The development of multidetectors for use in X‐ray and neutron scattering experiments has created an interest in methods for integrating Bragg peaks in three‐dimensional data arrays representing intensity scattered from single crystals. A method of using a priori information, extracted from the strongest peaks, to obtain statistically optimum results has been developed at the Institut Laue–Langevin (ILL), Grenoble. The method is outlined in this paper and results of its application to neutron diffraction are discussed.

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Crystals of hen egg white lysozyme soaked in 15% (v/v) dimethyl sulfoxide have been studied with single-crystal neutron diffraction to determine the effect of the solvent molecules on the protein configuration. A total of 9423 statistically significant Bragg reflections to a resolution of approximately 1.8 A were used to locate 6 dimethyl sulfoxide molecules, and structure refinements including a model for the flat solvent lead to a final crystallographic agreement factor of 0.130. The mode of location of the dimethyl sulfoxide molecules was compared with that in previous studies employing ethanol. This showed that hydrophobic interactions can be an essential factor in fixing the probe molecules on the protein surface. There was, however, no sign of any significant change in the protein configuration; so although possibly at higher concentrations of dimethyl sulfoxide the protein will unfold, there was no indication of any precursor effect.