[ALICE3] TRKFT3: first implementation to store Time of Arrival into digits (#16012)

Author: atriolo

DataFormats/Detectors/Upgrades/ALICE3/TRKFT3/common/include/DataFormatsTRKFT3/Digit.h

@@ -22,13 +22,14 @@ namespace o2::trkft3
 class Digit
 {
  public:
-  Digit(UShort_t chipindex = 0, UShort_t row = 0, UShort_t col = 0, Int_t charge = 0);
+  Digit(UShort_t chipindex = 0, UShort_t row = 0, UShort_t col = 0, Int_t charge = 0, float toa = 0);
   ~Digit() = default;
 
   UShort_t getChipIndex() const { return mChipIndex; }
   UShort_t getColumn() const { return mCol; }
   UShort_t getRow() const { return mRow; }
   Int_t getCharge() const { return mCharge; }
+  float getTimeOfArrival() const { return mToA; }
 
   void setChipIndex(UShort_t index) { mChipIndex = index; }
   void setPixelIndex(UShort_t row, UShort_t col)
@@ -38,6 +39,7 @@ class Digit
   }
   void setCharge(Int_t charge) { mCharge = charge < USHRT_MAX ? charge : USHRT_MAX; }
   void addCharge(int charge) { setCharge(charge + int(mCharge)); }
+  void setToA(float toa) { mToA = toa; }
 
   std::ostream& print(std::ostream& output) const;
   friend std::ostream& operator<<(std::ostream& output, const Digit& digi)
@@ -51,8 +53,9 @@ class Digit
   UShort_t mRow = 0;
   UShort_t mCol = 0;
   UShort_t mCharge = 0;
+  float mToA = 0; // TimeOfArrival, set to float at the moment. TODO: implement correctly the size https://indico.cern.ch/event/1724141/contributions/7252329/attachments/3336751/5980668/data_throughput_estimation.pdf
 
-  ClassDefNV(Digit, 1);
+  ClassDefNV(Digit, 2);
 };
 
 } // namespace o2::trkft3

DataFormats/Detectors/Upgrades/ALICE3/TRKFT3/common/src/Digit.cxx

@@ -16,14 +16,15 @@ ClassImp(o2::trkft3::Digit);
 
 using namespace o2::trkft3;
 
-Digit::Digit(UShort_t chipindex, UShort_t row, UShort_t col, Int_t charge)
+Digit::Digit(UShort_t chipindex, UShort_t row, UShort_t col, Int_t charge, float toa)
   : mChipIndex(chipindex), mRow(row), mCol(col)
 {
   setCharge(charge);
+  setToA(toa);
 }
 
 std::ostream& Digit::print(std::ostream& output) const
 {
-  output << "TRKFT3Digit chip [" << mChipIndex << "] R:" << mRow << " C:" << mCol << " Q: " << mCharge;
+  output << "TRKFT3Digit chip [" << mChipIndex << "] R:" << mRow << " C:" << mCol << " Q: " << mCharge << " ToA: " << mToA;
   return output;
 }

Detectors/Upgrades/ALICE3/TRKFT3/common/simulation/CMakeLists.txt

@@ -28,4 +28,5 @@ o2_target_root_dictionary(TRKFT3Simulation
                                   include/TRKFT3Simulation/DigiParams.h
                                   include/TRKFT3Simulation/Digitizer.h
                                   include/TRKFT3Simulation/DPLDigitizerParam.h
+                                  include/TRKFT3Simulation/PreDigit.h
                           LINKDEF src/TRKFT3SimulationLinkDef.h)

Detectors/Upgrades/ALICE3/TRKFT3/common/simulation/include/TRKFT3Simulation/ChipDigitsContainer.h

@@ -12,8 +12,9 @@
 #ifndef ALICEO2_TRK_CHIPDIGITSCONTAINER_
 #define ALICEO2_TRK_CHIPDIGITSCONTAINER_
 
-#include "ITSMFTBase/SegmentationAlpide.h"
-#include "ITSMFTSimulation/ChipDigitsContainer.h"
+#include "TRKFT3Simulation/PreDigit.h"
+#include "SimulationDataFormat/MCCompLabel.h"
+#include "DataFormatsITSMFT/NoiseMap.h"
 #include "TRKBase/SegmentationChip.h"
 #include "TRKBase/Specs.h"
 #include "TRKFT3Simulation/DigiParams.h"
@@ -23,27 +24,64 @@
 namespace o2::trkft3
 {
 
-class ChipDigitsContainer : public o2::itsmft::ChipDigitsContainer
+/// @class ChipDigitsContainer
+/// @brief Container for simulated points connected to a given chip
+
+class ChipDigitsContainer
 {
  public:
+  /// Default constructor
   explicit ChipDigitsContainer(UShort_t idx = 0);
 
