Describes the waveform from a single photoelectron. More...

#include <AsymExpPulseFunction.h>

Inheritance diagram for icarus::opdet::AsymExpPulseFunction< T >:

Public Types
using	ADCcount = typename Base_t::ADCcount
	Type for ADC counts (floating point). More...

using	Time = typename Base_t::Time
	Type of time being used. More...

Public Types inherited from icarus::opdet::PhotoelectronPulseFunction< T >
using	ADCcount = util::quantities::counts_f
	Type for ADC counts (floating point). More...

using	Time = T
	Type of time being used. More...

Public Member Functions
	AsymExpPulseFunction (ADCcount amplitude, Time peakTime, Time raiseTau, Time fallTau)
	Constructor: assigns the parameters of the shape. More...

Parameter accessors.
Time	raiseTau () const

Time	fallTau () const

ADCcount	amplitude () const

Public Member Functions inherited from icarus::opdet::PhotoelectronPulseFunction< T >
virtual	~PhotoelectronPulseFunction ()=default

ADCcount	evaluateAt (Time time) const
	Evaluates the pulse at the given time. More...

ADCcount	operator() (Time time) const
	Alias of `evaluateAt()`. More...

Time	peakTime () const
	Returns the time at which the first peak is found. More...

ADCcount	peakAmplitude () const
	Returns the amplitude of the first peak in ADC counts. More...

ADCcount	baseline () const
	Returns the baseline of the pulse in ADC counts. More...

int	polarity () const
	Returns the polarity of the pulse (`+1`: positive, or `-1`: negative). More...

void	dump (std::ostream &out, std::string const &indent, std::string const &firstIndent) const
	Prints on stream the parameters of this shape. More...

void	dump (std::ostream &&out, std::string const &indent="") const

std::string	toString (std::string const &indent, std::string const &firstIndent) const
	Returns the parameters of this shape as a descriptive string. More...

std::string	toString (std::string const &indent="") const

Static Public Member Functions
static double	Exponential (Time t, Time tau)
	Returns the value of an exponential: `exp(-t/tau)`. More...

static double	ExponentialDiff (Time t, Time raise, Time fall)
	Returns the value of an exponential: `exp(-t/tau)`. More...

Private Types
using	Base_t = icarus::opdet::PhotoelectronPulseFunction< T >

Private Member Functions
Time	myPeakTime () const
	Returns the time of the peak. More...

ADCcount	myAmplitude () const
	Returns the amplitude of the pulse from the baseline, including its sign. More...

virtual ADCcount	doEvaluateAt (Time time) const override
	Evaluates the pulse at the given time. More...

virtual Time	doPeakTime () const override
	Returns the time at which the first peak is found. More...

virtual ADCcount	doPeakAmplitude () const override
	Returns the amplitude of the first peak in ADC counts. More...

virtual void	doDump (std::ostream &out, std::string const &indent, std::string const &firstIndent) const override
	Prints on stream the parameters of this shape. More...

Static Private Member Functions
static Time	expDiffPeak (Time raiseTau, Time fallTau)
	Returns the time value at which `ExponentialDiff()` is maximum. More...

template<typename V >
static V	round (V value)

Private Attributes
ADCcount const	fAmplitude
	Amplitude at peak (transition). More...

Time const	fPeakTime
	Time of maximum signal. More...

Time const	fRaiseTau
	Time constant of signal rise. More...

Time const	fFallTau
	Time constant of signal fall. More...

Time const	fRaiseTime
	Time when the signal starts rising above baseline. More...

ADCcount const	fA
	Normalization factor in the functional form. More...

Additional Inherited Members
Protected Member Functions inherited from icarus::opdet::PhotoelectronPulseFunction< T >
virtual ADCcount	doEvaluateAt (Time time) const =0
	Implementation of the function evaluation at `time`. More...

virtual ADCcount	doBaseline () const
	Returns the baseline of the pulse. More...

virtual int	doPolarity () const
	Returns the polarity of the pulse (+1 or -1). More...

Detailed Description

template<typename T>
class icarus::opdet::AsymExpPulseFunction< T >

Describes the waveform from a single photoelectron.

Template Parameters

Time	type of time unit to be used

This functor (class behaving like a function) describes the shape of the response to a single photoelectron as an exponentially raising and then exponentially falling shape:

$A \left[ exp(-(t - t_{0})/\tau_{s}) - exp(-(t - t_{0})/\tau) \right]$

with $\tau_{s}$ the rise time and $\tau$ the fall time; $t_{0}$ is the start of the signal formation, i.e. the time at which the signal starts raising.

Note that $t_{0}$ is not the peak time, and $ A $ is not the peak amplitude of the signal.

Definition at line 30 of file AsymExpPulseFunction.h.

Member Typedef Documentation

template<typename T >

using icarus::opdet::AsymExpPulseFunction< T >::ADCcount = typename Base_t::ADCcount

Type for ADC counts (floating point).

Definition at line 57 of file AsymExpPulseFunction.h.

template<typename T >

using icarus::opdet::AsymExpPulseFunction< T >::Base_t = icarus::opdet::PhotoelectronPulseFunction<T>

private

Definition at line 53 of file AsymExpPulseFunction.h.

template<typename T >

using icarus::opdet::AsymExpPulseFunction< T >::Time = typename Base_t::Time

Type of time being used.

Definition at line 59 of file AsymExpPulseFunction.h.

