**Figure 4**
(*a*) Raw mean intensities 〈*I*〉 (solid squares) and 〈*I*/σ_{I}〉 (open squares) as a function of the uncorrected dose. Black and dashed lines: fits by exponential functions. Vertical dashed and dashed-dotted lines indicate the *D*_{1/2} obtained with the uncorrected dose. (*b*) Normalized quantities *M*_{n} plotted as a function of adjusted dose. Average intensity 〈*I*〉_{free} (red solid squares) and 〈*I*/σ_{I}〉_{free} (red open squares) are plotted as a function of adjusted dose. Red solid line: fit by a straight line. Thin dotted line: fit by an exponential function. The dashed vertical line indicates the corresponding *D*_{1/2}. Black solid and black open triangles: variation of the mean intensity 〈*I*〉_{L} and 〈*I*/σ_{I}〉_{L}, respectively, observed in the control experiment as a function of virtual dose. The black solid and dashed lines are fits by a straight line. (*c*) Normalized *R*^{AO} values (black spheres) as a function of adjusted dose. Black dashed curve: fit by a single exponential. The horizontal/vertical dashed lines indicate *R*_{1/2}^{AO} and the corresponding kinetic dose limit *D*_{1/2}^{K}. (*d*) Red squares: relaxation times τ_{RSV1} from the SVD analysis as a function of adjusted dose. The red dashed line is a guide to the eye. Green triangles: inverse of the rate coefficient (relaxation time τ_{post}) obtained from posterior analysis. The green dashed line is a guide to the eye. Black spheres: difference between τ_{post} and τ_{RSV1}. The dashed vertical line indicates the kinetic dose limit *D*_{1/2}^{K}. |