-  using Segmentation = o2::trk::SegmentationChip;
+  /// Destructor
+  ~ChipDigitsContainer() = default;
+
+  std::map<ULong64_t, o2::trkft3::PreDigit>& getPreDigits() { return mDigits; }
+  bool isEmpty() const { return mDigits.empty(); }
+  void setNoiseMap(const o2::itsmft::NoiseMap* mp) { mNoiseMap = mp; }
+  void setDeadChanMap(const o2::itsmft::NoiseMap* mp) { mDeadChanMap = mp; }
+  void setChipIndex(UShort_t ind) { mChipIndex = ind; }
+  UShort_t getChipIndex() const { return mChipIndex; }
+
+  o2::trkft3::PreDigit* findDigit(ULong64_t key);
+  void addDigit(ULong64_t key, UInt_t roframe, UShort_t row, UShort_t col, int charge, o2::MCCompLabel lbl, float toa = 0.f);
+  template <int DetID>
+  void addNoise(UInt_t rofMin, UInt_t rofMax, const o2::trkft3::DigiParams<DetID>* params, int subDetID, int layer);
 
   /// Get global ordering key made of readout frame, column and row
   static ULong64_t getOrderingKey(UInt_t roframe, UShort_t row, UShort_t col)
   {
     return (static_cast<ULong64_t>(roframe) << (8 * sizeof(UInt_t))) + (static_cast<ULong64_t>(col) << (8 * sizeof(Short_t))) + row;
   }
 
-  /// Adds noise digits, deleted the one using the itsmft::DigiParams interface
-  void addNoise(UInt_t rofMin, UInt_t rofMax, const o2::itsmft::DigiParams* params, int maxRows = o2::itsmft::SegmentationAlpide::NRows, int maxCols = o2::itsmft::SegmentationAlpide::NCols) = delete;
-  template <int DetID>
-  void addNoise(UInt_t rofMin, UInt_t rofMax, const o2::trkft3::DigiParams<DetID>* params, int subDetID, int layer);
+  bool isDisabled() const { return mDisabled; }
+  void disable(bool v) { mDisabled = v; }
 
-  ClassDefNV(ChipDigitsContainer, 1);
+ protected:
+  UShort_t mChipIndex = 0; ///< chip index
+  bool mDisabled = false;
+  const o2::itsmft::NoiseMap* mNoiseMap = nullptr;
+  const o2::itsmft::NoiseMap* mDeadChanMap = nullptr;
+  std::map<ULong64_t, o2::trkft3::PreDigit> mDigits; ///< Map of fired pixels, possibly in multiple frames
+
+  ClassDefNV(ChipDigitsContainer, 2);
 };
 
+//_______________________________________________________________________
+inline o2::trkft3::PreDigit* ChipDigitsContainer::findDigit(ULong64_t key)
+{
+  // finds the digit corresponding to global key
+  auto digitentry = mDigits.find(key);
+  return digitentry != mDigits.end() ? &(digitentry->second) : nullptr;
+}
+
+//_______________________________________________________________________
+inline void ChipDigitsContainer::addDigit(ULong64_t key, UInt_t roframe, UShort_t row, UShort_t col,
+                                          int charge, o2::MCCompLabel lbl, float toa)
+{
+  mDigits.emplace(key, o2::trkft3::PreDigit(roframe, row, col, charge, lbl, toa));
+}
+
 } // namespace o2::trkft3
 
 template <int DetID>
@@ -83,10 +121,10 @@ void o2::trkft3::ChipDigitsContainer::addNoise(UInt_t rofMin, UInt_t rofMax, con
       }
       auto key = getOrderingKey(rof, row, col);
       if (!findDigit(key)) {
-        addDigit(key, rof, row, col, nel, o2::MCCompLabel(true));
+        addDigit(key, rof, row, col, nel, o2::MCCompLabel(true), 0.f); /// TODO: find a better ToA for noise
       }
     }
   }
 }
 
-#endif // ALICEO2_TRK_CHIPDIGITSCONTAINER_
+#endif /* defined(ALICEO2_TRK_CHIPDIGITSCONTAINER_) */

Detectors/Upgrades/ALICE3/TRKFT3/common/simulation/include/TRKFT3Simulation/Digitizer.h

