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/** \file LaserBeamsBarrel.cc
*
*
* $Date: 2010/09/09 18:22:48 $
* $Revision: 1.7 $
* \author Maarten Thomas
*/
#include "Alignment/LaserAlignmentSimulation/interface/LaserBeamsBarrel.h"
#include "FWCore/AbstractServices/interface/RandomNumberGenerator.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include "FWCore/ServiceRegistry/interface/Service.h"
#include <CLHEP/Random/RandGaussQ.h>
#include "G4ParticleDefinition.hh"
#include "G4ParticleGun.hh"
#include <CLHEP/Units/SystemOfUnits.h>
#include "globals.hh" // Global Constants and typedefs
LaserBeamsBarrel::LaserBeamsBarrel() : theParticleGun(nullptr), theDRand48Engine(nullptr) {
G4int nPhotonsGun = 1;
G4int nPhotonsBeam = 1;
G4double Energy = 1.15 * CLHEP::eV;
// call constructor with options
LaserBeamsBarrel(nPhotonsGun, nPhotonsBeam, Energy);
}
LaserBeamsBarrel::LaserBeamsBarrel(G4int nPhotonsInGun, G4int nPhotonsInBeam, G4double PhotonEnergy)
: thenParticleInGun(0), thenParticle(0), thePhotonEnergy(0), theParticleGun(), theDRand48Engine() {
/* *********************************************************************** */
/* initialize and configure the particle gun */
/* *********************************************************************** */
// the Photon energy
thePhotonEnergy = PhotonEnergy;
// number of particles in the Laser beam
thenParticleInGun = nPhotonsInGun;
// number of particles in one beam. ATTENTION: each beam contains
// nParticleInGun with the same startpoint and direction. nParticle gives the
// number of particles in the beam with a different startpoint. They are used
// to simulate the gaussian beamprofile of the Laser Beams.
thenParticle = nPhotonsInBeam;
// create the particle gun
theParticleGun = new G4ParticleGun(thenParticleInGun);
// default kinematics
G4ParticleTable *theParticleTable = G4ParticleTable::GetParticleTable();
G4ParticleDefinition *theOpticalPhoton = theParticleTable->FindParticle("opticalphoton");
theParticleGun->SetParticleDefinition(theOpticalPhoton);
theParticleGun->SetParticleTime(0.0 * CLHEP::ns);
theParticleGun->SetParticlePosition(G4ThreeVector(-500.0 * CLHEP::cm, 0.0 * CLHEP::cm, 0.0 * CLHEP::cm));
theParticleGun->SetParticleMomentumDirection(G4ThreeVector(5.0, 3.0, 0.0));
theParticleGun->SetParticleEnergy(10.0 * CLHEP::keV);
setOptPhotonPolar(90.0);
// initialize the random number engine
theDRand48Engine = new CLHEP::DRand48Engine();
}
LaserBeamsBarrel::~LaserBeamsBarrel() {
if (theParticleGun != nullptr) {
delete theParticleGun;
}
if (theDRand48Engine != nullptr) {
delete theDRand48Engine;
}
}
void LaserBeamsBarrel::GeneratePrimaries(G4Event *myEvent) {
// this function is called at the beginning of an Event in
// LaserAlignment::upDate(const BeginOfEvent * myEvent)
// use the random number generator service of the framework
edm::Service<edm::RandomNumberGenerator> rng;
unsigned int seed = rng->mySeed();
// set the seed
theDRand48Engine->setSeed(seed);
// number of LaserBeams
const G4int nLaserBeams = 8;
// z position of the Laserdiodes (value from design drawings)
G4double LaserPositionZ = 1137.0 * CLHEP::mm;
// Radius of the Laser ring
G4double LaserRingRadius = 564.0 * CLHEP::mm;
// phi positions of the Laserdiodes (from CMS Note 2001/053 or from
// http://abbaneo.home.cern.ch/abbaneo/cms/layout)
G4double LaserPhi[nLaserBeams] = {G4double(7.0 / 112.0) * G4double(2.0 * M_PI),
G4double(23.0 / 112.0) * G4double(2.0 * M_PI),
G4double(33.0 / 112.0) * G4double(2.0 * M_PI),
G4double(49.0 / 112.0) * G4double(2.0 * M_PI),
G4double(65.0 / 112.0) * G4double(2.0 * M_PI),
G4double(77.0 / 112.0) * G4double(2.0 * M_PI),
G4double(93.0 / 112.0) * G4double(2.0 * M_PI),
G4double(103.0 / 112.0) * G4double(2.0 * M_PI)};
// width of the LaserBeams
G4double LaserBeamSigmaX = 0.5 * CLHEP::mm;
G4double LaserBeamSigmaY = 0.5 * CLHEP::mm;
// get the definition of the optical photon
G4ParticleTable *theParticleTable = G4ParticleTable::GetParticleTable();
G4ParticleDefinition *theOpticalPhoton = theParticleTable->FindParticle("opticalphoton");
// loop over the LaserBeams
for (int theBeam = 0; theBeam < nLaserBeams; theBeam++) {
// code for forward and backward beam
// calculate x and y position of the current laser diode
G4double LaserPositionX = cos(LaserPhi[theBeam]) * LaserRingRadius;
G4double LaserPositionY = sin(LaserPhi[theBeam]) * LaserRingRadius;
// loop over all the particles in one beam
for (int theParticle = 0; theParticle < thenParticle; theParticle++) {
// get randomnumbers and calculate the position
CLHEP::RandGaussQ aGaussObjX(*theDRand48Engine, LaserPositionX, LaserBeamSigmaX);
CLHEP::RandGaussQ aGaussObjY(*theDRand48Engine, LaserPositionY, LaserBeamSigmaY);
G4double theXPosition = aGaussObjX.fire();
G4double theYPosition = aGaussObjY.fire();
G4double theZPosition = LaserPositionZ;
// set the properties of the newly created particle
theParticleGun->SetParticleDefinition(theOpticalPhoton);
theParticleGun->SetParticleTime(0.0 * CLHEP::ns);
theParticleGun->SetParticlePosition(G4ThreeVector(theXPosition, theYPosition, theZPosition));
theParticleGun->SetParticleEnergy(thePhotonEnergy);
// loop over both directions of the beam
for (int theDirection = 0; theDirection < 2; theDirection++) {
// shoot in both beam directions ...
if (theDirection == 0) // shoot in forward direction (+z)
{
theParticleGun->SetParticleMomentumDirection(G4ThreeVector(0.0, 0.0, 1.0));
// set the polarization
setOptPhotonPolar(90.0);
// generate the particle
theParticleGun->GeneratePrimaryVertex(myEvent);
} else if (theDirection == 1) // shoot in backward direction (-z)
{
theParticleGun->SetParticleMomentumDirection(G4ThreeVector(0.0, 0.0, -1.0));
// set the polarization
setOptPhotonPolar(90.0);
// generate the particle
theParticleGun->GeneratePrimaryVertex(myEvent);
}
} // end looop over both beam directions
} // end looop over particles in beam
} // end loop over beams
}
void LaserBeamsBarrel::setOptPhotonPolar(G4double Angle) {
/* *********************************************************************** */
/* to get optical processes working properly, you have to make sure *
* that the photon polarisation is defined. */
/* *********************************************************************** */
// first check if we have an optical photon
if (theParticleGun->GetParticleDefinition()->GetParticleName() != "opticalphoton") {
edm::LogWarning("SimLaserAlignment:LaserBeamsBarrel")
<< "<LaserBeamsBarrel::setOptPhotonPolar()>: WARNING! The ParticleGun "
"is not an optical photon";
return;
}
// G4cout << " AC1CMS: The ParticleGun is an " <<
// theParticleGun->GetParticleDefinition()->GetParticleName();
G4ThreeVector normal(1.0, 0.0, 0.0);
G4ThreeVector kphoton = theParticleGun->GetParticleMomentumDirection();
G4ThreeVector product = normal.cross(kphoton);
G4double modul2 = product * product;
G4ThreeVector e_perpendicular(0.0, 0.0, 1.0);
if (modul2 > 0.0) {
e_perpendicular = (1.0 / sqrt(modul2)) * product;
}
G4ThreeVector e_parallel = e_perpendicular.cross(kphoton);
G4ThreeVector polar = cos(Angle) * e_parallel + sin(Angle) * e_perpendicular;
// G4cout << ", the polarization = " << polar << G4endl;
theParticleGun->SetParticlePolarization(polar);
}
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