Most probable charge deposit signal normalised to that ofminimum ionising particles as a function of $\beta\gamma$. The data are from measurements performed in test beam runs, \pp collisions at \mbox{\sqrts = 7 TeV}, and cosmic-ray runs. Uncertainties in momentum and thus $\beta\gamma$ determination are drawn as horizontal and statistical uncertainties as vertical error bars. The shown fits correspond to the Equations \ref{equ:aleph} and \ref{equ:logistic} described in the text.