MODERATE RESOLUTION X-RAY REFLECTIVITY

We demonstrate that x-ray reflectivity data covering eight decades of intensity can be obtained from a rotating anode source. Our moderate resolution configuration uses a bent graphite monochromator in contrast to the usual high resolution measurement which uses a silicon or germanium monochromator. Illustrative data show that moderate resolution is appropriate for probing a wide variety of surfaces and films. The availability in our configuration of roughly 100 times the incident intensity of a high resolution experiment using a laboratory source allows measurements over a broader angular range which in turn allows us to probe short length scale details of interface structure and tightens the constraints on models of interface structure. Both specular and diffuse scattering signals are accessible. A discussion of reciprocal space resolution explains why there is almost no difference in effective resolutions in the measurement of diffuse scattering.