Run 19 residuals (initial look)

This is an initial look at some along-the-padrow residuals in the TPC for Run 19. This is using 137k events from run 20054041, which is before beam was settled, so there may be rather crazy backgrounds. But it's worth a look anyhow. Also of note, RDOs that are off include 5-7, 5-8, 18-5, accounting for the absence of hits in these locations. And the HV channels 3-1 and 3-5 are believed to be incorrectly swapped (i.e. 3-1 is incorrectly at 1390 V and 3-5 is incorrectly at 1070 V), likely accounting for the poor hit reconstruction in the middle of sector 3. No SpaceCharge & GridLeak corrections have been applied, but the Padrow 40 static correction is applied.

Cuts applied include:
  • TCut cutEdges = "abs(atan(mHitsG.lYHit/mHitsG.lXHit))<0.2"; // avoids sector edges
  • TCut cutPrompt = "abs(mHitsG.lZHit)<200"; // avoids prompt hits
  • TCut cutQA = "mHitsG.mPt>0.5&&mHitsG.mPt<10&&mHitsG.nTpcHits>=50"; // long and reasonable tracks
Other observations:
  1. GridLeak distortion is more apparent in some sectors than others. This has been observed before. But some step up (e.g. sector 5) and some step down (e.g. sector 6), which is confusing.
  2. Several sectors have a large swing for the outermost padrows. Again, some swing up (e.g. sectors 7, 23, 24), while some swing down (e.g. sectors 1, 2, 10, 12, 15, 19), which is confusing. Are these outer grid leaks (but they should all swing the same way)? There is no sign of any field cage shorts in this data (would be seen for all sectors on either side).
Click on the plot for a larger version: