Use minimum number of photons to define Cherenkov measurement (#53)

Author: preghenella

src/RICHdetector.cc

@@ -51,12 +51,12 @@ RICHdetector::getMeasuredAngle(const Track &track) const
   auto angle = cherenkovAngle(particle->P, mass);
   auto nph_av = numberOfPhotons(angle); // average number of photons
   auto nph = gRandom->Poisson(nph_av); // random number of photons
-  if (nph <= 0) return {0., 0.};
+  if (nph < mMinPhotons) return {0., 0.};
   auto nph_el = 0; // number of photo-electrons
   for (int i = 0; i < nph; ++i) {
     if (gRandom->Uniform() < mEfficiency) nph_el++;
   }
-  if (nph_el <= 0) return {0., 0.};
+  if (nph_el < mMinPhotons) return {0., 0.};
   auto sigma = mSigma / sqrt(nph_el);
   angle = gRandom->Gaus(angle, sigma);
   return {angle, sigma};

src/RICHdetector.hh

@@ -24,6 +24,7 @@ public:
   void setRadiatorLength(float val) { mRadiatorLength = val; };
   void setEfficiency(float val) { mEfficiency = val; };
   void setSigma(float val) { mSigma = val; };
+  void setMinPhotons(int val) { mMinPhotons = val; };
 
   void makePID(const Track &track, std::array<float, 5> &deltaangle, std::array<float, 5> &nsigma) const;
   std::pair<float, float> getMeasuredAngle(const Track &track) const;
@@ -49,7 +50,7 @@ protected:
   float mRadiatorLength = 2.; // [cm]
   float mEfficiency = 0.4;
   float mSigma = 7.e-3; // [rad]
-  float mMinPhotons = 3.;
+  int mMinPhotons = 3;
 
 };