PMT signal processor interface. More...

#include <JPMTSignalProcessorInterface.hh>

Inheritance diagram for JDETECTOR::JPMTSignalProcessorInterface:

Public Member Functions
	JPMTSignalProcessorInterface ()
	Default constructor. More...

virtual	~JPMTSignalProcessorInterface ()
	Virtual destructor. More...

void	operator() (const JCalibration &calibration, const JPMTData< JPMTSignal > &input, JPMTData< JPMTPulse > &output) const
	Process hits. More...

virtual bool	applyQE () const
	Apply relative QE. More...

virtual double	getRandomTime (const double t_ns) const
	Get randomised time according transition time distribution. More...

virtual bool	compare (const JPhotoElectron &first, const JPhotoElectron &second) const
	Compare arrival times of photo-electrons. More...

virtual double	getRandomAmplitude (const int NPE) const
	Get randomised amplitude according gain and gain spread. More...

virtual double	getProbability (const double npe, const int NPE) const
	Get probability for given charge. More...

virtual bool	applyThreshold (const double npe) const
	Apply threshold. More...

virtual double	getRiseTime (const double npe) const
	Get time to pass threshold. More...

virtual double	getTimeOverThreshold (const double npe) const
	Get time over threshold (ToT). More...

virtual double	getDerivative (const double npe) const
	Get derivative of number of photo-electrons to time over threshold. More...

virtual double	getSurvivalProbability (const int NPE) const
	Probability that a hit survives the simulation of the PMT. More...

virtual void	merge (JPMTData< JPMTPulse > &data) const
	Merging of PMT hits. More...

double	getNPE (const double tot_ns, const double eps=1.0e-3) const
	Get number of photo-electrons. More...

Static Public Member Functions
static double	getTmin ()
	Get two photo-electron resolution for time-over-threshold. More...

static double	getQmin ()
	Get minimal width of charge distribution. More...

Private Attributes
JPMTData< JPhotoElectron >	buffer

Detailed Description

PMT signal processor interface.

This class supports the implementation of the PMT simulator interface using an alternative set of virtual methods. These methods constitute a user interface to the expected performance of a PMT.

Each photon is converted to a photo-electron using member method JPMTSignalProcessorInterface::getRandomTime. For this, the data structure JPhotoElectron is used. Note that the quantum efficiency (QE) of the PMT actually is included in the simulation of the detector response. All photo-electrons are then time sorted. The photo-electrons which simultaneously arrive are merged. The corresponding condition is defined by member method JPMTSignalProcessorInterface::compare. The time of the combined signal is determined by the time of the first photo-electron and the rise time of the analogue pulse to the threshold of the discriminator. In this, the actual amplitude of the combined analogue signal and the calibration of the PMT are taken into account. The amplitude of the combined analogue signal is simulated using member method JPMTSignalProcessorInterface::getRandomAmplitude. For this, the data structure JPMTSignal is used.

The analogue signals of the PMT are processed by a discriminator. This discriminator produces a time-over-threshold signal for each analogue signal that passes a preset threshold. The output signal is described by the time of the leading edge and the length of the time-over-threshold signal. For this, the data structure JPMTPulse is used. The determination of the time of the leading edge and the length of the time-over-threshold signal require a designated model. The class JPMTAnalogueSignalProcessor provides for an implementation of such a model.

Overlapping time-over-threshold pulses are merged. The time of the leading edge is then set to the earliest leading edge and the time-over-threshold to the difference between the latest trailing edge and the earliest leading edge. The merging of hits is implemented in member method JPMTSignalProcessorInterface::merge.

The default implementation of these virtual methods corresponds to no smearing and a time-over-threshold value equal to a fixed two photo-electron resolution. The width of the charge distribution and the two photo-electron resolution are implemented in methods JPMTSignalProcessorInterface::getQmin() and JPMTSignalProcessorInterface::getTmin(), respectively. For a realistic PMT simulation, the derived class should provide for an implementation of each of these virtual methods.

