Least counts

D. Peressounko 2003
Revised by A. Kazantsev 2004
stkav@rcf.rhic.bnl.gov
This set of macros calculates Least Count parameters i.e. offset and TOF slope in ns/(1000*chan). This macro fits dependence on delay for each module by linear function and saves the offset and Slope parameters. Then it calculates offsets and slopes distributions, fits them with Gaus and extracts means and sigmas. Using mean and deviation, we estimate good/bad modules. We find that the best results are obtained if we assume that good modules are insude the range (mean-4*sigma)<LeastCount<(mean+6*sigma) Once module's parameters are outsude this range, we repare it: If there are 12 subsequent mudules (whole 1/2 of ASIC), we assume, that it was really dead and put mean parameters for offset and slope. If this is not full 1/2 ASIC, we calculate average offset and slope in this 1/2 ASIC and put into this (or these) module(s). For reference, we create a figure with fit of delay dependence for each bad channel and put it into dir Figs. Finally, we write resulting parameters into the dir Data. /home/phnxpbgl/work/RawData/calib/timing
  1. Make sure that HV is on.
  2. Force anyone using DAQ to leave it for 15 minutes
  3. Load Calibration trigger configuration
  4. Make sure that PPG signal reach LEDs.
  5. Take an LED run (one have to use partition including GL1)
  6. Insert a 8 ns cable delay to extend PPG cable
  7. Repeat stages 5 and 6 three-four times. Four runs is enough to calculate least counts. Taking more runs is senseless as our TAC range is less than 40 ns.
  8. Write run names (pathes) and delays (in ns) in file DelayRuns.list like: 
    

            /common/a1/calibdata/pbgl/av0212/rc-0114447-EMC.E.B.prdf     0
    

            /common/a1/calibdata/pbgl/ts0212/rc-0114461-EMC.E.B.prdf     8
    

            /common/a1/calibdata/pbgl/ts0212/rc-0114462-EMC.E.B.prdf    16
    

            /common/a1/calibdata/pbgl/ts0212/rc-0114463-EMC.E.B.prdf    24
  9. Run root -q -l writeDelayHistos.cmd and after that root -q -l writeDelayHistos.cmd\(1\)
  10. Once histograms are created (files like Delay_24_E0_PED.root), run macros root MakeFits.C and root MakeFits.C\(1\)
Last update:
Andrey Kazantsev