@@ -44,7 +44,7 @@ class Digitizer
 {
   static_assert(DetID == o2::detectors::DetID::TRK || DetID == o2::detectors::DetID::FT3, "only TRK and FT3 digitizers are supported");
   using GeometryTGeo = std::conditional_t<DetID == o2::detectors::DetID::TRK, o2::trk::GeometryTGeo, o2::ft3::GeometryTGeo>;
-  using ExtraDig = std::vector<itsmft::PreDigitLabelRef>; ///< container for extra contributions to PreDigits
+  using ExtraDig = std::vector<trkft3::PreDigitLabelRef>; ///< container for extra contributions to PreDigits
 
  public:
   void setDigits(std::vector<o2::trkft3::Digit>* dig) { mDigits = dig; }
@@ -94,7 +94,7 @@ class Digitizer
 
  private:
   void processHit(const o2::trkft3::Hit& hit, uint32_t& maxFr, int evID, int srcID, int rofLayer);
-  void registerDigits(o2::trkft3::ChipDigitsContainer& chip, uint32_t roFrame, float tInROF, int nROF,
+  void registerDigits(o2::trkft3::ChipDigitsContainer& chip, uint32_t roFrame, float toaInROF, int nROF,
                       uint16_t row, uint16_t col, int nEle, o2::MCCompLabel& lbl, int layer);
 
   ExtraDig* getExtraDigBuffer(uint32_t roFrame)

Detectors/Upgrades/ALICE3/TRKFT3/common/simulation/include/TRKFT3Simulation/PreDigit.h

@@ -0,0 +1,52 @@
+// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
+// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+// All rights not expressly granted are reserved.
+//
+// This software is distributed under the terms of the GNU General Public
+// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+/// \file PreDigit.h
+/// \brief Definition of the digit contribution from single hit for TRK/FT3 (based on o2::itsmft::PreDigit, with time of arrival)
+#ifndef ALICEO2_TRKFT3_PREDIGIT_H
+#define ALICEO2_TRKFT3_PREDIGIT_H
+
+#include "SimulationDataFormat/MCCompLabel.h"
+
+namespace o2::trkft3
+{
+
+// PreDigit is a contribution to the digit from a single hit which happen
+// to be registered 1st in given chip row/column/roframe
+// Eventual extra contributions will be registered as PreDigitExtra, pointed by
+// the "next" index
+
+// PreDigitExtra registers additional contributions to the same row/column/roframe
+struct PreDigitLabelRef {
+  o2::MCCompLabel label; ///< hit label
+  int next = -1;         ///< eventual next contribution to the same pixel
+  PreDigitLabelRef(o2::MCCompLabel lbl = 0, int nxt = -1) : label(lbl), next(nxt) {}
+
+  ClassDefNV(PreDigitLabelRef, 1);
+};
+
+struct PreDigit {
+  UShort_t row = 0;          ///< Pixel index in X
+  UShort_t col = 0;          ///< Pixel index in Z
+  UInt_t roFrame = 0;        ///< Readout frame
+  int charge = 0;            ///< N electrons
+  float toa = 0.f;           ///< Time of arrival in ns (earliest contribution)
+  PreDigitLabelRef labelRef; ///< label and reference to the next one
+
+  PreDigit(UInt_t rf = 0, UShort_t rw = 0, UShort_t cl = 0, int nele = 0, o2::MCCompLabel lbl = 0, float t = 0.f)
+    : row(rw), col(cl), roFrame(rf), charge(nele), toa(t), labelRef(lbl) {}
+
+  ClassDefNV(PreDigit, 1);
+};
+
+} // namespace o2::trkft3
+
+#endif /* ALICEO2_TRKFT3_PREDIGIT_H */

Detectors/Upgrades/ALICE3/TRKFT3/common/simulation/src/ChipDigitsContainer.cxx

@@ -13,5 +13,4 @@
 
 using namespace o2::trkft3;
 
-ChipDigitsContainer::ChipDigitsContainer(UShort_t idx)
-  : o2::itsmft::ChipDigitsContainer(idx) {}
+ChipDigitsContainer::ChipDigitsContainer(UShort_t idx) : mChipIndex(idx) {}

