ALFA_SensitiveDetector can make hits with
0<plate<10. The hit plotting code in
a maximum value of 10 when it uses
plate as the index to arrays, so when a
plate==100 is processed this ends up well outside the array and
corrupts the stack. The fix is to put the
GVS hits into a separate histogram,
skipping the stage where they are used as the index to an array.