/** @file CbmStsParSensorCond.cxx
 ** @author Volker Friese <v.friese@gsi.de>
 ** @date 28.06.2014
 **/
#include "CbmStsParSensorCond.h"

#include <cmath>                // for pow

#include <iostream>             // for operator<<, basic_ostream, stringstream
#include <string>               // for char_traits
#include <sstream>              // for stringstream

using std::string;
using std::stringstream;

ClassImp(CbmStsParSensorCond)

// -----   Default constructor   -------------------------------------------
CbmStsParSensorCond::CbmStsParSensorCond() { }
// -------------------------------------------------------------------------



// -----   Standard constructor   ------------------------------------------
CbmStsParSensorCond::CbmStsParSensorCond(Double_t vFd,
                                         Double_t vBias,
                                         Double_t temperature,
                                         Double_t cCoupling,
                                         Double_t cInterstrip) :
                                         fVfd(vFd),
                                         fVbias(vBias),
                                         fTemperature(temperature),
                                         fCcoupling(cCoupling),
                                         fCinterstrip(cInterstrip)
{
  Init();
}
// -------------------------------------------------------------------------



// -----   Copy constructor   ----------------------------------------------
CbmStsParSensorCond::CbmStsParSensorCond(const CbmStsParSensorCond& other)
: fVfd(other.fVfd),
  fVbias(other.fVbias),
  fTemperature(other.fTemperature),
  fCcoupling(other.fCcoupling),
  fCinterstrip(other.fCinterstrip)
{
  Init();
}
// -------------------------------------------------------------------------



// -----   Destructor   ----------------------------------------------------
CbmStsParSensorCond::~CbmStsParSensorCond() { }
// -------------------------------------------------------------------------



// -----  Calculate Hall mobility parameters   -----------------------------
void CbmStsParSensorCond::Init() {

  // Cross-talk coefficient
  fCrossTalkCoeff = 0.;
  if ( fCinterstrip + fCcoupling != 0. )
    fCrossTalkCoeff = fCinterstrip / (fCinterstrip + fCcoupling);

  // These are the parameters needed for the calculation of the Hall
  // mobility, i.e. the mobility of charge carriers in the silicon
  // in the presence of a magnetic field. They depend on the temperature.
  // Values and formulae are taken from
  // V. Bartsch et al., Nucl. Instrum. Methods A 497 (2003) 389

  assert(fTemperature > 0.);

  // --- Electrons
  fMuLowE = 1417.  * pow (fTemperature / 300., -2.2); // cm^2 / (V s)
  fBetaE  = 1.109  * pow (fTemperature / 300., 0.66);
  fVsatE  = 1.07e7 * pow (fTemperature / 300., 0.87); // cm / s
  fRhallE = 1.15;

  // --- Holes
  fMuLowH = 470.5   * pow (fTemperature / 300., -2.5); // cm^2 / (V s)
  fBetaH  = 1.213   * pow (fTemperature / 300., 0.17);
  fVsatH  = 0.837e7 * pow (fTemperature / 300., 0.52); // cm / s
  fRhallH = 0.7;

  fIsInit = kTRUE;

}
// -------------------------------------------------------------------------



// -----   Hall mobility   -------------------------------------------------
Double_t CbmStsParSensorCond::GetHallMobility(Double_t eField,
                                              Int_t chargeType) const {

  assert(fIsInit);
  assert( chargeType == 0 || chargeType == 1);

  Double_t muLow = 0.;   // mobility at low electric field
  Double_t beta  = 0.;   // exponent
  Double_t vSat  = 0.;   // saturation velocity
  Double_t rHall = 0.;   // Hall scattering factor

  if ( chargeType == 0 ) {   // electrons
    muLow = fMuLowE;
    beta  = fBetaE;
    vSat  = fVsatE;
    rHall = fRhallE;
  }  //? electron
  else {                     // holes
    muLow = fMuLowH;
    beta  = fBetaH;
    vSat  = fVsatH;
    rHall = fRhallH;
  }  //? holes

  Double_t factor = pow( muLow * eField / vSat, beta );
  Double_t muHall = rHall * muLow / pow( 1 + factor, 1./beta );
  return muHall;
}
// -------------------------------------------------------------------------



// -----   Copy assignment operator   --------------------------------------
CbmStsParSensorCond&
CbmStsParSensorCond::operator=(const CbmStsParSensorCond& other) {
  fVfd = other.fVfd;
  fTemperature = other.fTemperature;
  fCcoupling = other.fCcoupling;
  fCinterstrip = other.fCinterstrip;
  Init();
  return *this;
}
// -------------------------------------------------------------------------



// -----   Set condition parameters   --------------------------------------
void CbmStsParSensorCond::SetParams(Double_t vFd, Double_t vBias,
                                    Double_t temperature, Double_t cCoupling,
                                    Double_t cInterstrip) {
  fVfd = vFd;
  fVbias = vBias;
  fTemperature = temperature;
  fCcoupling = cCoupling;
  fCinterstrip = cInterstrip;
  Init();
}
// -------------------------------------------------------------------------



// -----   String output   -------------------------------------------------
string CbmStsParSensorCond::ToString() const {
  stringstream ss;
  if ( fIsInit ) {
    ss << "VFD " << fVfd << " V | V(bias) " << fVbias << " V | T "
        << fTemperature << " K | C(coupl.) " << fCcoupling
        << " pF | C(int.) " << fCinterstrip <<  " pF | cross-talk coeff. "
        << fCrossTalkCoeff;
  }
  else {
    ss << "VFD " << fVfd << " V | V(bias) " << fVbias << " V | T "
        << fTemperature << " K | C(coupl.) " << fCcoupling
        << " pF | C(int.) " << fCinterstrip <<  " pF | not initialised!";
  }
  return ss.str();
}
// -------------------------------------------------------------------------