* provided "as is" without express or implied warranty. *
**************************************************************************/
-/*
-$Log$
-Revision 1.3 2003/06/26 08:45:22 morsch
-- Vertex using Vertex() method.
-- Use member data in GetNumberOfSlowNucleons call.
+/* $Id$ */
-Revision 1.2 2003/03/25 09:55:24 morsch
-Numbers of slow nucleons either from model or user set.
-
-Revision 1.1 2003/03/24 16:49:23 morsch
-Slow nucleon generator and model.
-
-*/
-
-/*
- Generator for slow nucluons in pA interactions.
- Source is modelled by a relativistic Maxwell distributions.
- Original code by Ferenc Sikler <sikler@rmki.kfki.hu>
- */
+//
+// Generator for slow nucleons in pA interactions.
+// Source is modelled by a relativistic Maxwell distributions.
+// This class cooparates with AliCollisionGeometry if used inside AliGenCocktail.
+// In this case the number of slow nucleons is determined from the number of wounded nuclei
+// using a realisation of AliSlowNucleonModel.
+// Original code by Ferenc Sikler <sikler@rmki.kfki.hu>
+//
#include <TDatabasePDG.h>
#include <TPDGCode.h>
#include <TH2F.h>
+#include <TH1F.h>
+#include <TF1.h>
#include <TCanvas.h>
#include "AliCollisionGeometry.h"
// Default constructor
fSlowNucleonModel = 0;
fCollisionGeometry = 0;
+ fDebugHist1 = 0;
+ fDebugHist2 = 0;
}
AliGenSlowNucleons::AliGenSlowNucleons(Int_t npart)
fDebug = 0;
}
+//____________________________________________________________
+AliGenSlowNucleons::AliGenSlowNucleons(const AliGenSlowNucleons & sn):
+ AliGenerator(sn)
+{
+// Copy constructor
+ sn.Copy(*this);
+}
+
//____________________________________________________________
AliGenSlowNucleons::~AliGenSlowNucleons()
{
delete fSlowNucleonModel;
}
+void AliGenSlowNucleons::SetProtonDirection(Float_t dir) {
+// Set direction of the proton to change between pA (1) and Ap (-1)
+ fProtonDirection = dir / TMath::Abs(dir);
+}
void AliGenSlowNucleons::Init()
{
if (fDebug) {
fDebugHist1 = new TH2F("DebugHist1", "nu vs N_slow", 100, 0., 100., 20, 0., 20.);
fDebugHist2 = new TH2F("DebugHist2", "b vs N_slow", 100, 0., 100., 15, 0., 15.);
+ fCosThetaGrayHist = new TH1F("fCosThetaGrayHist", "Gray particles angle", 100, -1., 1.);
+ }
+ //
+ // non-uniform cos(theta) distribution
+ //
+ if(fThetaDistribution != 0) {
+ fCosTheta = new TF1("fCosTheta",
+ "(2./3.14159265358979312)/(exp(2./3.14159265358979312)-exp(-2./3.14159265358979312))*exp(2.*x/3.14159265358979312)",
+ -1., 1.);
}
}
void AliGenSlowNucleons::FinishRun()
{
+// End of run action
+// Show histogram for debugging if requested.
