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00001 #include "SimTracker/SiStripDigitizer/interface/SiHitDigitizer.h"
00002 #include "SimDataFormats/TrackingHit/interface/PSimHit.h"
00003 #include "SimTracker/SiStripDigitizer/interface/SiLinearChargeCollectionDrifter.h"
00004 #include "SimTracker/SiStripDigitizer/interface/SiLinearChargeDivider.h"
00005 
00006 #include "DataFormats/GeometryVector/interface/LocalPoint.h"
00007 #include "SimTracker/SiStripDigitizer/interface/SiTrivialInduceChargeOnStrips.h"
00008 #include "FWCore/ParameterSet/interface/ParameterSet.h"
00009 #include "FWCore/MessageLogger/interface/MessageLogger.h"
00010 
00011 #define CBOLTZ (1.38E-23)
00012 #define e_SI (1.6E-19)
00013 
00014 SiHitDigitizer::SiHitDigitizer(const edm::ParameterSet& conf,CLHEP::HepRandomEngine& eng ):conf_(conf),rndEngine(eng){
00015   
00016   // Construct default classes
00017   depletionVoltage       = conf_.getParameter<double>("DepletionVoltage");
00018   appliedVoltage         = conf_.getParameter<double>("AppliedVoltage");
00019   chargeMobility         = conf_.getParameter<double>("ChargeMobility");
00020   temperature            = conf_.getParameter<double>("Temperature");
00021   gevperelectron         = conf_.getParameter<double>("GevPerElectron");
00022   chargeDistributionRMS  = conf_.getParameter<double>("ChargeDistributionRMS");
00023   noDiffusion            = conf_.getParameter<bool>("noDiffusion");
00024   double diffusionConstant = CBOLTZ/e_SI * chargeMobility * temperature;
00025   if (noDiffusion) diffusionConstant *= 1.0e-3;
00026   
00027   theSiChargeDivider = new SiLinearChargeDivider(conf_,rndEngine);
00028   
00029   theSiChargeCollectionDrifter = 
00030     new SiLinearChargeCollectionDrifter(diffusionConstant,
00031                                         chargeDistributionRMS,
00032                                         depletionVoltage,
00033                                         appliedVoltage);
00034 
00035   theSiInduceChargeOnStrips = new SiTrivialInduceChargeOnStrips(conf,gevperelectron);
00036 }
00037 
00038 SiHitDigitizer::~SiHitDigitizer(){
00039   delete theSiChargeDivider;
00040   delete theSiChargeCollectionDrifter;
00041   delete theSiInduceChargeOnStrips;
00042 }
00043 
00044 void 
00045 SiHitDigitizer::processHit(const PSimHit* hit, const StripGeomDetUnit& det, GlobalVector bfield,float langle,
00046                            std::vector<double>& locAmpl, size_t& firstChannelWithSignal, size_t& lastChannelWithSignal){
00047   
00048   // Compute the drift direction for this det
00049   double moduleThickness = det.specificSurface().bounds().thickness(); // active detector thicness
00050   double timeNormalisation = (moduleThickness*moduleThickness)/(2.*depletionVoltage*chargeMobility);
00051   LocalVector driftDir = DriftDirection(&det,bfield,langle);
00052   
00053   // Fully process one SimHit
00054   theSiInduceChargeOnStrips->induce(
00055       theSiChargeCollectionDrifter->drift(
00056           theSiChargeDivider->divide(hit, driftDir, moduleThickness, det),
00057           driftDir,moduleThickness,timeNormalisation),
00058       det,locAmpl,firstChannelWithSignal,lastChannelWithSignal);
00059 }
/data/refman/pasoursint/CMSSW_4_4_5_patch3/src/SimTracker/SiStripDigitizer/src/SiHitDigitizer.cc
