...
Originally 3 runs failed due to NFS problems - they've since been re-run but I didn't included them ..I'd already started looking at the other 97 runs and was too lazy to toss them in. So in reality, this considers 4.85 million generated events which resulted in 1,213,381 3-in-a-row triggers
Out of those triggers 364 events showed no hits in the ACD - where hit was defined as 0.1 MIP.
These events were peeled from the MC, DIGI, and RECON TTrees and are available here:
ftp://ftp-glast.slac.stanford.edu/glast.u15/DataServer/1130309366381/
All the events were viewed in the event display to categorize them.
There are some classes of events that should be discarded:
95 completely missed the instrument, the trigger was the result of noise
51 were CAL events that had backsplash which triggered the TKR and just didn't happen to hit a tile
2 hit the space-craft and interacted causing backsplash.
So that leaves us with 216 to consider.
Of these 134 truly missed any active material in the ACD.
*64 of the remaining events did have at least one MC "hit" within a tile, but the tile was determined to be below threshold by the digitization algorithm.
18 had MC "hits" in ribbons that were determined to be below threshold in the digitization algorithm (though we should note that the algorithm for the ribbons needs adjustment - namely in terms of the mean number of PEs by position along the ribbon)*
Of the 134 that failed to go through any active material in the ACD: 115
118 slipped through the gaps along the corners where the side tiles meet.
and
16 went through between two columns of side tiles on the same face..., but didn't' seem to go through a ribbon.. need to look at those a bit more closely I suspect.
3 seemingly fell through some gap in top
