Geant4 primary events are extracted from Neven's PAW Ntuple (on Juliette's website) due to lacking own generator.
Shielding wall is made out of lead, everthing is air so far. Dimensions and location derived from SolidWorks drawings,
may change with collimator design. At present only one VDC with position sensible U and V plane inserted. VDC is tilted
by 45 deg in respect to center track of 20.8 deg. The local hits are stored in ROOT histograms, ntuple with
all relevant track parameter will follow.