Run 2004 Gain Matching for Towers 5TA-8TE
  • The calibration of towers 5TA-8TE for RUN3 was performed with the HV settings in file iii-J.kreml
    .
  • Using the RUN3 calibration and IDEAL calibration for each tower, along with an empirically determined power law relationship, the new HV file iv-A.kreml was created using macro BestGuess.C .
    GRUN3/GIDEAL = (HViii-J.kreml/HViv.kreml)8.3

  • Voltages from both HV files were loaded and LED spectra recorded. Each LED peak was fit with a Gaussian and the ratio of the centroids from each HV setting was calculated.

  • Below is a plot of "Conformity" :
    Conformity = (GRUN3/GIDEAL)/ (LEDiii-J.kreml/LEDiv.kreml) ===>>> 1?




  • The peak at -1 represents the towers which were nonfunctional during run2003 (and therefore have no calibration)
    1. PMT 5TC12,PMT 5TD04,PMT 5TD10,6TA12,6TB04,6TC09,7TB09
  • The peak at -2 represents the towers which were functional during run 2003 but are showing problems now
    1. PMT 5TE03,6TD10,6TB07 -- known problems
    2. 6TD11 -- shows LED but doesn't change with HV -- special case

    Of the remaining 145 "good" towers 40% of them deviate by more than 5% from a conformity = 1. The majority of the tower with 10% or more deviation from 1 are towers 1-3. These towers required the largest gain change and therefore are most sensitive to an incorrect power law value (8.3).



    This process was iterated a second time using a new HV file iv-B.kreml . In this iteration all towers with 0.97 < conformity < 1.03 were held at the same voltage and all other tubes changed according to same power law relationship. The result is that 14% of the 146 "good" towers deviate by more than 5% from a conformity of 1. Only 2 tubes deviate by more than 10%. The tube with conformity = 0.6 is 6TE11, which showed "deviant" behavior in the 1st iteration and will have to be set by hand.


    The conformity of the tubes with unchanged voltages should not vary from Iteration 1-2. It appears this is true to about 1%:
    TOWER 5TA08 1st Iteration --> 1.0283 2nd Iteration --> 1.0128
    TOWER 5TB12 1st Iteration --> 1.0074 2nd Iteration --> 1.0106

    Towers 7TD - 8TE
    The entire calibration procedure was repeated at a later time for tower 7TD-8TE.Below is a plot from the 2nd iteration of gain matching:



  • The peak at -1 represents the towers which were nonfunctional during run2003 (and therefore have no calibration)
    1. 7TD08,8TD08,8TE04,8TE12,8TD04
  • The peak at -2 represents the towers which were functional during run 2003 but are showing problems now
    1. 7TE07
  • The peak at 2.7 is a tower which was set too low in the HV_J file from run 2003. The appropriate gain change assigned in making iv_08_B.epics lowered the gain even more so a LED peak was not present in 1st iteration. 800 V was assigned in the 2nd iteration. This tube will have to be calibrated via the slope method
    1. 8TD09
    A zoomed in view of the above plot shows very good agreement with desired gains



    The final HV files containing the voltages after the 2nd iteration of gain matching are iv_08_B.epics , iv_07_B.epics , iv_06_B.epics , and iv_05_B.epics . In these files any tubes which had a flag -1 or -2 in this analysis were set to 800 V and will have to be calibrated via the slope method.

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    A comparison of the HV determined from Sasha's PMT characterization, iv-Piotr.kreml , and the HV from the 2nd Iteration of Gain Matching was made for sectors 5TC,6TA-6TE,7TA-7TC. Below is a plot of the ratio of the LED peak centroid of Sasha's HV to the 2nd Iteration HV. The top panel contains data from all subsectors. The 2nd plot contains only towers from sector 6 and the 3rd plot only from sector 7. There appears to be a systematic difference between the tubes in sector 6 and 7. The towers which have a ratio < 2 are: 6TB05,6TD07,6TD08,6TD11,6TE10-12,7TA05,7TA12,all of 7TB and 7TC. All other towers were either uncalibrated or have a ratio > 2. A complete table is at the bottom of the page "sasha.summary".

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    The Table calib1_summary.csv contains the calibration Gains, LED Centroids and errors for tower 5TA-7TC for the 1st Iteration of Gain matching.
    The Table calib2_summary.csv contains the calibration Gains, LED Centroids and errors for tower 5TA-7TC for the 2nd Iteration of Gain matching.
    The Table calibB_summary.csv contains the calibration Gains, LED Centroids and errors for tower 7TD-8TE for the 1st Iteration of Gain matching.
    The Table calibB2new_summary.csv contains the calibration Gains, LED Centroids and errors for tower 7TD-8TE for the 2nd Iteration of Gain matching.
    The Table sasha_summary.csv contains the LED centroid and errors for Sasha HV and 2nd Iteration HV as well as the ratio fo the two and error.

    These tables were produced using input file gain.list and gainB.list with macro LedCalib.C . Logbook entrys #506,#508,#509 and #510 contain datafile, histograms and macro locations.