Obtaining the Space-Time Relationship of Drift Tubes from the Drift-Time Spectrum

Autocalibration of MDT chambers requires a good start-value for the space-time relation\-ship. This note presents two improvements on the ``Integration Method'': the first corrects for $\delta$-rays, the second also takes into account resolution and efficiency effects. Both methods use only the drift-time spectrum. The new methods improve the rms error from 345\,$\mu$m to 80\,$\mu$m and 18\,$\mu$m respectively.