Protein crystallography with spallation neutrons.

Spallation neutrons are ideal for diffraction studies of proteins and oriented molecular complexes. With spallation neutrons and their time-dependent wavelength structure, one can select data with an optimal wavelength band and cover the whole Laue spectrum as time (wavelength) resolved diffraction data. This optimises data quality with best peak to background ratios and provides spatial and energy resolution to eliminate peak overlaps. Such a Protein Crystallography Station (PCS) has been built and tested at Los Alamos Neutron Science Centre. A partially coupled moderator is used to increase flux and data are collected by a cylindrical He3 detector covering 120 degrees with 200 mm height. The PCS is described along with some examples of data collected from proteins.