Demonstrator_Noise.C

Example of a ROOT macro that computes the average fluctuations over time buckets, for all channels.

*  [ROOT]  .L Demonstrator_Noise.C
*  [ROOT]  PlotDemonstrator_Noise ( "../../data/Demonstrator/run_baseline.dat", 0, 0, 1, 17 );
*  

The processing is done by the functions from the GETRoot library for the channels mean and RMS samples, and then by the macro for averaging the RMS over time buckets.

//======================================================================
//  ROOT macros for TPC Demonstrator system
//    - read a test baseline file (2 CoBo modules / 8 AsAd)
//    - compute RMS sample for all channels
//    - for each channel, compute the average RMS and its standard
//      deviation -> average nois for the channel
//
//======================================================================
/*
These macros require to load the GET libraries
  gROOT->Macro ( (getenv("GET_BASE")+string("/root/GETRootLibs.C")).c_str() );

To execute the macro
  .L Demonstrator_Noise.C
  PlotDemonstrator_Noise ( "../../data/Demonstrator/run_baseline.dat" );
*/

//----------------------------------------------------------------------
//  This function reads all events from a TPC demonstrator run file
//  (a baseline run).
//  For all channels, it creates the average samples for each channel,
//  then the RMS samples.
//
//  Then for each channel, the average value of the RMS sample is computed
//  (averaging over time buckets), and its variation.
//  This is plotted for all channels
void PlotDemonstrator_Noise ( const string & data_file )
{
  GSetVerboseLevel(3);
  getProcessedInfoCount = 5;

  gStyle->SetPadLeftMargin  ( 0.06 );
  gStyle->SetPadRightMargin ( 0.02 );
  gStyle->SetTitleOffset  ( 1.0,  "X" );
  gStyle->SetTitleOffset  ( 0.5,  "Y" );
  gStyle->SetTitleSize    ( 0.05, "XYZ" );
  gStyle->SetLabelSize    ( 0.05, "XY" );
  gStyle->SetLabelSize    ( 0.04, "Z" );
  gStyle->SetLabelOffset  ( 0.005, "Z" );

  // create the GET system
  u_short ncobo = 2;        // 2 CoBo modules (TPC demonstrator)
  u_int   n     = 512;      // 512 samples / channel
  double  dt    = 0.01;     // 0.01 us sampling time
  GETSystem gDem(ncobo,n,dt);

  //------------------------------------------------------------
  // Compute the average / RMS for all channels
  cout << endl
       << "Computing RMS samples" << endl;
  u_int nr = GETSystemMean ( gDem, data_file, 0, false );

  cout << "Number of events read: " << nr << endl
       << endl;

  if (nr > 0)
  {
    // call GET/ROOT function to build RMS samples, with respect
    // to current content of the channels (mean values)
    GETSystemStdDeviation ( gDem, data_file, 0, false );

  //------------------------------------------------------------
  // For each channel, compute the mean RMS over time buckets

    u_int nch = gDem.GetTotalChannelCount();
    TGraphErrors * gr_noise = new TGraphErrors ( nch );
    TGraph       * gr_pts   = new TGraphErrors ( nch );

    for ( u_int k = 0; k < nch; ++k )
    {
      GETSample * out = &(gDem.GetTotalChannel(k)->OutSample());
      double  rms = out->GetMean ( );   // average fluctuation over time buckets
      double  sig = out->GetRMS  ( );

      gr_pts->SetPoint        ( k,  k, rms );
      gr_noise->SetPoint      ( k,  k, rms );
      gr_noise->SetPointError ( k, 0., sig );
    }

    gr_noise->SetTitle ( "Average channels noise" );
    gr_noise->SetLineColor ( kRed+1 );
    gr_noise->SetLineWidth ( 1 );
    gr_noise->SetLineStyle ( 1 );
    gr_noise->SetMarkerColor ( kRed+1 );
    gr_noise->SetMarkerStyle ( 20 );
    gr_noise->SetMarkerSize  ( 0.3 );
    gr_pts->SetMarkerColor ( 1 );
    gr_pts->SetMarkerStyle ( 20 );
    gr_pts->SetMarkerSize  ( 0.5 );
    gr_noise->GetXaxis()->SetRangeUser ( -1., nch );
    gr_noise->GetXaxis()->SetTitle ( "channel index" );
    gr_noise->GetYaxis()->SetTitle ( "noise (coder units)" );
    gr_noise->GetXaxis()->CenterTitle ( );
    gr_noise->GetYaxis()->CenterTitle ( );

    TCanvas * canvas = new TCanvas ( "PlotNoiseSummary", "PlotNoiseSummary", 1500, 400 );
    gr_noise->Draw ( "AP" );
    gr_pts->Draw ( "P" );
    canvas->Update();

    // create an EPS file
    gSystem->mkdir ( "plots", kTRUE );
    canvas->SaveAs ( "plots/Demonstrator_Noise.eps" );
  }

}