if (fDebug) {
TCanvas *c = new TCanvas("c","Canvas 1",400,10,600,700);
c->Divide(2,1);
fDebugHist1->Draw();
c->cd(2);
fDebugHist2->Draw();
+ c->cd(3);
+ fCosThetaGrayHist->Draw();
}
}
}
//
- Float_t p[3];
+ Float_t p[3], theta=0;
Float_t origin[3] = {0., 0., 0.};
Float_t polar [3] = {0., 0., 0.};
Int_t nt, i, j;
fCharge = 1;
kf = kProton;
for(i = 0; i < fNgp; i++) {
- GenerateSlow(fCharge, fTemperatureG, fBetaSourceG, p);
- SetTrack(fTrackIt, -1, kf, p, origin, polar,
+ GenerateSlow(fCharge, fTemperatureG, fBetaSourceG, p, theta);
+ if (fDebug) fCosThetaGrayHist->Fill(TMath::Cos(theta));
+ PushTrack(fTrackIt, -1, kf, p, origin, polar,
0., kPNoProcess, nt, 1.);
KeepTrack(nt);
}
fCharge = 0;
kf = kNeutron;
for(i = 0; i < fNgn; i++) {
- GenerateSlow(fCharge, fTemperatureG, fBetaSourceG, p);
- SetTrack(fTrackIt, -1, kf, p, origin, polar,
+ GenerateSlow(fCharge, fTemperatureG, fBetaSourceG, p, theta);
+ if (fDebug) fCosThetaGrayHist->Fill(TMath::Cos(theta));
+ PushTrack(fTrackIt, -1, kf, p, origin, polar,
0., kPNoProcess, nt, 1.);
KeepTrack(nt);
}
fCharge = 1;
kf = kProton;
for(i = 0; i < fNbp; i++) {
- GenerateSlow(fCharge, fTemperatureB, fBetaSourceB, p);
- SetTrack(fTrackIt, -1, kf, p, origin, polar,
+ GenerateSlow(fCharge, fTemperatureB, fBetaSourceB, p, theta);
+ PushTrack(fTrackIt, -1, kf, p, origin, polar,
0., kPNoProcess, nt, 1.);
KeepTrack(nt);
}
fCharge = 0;
kf = kNeutron;
for(i = 0; i < fNbn; i++) {
- GenerateSlow(fCharge, fTemperatureB, fBetaSourceB, p);
- SetTrack(fTrackIt, -1, kf, p, origin, polar,
+ GenerateSlow(fCharge, fTemperatureB, fBetaSourceB, p, theta);
+ PushTrack(fTrackIt, -1, kf, p, origin, polar,
0., kPNoProcess, nt, 1.);
KeepTrack(nt);
}
-void AliGenSlowNucleons::GenerateSlow(Int_t charge, Double_t T, Double_t beta, Float_t* q)
+void AliGenSlowNucleons::GenerateSlow(Int_t charge, Double_t T,
+ Double_t beta, Float_t* q, Float_t &theta)
+
+{
/*
Emit a slow nucleon with "temperature" T [GeV],
from a source moving with velocity beta
Three-momentum [GeV/c] is given back in q[3]
*/
-{
- Double_t m, pmax, p, f, theta, phi;
-
+ Double_t m, pmax, p, f, phi;
TDatabasePDG * pdg = TDatabasePDG::Instance();
const Double_t kMassProton = pdg->GetParticle(kProton) ->Mass();
const Double_t kMassNeutron = pdg->GetParticle(kNeutron)->Mass();
}
while(f < Rndm());
- /* Spherical symmetric emission */
- theta = TMath::ACos(2. * Rndm() - 1.);
+ /* Spherical symmetric emission for black particles (beta=0)*/
+ if(beta==0 || fThetaDistribution==0) theta = TMath::ACos(2. * Rndm() - 1.);
+ /* cos theta distributed according to experimental results for gray particles (beta=0.05)*/
+ else if(fThetaDistribution!=0){
+ Double_t costheta = fCosTheta->GetRandom();
+ theta = TMath::ACos(costheta);
+ }
+ //
phi = 2. * TMath::Pi() * Rndm();
/* Determine momentum components in system of the moving source */
/* Transform to laboratory system */
Lorentz(m, fBeta, q);
+ q[2] *= fProtonDirection;
}
Double_t AliGenSlowNucleons::Maxwell(Double_t m, Double_t p, Double_t T)
q[2] = gamma * (q[2] + beta*energy);
}
+
+AliGenSlowNucleons& AliGenSlowNucleons::operator=(const AliGenSlowNucleons& rhs)
+{
+// Assignment operator
+ rhs.Copy(*this);
+ return *this;
+}
+
+void AliGenSlowNucleons::Copy(TObject&) const
+{
+ //
+ // Copy
+ //
+ Fatal("Copy","Not implemented!\n");
+}
+
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff