A module for optical MC testing and library building. More...

Inheritance diagram for evgen::LightSource:

Classes
class	MaterialPointFilter
	Filters a point according to the material at that point. More...

Public Member Functions
	LightSource (fhicl::ParameterSet const &pset)

void	produce (art::Event &evt)

void	beginRun (art::Run &run)

Private Member Functions
simb::MCTruth	Sample ()

void	checkMaterials () const
	Throws an exception if any of the configured materials is not present. More...

bool	readParametersFromInputFile ()

Private Attributes
std::string	fVersion

std::ifstream	fInputFile

std::string	fFileName

char	fDummyString [256]

TTree *	fPhotonsGenerated

TLorentzVector	fShotPos

TLorentzVector	fShotMom

Int_t	fEvID

int	fSourceMode

bool	fFillTree

int	fPosDist

int	fTDist

int	fPDist

std::set< std::string > const	fSelectedMaterials
	Names of materials to consider scintillation from. More...

int	fXSteps

int	fYSteps

int	fZSteps

sim::PhotonVoxelDef	fThePhotonVoxelDef

int	fVoxelCount

int	fCurrentVoxel

geo::Vector_t	fTPCCenter

std::vector< double >	fRegionMin

std::vector< double >	fRegionMax

bool	fUseCustomRegion

geo::Point_t	fCenter
	Central position of source [cm]. More...

bool	fPointSource

double	fT

double	fSigmaX

double	fSigmaY

double	fSigmaZ

double	fSigmaT

double	fP

double	fSigmaP

int	fN

double const	fNMaxF
	Maximum number of attempted samplings (factor on top of `fN`). More...

int	fFirstVoxel

int	fLastVoxel

CLHEP::HepRandomEngine &	fEngine

geo::GeometryCore const &	fGeom
	Geometry service provider (cached). More...

Static Private Attributes
static const int	kUNIF = 0

static const int	kGAUS = 1

static const int	kFILE = 0

static const int	kSCAN = 1

Detailed Description

A module for optical MC testing and library building.

Light source event generator which simulate an extended isotropic photon source.

The light source can be run in two modes, file mode or scan mode. Each requires the specification of a different set of parameters.

File mode

Light source position, intensity and shape are supplied on an event by event basis in a text file. See the example provided for the format. Pararmeters required:

int32   SourceMode = 0      - sets light source to file mode
string  FileName            - file of per event light source specifications
int32   PosDist             - how to distribute production points sampled in momentum, position
int32   PDist                   and time ranges specified.  For all of these :
int32   TDist                   0 = uniform and 1 = gauss
bool    FillTree            - whether to write a tree of photon production points to fileservice

Upon reaching the end of the file, the light source will loop back to the first point. hence a one line text file will give a constant light source size, position and intensity.

Scan mode

Divide volume into cuboidal regions and produce an isotropic light source in each, using one region per event. User can specify either to use the full detector volume or some custom specified volume.

This mode is used when building a fast photon sim library, and performing volume scan sensitivity studies.

int32   SourceMode = 1      - sets light source to scan mode
int32   N                   - number of photons to shoot from each point
double  P                   - peak photon momentum (or energy) in eV
double  SigmaP              - momentum distribution width
double  XSteps              - Number of regions to divide volume into in each direction
double  YSteps
double  ZSteps
double  T0                  - Peak time of photon production
double  SigmaT              - time distribution width
int32   PosDist             - how to distribute production points sampled in momentum, position
int32   PDist                 and time ranges specified.  For all of these :
int32   TDist                   0 = uniform and 1 = gaussian
bool    FillTree            - whether to write a tree of photon production points to fileservice
bool    UseCustomRegion     - supply our own volume specification or use the full detector volume?
vdouble[3]  RegionMin       - bounding corners of the custom volume specification
vdouble[3]  RegionMax           (only used if UseCustomRegion=true)

Configuration parameters

This is a partial list of the supported configuration parameters:

SelectMaterials (list of strings, default: empty): if specified, generation points are required to be in a volume with any of the materials included in this list; a useful value is SelectMaterials: [ "LAr" ], which generates photons only in liquid argon; the rest of the constraints are also respected (that means that if the configured generation volume has none of the selected materials, generation can go on forever: see NMaxFactor configuration parameter)
NMaxFactor (real value, default: 100 times N): as a safety valve, do not attempt more than this times the requested number of photons: for example, in an event where 500 photons are required, with NMax: 20 no more than 10000 generations will be attempted; this is useful if the generation volume efficiency can't be guaranteed to be high (e.g. if only generation in liquid argon is requested in a generation volume that is entirely made of steel).

