Quantitive analysis of Laue diffraction patterns recorded with a 120 ps exposure from an X-ray undulator

X-ray Laue diffraction patterns with an exposure time of 120 ps have been obtained from single crystals of an indole alkaloid and of the enzyme lysozyme using the X-rays emitted as a single bunch of electrons traverses a hard X-ray undulator inserted in CESR, the Cornell Electron-Positron Storage Ring. The patterns were recorded on a sensitive storage-phosphor detector. Despite complexities posed by the sharp variation of the incident X-ray spectrum with wavelength and the weakness of the diffraction patterns, accurate crystallographic structure amplitudes were extracted from the Laue intensities by the generalized scale-factor approach to the determination of the wavelength- and position-dependent correction factors. The results show that crystallography is feasible on the 100 ps time scale and open up the prospect of time-resolved measurements of ultra-rapid changes in molecular structure.