tracking::reco::SiStripWaveformBuilder Class Reference

Assemble per-trigger pedestal-subtracted hits into full per-channel waveforms. More...

#include <SiStripWaveformBuilder.h>

Public Member Functions
	SiStripWaveformBuilder (const std::string &name, framework::Process &process)
void	configure (framework::config::Parameters &ps) override
	Callback for the EventProcessor to configure itself from the given set of parameters.
void	produce (framework::Event &event) override
	Process the event and put new data products into it.
void	onProcessEnd () override
	Callback for the EventProcessor to take any necessary action when the processing of events finishes, such as calculating job-summary quantities.
Public Member Functions inherited from framework::Producer
	Producer (const std::string &name, Process &process)
	Class constructor.
virtual void	process (Event &event) final
	Processing an event for a Producer is calling produce.
Public Member Functions inherited from framework::EventProcessor
	DECLARE_FACTORY (EventProcessor, EventProcessor *, const std::string &, Process &)
	declare that we have a factory for this class
	EventProcessor (const std::string &name, Process &process)
	Class constructor.
virtual	~EventProcessor ()=default
	Class destructor.
virtual void	beforeNewRun (ldmx::RunHeader &run_header)
	Callback for Producers to add parameters to the run header before conditions are initialized.
virtual void	onNewRun (const ldmx::RunHeader &run_header)
	Callback for the EventProcessor to take any necessary action when the run being processed changes.
virtual void	onFileOpen (EventFile &event_file)
	Callback for the EventProcessor to take any necessary action when a new event input ROOT file is opened.
virtual void	onFileClose (EventFile &event_file)
	Callback for the EventProcessor to take any necessary action when a event input ROOT file is closed.
virtual void	onProcessStart ()
	Callback for the EventProcessor to take any necessary action when the processing of events starts, such as creating histograms.
template<class T >
const T &	getCondition (const std::string &condition_name)
	Access a conditions object for the current event.
TDirectory *	getHistoDirectory ()
	Access/create a directory in the histogram file for this event processor to create histograms and analysis tuples.
void	setStorageHint (framework::StorageControl::Hint hint)
	Mark the current event as having the given storage control hint from this module_.
void	setStorageHint (framework::StorageControl::Hint hint, const std::string &purposeString)
	Mark the current event as having the given storage control hint from this module and the given purpose string.
int	getLogFrequency () const
	Get the current logging frequency from the process.
int	getRunNumber () const
	Get the run number from the process.
std::string	getName () const
	Get the processor name.
void	createHistograms (const std::vector< framework::config::Parameters > &histos)
	Internal function which is used to create histograms passed from the python configuration @parma histos vector of Parameters that configure histograms to create.

Private Attributes
std::string	input_collection_ {"TrackerHits"}
std::string	input_pass_name_ {""}
std::string	output_collection_ {"TrackerWaveforms"}
double	high_threshold_
	per-sample significance for high-threshold cut
int	min_high_samples_ {4}
	min samples exceeding high_threshold
double	low_threshold_
	per-sample significance for consecutive-streak cut
int	min_consecutive_low_
	min consecutive samples exceeding low_threshold
int	n_triggers_ {10}
	expected APV triggers per RoR
std::unique_ptr< tracking::digitization::PulseShape >	pulse_shape_
	Pulse shape used for the per-waveform fit test (built lazily in produce).
long	n_fit_attempted_ {0}
	waveforms passed to the fitter
long	n_fit_failed_ {0}
	fits that did not converge

Additional Inherited Members
Protected Member Functions inherited from framework::EventProcessor
void	abortEvent ()
	Abort the event immediately.
Protected Attributes inherited from framework::EventProcessor
HistogramPool	histograms_
	helper object for making and filling histograms
NtupleManager &	ntuple_ {NtupleManager::getInstance()}
	Manager for any ntuples.
logging::logger	the_log_
	The logger for this EventProcessor.

Detailed Description

Assemble per-trigger pedestal-subtracted hits into full per-channel waveforms.

Each RoR issues n_triggers APV triggers, each producing a 3-sample (pedestal-subtracted) RawSiStripHit per channel. This producer groups all trigger hits for the same (feb, hybrid, pchannel), sorts by apv_trigger, and concatenates their samples into a SiStripWaveform with n_triggers*3 samples ordered as [s0_t0, s1_t0, s2_t0, s0_t1, ...].

