Alignment parameters obtained starting from the alignment parameters of the
colums (from test beam), by means of ground muons. 

STEP1
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Alignment parameters are first corrected for the AVERAGE shift (NB only
TRASLATIONS) of the PLANE (evaluated from residual distributions, obtained by 
using alignment parameters of the colums). 

STEP2
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Muon tracks crossing two different colums were selected, and parameters were
corrected for the relative misalignment of the colums.