In the 2015 runs, the timestamp of an event (event.getTimeStamp() in java, or event_time in the DST) was the number of ns since the epoch, which is a useful quantity for my time dependent ecal gain corrections. In the 2016 data, however, the starting point was changed to something like 20-something seconds or 4000-something seconds before the beginning of the run.
1) how do i get the number of ns from the epoch in Java?
2) why was this change made? Should we fix this in the next reconstruction pass?
thanks.
