SimpleTDCCountTranslator.cc

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
 
#include <cdc/translators/SimpleTDCCountTranslator.h>
#include <cdc/geometry/CDCGeometryPar.h>
 
using namespace std;
using namespace Belle2;
using namespace CDC;
 
double SimpleTDCCountTranslator::getDriftLength(unsigned short tdcCount,
                                                const WireID& wireID,
                                                double timeOfFlightEstimator,
                                                bool,
                                                double z,
                                                double,
                                                double,
                                                unsigned short)
{
  const double driftTime = getDriftTime(tdcCount, wireID, timeOfFlightEstimator, z, 0);
 
  //Now we have an estimate for the time it took from the ionisation to the hitting of the wire.
  //Need to reverse calculate the relation between drift lenght and drift time.
  double driftL = (driftTime >= 0.) ? driftTime * 4e-3 : -999.;
  return driftL;
}
 
double SimpleTDCCountTranslator::getDriftTime(unsigned short tdcCount,
                                              const WireID& wireID,
                                              double timeOfFlightEstimator,
                                              double z,
                                              unsigned short)
{
  // translate TDC Count into time information:
  CDCGeometryPar& geometryPar = CDCGeometryPar::Instance();
  double driftTime = (static_cast<double>(geometryPar.getTdcOffset() - (tdcCount + 0.5))); // 1 Unit in the TDC count equals 1 ns
 
  // Need to undo everything the simple digitization does in reverse order.
  // First: Undo propagation in wire, if it was used:
  if (m_useInWirePropagationDelay) {
    //    CDCGeometryPar& geometryPar = CDCGeometryPar::Instance();
    //    m_backWirePos =   geometryPar.wireBackwardPosition(wireID);
    m_backWirePos =   geometryPar.wireBackwardPosition(wireID, CDCGeometryPar::c_Aligned);
    //subtract distance divided by speed of electric signal in the wire from the drift time.
    driftTime -= (z - m_backWirePos.Z()) / 27.25;
  }
 
  // Second: correct for event time. If this wasn't simulated, m_eventTime can just be set to 0.
  driftTime -= m_eventTime;
 
  //Third: If time of flight was simulated, this has to be undone, too. If it wasn't timeOfFlightEstimator should be taken as 0.
  driftTime -= timeOfFlightEstimator;
 
  return driftTime;
}
 
double SimpleTDCCountTranslator::getDriftLengthResolution(double,
                                                          const WireID&,
                                                          bool,
                                                          double,
                                                          double,
                                                          double)
{
//  return 0.000169 + 1.3333333E-6; // (130 µm)^2 in cm^2 + (40/sqrt(12) µm)^2 also in cm
  return 0.000169;  //the above should be taken into account in the digitizer, not here
}