Definition at line 69 of file JPMTSignalProcessorInterface.hh.

Constructor & Destructor Documentation

◆ JPMTSignalProcessorInterface()

JDETECTOR::JPMTSignalProcessorInterface::JPMTSignalProcessorInterface ( )

inline

Default constructor.

Definition at line 74 of file JPMTSignalProcessorInterface.hh.

75 {}

◆ ~JPMTSignalProcessorInterface()

virtual JDETECTOR::JPMTSignalProcessorInterface::~JPMTSignalProcessorInterface ( )

inlinevirtual

Virtual destructor.

Definition at line 81 of file JPMTSignalProcessorInterface.hh.

82 {}

Member Function Documentation

◆ operator()()

void JDETECTOR::JPMTSignalProcessorInterface::operator()	(	const JCalibration &	calibration,
		const JPMTData< JPMTSignal > &	input,
		JPMTData< JPMTPulse > &	output
	)		const

inline

Process hits.

Parameters

calibration	PMT calibration
input	PMT signals
output	PMT hits

Definition at line 92 of file JPMTSignalProcessorInterface.hh.

     {
       // apply transition time distribution to each photo-electron.
  
       buffer.clear();
       
       for (JPMTData<JPMTSignal>::const_iterator hit = input.begin(); hit != input.end(); ++hit) {
         for (int i = 0; i != hit->npe; ++i) {
           if (applyQE()) {
             buffer.push_back(JPhotoElectron(getRandomTime(hit->t_ns)));
           }
         }
       }
  
       if (!buffer.empty()) {
       
         buffer.push_back(JPhotoElectron::getEndMarker());
       
         buffer.sort();
       
       
         // generate PMT hits from time sequence of photo-electrons.
         
         for (JPMTData<JPhotoElectron>::const_iterator q = buffer.begin(), p = q++; q != buffer.end(); ++q) {
           
           while (compare(*p,*q)) {
             ++q;
           }
           
           const double npe = getRandomAmplitude(distance(p,q));
           
           if (applyThreshold(npe)) {
             output.push_back(JPMTPulse(putTime(p->t_ns + getRiseTime(npe), calibration), getTimeOverThreshold(npe)));
           }
           
           p = q;
         }
         
         // merge overlapping PMT hits.
       
         merge(output);
       }
     }

◆ applyQE()

virtual bool JDETECTOR::JPMTSignalProcessorInterface::applyQE ( ) const

inlinevirtual

Apply relative QE.

The default implementation returns always true.

Returns: true

Reimplemented in JDETECTOR::JPMTAnalogueSignalProcessor.

Definition at line 145 of file JPMTSignalProcessorInterface.hh.

     {
       return true;
     }

◆ getRandomTime()

virtual double JDETECTOR::JPMTSignalProcessorInterface::getRandomTime ( const double t_ns ) const

inlinevirtual

Get randomised time according transition time distribution.

The default implementation returns the given value.

Parameters

t_ns time [ns]

Returns: time [ns]

Reimplemented in JDETECTOR::JPMTAnalogueSignalProcessor.

Definition at line 158 of file JPMTSignalProcessorInterface.hh.

     {
       return t_ns;
     }

◆ compare()

virtual bool JDETECTOR::JPMTSignalProcessorInterface::compare	(	const JPhotoElectron &	first,
		const JPhotoElectron &	second
	)		const

inlinevirtual

Compare arrival times of photo-electrons.

Two (or more) photo-electrons are merged if they are comparable. The default implementation returns uses JPMTSignalProcessorInterface::getTmin() as time window.

Parameters

first	first photo-electron
second	second photo-electron

Returns: false

Reimplemented in JDETECTOR::JPMTAnalogueSignalProcessor.

Definition at line 174 of file JPMTSignalProcessorInterface.hh.

