Determination of the rocking curve and reflection efficiency of a SiO2 crystal imager using Zr, Nb, Mo AND Ag Kα x-rays

The diffraction and reflection of x-rays by crystalline structures is important in diagnosing the properties of hot, dense, strongly emitting plasmas such as those that are generated by intense laser light. The rocking curve and reflection efficiency of a SiO2 crystal has been measured for four different x-ray energies, E = 15.690, 16.521, 17.374, and 22.1629 keV corresponding to the Kα lines of Zr, Nb, Mo and Ag, respectively. The crystal is Quartz with Miller indices of [2354]. It is used for x-ray imaging and has a spherically curved surface with a focal length of 25 cm. The x-rays, which were provided by the National Synchrotron Light Source at Brookhaven National Laboratory, were collimated and polarized in the horizontal plane with an energy bandwidth ΔE/E ∼ 10−4. The x-ray flux was measured using an ion chamber. The crystal was mounted in a goniometer and swept in the vertical through an angle of 4° in 0.025° steps centered on the expected reflection direction. The reflected x-rays were detected using imaging plates. The rocking curves and reflectivity data will be presented.