(a) Decrease in maximum resolution as a function of dose for 15 sequential datasets measured from an AcNiR crystal. (b) Refined B-factors in the 15 sequential datasets for all atoms (open squares), T1Cu (black squares) and T2Cu (diamonds). Note that the occupancy of the T2Cu atom was 0.8. The ratios of Cu-atom to all-atom B-factors were 0.92 (dataset 1) increasing to 1.03 (dataset 15) for T1Cu, with corresponding values for T2Cu of 0.88 and 1.01. In dataset 9, the first for which structure solution and building was not automatically forthcoming, the ratio of Cu-atom to all-atom B-factor was 0.99 for T1Cu and 0.92 for the T2Cu. A slight increase in these ratios was thus observed with increasing dose, such that the Cu atoms were less disordered than the average atom in dataset 1 but had above-average B-factors by the end of the experiment.