Efficiency calibrations of cylindrically bent transmission crystals in the 20 to 80 keV x-ray energy range

Two quartz (10-11) crystals were cylindrically bent to a 25: 4 cm radius of curvature and were mounted in identical Cauchois-type transmission spectrometers, and the crystal diffraction efficiencies were measured to 5% absolute accuracy using narrow bandwidth x-ray source fluences in the 20 to 80 keV energy range. The measured integrated reflectivity values were compared to calculations performed using a computational model that accounts for the diffraction geometry of the bent transmission crystal. These crystal calibrations enable the accurate measurement of absolute hard x- ray emission levels from laser- produced plasmas and other laboratory sources.