PulseShape.h

#pragma once
 
#include <cmath>
#include <memory>
#include <string>
 
namespace ldmx {
 
class PulseShape {
 public:
  virtual ~PulseShape() = default;
 
  virtual double eval(double t) const = 0;
 
  static std::unique_ptr<PulseShape> make(const std::string& name, double tp,
                                          double tp2 = 0.0);
};
 
// ---------------------------------------------------------------------------
// CR-RC shaper (single-pole)
// ---------------------------------------------------------------------------
 
class CRRCShape : public PulseShape {
 public:
  explicit CRRCShape(double tp) : tp_(tp) {}
 
  double eval(double t) const override {
    if (t <= 0.0) return 0.0;
    return (t / tp_) * std::exp(1.0 - t / tp_);
  }
 
 private:
  double tp_;
};
 
// ---------------------------------------------------------------------------
// Four-pole shaper (CR + 3 RC stages)
// ---------------------------------------------------------------------------
 
class FourPoleShape : public PulseShape {
 public:
  FourPoleShape(double tp, double tp2);
 
  double eval(double t) const override;
 
 private:
  double tp_, tp2_;
  double a_, b_;
  double peak_amp_;  
};
 
// ---------------------------------------------------------------------------
// HGCROC shaper
// ---------------------------------------------------------------------------
 
class HgcrocShape : public PulseShape {
 public:
  HgcrocShape(double rate_up, double time_up, double rate_dn, double time_dn,
              double time_peak);
 
  double eval(double t) const override;
 
 private:
  double rate_up_, time_up_, rate_dn_, time_dn_, time_peak_;
  double norm_;  
};
 
}  // namespace ldmx