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SSD pedestal runs stability

Updated on Fri, 2014-05-16 09:28. Originally created by bouchet on 2014-03-16 11:37.
  1. look at the pedestal file taken with the SSD
  2. only st_pedestal_***.daq files are used (pedestal run using Tonko's routine : $STAR/StRoot/RTS/src/DAQ_SST/sstPed.cxx
  3. plot <ped> and <rms> for the chips on side P and side N : total is 16(wafers)*6chips = 96 entries per ladder
  4. repeat for all runs
List of runs so far :
/star/data03/daq/2014/055/15055023/st_pedestal_adc_15055023_raw_0000001.daq
/star/data03/daq/2014/055/15055035/st_pedestal_15055035_raw_0000001.daq
/star/data03/daq/2014/055/15055098/st_pedestal_15055098_raw_0000001.daq
/star/data03/daq/2014/055/15055099/st_pedestal_15055099_raw_0000001.daq
/star/data03/daq/2014/070/15070091/st_pedestal_15070091_raw_0000001.daq
/star/data03/daq/2014/070/15070096/st_pedestal_15070096_raw_0000001.daq


Pedestal and rms are calculated as (according Tonko) :
ADCprime  = (ADC+300)%1024
Ped       = mean(ADCprime)
ADC2prime = ADCprime * ADCprime
RMS       = sqrt(mean(ADC2prime) - Ped*Ped))
but later the rms is multiplied by 16 :
for(s=0;s<SST_STRIP_COU;s++) {
 short pp ;
 pp = (short)(ped->ped[f][h][s] + 0.5)  ;
 *dta++ = pp;
 pp = (u_short)(ped->rms[f][h][s]*16.0  + 0.5) ;
 *dta++ = pp ;
 }
which is taken into account in Long's DaqMaker.

Fig 1 : <ped> vs. Ladders sideP for run 15055098


Fig 2 : <rms> vs. Ladders side P for run 15055098

Fig 3 : example : <ped> chip 18 ladder 1 side P vs. run number (see Fig1 bottom left)


This pdf file shows <ped> and <rms> on P and N side for 4 of the pedestal runs.
Although we cannot conclude yet about the statibility (only 6 runs and it represents only 2 days, and some of the runs were close in time), we can already see some chips that remained bad (<rms> plots)
 






 

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