Definition at line 131 of file LightSource_module.cc.

Constructor & Destructor Documentation

evgen::LightSource::LightSource ( fhicl::ParameterSet const & pset )

explicit

Definition at line 270 of file LightSource_module.cc.

     : art::EDProducer{pset}
     , fSourceMode{pset.get<int>("SourceMode")}
     , fFillTree{pset.get<bool>("FillTree")}
     , fPosDist{pset.get<int>("PosDist")}
     , fTDist{pset.get<int>("TDist")}
     , fPDist{pset.get<int>("PDist")}
     , fSelectedMaterials{makeSet(pset.get<std::vector<std::string>>("SelectMaterials", {}))}

Member Function Documentation

void evgen::LightSource::beginRun ( art::Run & run )

Definition at line 378 of file LightSource_module.cc.

   {
     run.put(std::make_unique<sumdata::RunData>(fGeom.DetectorName()));
 
     fCurrentVoxel = fFirstVoxel;
   }

void evgen::LightSource::checkMaterials ( ) const

private

Throws an exception if any of the configured materials is not present.

Definition at line 550 of file LightSource_module.cc.

   {
 
     TGeoManager const& manager = *(fGeom.ROOTGeoManager());
 
     { // start scope
       mf::LogDebug log("LightSource");
       auto const& matList = *(manager.GetListOfMaterials());
       log << matList.GetSize() << " elements/materials in the geometry:";
       for (auto const* obj : matList) {
         auto const mat = dynamic_cast<TGeoMaterial const*>(obj);
         log << "\n  '" << mat->GetName() << "' (Z=" << mat->GetZ() << " A=" << mat->GetA() << ")";
       } // for
     }   // end scope
 
     std::set<std::string> missingMaterials;
     for (auto const& matName : fSelectedMaterials) {
       if (!manager.GetMaterial(matName.c_str())) missingMaterials.insert(matName);
     }
     if (missingMaterials.empty()) return;
 
     art::Exception e(art::errors::Configuration);
     e << "Requested filtering on " << missingMaterials.size()
       << " materials which are not present in the geometry:";
     for (auto const& matName : missingMaterials)
       e << "\n  '" << matName << "'";
     throw e << "\n";
 
   } // LightSource::checkMaterials()

void evgen::LightSource::produce ( art::Event & evt )

Definition at line 387 of file LightSource_module.cc.

   {
     if(fSourceMode==kFILE) {
       //  Each event, read coordinates of gun and number of photons to shoot from file
 
       // read in one line
       if(!readParametersFromInputFile()){
         // Loop file if required
         mf::LogWarning("LightSource") << "EVGEN Light Source : Warning, reached end of file,"
                                       << " looping back to beginning";
         fInputFile.clear();
         fInputFile.seekg(0, std::ios::beg);
         fInputFile.getline(fDummyString, 256);
 
         if(!readParametersFromInputFile()) {
           throw cet::exception("LightSource") << "EVGEN Light Source : File error in "
                                               << fFileName << "\n";
         }
 
       }
 
       fThePhotonVoxelDef = sim::PhotonVoxelDef(fCenter.X() - fSigmaX,
                                                fCenter.X() + fSigmaX,
                                                1,
                                                fCenter.Y() - fSigmaY,
                                                fCenter.Y() + fSigmaY,
                                                1,
                                                fCenter.Z() - fSigmaZ,
                                                fCenter.Z() + fSigmaZ,
                                                1);
 
       fCurrentVoxel=0;
     }
     else if (fSourceMode == kSCAN) {
       //  Step through detector using a number of steps provided in the config file
       //  firing a constant number of photons from each point
       fCenter = fThePhotonVoxelDef.GetPhotonVoxel(fCurrentVoxel).GetCenter();
     }
     else {
       //  Neither file or scan mode, probably a config file error
       throw cet::exception("LightSource") << "EVGEN : Light Source, unrecognised source mode\n";
     }
 
     auto truthcol = std::make_unique<std::vector<simb::MCTruth>>();
 
     truthcol->push_back(Sample());
     int const nPhotons = truthcol->back().NParticles();
 
     evt.put(std::move(truthcol));
 
     phot::PhotonVisibilityService* vis = nullptr;
     try {
       vis = art::ServiceHandle<phot::PhotonVisibilityService>().get();
     }
     catch (art::Exception const& e) {
       // if the service is not configured, then this is not a build job
       // (it is a simple generation job instead)
       if (e.categoryCode() != art::errors::ServiceNotFound) throw;
     }
 
     if (vis && vis->IsBuildJob()) {
       mf::LogVerbatim("LightSource") << "Light source : Stowing voxel params ";
       vis->StoreLightProd(fCurrentVoxel, nPhotons);
     }
 
     if (fCurrentVoxel != fLastVoxel) { ++fCurrentVoxel; }
     else {
       mf::LogVerbatim("LightSource")
         << "EVGEN Light Source fully scanned detector.  Starting over.";
       fCurrentVoxel = fFirstVoxel;
     }
   }

bool evgen::LightSource::readParametersFromInputFile ( )

private

Reads from fInputFile all other parameters in one line.

