the n=2 to 1 transitions in heliumlike krypton and innershell excited lithiumlike krypton utilizing a conventional reflection-type crystal spectrometer of von Hamos geometry. The electron-excitation-energy selective measurements map the contribution of the dielectronic recombination lines providing the means of accurate interpretation of the line profiles of the characteristic K alpha x-ray emission of plasmas. The high-resolution measurements of the n=2 to 1 transitions in heliumlike xenon and hydrogenlike xenon were based on a new transmission-type crystal spectrometer of DuMond geometry. The resolving power of the developed spectrometer was sufficient for charge state specific observation allowing the determination of the electron-impact excitation cross section for the hydrogen- and helium-like Kalpha transitions. The disagreement with theoretical values is a measure of the magnitude of the Breit interaction for the highly charged ions. (author)