Constructor & Destructor Documentation

template<typename T >

icarus::opdet::AsymExpPulseFunction< T >::AsymExpPulseFunction	(	ADCcount	amplitude,
		Time	peakTime,
		Time	raiseTau,
		Time	fallTau
	)

Constructor: assigns the parameters of the shape.

Parameters

amplitude	the maximum amplitudes of the shape (at transition)
peakTime	the time of the maximum amplitude of the shape
raiseTau	the raise time (exponential parameter) of the shape
fallTau	the decay time (exponential parameter) of the shape

The time parameters (peakTime, raiseTau and fallTau) must be measured in same unit. The peakTime defines the position of the shape with respect to time 0.

Note: The construction parameters are not the ones described by the functional form documented in the class, $A \left[ exp(-(t - t_{0})/\tau_{s}) - exp(-(t - t_{0})/\tau) \right]$ : the amplitude parameter is the actual maximum of the signal response, and peakTime is the actual time at which the signal peaks. These parameters are more easily read from a measured waveform.

Definition at line 165 of file AsymExpPulseFunction.h.

   : fAmplitude(amplitude)
   , fPeakTime(peakTime)
   , fRaiseTau(raiseTau)
   , fFallTau(fallTau)
   , fRaiseTime(fPeakTime - expDiffPeak(fRaiseTau, fFallTau))
   , fA(fAmplitude/ExponentialDiff(fPeakTime - fRaiseTime, fRaiseTau, fFallTau))
 {
   // numerical sanity checks (for debugging only)
   assert(std::isnormal(fA.value()));
 } // icarus::opdet::AsymExpPulseFunction<>::AsymExpPulseFunction()

Member Function Documentation

template<typename T >

ADCcount icarus::opdet::AsymExpPulseFunction< T >::amplitude ( ) const

inline

Definition at line 94 of file AsymExpPulseFunction.h.

94 { return fAmplitude; }

icarus::opdet::AsymExpPulseFunction::fAmplitude

ADCcount const fAmplitude

Amplitude at peak (transition).

Definition: AsymExpPulseFunction.h:106

template<typename T >

void icarus::opdet::AsymExpPulseFunction< T >::doDump	(	std::ostream &	out,
		std::string const &	indent,
		std::string const &	firstIndent
	)		const

overrideprivatevirtual

Prints on stream the parameters of this shape.

Parameters

out	the stream to write into
indent	indentation string, prepended to all lines except first
indentFirst	indentation string prepended to the first line

Reimplemented from icarus::opdet::PhotoelectronPulseFunction< T >.

Definition at line 196 of file AsymExpPulseFunction.h.

 {
   out << firstIndent
     << "Pulse shape: exponential sum with peak at "
       << myPeakTime() << " and amplitude " << amplitude()
       << ", time constants: " << raiseTau() 
       << " (raise) and " << fallTau() << " (fall)"
     << indent << "  start at " << fRaiseTime << ", normalization factor " << fA
     << '\n';
 } // icarus::opdet::AsymExpPulseFunction<>::doDump()

template<typename T >

auto icarus::opdet::AsymExpPulseFunction< T >::doEvaluateAt ( Time time ) const

overrideprivatevirtual

Evaluates the pulse at the given time.

Parameters

time	time to evaluate the shape at

The scale of the time is defined by the transition time passed at construction.

Definition at line 185 of file AsymExpPulseFunction.h.

 {
   return (time <= fRaiseTime)
     ? ADCcount{ 0 }
     : round(fA * ExponentialDiff(time - fRaiseTime, fRaiseTau, fFallTau) );
 } // icarus::opdet::AsymExpPulseFunction<>::doEvaluateAt()

template<typename T >

virtual ADCcount icarus::opdet::AsymExpPulseFunction< T >::doPeakAmplitude ( ) const

inlineoverrideprivatevirtual

Returns the amplitude of the first peak in ADC counts.

Reimplemented from icarus::opdet::PhotoelectronPulseFunction< T >.

Definition at line 135 of file AsymExpPulseFunction.h.

135 { return myAmplitude(); }

icarus::opdet::AsymExpPulseFunction::myAmplitude

ADCcount myAmplitude() const

Returns the amplitude of the pulse from the baseline, including its sign.

Definition: AsymExpPulseFunction.h:118

template<typename T >

virtual Time icarus::opdet::AsymExpPulseFunction< T >::doPeakTime ( ) const

inlineoverrideprivatevirtual

Returns the time at which the first peak is found.

Implements icarus::opdet::PhotoelectronPulseFunction< T >.

Definition at line 132 of file AsymExpPulseFunction.h.

132 { return myPeakTime(); }

icarus::opdet::AsymExpPulseFunction::myPeakTime

Time myPeakTime() const

Returns the time of the peak.

Definition: AsymExpPulseFunction.h:115

template<typename T >

auto icarus::opdet::AsymExpPulseFunction< T >::expDiffPeak	(	Time	raiseTau,
		Time	fallTau
	)

staticprivate

Returns the time value at which ExponentialDiff() is maximum.

Definition at line 214 of file AsymExpPulseFunction.h.

 {
   // the strange order of the operations makes sure that if Time defines
   // difference (into Time), ratio (into scalar) and multiplication to scalar,
   // the expression is valid.
   return
     raiseTau * (fallTau / (raiseTau - fallTau)) * std::log(raiseTau/fallTau);
 } // icarus::opdet::AsymExpPulseFunction<T>::expDiffPeak()