The dose-response behavior of the radical in a lysozyme crystal observed through UV–Vis absorption spectroscopy. (a) The spectra show the rapid rise in the overall signal owing to the increase in radical concentration and the temporal evolution of absorption peaks at 400 and 580 nm. An isosbestic point is present at 480 nm. (b) Absorbance at 400 nm ( radical signal) as a function of absorbed dose with single- and double-exponential fits overlaid (residuals are shown in the Supplementary Material). The crystal was subjected to a total absorbed dose of ∼5 MGy (∼80 s at 61.8 kGy s−1) before the shutter was closed (see text for details). (c) Variation in fit parameters as a function of dose rate; no systematic trend is observed.