A primary linearisation curve must be recorded for every measuring channel.This is done using a calibration plate set with known individual plate thicknesses. These plates are stacked to create different thickness values and the standardised value MN for these thickness values is noted. Using these data, the internal IMS-tool "µ-Program" then creates a linearisation file containing all the data needed to represent the absorption curve mathematically. With the help of these data the non-linear MN value is converted into a linear value (LW).