source: JEM-EUSO/equalization_gain/branches/analclass-Sylvie/HowToEaqualizeGain.txt @ 196

20/09/2013 How to eaqualize the gain of MAPMTs on an EC_Unit
Written by Hiroko Miyamoto


First of all, things are not fully automatick yet as we are still
looking for the best way to carry it out.



<STEP 1> Organize your directories (I prefer to use bash.sh
instead of csh,tcsh):
% mkdir YOUR_DIR/analysis
% mkdir YOUR_DIR/analysis/src
% mkdir YOUR_DIR/analysis/data
% export YOUR_DIR/analysis/src srcDIR
% export YOUR_DIR/analysis/data dataDIR

make your data directory for the day. e.g.,:
% mkdir $dataDIR/yYYmMMdDD-APC
% cd yYYmMMdDD-APC


<STEP 2> Modify data file obtained by LabView to fit and make
data directories for the analysis:
There are many ways to do this, and you can do as you wish.
Ask Pierre to make the data file which includes DAC values
and data for ASIC_C and ASIC_D at the beginning as he knows
what I mean.

If you want, the data obtained by LabView can be used as itself
with modifying the parameter on my makeDataFile.sh script.
I leave it for right now because we haven't fixed the data format
yet, at least by the last time I was there.


% cp -p data_s_curves_runXX.data .
% sh $srcDIR/makeDataFile.sh data_s_curves_runXX

This sh automatically makes two directories data_s_curves_runXX_C
and data_s_curves_runXX_D for the data of ASIC_C and ASIC_D respectively.

From next steps, it totally depends on which data you are taking.
Assume you want to analyse the data of ASIC_C.


<STEP 3> Run ROOT, search the suitable parameters for each data
% cd data_s_curves_runXX_C
% ln -s ../FORMER_GAIN_DATA.txt gain-org.txt

Usually, the following command is not necessary as long as the data
includes pedestal, otherwise:
% ln -s ../$pedestal_data_directory_D/*.dat .

Check the parameters in header file or directory input the parameter
in main function as you can see in the source code.
This totally depends on the data. You have to modify it to suitable
parameters.

% root -l

Set the parameters on the top of the program depending on your analysis.
• General policy: parameters starting with "k" at the beginning is
fixed global parameter and usually set in the header file, never change
through the program.
• kDrawCh: channel just you want to check on display. doens't effect
the analysis. 
• fname, fname_ped (kFname, kFnamePed): "YOUR DATA FILE" without ".data".
See examples in the header file.
• dac_half_spe_fix: set DAC value only when you want to adjust the gain
to particular pulse height (DAC value) instead of either average of the
pulse height of reference pixel. Usually just leave it -1.
• fit_min, fit_max (kFitMin, kFitMax): leave them as default,
it is not currently used for the analysis.
• fit_min_scurve, fit_max_scurve (kFitMinS, kFitMaxS): define the range
of s-curve fitting. search proper values by yourself with running root
program a few times.
• kBoard: don't forget to change 0(C) or 1(D) depending on which ASIC
you're analysing
• kChRef (kRefCh): a pixel whose gain remains 64 thorough the gain
adjustment.
• checkAve: for the first run, set this parameter 1, and find a pixel
which remains 64. In the case of parameter 1, all the gains are adjusted
to the average pulse height.
Once you choose the reference pixel, set the parameter 0, as well as
set kRefCh the pixel number. (better to keep in the header file for the
record of each PMTs.)

Once you set all the parameters above, then
[].L PlotScurvesAll-diffFit.C
[]PlotScurve()

Repeat until you define all the parameters above.


<STEP 4> Make the gain table
Once you decide the parameters and modify the header file, then run
% root -l > tmp.data
[].L PlotScurvesAll-diffFit.C
[]PlotScurve()
[].q

If you have the data of ASIC_D, go to the directory of ASIC_D
and do the same.

% cd ../
Check the paramters in $srcDIR/makeGainTable.sh and run
You should add/remove #s depending on which data you're analysing.
% sh makeGainTable.sh
Or type by your hands the commands in the script file.

If everything has been done properly, you should get a gain
table with a proper format.
I would recommend that when you make tmp.data file, to include
the value of threshold used, and the number of iteration, e.g.,
tmp-th180-it0.data
And then do the iteration of the analysis with the data with
the obtained gain table until you get reasonable uniformity.

NOTE that, sometimes PMT gain or efficiency is too low to obtain
the inflection point, in this case the program outputs the -1 for
flag_fit. If it remains -1 after some trials, you should adjust
by hand. Ask Philippe for detailes.


<STEP 5> Adjust gain of EC_unit
Once you succeed to obtain all the gain tables:
1) check the pulse height (dac_sfit[kChRef]-dac_ped[kChRef])
2) choose 1 of 4 PMTs in EC_unit
3) take the ratio of pulse height between reference pixels
4) multiply the gain table by the ratio above
5) combine all the gain tables


Good luck!