     {
       return second.t_ns - first.t_ns <= getTmin();
     }

◆ getRandomAmplitude()

virtual double JDETECTOR::JPMTSignalProcessorInterface::getRandomAmplitude ( const int NPE ) const

inlinevirtual

Get randomised amplitude according gain and gain spread.

The default implementation returns the given value.

Parameters

NPE	number of photo-electrons

Returns: number of photo-electrons

Reimplemented in JDETECTOR::JPMTAnalogueSignalProcessor.

Definition at line 187 of file JPMTSignalProcessorInterface.hh.

     {
       return (double) NPE;
     }

◆ getProbability()

virtual double JDETECTOR::JPMTSignalProcessorInterface::getProbability	(	const double	npe,
		const int	NPE
	)		const

inlinevirtual

Get probability for given charge.

Parameters

npe	observed number of photo-electrons
NPE	true number of photo-electrons

Returns: probability [npe^-1]

Reimplemented in JDETECTOR::JPMTAnalogueSignalProcessor.

Definition at line 200 of file JPMTSignalProcessorInterface.hh.

     {
       return (fabs(npe - NPE) < 0.5*getQmin() ? 1.0/getQmin() : 0.0);
     }

◆ applyThreshold()

virtual bool JDETECTOR::JPMTSignalProcessorInterface::applyThreshold ( const double npe ) const

inlinevirtual

Apply threshold.

The default implementation returns always true.

Parameters

npe	number of photo-electrons

Returns: true if pass; else false

Reimplemented in JDETECTOR::JPMTAnalogueSignalProcessor.

Definition at line 213 of file JPMTSignalProcessorInterface.hh.

     {
       return true;
     }

◆ getRiseTime()

virtual double JDETECTOR::JPMTSignalProcessorInterface::getRiseTime ( const double npe ) const

inlinevirtual

Get time to pass threshold.

The default implementation returns 0.

Parameters

npe	number of photo-electrons

Returns: time [ns]

Reimplemented in JDETECTOR::JPMTAnalogueSignalProcessor.

Definition at line 226 of file JPMTSignalProcessorInterface.hh.

     {
       return 0.0;
     }

◆ getTimeOverThreshold()

virtual double JDETECTOR::JPMTSignalProcessorInterface::getTimeOverThreshold ( const double npe ) const

inlinevirtual

Get time over threshold (ToT).

The default implementation returns JPMTSignalProcessorInterface::getTmin().

Parameters

npe	number of photo-electrons

Returns: ToT [ns]

Reimplemented in JDETECTOR::JPMTAnalogueSignalProcessor.

Definition at line 239 of file JPMTSignalProcessorInterface.hh.

     {
       return getTmin();
     }

◆ getDerivative()

virtual double JDETECTOR::JPMTSignalProcessorInterface::getDerivative ( const double npe ) const

inlinevirtual

Get derivative of number of photo-electrons to time over threshold.

The default implementation returns infinity.

Parameters

npe	number of photo-electrons

Returns: dnpe/dToT [ns^-1]

Reimplemented in JDETECTOR::JPMTAnalogueSignalProcessor.

Definition at line 252 of file JPMTSignalProcessorInterface.hh.

     {
       return std::numeric_limits<double>::max();
     }

◆ getSurvivalProbability()

virtual double JDETECTOR::JPMTSignalProcessorInterface::getSurvivalProbability ( const int NPE ) const

inlinevirtual

Probability that a hit survives the simulation of the PMT.

The default implementation returns 1 if given value larger than 0.

Parameters

NPE	number of photo-electrons

Returns: probability

Reimplemented in JDETECTOR::JPMTAnalogueSignalProcessor.

Definition at line 265 of file JPMTSignalProcessorInterface.hh.

     {
       if (NPE > 0)
         return 1.0;
       else
         return 0.0;
     }

◆ merge()

virtual void JDETECTOR::JPMTSignalProcessorInterface::merge ( JPMTData< JPMTPulse > & data ) const

inlinevirtual

Merging of PMT hits.

