void plot_Amp() {
//----------------------------------------------
// 2016.4.1  updated for ROOT 6
// 2010.10.1  original with help of J. Kaplon
//---------------------------------------
//
TCanvas *c1 = new TCanvas("c1","A Simple Graph",0,0,700,500);
//c1->SetFillStyle(4100);
gStyle->SetOptStat(0);
c1->SetGrid();

int ixmax = 202;
 double A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z;
//
TLegend *leg = new TLegend(0.50,0.60,0.92,0.93,"Signal/crosstalk pulse shape for #delta input");
//
for (int k=0; k<6; k++){
 double x[ixmax], y[ixmax];
for (int it=0; it<ixmax; it++) {
double t = it*0.5 ;
x[it] = it*0.5;
//
//-----------SCT digitization model----signal---------------
if(k==0){
double m_PeakTime = 21.;
double m_NormConstCentral = (exp(3.0)/27.0);
double tC = t / (m_PeakTime/3.0) ;
y[it] = tC*tC*tC*exp(-tC)  * m_NormConstCentral ;
}   
//-----------SCT digitization model----crosstalk---------------
if(k==1){
double m_PeakTime = 21.;
double m_NormConstNeigh =  exp(3.0-sqrt(3.0))/(6*(2.0*sqrt(3.0)-3.0));
m_NormConstNeigh *= 0.05;
double tC = t / (m_PeakTime/3.0) ;
y[it] = tC*tC*exp(-tC)*(3.0-tC) * m_NormConstNeigh ;
}
//-----------220 uA---non-irradiated--------signal---------------
if(k==2){
A=0.31123;B=4.6855;C=0.134685;D=0.0879467;E=8.77451;F=0.104167;
G=9.39697;H=0.527247;I=0.25;
y[it] = 2*(A*cos(D*t)-B*sin(D*t))*exp(-C*t)+E*exp(-F*t)+(-G-H*t)*exp(-I*t);
y[it]*=1./0.338;
}
//-----------220 uA--------------crosstalk---------------
if(k==3){
A=0.176508;B=0.538337;C=0.196667;D=2.96078;E=0.134685;
F=0.0879467;G=20.1466;H=0.124127;I=8.77451;J=0.104167;
K=11.5889;L=0.831773;M=0.25;
y[it] = A*exp(-B*t) -2*(C*cos(F*t)-D*sin(F*t))*exp(-E*t)-G*exp(-H*t)
+I*exp(-J*t)+(K+L*t)*exp(-M*t);
y[it]*=1./0.338;
}
//---------------130 uA--------irradiated----------------------
if(k==4) {
A=3.7761;B=0.104167;C=0.91214;D=0.492782;E=0.0651927;F=0.0898136;
G=1.95182;H=0.125024;I=0.25;
y[it] = A*exp(-B*t)-2*(C*cos(F*t)+D*sin(F*t))*exp(-E*t)-(G+H*t)*exp(-I*t);
y[it]*=1./0.347;
}
//----------------130uA---------irradiated crosstalk----------------
if(k==5) {
A=1.45105;B=4.13585;C=0.149649;D=0.0866995;E=3.7761;
F=0.104167;G=0.638498;H=0.344948;I=0.0651927;J=0.0898136;
K=7.95519;L=0.422717;M=0.25;
y[it]=2*(A*cos(D*t)-B*sin(D*t))*exp(-C*t)+E*exp(-F*t)
+2*(G*cos(J*t)+H*sin(J*t))*exp(-I*t)-(K+L*t)*exp(-M*t);
y[it]*=1./0.347;
}
//cout<<"k,t,x,y="<<k<<" "<<t<<" "<<x[it]<<" "<<y[it]<<endl;
}
  TGraph *h1 = new TGraph(ixmax, x, y);
  h1->GetXaxis()->SetRangeUser(0.,100.);
  h1->GetXaxis()->SetTitle("time [ns]");
  h1->GetXaxis()->SetTitleOffset(1.0);
  h1->GetYaxis()->SetTitle("Pulse height");
  h1->GetYaxis()->SetTitleOffset(1.2);
  h1->SetMaximum(1.2);
  h1->SetMinimum(-0.2);
  h1->SetLineColor(k+1);
  h1->SetLineColor(4);
  if(k<2) h1->SetLineColor(1);
  if(k>3) h1->SetLineColor(2);
  h1->SetLineWidth(2);
  if(k==1 || k==3 || k==5) h1->SetLineStyle(2);
  if(k==0) h1->Draw("AL");
  if(k!=0) h1->Draw("SAME L");
  switch(k){
   case 0:leg->AddEntry(h1,"SCT Digitization : signal","l");break;
   case 1:leg->AddEntry(h1,"SCT Digitization : crosstalk","l");break;
   case 2:leg->AddEntry(h1,"un-irradiated (Ic=220#muA): signal","l");break;
   case 3:leg->AddEntry(h1,"un-irradiated (Ic=220#muA): crosstalk","l");break;
   case 4:leg->AddEntry(h1,"irradiated (Ic=130#muA): signal","l");break;
   case 5:leg->AddEntry(h1,"irradiated (Ic=130#muA): crosstalk","l");break;
   }
}

zero= new TLine(0,0,100,0);
zero->Draw();
leg->SetFillColor(10);leg->SetBorderSize(2);
leg->SetTextSize(0.030); leg->Draw(); 
c1->Print("Amp.png");
}