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Status of PbGl MC

Status of PbGl MC. Emanuele Leonardi INFN Roma P326 Veto Meeting – 11/9/2007. Geometry. PbGl bloc design from Opal docs ~10x10cm front face ~11x11cm back (readout) face Blocs with 16 different shapes Cylindrical light-guide on back face (6-8 cm)

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Status of PbGl MC

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  1. Status of PbGl MC Emanuele Leonardi INFN Roma P326 Veto Meeting – 11/9/2007

  2. Geometry • PbGl bloc design from Opal docs • ~10x10cm front face • ~11x11cm back (readout) face • Blocs with 16 different shapes • Cylindrical light-guide on back face (6-8 cm) • Currently we use squared faces with a 0.5cmx0.5cm center displacement • Can be changed via datacard • Real shape will be added if needed E.Leonardi - PbGl MC - Veto meeting

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  6. Materials • Leadglass + light guide : Schott SF57 • Density : • Datasheet: 5.51 gr/cm3 • Other sources: 5.57-5.6 gr/cm3 • Used: 5.57 gr/cm3 • Composition: • SIO2 PbO Na2O K2O As2O3 • 22-26% 72-76 0.5-1.5 0.5-1.5 Traces Datasheet • 24% 74% 1% 1% 0% Used • Radiation length: • 1.5 cm from literature • 1.507cm from G4 E.Leonardi - PbGl MC - Veto meeting

  7. Physics List • August version of PbGl MC used an optical-studies-oriented PL • E.m. + optical processes only • No photonuclear effect! • BTF MC uses the standard LHEP PL • E.m. and hadronic processes • Photonuclear effect included • Total cross section OK, neutrons production not optimal • No optical processes E.Leonardi - PbGl MC - Veto meeting

  8. Physics List • New PL created last week by merging LHEP with optical physics • Comparison with LHEP is OK • Measured cross section with 10^6 event • All optical processes are there • Tests are underway E.Leonardi - PbGl MC - Veto meeting

  9. // default cut value is 0.7mm as in LHEP 4.2 defaultCutValue = 0.7*mm; // EM Physics RegisterPhysics( new G4EmStandardPhysics("standard EM",ver)); // Synchroton Radiation & GN Physics RegisterPhysics( new G4EmExtraPhysics("extra EM")); // General Physics - i.e. decay RegisterPhysics( new G4DecayPhysics("decay",ver) ); // Hadron Elastic scattering RegisterPhysics( new G4HadronElasticPhysics("LElastic",ver,false)); // Hadron Physics RegisterPhysics( new HadronPhysicsLHEP("hadron")); // Ion Physics RegisterPhysics( new G4IonPhysics("ion")); // Optical Physics RegisterPhysics( new OpticalPhysics("optical")); LHEP pManager = G4OpticalPhoton::OpticalPhoton()->GetProcessManager(); pManager->AddDiscreteProcess(theAbsorptionProcess); pManager->AddDiscreteProcess(theRayleighScattering); pManager->AddDiscreteProcess(theBoundaryProcess); pManager->AddDiscreteProcess(theWLSProcess); theParticleIterator->reset(); while( (*theParticleIterator)() ){ G4ParticleDefinition* particle = theParticleIterator->value(); pManager = particle->GetProcessManager(); if(theCerenkovProcess->IsApplicable(*particle)){ pManager->AddContinuousProcess(theCerenkovProcess); } if(theScintProcess->IsApplicable(*particle)){ pManager->AddProcess(theScintProcess); } } E.Leonardi - PbGl MC - Veto meeting

  10. Optical Properties • Refractive index : 1.84 @1.9eV - 1.91 @3.1eV • Absorption length: • Datasheet: 420cm @1.9-2.3eV, 0cm above 3.1eV • Measured: 60cm @1.9-2.3eV Energy Ref.Idx A.L. A.L.(measured) 1.88914eV 1.83650 420cm 60cm 1.92582eV 1.83808 420cm 60cm 1.95929eV 1.83957 420cm 60cm 2.10392eV 1.84636 420cm 60cm 2.11001eV 1.84666 420cm 60cm 2.27035eV 1.85504 420cm 57cm 2.55059eV 1.87204 144cm 49cm 2.58300eV 1.87425 130cm 48cm 2.84497eV 1.89393 34cm 29cm 3.06360eV 1.91366 8cm 8cm E.Leonardi - PbGl MC - Veto meeting

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  12. Optical Surface • A real PbGl bloc is wrapped with a black sheet of vinyl fluoride+polyester. Inside of sheet is coated with Al to improve reflectivity. • Current simulation applies Al coating directly to PbGl surface • Surface model simulates spike reflection with a fixed reflectivity • default is 90%, easy to modify // LeadGlass-Aluminum coating G4OpticalSurface* OpPbGlSurface = new G4OpticalSurface("PbGl_Al"); OpPbGlSurface->SetType(dielectric_metal); OpPbGlSurface->SetFinish(polished); OpPbGlSurface->SetModel(glisur); E.Leonardi - PbGl MC - Veto meeting

  13. Hits • Optical photons are tracked till: • they are absorbed by PbGl • they are absorbed by Al wall • they reach the PMT surface and are not reflected • A Hit is a photon reaching the PMT surface • Hits data are written to file in a pure ROOT format (no G4 dependencies) Int_t fPMTId; // Id of PMT Double_t fETot; // Energy of photon (eV) Double_t fTime; // Hit time (ns) Double_t fRadius; // Impact distance from PMT center (mm) Double_t fCosTheta; // Cosine of impact angle on PMT surface E.Leonardi - PbGl MC - Veto meeting

  14. Histograms • Several histograms are filled by the simulation program • When an optical photon is generated • When an optical photon is absorbed • When a hit is created • At the end of each event • Histograms can be easily added E.Leonardi - PbGl MC - Veto meeting

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  17. Digitization • Digitization program is G4-independent • Reads Hits file in ROOT format • Writes Digi file in ROOT format • Simple model for the Hamamatsu R2238 PMT is used • Q.E.(λ) • Calibration from BTF E.Leonardi - PbGl MC - Veto meeting

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