Grazing Incidence X-ray Diffraction Studies of Thin Films Using an Imaging Plate Detection System

First results of the grazing incidence X-ray diffraction patterns of cadmium arachidate Langmuir−Blodgett (LB) films measured using imaging plate detection are presented and discussed. The use of imaging plates has made possible the observation of diffraction peaks at far higher values of wavevector transfer than have been observed previously with other methods of detection, with a dramatic increase in signal-to-noise ratio. Values of in-plane d -spacing, area per molecule, and positional correlation length of the hexatic-B phase of a monolayer of cadmium arachidate are in excellent agreement with previous measurements. Multilayer LB films showed, in addition to the in-plane spots Q 110 and Q 200, sets of off-plane diffraction spots ( Q h k l, l > 0) which are observed up to a Q z value of 3.3 Å -1 . Spots with both odd and even values of l are observed.