PMT timing offsets

The goal here is to set time offsets for all PMT's such that t=0 corresponds as closely as possible to the moment photons imping on the target.

First, I used the clean photon peak from a CF252 run to synchronize all the detectors. Here is what the timing spectra look like after these offsets are applied:

Next, I take the difference between per pulse normalized TDC spectra of empty target runs and Al runs. Next, a single offset is applied to all detectors so that the photon peak lies at 4 ns - or the time it takes light to travel the distance from target to detector.

These are the resulting offsets:

D30T_offset = -17.2 D30B_offset = -30.4 D54T_offset = -13.9 D54B_offset = -24.9 D78T_offset = -18.5 D78B_offset = -33.2 D102T_offset = -29.6 D102B_offset = -28.0 D126T_offset = -14.9 D126B_offset = -25.2 D150T_offset = -18.0 D150B_offset = -25.9 D210T_offset = -17.7 D210B_offset = -27.9 D234T_offset = -14.5 D234B_offset = -27.8 D258T_offset = -1.2 D258B_offset = -22.8 D282T_offset = -13.9 D282B_offset = -28.2 D306T_offset = -15.4 D306B_offset = -27.9 D330T_offset = -17.0 D330B_offset = -33.0