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There are very noticeable outliers in the TkrDigiLayer and TkrDigiTower plots. I'm not sure what should be special in the overlays for Layers 7 and 17 or Towers 0 and 8? Calibration mismatch? The overlays are derived from data, but the system tests use ideal calibrations. (Nope. From Leon: the overlay events are type 0, where the specific calibration info is removed.) Seems like a big difference for that. Something else funny with the systests? Note that the system tests pass all events, and there is no filtering or trigger criteria applied to the digi distributions.
You may have already guessed... these are hot tracker strips in the PT (periodic trigger) events. I believe the most recent overlay events are selected over the full precession period (~55 days) and the selected period started close to the beginning of science ops. See this presentation from Hiro at the Sept collaboration meeting. The two layers outside specification at that time were Tower 0 X7 (32 strips) and Tower 8 X17.
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The layer and tower outliers are there throughout, but are expected - explained above.
A secondary item is if the AllGammaOverlay test is sufficient at the system test level. Do we want additional tests for specific energies or maybe magnetic latitudes?
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