Equalisation of the PMT response to charge particles for the LUCID detector of the ATLAS experiment

With a view to the Run II of LHC, 44 Hamamatsu R760 PMTs have been calibrated with a 207Bi source. The working point of each PMT has been xed in order to equalise the PMT gain at a value smaller than $10^{5}$. Studies on the reproducibility and the stability in time of such calibration permitted to reach a 5% accuracy on PMT gain. In addition, an evaluation of the relative gain of 10 modied PMTs has been performed.