The per-channel noise used for the significance cuts is obtained from the TrackerPedestals conditions object (a service); the physical strip number (pchannel) is derived from the hit's apv_id/channel via channelmap.

Two-stage threshold applied before writing:

1. High-threshold count: at least min_high_samples samples with ADC/noise > high_threshold (default: 4 samples > 5σ).
2. Consecutive low-threshold streak: at least min_consecutive_low consecutive samples with ADC/noise > low_threshold (default: 5 consecutive samples > 3σ). Both conditions must be satisfied; this strongly suppresses noise while retaining real APV25 signal pulses.

Definition at line 36 of file SiStripWaveformBuilder.h.

Constructor & Destructor Documentation

SiStripWaveformBuilder()

tracking::reco::SiStripWaveformBuilder::SiStripWaveformBuilder ( const std::string & name, framework::Process & process )

inline

Definition at line 38 of file SiStripWaveformBuilder.h.

      : framework::Producer(name, process) {}

Member Function Documentation

configure()

void tracking::reco::SiStripWaveformBuilder::configure ( framework::config::Parameters & parameters )

overridevirtual

Callback for the EventProcessor to configure itself from the given set of parameters.

The parameters a processor has access to are the member variables of the python class in the sequence that has class_name equal to the EventProcessor class name.

For an example, look at MyProcessor.

Parameters

parameters

Parameters for configuration.

Reimplemented from framework::EventProcessor.

Definition at line 14 of file SiStripWaveformBuilder.cxx.

                                                                    {
  input_collection_ =
      ps.get<std::string>("input_collection", input_collection_);
  input_pass_name_ = ps.get<std::string>("input_pass_name", input_pass_name_);
  output_collection_ =
      ps.get<std::string>("output_collection", output_collection_);
  high_threshold_ = ps.get<double>("high_threshold", high_threshold_);
  min_high_samples_ = ps.get<int>("min_high_samples", min_high_samples_);
  low_threshold_ = ps.get<double>("low_threshold", low_threshold_);
  min_consecutive_low_ =
      ps.get<int>("min_consecutive_low", min_consecutive_low_);
  n_triggers_ = ps.get<int>("n_triggers", n_triggers_);
}

References framework::config::Parameters::get(), high_threshold_, low_threshold_, min_consecutive_low_, min_high_samples_, and n_triggers_.

onProcessEnd()

void tracking::reco::SiStripWaveformBuilder::onProcessEnd ( )

overridevirtual

Callback for the EventProcessor to take any necessary action when the processing of events finishes, such as calculating job-summary quantities.

Reimplemented from framework::EventProcessor.

Definition at line 164 of file SiStripWaveformBuilder.cxx.

                                          {
  const long n_ok = n_fit_attempted_ - n_fit_failed_;
  const double fail_pct =
      n_fit_attempted_ > 0
          ? 100.0 * static_cast<double>(n_fit_failed_) / n_fit_attempted_
          : 0.0;
  ldmx_log(info) << "Fit summary: " << n_fit_attempted_ << " attempted, "
                 << n_ok << " converged, " << n_fit_failed_ << " failed ("
                 << fail_pct << "%)";
}

References n_fit_attempted_, and n_fit_failed_.

produce()

void tracking::reco::SiStripWaveformBuilder::produce ( framework::Event & event )

overridevirtual

Process the event and put new data products into it.

Parameters

event

The Event to process.

Implements framework::Producer.

Definition at line 28 of file SiStripWaveformBuilder.cxx.

                                                          {
  const auto& peds =
      getCondition<TrackerPedestals>(TrackerPedestals::CONDITIONS_NAME);
 
  const auto& hits = event.getCollection<ldmx::RawSiStripHit>(input_collection_,
                                                              input_pass_name_);
 
  // Build the pulse shape once (reused for every channel fit this job).
  if (!pulse_shape_) {
    pulse_shape_ = tracking::digitization::PulseShape::make(
        std::string(tracking::digitization::PULSE_SHAPE_NAME),
        tracking::digitization::PEAKING_TIME_NS,
        tracking::digitization::SECOND_TIME_CONST_NS);
  }
 
  // Key: encodes (feb, hybrid, pchannel) uniquely.
  // Value: vector of (apv_trigger, samples) pairs.
  struct TriggerSamples {
    uint16_t apv_trigger_;
    std::vector<short> samples_;
  };
  struct ChannelInfo {
    float noise_{0};
    uint8_t hybrid_id_{0};
    uint8_t feb_id_{0};
    std::vector<TriggerSamples> triggers_;
  };
 
