DistributionChannelTool.h

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/*
 * DistributionChannelTool.h
 *
 *  This tool calculates the fraction of the total path length
 *  of a track in the core of each fibre that was hit along with
 *  the position of the fibre.
 *
 *  Created on 03 Mar 2020
 *      Author: Valerio Formato (based on code by Junjing Wang)
 */

// clang-format off
  // sipm setup parameters

  //  Mat and SiPMs
  //  -----------------------------------------------------------
  //  |---------------|    |---------------|    |---------------|
  //  |               |    |               |    |               |
  //  |    SiPM0      |0.09|    SiPM1      |0.09|    SiPM2      |
  //  |   32.54mm     | mm |   32.54mm     | mm |   32.54mm     |
  //  |               |    |               |    |               |
  //  |---------------|    |---------------|    |---------------|
  //  -----------------------------------------------------------
  //  \_________________________97.8mm__________________________/
  //
  //
  // SiPM structure
  //
  //  ==================================================
  //  |    |                |    |                 |    |
  //  |    |                |    |                 |    |
  //  |    |  active die0   |    |  active die0    |    |
  //  |0.16|                |0.22|                 |0.16|
  //  | mm |  0.25mm*64     | mm |  0.25mm*64      | mm |
  //  |    |                |    |                 |    |
  //  |    |                |    |                 |    |
  //  |    |                |    |                 |    |
  //  ==================================================
  //  \__________________32.54mm_______________________/
  //
  //
  // gap between SiPMs is actually determined by FitGeoParams dynamically
// clang-format on

#ifndef HERD_DISTRIBUTIONCHANNELTOOL_H_
#define HERD_DISTRIBUTIONCHANNELTOOL_H_

#include "dataobjects/FitGeoParams.h"

// this in c++17 will become
// namespace Herd::FitDigitizationTools {
namespace Herd {
namespace FitDigitizationTools {

class DistributionChannelTool {
public:
  /*
  G4int targetChannel(double posX, double posZ,
                      double dXdY, double dZdY);
                                          */
  static int targetChannel(double posX, double posZ, double dXdY, double dZdY, const FitGeoParams &geoParams);

private:
  // members for detailed simulation
  static constexpr double m_channelSizeZ = 0.1625;  //"Channel width in z direction (local coordinates)"
  static constexpr double m_epoxyWidth = 0.01;      // "Thickness of the epoxy layer between fibre ends and SiPMs"
  static constexpr double m_airWidth = 0.002;       // "Thickness of the air layer between fibre ends and SiPMs"
  static constexpr double m_refractionIndex = 1.52; // refraction index of sipm's epoxy

  // gcc marks this function as unused, even if it is not (maybe because it's used in a try block)
  static std::pair<int, double> calculateChannelAndFrac(double localX, const FitGeoParams &geoParams);

  static double findFinalPosSlope(double pos, double slope) { return pos + m_epoxyWidth * slope; }
};
} // namespace FitDigitizationTools
} // namespace Herd
#endif // DISTRIBUTIONCHANNELTOOL_H