In This Package:

GtDiffuserBallTool.h

Go to the documentation of this file.

/******************************************************************************
 * GtDiffuserBallTool - LED light source for calibration
 *
 * Tool to generate photons from surface of diffuser ball, used in AD 
 * calibration. It chooses a random point on the ball as the photon 
 * vertex and emits a photon in a uniform random direction, away from the ball.
 * The vertices may be distributed isotropically or anisotropically. 
 * The momentum direction is on a hemisphere, whose plane lies tangent to the 
 * vertex. 
 *
 * The light emitted from the LED has 4 options for m_wavelengthMode to describe
 * the LED wavelength spectrum:
 * "Fixed"   - monochromatic (default)
 * "Uniform" - uniformly distributed with mean m_wavelength and half-range 
 *             m_wavelengthSpread
 * "Smeared" - gaussian distributed with mean of m_wavelength 
 * "Defined" - user-defined PDF for random number generator
 *
 * The light emitted from the LED has 2 options for m_timingMode to describe
 * the LED timing distribution within an event:
 * "Instant" - all vertices within an event are emitted simultaneously at 
 *             the beginning of the event (t=0) (default)
 * "Defined" - user-defined PDF for random number generator
 *
 * "Defined" m_modeWave (m_modeTime) has 2 vectors the user must input - Python 
 * lists will convert to vectors. Variable m_pdfWave (m_pdfTime) for property 
 * PdfWave (PdfTime) is a vector containing the bin content for the wavelength 
 * spectrum (timing distribution) histogram. Variable m_edgesWave (m_edgesTime) 
 * for property PdfEdgesWave (PdfEdgesTime) is a vector containing the bin edges 
 * of the histogram. Inputting this allows for dealing with uneven bin sizes. 
 * The pdf does not need to be normalized. Obviously, m_edges should have one 
 * more element than m_pdf.
 *
 *
 *
 * Kim Boddy, kboddy@caltech.edu
 * 05 Aug 2008
 * 06 Jan 2009, Include anisotropy
 *****************************************************************************/

#ifndef GTDIFFUSERBALLTOOL_H
#define GTDIFFUSERBALLTOOL_H

#include "GenTools/IHepMCEventMutator.h"
#include "GaudiAlg/GaudiTool.h"
#include "GaudiKernel/RndmGenerators.h"


class GtDiffuserBallTool : public GaudiTool,
                           virtual public IHepMCEventMutator
{
 public: 
  GtDiffuserBallTool(const std::string& type,
                     const std::string& name, 
                     const IInterface* parent);
  virtual ~GtDiffuserBallTool();

  // GaudiTool interface
  virtual StatusCode initialize();
  virtual StatusCode finalize();

  // HepMCEventMutator interface
  virtual StatusCode mutate(HepMC::GenEvent& event);
 
 private:

  // Number of photons per event to generate, default = 3500
  int m_particlesPerEvent;
  
  // Mode to smear event-by-event number of photons
  // Fixed: No fluctuation
  // Gaus: Gaussian distributed
  // Lorentz: Lorentz distributed
  std::string m_particlesPerEventMode;
  // Width of photon number distribution (sigma for Gaus, FWHM for Lorentz)
  int m_particlesPerEventSpread;
  
  // Mode to operate wavelength
  // Fixed:   LED emits monochromatic light (default)
  // Uniform: LED emits uniform light
  // Smeared: LED emits gaussian distributed light 
  // Defined: LED emits user-defined spectrum of light
  std::string m_wavelengthMode;

  // Mode to operate timing distribution
  // Instant: LED emits light instantaneously at beginning of event (default) 
  // Defined: LED emits light with user-defined timing distribution
  std::string m_timingMode;

  // Wavelength of photons from LED, default is 430 nm (2.9 eV)
  double m_wavelength;

  // Spread (sigma of Gaussian or 1/2 range of uniform) for wavelength spectrum, default is 5nm
  double m_wavelengthSpread;

  // Frequency of pulses from LED - default is 500 Hz
  double m_pulseFrequency;

  // Radius of diffuser ball - default is 0.9525 cm (0.75 inch diameter)
  double m_radius;

  // Turn on (true) or off (false) anisotropy - default is on
  bool m_anisotropy;
  // If true, create bright spot on diffuser ball - default is theta=0, phi=0
  double m_bright_theta;
  double m_bright_phi;

  // Property: Reduce the number of photons and scale the weight of
  // each to compensate.  Default scaling is 3.7 (based on maximum
  // quantum eff.)
  double m_photonScaleWeight;

  // Name of geometry positioner for the diffuser ball
  std::string m_geomPosToolName;

  std::string m_particleName; // The PDG name for the particle
  int m_pid;                  // PDG particle ID

  Rndm::Numbers m_uni,m_randWave,m_randTime, m_randPartNo;

  // user-defined PDF and associated bin edges for LED spectrum 
  // default is single count in narrow bin centered around default m_wavelength
  std::vector<double> m_pdfWave;
  std::vector<double> m_edgesWave;
  std::vector<double> m_cdfWave; // Transient storage of Cum. Dist. Func.

  // user-defined PDF and associated bin edges for timing distribution within an event
  // default is single count in narrow bin near t=0
  std::vector<double> m_pdfTime;
  std::vector<double> m_edgesTime;
  std::vector<double> m_cdfTime; // Transient storage of Cum. Dist. Func.

  StatusCode oneVertex(HepMC::GenEvent& event);
  double GetWave();
  double GetTime();
  double ConvertCdfRand(const double& rand, const std::vector<double>& cdf, 
                        const std::vector<double>& edges);

};


#endif //GTDIFFUSERBALLTOOL_H

---