Falsifying the padrow-by-padrow T0s

When I studied cosmic rays taken during Run 11, I looked at the z residuals and saw quite a few artifacts. which implied that perhaps there were issues with the padrow-by-padrow T0s. Here are the padrow-by-padrow T0s from the DB from the record for 2010-12-20 00:00:01, which is used for Run 11:


  • Find the mean padrow T0 in each sector, <T0>[sector]
  • Convert (T0 - <T0>[sec]) into a z position by multiplying by 5.5 cm/μs, and by -1 for the east side
  • Plot the profile using a layout just as done with the z residuals in the cosmics

The results clearly implicate the padrow T0s as the cause of the z residuals, with a striking similarity between the two plots. Here I shrink them and put them next to each other for comparison Open each image in a new window/tab for a larger view.

Padrow T0 - <T0>[sec] Z residuals from cosmics


These are probably false T0s. 


Update [2011-09-19]: Using T0s determined from prompt TPC hits, located in the file /afs/rhic.bnl.gov/star/packages/.DEV2/StarDb/Calibrations/tpc/tpcPadrowT0.20100314.000001.C, I see much less correlation with the cosmic ray residuals, but there are still a few notable points of correlation in sectors 20, 23, and 24: