Calibration of the pad readout wire proportional chambers for the HPC calorimeter

The authors describe the setup used to calibrate the individual channels of the readout chambers for the High-Density Projection Chamber (HPC), the large-angle calorimeter of the DELPHI experiment. Due to the lack of test beam time this will be the only calibration of the 22000 readout channels before the installation on the beam at LEP, Percent level accuracy on the equalization of the individual channel response was achieved. The coupling of the pulsing system to each channel was also measured accurately. Results on more than 90 chambers are reported