  The principles of the calibration of a time projection chamber with
radioactive Krypton-83 are explained. The calculation of gain correction
factors and the methods of obtaining a precise energy calibration are
illustrated. The properties and advantages of \nuc{83m}{Kr} are summarized and
compared to other radioactive calibration sources. It was shown that the
Krypton calibration for the STAR FTPC is feasible and recommendable although
the pad geometry of the FTPC causes a considerable deterioration of the
measured spectrum due to only partially detected charge clusters.