Returns: whether all reading were successful (ifstream::good()).

Definition at line 621 of file LightSource_module.cc.

                                                 {
     double x, y, z;
     fInputFile >> x >> y >> z >> fT
       >> fSigmaX >> fSigmaY >> fSigmaZ >> fSigmaT
       >> fP >> fSigmaP >> fN;
     fCenter = { x, y, z };
     if (!fInputFile.good()) return false;
 
     std::string dummy;
     std::getline(fInputFile, dummy); // this can fail for what I care
     return true;
   } // LightSource::readParametersFromInputFile()

simb::MCTruth evgen::LightSource::Sample ( )

private

Definition at line 461 of file LightSource_module.cc.

   {
     mf::LogVerbatim("LightSource") << "Light source debug : Shooting at " << fCenter;
 
     CLHEP::RandFlat flat(fEngine, -1.0, 1.0);
     CLHEP::RandGaussQ gauss(fEngine);
 
     MaterialPointFilter filter(fGeom, fSelectedMaterials);
 
     simb::MCTruth mct;
     mct.SetOrigin(simb::kSingleParticle);
 
     unsigned long long int const nMax = static_cast<unsigned long long int>(double(fN) * fNMaxF);
     unsigned long long int fired = 0ULL;
     while (mct.NParticles() < fN) {
       if (fired >= nMax) break;
 
       // Choose momentum (supplied in eV, convert to GeV)
       double const p =
         1e-9 * ((fPDist == kGAUS) ? gauss.fire(fP, fSigmaP) : fP + fSigmaP * flat.fire());
 
       // Choose position
       ++fired;
       geo::Point_t x;
       if (fPointSource) { x = fCenter; }
       else {
         if (fPosDist == kGAUS) {
           x = {gauss.fire(fCenter.X(), fSigmaX),
                gauss.fire(fCenter.Y(), fSigmaY),
                gauss.fire(fCenter.Z(), fSigmaZ)};
         }
         else {
           x = {fCenter.X() + fSigmaX * flat.fire(),
                fCenter.Y() + fSigmaY * flat.fire(),
                fCenter.Z() + fSigmaZ * flat.fire()};
         }
 
         if (!filter.accept(x)) continue;
       }
 
       // Choose time
       double t;
       if (fTDist == kGAUS) { t = gauss.fire(fT, fSigmaT); }
       else {
         t = fT + fSigmaT * flat.fire();
       }
 
       //assume the position is relative to the center of the TPC
       //x += fTPCCenter;
 
       fShotPos = TLorentzVector(x.X(), x.Y(), x.Z(), t);
 
       // Choose angles
       double costh = flat.fire();
       double sinth = std::sqrt(1.0 - cet::square(costh));
       double phi = 2 * M_PI * flat.fire();
 
       // Generate momentum 4-vector
 
       fShotMom = TLorentzVector(p * sinth * cos(phi), p * sinth * sin(phi), p * costh, p);
 
       int trackid = -(mct.NParticles() +
                       1); // set track id to -i as these are all primary particles and have id <= 0
       std::string primary("primary");
       int PDG = 0; //optical photons have PDG 0
 
       simb::MCParticle part(trackid, PDG, primary);
       part.AddTrajectoryPoint(fShotPos, fShotMom);
 
       if (fFillTree) fPhotonsGenerated->Fill();
 
       mct.Add(part);
     }
 
     mf::LogInfo("LightSource") << "Generated " << mct.NParticles() << " photons after " << fired
                                << " tries.";
     if (mct.NParticles() < fN) {
       // this may mean `NMaxFactor` is too small, or the volume is wrong;
       // or it may be just expected
       mf::LogWarning("LightSource")
         << "Warning: " << mct.NParticles() << " photons generated after " << fired << " tries, but "
         << fN << " were requested.";
     }
 
     return mct;
   } // LightSource::Sample()

Member Data Documentation

geo::Point_t evgen::LightSource::fCenter

private

Central position of source [cm].

Definition at line 231 of file LightSource_module.cc.

int evgen::LightSource::fCurrentVoxel

private

Definition at line 222 of file LightSource_module.cc.

char evgen::LightSource::fDummyString[256]

private

Definition at line 196 of file LightSource_module.cc.

