void Config(Int_t Particle, Int_t thickness)
{

Text_t filename[50];

new TGeant3("C++ Interface to Geant3");

//=======================================================================
//  Create the output file

sprintf(filename,"galice_identi_%d_%d.root",Particle,thickness);
printf(">>> Output file is %s \n",filename);   

TFile *rootfile = new TFile(filename,"recreate");
rootfile->SetCompressionLevel(2);
TGeant3 *geant3 = (TGeant3*)gMC;

//=======================================================================
// ******* GEANT STEERING parameters FOR ALICE SIMULATION *******
geant3->SetTRIG(1); //Number of events to be processed 
geant3->SetSWIT(4,10);
geant3->SetDEBU(0,0,1);
//geant3->SetSWIT(2,2);
geant3->SetERAN(1.e-6,1.e3,90);
geant3->SetDCAY(1);
geant3->SetPAIR(1);
geant3->SetCOMP(1);
geant3->SetPHOT(1);
geant3->SetPFIS(0);
geant3->SetDRAY(0);
geant3->SetANNI(1);
geant3->SetBREM(1);
geant3->SetMUNU(1);
geant3->SetCKOV(1);
geant3->SetHADR(1); //Select pure GEANH (HADR 1) or GEANH/NUCRIN (HADR 3)
geant3->SetLOSS(2);
geant3->SetMULS(1);
geant3->SetRAYL(1);
geant3->SetAUTO(1); //Select automatic STMIN etc... calc. (AUTO 1) or manual (AUTO 0)
geant3->SetABAN(0); //Restore 3.16 behaviour for abandoned tracks
geant3->SetOPTI(2); //Select optimisation level for GEANT geometry searches (0,1,2)
Float_t cut    = 1.e-3; // 1MeV cut by default
Float_t tofmax = 1.e10;
//             GAM ELEC NHAD CHAD MUON EBREM MUHAB EDEL MUDEL MUPA TOFMAX
geant3->SetCUTS(cut,cut, cut, cut, cut, cut,  cut,  cut, cut,  cut, tofmax);
//
///=======================================================================
// --- Specify event type to be tracked through the ALICE setup
// --- All positions are in cm, angles in degrees, and P and E in GeV
//
AliGenBox *gener=new AliGenBox(1);
gener->SetPart(Particle); // 22 is photon, 0 Geantino
gener->SetMomentumRange(2.995,3.0000);
gener->SetPhiRange(265., 285.);
gener->SetThetaRange(87., 93.);
gener->SetOrigin(0,0,0);        //vertex position
gener->SetSigma(0,0,5.6);         //Sigma in (X,Y,Z) (cm) on IP position
gener->Init();

gAlice->SetField(0,0);    //Specify maximum magnetic field in Tesla (neg. ==> default field)

Int_t iPHOS=1;


//=================== Alice BODY parameters =============================
AliBODY *BODY = new AliBODY("BODY","Alice envelop");



if(iPHOS) {
//=================== PHOS parameters ===========================

AliPHOS *PHOS  = new AliPHOSv0("PHOS","GPS2");
Float_t x = (Float_t) thickness / 100 ;
PHOS->GetGeometry()-> SetLeadConverterThickness(x);
}

 
         
}