Hits with overlapping time-over-threshold signals should -de facto- be combined. In this, the leading edge is maintained and the time-over-threshold is set to the difference between the overall trailing and leading edges. As a result, the number of PMT hits may be reduced.

Parameters

data PMT hits

Definition at line 284 of file JPMTSignalProcessorInterface.hh.

     {
       using namespace std;
       
       JPMTData<JPMTPulse>::iterator out = data.begin();
       
       for (JPMTData<JPMTPulse>::iterator i = data.begin(); i != data.end(); ) {
         
         double t1 = i->t_ns;
         double t2 = i->t_ns + i->tot_ns;
         
         while (++i != data.end() && i->t_ns < t2 + getTmin()) {
           t2 = max(t2, i->t_ns + i->tot_ns);
         }
         
         out->t_ns   = t1;
         out->tot_ns = t2 - t1;
         
         ++out;
       }
       
       data.resize(distance(data.begin(), out));
     }

◆ getNPE()

double JDETECTOR::JPMTSignalProcessorInterface::getNPE	(	const double	tot_ns,
		const double	eps = `1.0e-3`
	)		const

inline

Get number of photo-electrons.

Parameters

tot_ns	time over threshold [ns]
eps	precision

Returns: number of photo-electrons

Definition at line 316 of file JPMTSignalProcessorInterface.hh.

     {
       static const int N = 100;
  
       if (tot_ns > 0.0) {
  
         double xmin =   0.0;
         double xmax = 100.0;
       
         for (int i = 0; i != N; ++i) {
         
           const double x = 0.5 * (xmin + xmax);
           const double y = this->getTimeOverThreshold(x);
           
           if (fabs(y - tot_ns) < eps) {
             return x;
           }
           
           if (y < tot_ns)
             xmin = x;
           else
             xmax = x;
         }
  
         return 0.5 * (xmin + xmax);
  
       } else {
  
         double xmin = 0.0;
         double xmax = 2.0;
       
         for (int i = 0; i != N; ++i) {
           
           const double x = 0.5 * (xmin + xmax);
           const double y = this->getTimeOverThreshold(x);
  
           if (y == 0.0)
             xmin = x;
           else
             xmax = x;
         }
  
         return 0.5 * (xmin + xmax);
       }
     }

◆ getTmin()

static double JDETECTOR::JPMTSignalProcessorInterface::getTmin ( )

inlinestatic

Get two photo-electron resolution for time-over-threshold.

Returns: minimal time [ns]

Definition at line 369 of file JPMTSignalProcessorInterface.hh.

     {
       return 1.0;
     }

◆ getQmin()

static double JDETECTOR::JPMTSignalProcessorInterface::getQmin ( )

inlinestatic

Get minimal width of charge distribution.

Returns: minimal charge [npe]

Definition at line 380 of file JPMTSignalProcessorInterface.hh.

     {
       return 1.0e-3;
     }

Member Data Documentation

◆ buffer

JPMTData<JPhotoElectron> JDETECTOR::JPMTSignalProcessorInterface::buffer

mutableprivate

Definition at line 387 of file JPMTSignalProcessorInterface.hh.

The documentation for this class was generated from the following file:

JPMTSignalProcessorInterface.hh

Public Member Functions

Static Public Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ JPMTSignalProcessorInterface()

◆ ~JPMTSignalProcessorInterface()

Member Function Documentation

◆ operator()()

◆ applyQE()

◆ getRandomTime()

◆ compare()

◆ getRandomAmplitude()

◆ getProbability()

◆ applyThreshold()

◆ getRiseTime()

◆ getTimeOverThreshold()

◆ getDerivative()

◆ getSurvivalProbability()

◆ merge()

◆ getNPE()

◆ getTmin()

◆ getQmin()

Member Data Documentation

◆ buffer