CLHEP::HepRandomEngine& evgen::LightSource::fEngine

private

Definition at line 250 of file LightSource_module.cc.

Int_t evgen::LightSource::fEvID

private

Definition at line 202 of file LightSource_module.cc.

std::string evgen::LightSource::fFileName

private

Definition at line 195 of file LightSource_module.cc.

bool evgen::LightSource::fFillTree

private

Definition at line 206 of file LightSource_module.cc.

int evgen::LightSource::fFirstVoxel

private

Definition at line 247 of file LightSource_module.cc.

geo::GeometryCore const& evgen::LightSource::fGeom

private

Geometry service provider (cached).

Definition at line 251 of file LightSource_module.cc.

std::ifstream evgen::LightSource::fInputFile

private

Definition at line 194 of file LightSource_module.cc.

int evgen::LightSource::fLastVoxel

private

Definition at line 248 of file LightSource_module.cc.

int evgen::LightSource::fN

private

Definition at line 242 of file LightSource_module.cc.

double const evgen::LightSource::fNMaxF

private

Maximum number of attempted samplings (factor on top of fN).

Definition at line 245 of file LightSource_module.cc.

double evgen::LightSource::fP

private

Definition at line 238 of file LightSource_module.cc.

int evgen::LightSource::fPDist

private

Definition at line 209 of file LightSource_module.cc.

TTree* evgen::LightSource::fPhotonsGenerated

private

Definition at line 199 of file LightSource_module.cc.

bool evgen::LightSource::fPointSource

private

Definition at line 232 of file LightSource_module.cc.

int evgen::LightSource::fPosDist

private

Definition at line 207 of file LightSource_module.cc.

std::vector<double> evgen::LightSource::fRegionMax

private

Definition at line 227 of file LightSource_module.cc.

std::vector<double> evgen::LightSource::fRegionMin

private

Definition at line 226 of file LightSource_module.cc.

std::set<std::string> const evgen::LightSource::fSelectedMaterials

private

Names of materials to consider scintillation from.

Definition at line 212 of file LightSource_module.cc.

TLorentzVector evgen::LightSource::fShotMom

private

Definition at line 201 of file LightSource_module.cc.

TLorentzVector evgen::LightSource::fShotPos

private

Definition at line 200 of file LightSource_module.cc.

double evgen::LightSource::fSigmaP

private

Definition at line 239 of file LightSource_module.cc.

double evgen::LightSource::fSigmaT

private

Definition at line 237 of file LightSource_module.cc.

double evgen::LightSource::fSigmaX

private

Definition at line 234 of file LightSource_module.cc.

double evgen::LightSource::fSigmaY

private

Definition at line 235 of file LightSource_module.cc.

double evgen::LightSource::fSigmaZ

private

Definition at line 236 of file LightSource_module.cc.

int evgen::LightSource::fSourceMode

private

Definition at line 205 of file LightSource_module.cc.

double evgen::LightSource::fT

private

Definition at line 233 of file LightSource_module.cc.

int evgen::LightSource::fTDist

private

Definition at line 208 of file LightSource_module.cc.

sim::PhotonVoxelDef evgen::LightSource::fThePhotonVoxelDef

private

Definition at line 219 of file LightSource_module.cc.

geo::Vector_t evgen::LightSource::fTPCCenter

private

Definition at line 225 of file LightSource_module.cc.

bool evgen::LightSource::fUseCustomRegion

private

Definition at line 228 of file LightSource_module.cc.

std::string evgen::LightSource::fVersion

private

Definition at line 185 of file LightSource_module.cc.

int evgen::LightSource::fVoxelCount

private

Definition at line 221 of file LightSource_module.cc.

int evgen::LightSource::fXSteps

private

Definition at line 215 of file LightSource_module.cc.

int evgen::LightSource::fYSteps

private

Definition at line 216 of file LightSource_module.cc.

int evgen::LightSource::fZSteps

private

Definition at line 217 of file LightSource_module.cc.

const int evgen::LightSource::kFILE = 0

staticprivate

Definition at line 190 of file LightSource_module.cc.

const int evgen::LightSource::kGAUS = 1

staticprivate

Definition at line 189 of file LightSource_module.cc.

const int evgen::LightSource::kSCAN = 1

staticprivate

Definition at line 191 of file LightSource_module.cc.

const int evgen::LightSource::kUNIF = 0

staticprivate

Definition at line 188 of file LightSource_module.cc.

The documentation for this class was generated from the following file:

LightSource_module.cc

Classes

Public Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

File mode

Scan mode

Configuration parameters

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation