Good data:
/home/douglas/PiPToF/pip_cosmic5.dat
/home/douglas/PiPToF/pip_cosmic6.dat

Relative gains:
Position (in channels) of lower edge of Landau distribution in
gmean of qdcs from both ends of each bar

C0:73   C1:68   C2:79   C3:79
D0:61   D1:62   D2:67   D3:82
E0:62   E1:58   E2:54   E3:71   E4:62
F0:56   F1:60   F2:58   F3:49   F4:50   F5:65

i.e. The gains are set to within +- 20% in absolute terms, but note that
C-layer is 13.5cm high, whereas D-, E- and F-layers are 17.5cm high.
Some fine tuning is likely to be required with beam.

Droop:
This was obtained by splitting each bar into sectors and requiring
a coincidence between events in the equivalent sectors in the top and
bottom bars. i.e. The cosmic muons are constained to pass nearly
vertically through the bars.

The positions of the lower edge of the Landau distributions are given
as a function of sector number.

C-layer:
C0:     74      72      70      73
C1:     71      67      67      75
C2:     84      77      78      80
C3:     81      78      78      83

D-layer:
D0:     69      60      59      62
D1:     64      60      60      60
D2:     71      66      65      64
D3:     81      80      77      82

E-layer:
E0:     69      63      60      59      64      76
E1:     62      56      54      55      60      70
E2:     59      55      51      51      54      60
E3:     89      75      67      67      74      86
E4:     69      62      59      60      62      74

F-Layer:
F0:     61      54      54      54      56      59      66
F1:     67      62      59      58      60      64      72
F2:     69      63      57      57      56      58      62
F3:     57      50      48      47      48      53      55
F4:     52      49      48      47      49      52      57
F5:     71      67      63      62      64      70      79

i.e. Some residual droop is seen in most bars, especially close to the ends.