Noise level of the DCS module.
Fig9a: CV of DB for a fixed number of detection channels (4) as a function of
the count-rate, for different measurement durations. The dashed red line
represents the theoretical trend, and only its slope is significant.
Fig9b: Sum of the variance of the autocorrelation curves as a function of the
count-rate. Each line represents a different measurement duration (from 1 s up
to 100 s).
