Home » Blogs » pokhrel's blog

TPC Calibration: Run 21 OO200

Updated on Sat, 2023-02-11 12:27. Originally created by pokhrel on 2023-01-16 10:54.

 
Summary of the TPC SC&GL calibration for OO200 GeV (RFF and FF) datasets.  Calibration is done separately for these two datasets of different magnetic field settings. 
Working directory: /star/u/pokhrel/TPC_Cal/Run21/OO200/*
RFF Dataset
-> PCA done up to 4th iterations and stopped as there was no more improvement in the fit. 
-> The fit converges for 2-scalers (zdcw:vpdw). Good linearity between the measured and fitted. 
-> g2 and log(g5) are "AT LIMIT!". Ignored as their contribution is insignificant. 
-> Plot: SC fit
-> Final parameters : 
  *** FINAL CALIBRATION VALUES: ***

sc = (1.0 +/- 0.3862)*(1.168e-08*(zdcw-(3.546e+04 +/- 1.025e+04))+(7.437e-08*(vpdw)))
  with GL =  0.50 +/-  0.00

FF Dataset
-> PCA done up to 3rd iterations, no more improvement in the fit. 
-> Fit failed for varied GL. Fixing GL converges the fit. 
-> Both 1-scaler (bbce) and 2-scalers (bbcx:bbce) fit are equally good. However, macro always warns about the trustworthiness of the fit result (in all iterations).
-> Plot : SC fit (bbce)   SC fit (bbcx:bbce)
 -> Final parameters (either of 1- or 2-par fit):

-------> 1 - scaler <---------
*** FINAL CALIBRATION VALUES: ***
sc = (3.959e-08 +/- 2.027e-09) * ((bbce) - ( -7174 +/-   2078))
  with GL =  0.50 +/-  0.00
 

-------> 2 - scalers<---------
*** FINAL CALIBRATION VALUES: ***

sc = (1.0 +/- 0.1032)*(6.833e-08*(bbcx-( -1664 +/-   1401))+(4.009e-08*(bbce)))

  with GL =  0.50 +/-  0.00 
---------------------Detailed Calibration Progress (later iteration appears first) ------------------------
(First part is for RFF dataset and second is for FF dataset.)

1. Reversed Full Field (RFF)
-> TRG SETUP : production_OO_200GeV_2021
    -> STAR Magnets: -4,510.3 Amps     Polarity B (Reversed) Full Field
-> Data taking period: 2021-05-10 - 2021-05-16
-> Runs used for calibration: Runlist

Pass 4

USING STDDEV sc => 0.000086 :: gapf => 0.014317
 
 
*** FINAL CALIBRATION VALUES: ***
sc = (1.0 +/- 0.3862)*(1.168e-08*(zdcw-(3.546e+04 +/- 1.025e+04))+(7.437e-08*(vpdw)))
  with GL =  0.50 +/-  0.00
 
WARNING! Symptoms of non-linearity in chosen luminosity scaler!
  Suggestion: use more PCA variables

Plot: SC fit
Plot: GL fit



2. Full Field (FF)
-> TRG SETUP : production_FF_OO_200GeV_2021
    -> STAR Magnets: 4,511.2 Amps     Polarity A Full Field
-> Data taking period: 2021-05-17 - 2021-05-30
-> Runs used for calibration: Runlist. 

For the FF datasets, the coefficients must be passed to the "row.fullFieldA"

 A couple of iterations were made to reach to the Pass 06, which comes out with following features: 

--> Very large Gl value (3+/- 12) if allowed to float. So the GL is fixed to 0.5. 
-->  The best scalers combination found is "bbcw:vpde"
--> The second best scalers combination is "bbcx:bbce"

Pass 06
"bbcw:vpde" Combination Result (First Best):
USING STDDEV sc => 0.000072 :: gapf => 0.009744

*** FINAL CALIBRATION VALUES: ***
sc = (1.0 +/-  0.114)*(8.194e-08*(bbcw-( -4789 +/-   1168))+(-1.252e-07*(vpde)))
  with GL =  0.50 +/-  0.00

SCfit "bbcw:vpde"


"bbcx:bbce" Combination Result (Second Best)

USING STDDEV sc => 0.000072 :: gapf => 0.009726
*** FINAL CALIBRATION VALUES: ***
sc = (1.0 +/- 0.1122)*(5.618e-08*(bbcx-( -2229 +/-   1680))+(3.61e-08*(bbce)))
  with GL =  0.50 +/-  0.00

SCfit "bbcx:bbce"

 
»