X-ray line measurements with high efficiency Bragg crystals

We have studied the focusing properties of two highly oriented pyrolitic graphite (HOPG) spectrometers, which differ in the degree of the mosaic spread: ZYA with a low mosaic spread (γ=0.4 deg.) and ZYH with a large mosaic spread (γ=3.5 deg.). In order to asses the crystal performance for a variety of different experiments, various Kα and Kβ x-ray lines have been produced using a high-intensity (> or approx. 1017 W/cm2) short-pulse (∼100 fs) laser beam focused onto Ti, V, Zn, and Cu foils. The measured spectral resolution of the HOPG crystals in both first and second order diffraction has been compared with theoretical predictions. Using known values for the peak reflectivity of HOPG crystals, we have also computed Kα x-ray conversion efficiencies of Ti, V, Zn, and Cu. These results are important to estimate the optimal conditions under which different types of HOPG monochromators can be used for the detection of weak x-ray signals as the one encountered in x-ray Thomson/Compton scattering experiments