  // Use a map keyed by (feb, hybrid, pchannel) for grouping.
  std::map<uint32_t, ChannelInfo> channel_map;
 
  for (const auto& hit : hits) {
    const float noise = peds.noise(hit.getFebId(), hit.getHybridId(),
                                   hit.getApvId(), hit.getChannel());
    if (noise <= 0) continue;
 
    const int16_t pchannel =
        channelmap::pchannel(hit.getApvId(), hit.getChannel());
    uint32_t key =
        channelmap::groupKey(hit.getFebId(), hit.getHybridId(), pchannel);
 
    auto& ch = channel_map[key];
    ch.noise_ = noise;
    ch.hybrid_id_ = hit.getHybridId();
    ch.feb_id_ = hit.getFebId();
    ch.triggers_.push_back({hit.getApvTrigger(), hit.getSamples()});
  }
 
  std::vector<ldmx::SiStripWaveform> waveforms;
 
  for (auto& [key, ch] : channel_map) {
    // Sort triggers by apv_trigger index.
    std::sort(ch.triggers_.begin(), ch.triggers_.end(),
              [](const TriggerSamples& a, const TriggerSamples& b) {
                return a.apv_trigger_ < b.apv_trigger_;
              });
 
    // Assemble full waveform: [s0_t0, s1_t0, s2_t0, s0_t1, ...].
    std::vector<short> samples;
    samples.reserve(ch.triggers_.size() *
                    channelmap::K_SAMPLES_PER_APV_TRIGGER);
    for (const auto& trig : ch.triggers_) {
      for (short s : trig.samples_) samples.push_back(s);
    }
 
    if (samples.empty()) continue;
 
    // Condition 1: at least min_high_samples_ samples exceed high_threshold_.
    int n_high = 0;
    for (short s : samples)
      if (static_cast<float>(s) / ch.noise_ > high_threshold_) ++n_high;
    if (n_high < min_high_samples_) continue;
 
    // Condition 2: at least min_consecutive_low_ consecutive samples exceed
    // low_threshold_.
    int max_streak = 0, cur_streak = 0;
    for (short s : samples) {
      if (static_cast<float>(s) / ch.noise_ > low_threshold_) {
        max_streak = std::max(max_streak, ++cur_streak);
      } else {
        cur_streak = 0;
      }
    }
    if (max_streak < min_consecutive_low_) continue;
 
    int16_t pchannel = channelmap::pchannelFromGroupKey(key);
    uint8_t n_trig = static_cast<uint8_t>(
        std::min(static_cast<int>(ch.triggers_.size()), 255));
 
    // --- TEST: fit a CR-RC pulse shape to the full assembled waveform. ---
    // Samples are pedestal-subtracted (ped = 0) and lie on a uniform 25 ns
    // grid, so the scan range is sized to the waveform: T may peak anywhere
    // from before sample 0 to the last sample.
    const int n_samples = static_cast<int>(samples.size());
    const double t_scan_max =
        n_samples * tracking::digitization::SAMPLING_INTERVAL_NS;
    tracking::digitization::StripPulseFitter fitter(
        *pulse_shape_,
        /*t0_offset_ns=*/0.0,
        tracking::digitization::SAMPLING_INTERVAL_NS,
        /*pedestal_adc=*/0.0,
        /*noise_sigma_adc=*/ch.noise_,
        /*t_scan_min_ns=*/-50.0, t_scan_max, /*t_scan_step_ns=*/1.0);
    const auto fit = fitter.fit(samples);
    ++n_fit_attempted_;
    if (!fit.converged) ++n_fit_failed_;
 
    ldmx_log(trace) << "fit feb=" << static_cast<int>(ch.feb_id_)
                    << " hyb=" << static_cast<int>(ch.hybrid_id_)
                    << " pch=" << pchannel << " nsamp=" << n_samples
                    << " noise=" << ch.noise_
                    << " -> converged=" << (fit.converged ? "yes" : "no")
                    << " amp=" << fit.amplitude << " t0=" << fit.t0 << "ns"
                    << " chi2/ndf=" << fit.chi2 << "/" << fit.ndf << " ("
                    << (fit.ndf > 0 ? fit.chi2 / fit.ndf : 0.0) << ")";
 
