SiStripDigitizer/plugins/SiHitDigitizer.cc

0001 #include "SiHitDigitizer.h"
0002 #include "SimDataFormats/TrackingHit/interface/PSimHit.h"
0003 #include "SiLinearChargeCollectionDrifter.h"
0004 #include "SiLinearChargeDivider.h"
0005
0006 #include "DataFormats/GeometryVector/interface/LocalPoint.h"
0007 #include "SiTrivialInduceChargeOnStrips.h"
0008 #include "FWCore/ParameterSet/interface/ParameterSet.h"
0009 #include "FWCore/MessageLogger/interface/MessageLogger.h"
0010
0011 //#define CBOLTZ (1.38E-23)
0012 //#define e_SI (1.6E-19)
0013 static const double CBOLTZ_over_e_SI = 1.38E-23 / 1.6E-19;
0014 static const double noDiffusionMultiplier = 1.0e-3;
0015
0016 SiHitDigitizer::SiHitDigitizer(const edm::ParameterSet& conf)
0017     : depletionVoltage(conf.getParameter<double>("DepletionVoltage")),
0018       chargeMobility(conf.getParameter<double>("ChargeMobility")),
0019       theSiChargeDivider(new SiLinearChargeDivider(conf)),
0020       theSiChargeCollectionDrifter(new SiLinearChargeCollectionDrifter(
0021           CBOLTZ_over_e_SI * chargeMobility * conf.getParameter<double>("Temperature") *
0022               (conf.getParameter<bool>("noDiffusion") ? noDiffusionMultiplier : 1.0),
0023           conf.getParameter<double>("ChargeDistributionRMS"),
0024           depletionVoltage,
0025           conf.getParameter<double>("AppliedVoltage"))),
0026       theSiInduceChargeOnStrips(new SiTrivialInduceChargeOnStrips(conf, conf.getParameter<double>("GevPerElectron"))) {}
0027
0028 SiHitDigitizer::~SiHitDigitizer() {}
0029
0030 void SiHitDigitizer::processHit(const PSimHit* hit,
0031                                 const StripGeomDetUnit& det,
0032                                 GlobalVector bfield,
0033                                 float langle,
0034                                 std::vector<float>& locAmpl,
0035                                 size_t& firstChannelWithSignal,
0036                                 size_t& lastChannelWithSignal,
0037                                 const TrackerTopology* tTopo,
0038                                 CLHEP::HepRandomEngine* engine) {
0039   // Compute the drift direction for this det
0040   double moduleThickness = det.specificSurface().bounds().thickness();  // active detector thicness
0041   double timeNormalisation = (moduleThickness * moduleThickness) / (2. * depletionVoltage * chargeMobility);
0042   LocalVector driftDir = DriftDirection(&det, bfield, langle);
0043
0044   // Fully process one SimHit
0045   theSiInduceChargeOnStrips->induce(
0046       theSiChargeCollectionDrifter->drift(theSiChargeDivider->divide(hit, driftDir, moduleThickness, det, engine),
0047                                           driftDir,
0048                                           moduleThickness,
0049                                           timeNormalisation),
0050       det,
0051       locAmpl,
0052       firstChannelWithSignal,
0053       lastChannelWithSignal,
0054       tTopo);
0055 }