{
   gROOT->Reset();
   // wtopx,wtopy are the pixel coordinates of the top left corner of
   // the canvas (if wtopx < 0) the menubar is not shown)
   // ww is the canvas size in pixels along X
   // wh is the canvas size in pixels along Y
   c1 = new TCanvas("c1","ABS1 gauge calibration June 4 2008",200,10,700,500);

   c1->SetFillColor(42);
   c1->SetGrid();
   c1->GetFrame()->SetFillColor(21);
   c1->GetFrame()->SetBorderSize(12);
//    Tpad pad1("pad1"," ",0.1,0.6,0.6,0.9);
//    Tpad pad2("pad2"," ",0.1,0.6,0.6,0.9);
//    Tpad pad3("pad3"," ",0.1,0.6,0.6,0.9);
//    Tpad pad4("pad4"," ",0.1,0.6,0.6,0.9);
   c1->Divide(2,2);

   c1_1->cd();
   Int_t n = 8;  Int_t i;
   /* MKS data in mbar */
   Float_t y[n]  = {2.20e-5,6.00e-5,7.40e-5,10.6e-5,18.6e-5,42.2e-5,147.6e-5,4.30e-5};
   /* CV data in mbar*/
   Float_t x[n]  = {1.414e-6,7.340e-6,15.23e-6,31.26e-6,68.10e-6,170.7e-6,624.6e-6,9.894e-6};
   Float_t ex[n];    Float_t ey[n]; 

   /* stat error on MKS gauge (by eye, not from manual) in ubar :     0.010  */ 
   for(i=0; i<n ; ++i ) {     ey[i]=0.000010;     ex[i]=0.05*x[i];   }

   gr = new TGraphErrors(n,x,y,ex,ey);
   gr->SetTitle("CV");
   gr->SetMarkerColor(4);
   gr->SetMarkerStyle(21);
   gr->SetLineColor(2);
   gr->SetLineWidth(4);
   gr->GetYaxis()->SetTitle("MKS (mbar)");
   gr->GetXaxis()->SetTitle("CV (mbar)");
   gr->Draw("ALP");

  TF1 *f1 = new TF1("f1","pol1",0,5);
  gr->Fit("f1","Q");
//   TVectorD c_graph(2);
//   c_graph(0) = f1->GetParameter(0);
//   c_graph(1) = f1->GetParameter(1);

  /*********************/

   c1_2->cd();
   /* HV2 data in mbar*/
   Float_t x[n]  = {1.064e-6,5.756e-6,12.31e-6,25.60e-6,72.22e-6,288.2e-6,1978e-6,7.551e-6};
   Float_t ex[n]; 

   for(Int_t i=0; i<n ; ++i ) {    ex[i]=0.05*x[i];   }

   gr2 = new TGraphErrors(n,x,y,ex,ey);
   gr2->SetTitle("HV2");
   gr2->SetMarkerColor(4);
   gr2->SetMarkerStyle(21);
   gr2->SetLineColor(2);
   gr2->SetLineWidth(4);
   gr2->GetYaxis()->SetTitle("MKS (mbar)");
   gr2->GetXaxis()->SetTitle("HV2 (mbar)");
   gr2->Draw("ALP");

  TF1 *f2 = new TF1("f2","pol1",0,5);
  gr2->Fit("f2","Q");

  /*********************/

   c1_3->cd();
   /* HV2b data in mbar*/
   Float_t x[n]  = { 0.954e-6,5.033e-6,10.35e-6,20.63e-6,47.42e-6,112.5e-6,445.9e-6,6.246e-6};
   Float_t ex[n]; 

   for(Int_t i=0; i<n ; ++i ) {    ex[i]=0.05*x[i];   }

   gr3 = new TGraphErrors(n,x,y,ex,ey);
   gr3->SetTitle("HV2B");
   gr3->SetMarkerColor(4);
   gr3->SetMarkerStyle(21);
   gr3->SetLineColor(2);
   gr3->SetLineWidth(4);
   gr3->GetYaxis()->SetTitle("MKS (mbar)");
   gr3->GetXaxis()->SetTitle("HV2 (mbar)");
   gr3->Draw("ALP");

  TF1 *f3 = new TF1("f3","pol1",0,5);
  gr3->Fit("f3","Q");

  /*********************/

  n=4;
   c1_4->cd();
   /* HV2 data in mbar*/
   Float_t x[n]  = {5.756e-6,12.31e-6,25.60e-6,72.22e-6};
   Float_t ex[n]; 
   Float_t y[n]  = {9.00e-6,2.20e-5,5.40e-5,1.14e-4,2.09e-4};
   Float_t ex[n]; 
   Float_t ey[n]; 

   /* stat error on MKS gauge (by eye, not from manual) in ubar :     0.010  */ 
   for(i=0; i<n ; ++i ) {     ey[i]=0.000010;     ex[i]=0.05*x[i];   }
   gr4 = new TGraphErrors(n,x,y,ex,ey);
   gr4->SetTitle("HV2");
   gr4->SetMarkerColor(4);
   gr4->SetMarkerStyle(21);
   gr4->SetLineColor(2);
   gr4->SetLineWidth(4);
   gr4->GetYaxis()->SetTitle("MKS (mbar)");
   gr4->GetXaxis()->SetTitle("HV2 (mbar)");
   gr4->Draw("ALP");

  TF1 *f4 = new TF1("f4","pol1",0,5);
  gr4->Fit("f4","Q");

     c1->Print("2008june4.eps");
     c1->Update();


}