    waveforms.emplace_back(std::move(samples), pchannel, ch.hybrid_id_,
                           ch.feb_id_, n_trig);
    waveforms.back().setFitResult(
        static_cast<float>(fit.amplitude), static_cast<float>(fit.t0),
        static_cast<float>(fit.chi2), fit.ndf, fit.converged);
  }
 
  ldmx_log(debug) << "Built " << waveforms.size()
                  << " waveforms (>=" << min_high_samples_ << " samples @"
                  << high_threshold_ << "s, streak>=" << min_consecutive_low_
                  << " @" << low_threshold_ << "s) from " << hits.size()
                  << " hits";
 
  for (const auto& wf : waveforms) {
    ldmx_log(trace) << wf;
  }
 
  event.add(output_collection_, waveforms);
}

References tracking::reco::TrackerPedestals::CONDITIONS_NAME, tracking::digitization::StripPulseFitter::fit(), framework::EventProcessor::getCondition(), tracking::reco::channelmap::groupKey(), high_threshold_, tracking::reco::channelmap::K_SAMPLES_PER_APV_TRIGGER, low_threshold_, tracking::digitization::PulseShape::make(), min_consecutive_low_, min_high_samples_, n_fit_attempted_, n_fit_failed_, tracking::reco::channelmap::pchannel(), tracking::reco::channelmap::pchannelFromGroupKey(), and pulse_shape_.

Member Data Documentation

high_threshold_

double tracking::reco::SiStripWaveformBuilder::high_threshold_

private

Initial value:

{
      5.0}

per-sample significance for high-threshold cut

Definition at line 49 of file SiStripWaveformBuilder.h.

                        {
      5.0};                  

Referenced by configure(), and produce().

input_collection_

std::string tracking::reco::SiStripWaveformBuilder::input_collection_ {"TrackerHits"}

private

Definition at line 46 of file SiStripWaveformBuilder.h.

{"TrackerHits"};

input_pass_name_

std::string tracking::reco::SiStripWaveformBuilder::input_pass_name_ {""}

private

Definition at line 47 of file SiStripWaveformBuilder.h.

{""};

low_threshold_

double tracking::reco::SiStripWaveformBuilder::low_threshold_

private

Initial value:

{
      3.0}

per-sample significance for consecutive-streak cut

Definition at line 52 of file SiStripWaveformBuilder.h.

                       {
      3.0};  

Referenced by configure(), and produce().

min_consecutive_low_

int tracking::reco::SiStripWaveformBuilder::min_consecutive_low_

private

Initial value:

{
      5}

min consecutive samples exceeding low_threshold

Definition at line 54 of file SiStripWaveformBuilder.h.

                          {
      5};                

Referenced by configure(), and produce().

min_high_samples_

int tracking::reco::SiStripWaveformBuilder::min_high_samples_ {4}

private

min samples exceeding high_threshold

Definition at line 51 of file SiStripWaveformBuilder.h.

{4};  

Referenced by configure(), and produce().

n_fit_attempted_

long tracking::reco::SiStripWaveformBuilder::n_fit_attempted_ {0}

private

waveforms passed to the fitter

Definition at line 63 of file SiStripWaveformBuilder.h.

{0};  

Referenced by onProcessEnd(), and produce().

n_fit_failed_

long tracking::reco::SiStripWaveformBuilder::n_fit_failed_ {0}

private

fits that did not converge

Definition at line 64 of file SiStripWaveformBuilder.h.

{0};     

Referenced by onProcessEnd(), and produce().

n_triggers_

int tracking::reco::SiStripWaveformBuilder::n_triggers_ {10}

private

expected APV triggers per RoR

Definition at line 56 of file SiStripWaveformBuilder.h.

{10};  

Referenced by configure().

output_collection_

std::string tracking::reco::SiStripWaveformBuilder::output_collection_ {"TrackerWaveforms"}

private

Definition at line 48 of file SiStripWaveformBuilder.h.

{"TrackerWaveforms"};

pulse_shape_

std::unique_ptr<tracking::digitization::PulseShape> tracking::reco::SiStripWaveformBuilder::pulse_shape_

private

Pulse shape used for the per-waveform fit test (built lazily in produce).

Definition at line 59 of file SiStripWaveformBuilder.h.

Referenced by produce().

---

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

• Tracking/include/Tracking/Reco/SiStripWaveformBuilder.h
• Tracking/src/Tracking/Reco/SiStripWaveformBuilder.cxx