Simulation of beam bunch structure timing

[cerati]

This issue is to track the status of the simulation fo the BNB buch structure timing.

Based on a conversation with @jzennamo , the current status as of 2022/10/25 is:

1. The infrastructure exists and is used by default both by ICARUS and SBND
2. BNB parameters used by ICARUS and SBND are different (e.g. sigma 2.0 vs 1.308, ndtbucket 18.83 vs 19)
3. Corrections for simulating the time of flight within detectors is not accounted for

As techniques are being developed for resolving the timing in data at reconstruction level we should make sure that the simulated information is correct for proper data-MC comparison and modeling of selections.

[cerati]

Some other remarks from @PetrilloAtWork The sigma 2 was mostly a guess. The rest is much less so (BNB does go with 53.103 MHz AFAIK). The lack of correlation between time and location of the interaction translates into the neutrino "blinking" every 19 ns everywhere in the detector for ~2 ns, then disappear until the next bucket. That is not of any use IMO. In ICARUS we have two or three buckets travelling through the detector at once, and SBND has one most of the time. The infrastructure to account for this is not available, unless work has been done that I ignore, and it needs hooks in GENIEHelper and maybe the geometry driver of GENIE. I did not find a good way to implement it.