X - Ray Diffuse Scattering 9 . X - Ray Diffuse Scattering Academic and Research Staff

In this research program, modern x-ray scattering techniques are used to study the structures and phase transitions in novel states of condensed matter. We have two principal experimental facilities. At M.I.T. we have two high-resolution computer controlled x-ray spectrometers using a high intensity rotating anode x-ray generator. Two more spectrometers are currently under development. The angular resolution can be made as fine as 1.8 seconds of arc; this enables one to probe the development of order from distances of the order of the x-ray wavelength, -1 A , up to 30,000 A . The sample temperature may be varied between 2 K and 500 K with a relative accuracy of 2 x 103 K. We also have, in collaboration with IBM, a two spectrometer system at the National Synchrotron Light Source at Brookhaven National Laboratory. This makes possible high resolution scattering experiments with a flux more than three orders of magnitude larger than that from a rotating anode x-ray generator; this in turn has opened up a new generation of experiments. This facility is under continuous development to improve the optics and spectrometers. Synchrotron x-ray scattering experiments are also carried out on a wiggler beam line at the Stanford Synchrotron Radiation Laboratory.