Detectors/Upgrades/ALICE3/TRKFT3/common/simulation/src/Digitizer.cxx

@@ -226,8 +226,8 @@ void Digitizer<DetID>::fillOutputContainer(uint32_t frameLast, int layer)
         auto& preDig = iter->second; // preDigit
         if (preDig.charge >= mParams.getChargeThreshold()) {
           int digID = mDigits->size();
-          mDigits->emplace_back(chip.getChipIndex(), preDig.row, preDig.col, preDig.charge);
-          LOG(debug) << "Adding digit ID: " << digID << " with chipID: " << chip.getChipIndex() << ", row: " << preDig.row << ", col: " << preDig.col << ", charge: " << preDig.charge;
+          mDigits->emplace_back(chip.getChipIndex(), preDig.row, preDig.col, preDig.charge, preDig.toa);
+          LOG(debug) << "Adding digit ID: " << digID << " with chipID: " << chip.getChipIndex() << ", row: " << preDig.row << ", col: " << preDig.col << ", charge: " << preDig.charge << ", ToA: " << preDig.toa;
           mMCLabels->addElement(digID, preDig.labelRef.label);
           auto& nextRef = preDig.labelRef; // extra contributors are in extra array
           while (nextRef.next >= 0) {
@@ -297,6 +297,9 @@ void Digitizer<DetID>::processHit(const o2::trkft3::Hit& hit, uint32_t& maxFr, i
   float tTot = mParams.getSignalShape().getMaxDuration();
   // frame of the hit signal start wrt event ROFrame
   int roFrameRel = int(timeInROF * mParams.getROFrameLengthInv(rofLayer));
+  // Time of Arrival w.r.t. the start of the ROF where the signal starts (= w.r.t. roFrameAbs)
+  float toaInROF = timeInROF - roFrameRel * mParams.getROFrameLength(rofLayer);
+
   // frame of the hit signal end  wrt event ROFrame: in the triggered mode we read just 1 frame
   uint32_t roFrameRelMax = (timeInROF + tTot) * mParams.getROFrameLengthInv(rofLayer);
   int nFrames = roFrameRelMax + 1 - roFrameRel;
@@ -493,24 +496,25 @@ void Digitizer<DetID>::processHit(const o2::trkft3::Hit& hit, uint32_t& maxFr, i
       if (mDeadChanMap && mDeadChanMap->isNoisy(chipID, rowIS, colIS)) {
         continue;
       }
-      registerDigits(chip, roFrameAbs, timeInROF, nFrames, rowIS, colIS, nEle, lbl, rofLayer);
+      registerDigits(chip, roFrameAbs, toaInROF, nFrames, rowIS, colIS, nEle, lbl, rofLayer);
     }
   }
 }
 
 //________________________________________________________________________________
 template <int DetID>
-void Digitizer<DetID>::registerDigits(o2::trkft3::ChipDigitsContainer& chip, uint32_t roFrame, float tInROF, int nROF,
+void Digitizer<DetID>::registerDigits(o2::trkft3::ChipDigitsContainer& chip, uint32_t roFrame, float toaInROF, int nROF,
                                       uint16_t row, uint16_t col, int nEle, o2::MCCompLabel& lbl, int layer)
 {
   // Register digits for given pixel, accounting for the possible signal contribution to
-  // multiple ROFrame. The signal starts at time tInROF wrt the start of provided roFrame
+  // multiple ROFrame. The signal starts at time toaInROF wrt the start of provided roFrame
   // In every ROFrame we check the collected signal during strobe
   LOG(debug) << "Registering digits for chip " << chip.getChipIndex() << " at ROFrame " << roFrame
-             << " row " << row << " col " << col << " nEle " << nEle << " label " << lbl;
-  float tStrobe = mParams.getStrobeDelay(layer) - tInROF; // strobe start wrt signal start
-  for (int i = 0; i < nROF; i++) {                        // loop on all the ROFs occupied by the same signal to calculate the charge accumulated in that ROF
+             << " row " << row << " col " << col << " nEle " << nEle << " label " << lbl << " layer " << layer << " toa " << toaInROF;
+  float tStrobe = mParams.getStrobeDelay(layer) - toaInROF; // strobe start wrt signal start
+  for (int i = 0; i < nROF; i++) {                          // loop on all the ROFs occupied by the same signal to calculate the charge accumulated in that ROF
     uint32_t roFr = roFrame + i;
+    float toaROF = toaInROF - i * mParams.getROFrameLength(layer); // ToA w.r.t. start of ROF
     int nEleROF = mParams.getSignalShape().getCollectedCharge(nEle, tStrobe, tStrobe + mParams.getStrobeLength(layer));
     tStrobe += mParams.getROFrameLength(layer); // for the next ROF
 
@@ -525,14 +529,15 @@ void Digitizer<DetID>::registerDigits(o2::trkft3::ChipDigitsContainer& chip, uin
       mEventROFrameMin = roFr;
     }
     auto key = chip.getOrderingKey(roFr, row, col);
-    o2::itsmft::PreDigit* pd = chip.findDigit(key);
+    o2::trkft3::PreDigit* pd = chip.findDigit(key);
     if (!pd) {
-      chip.addDigit(key, roFr, row, col, nEleROF, lbl);
+      chip.addDigit(key, roFr, row, col, nEleROF, lbl, toaROF);
       LOG(debug) << "Added digit with key: " << key << "  ROF: " << roFr << "  row: " << row << "  col: " << col << "  charge: " << nEleROF;
     } else { // there is already a digit at this slot, account as PreDigitExtra contribution
       LOG(debug) << "Added to pre-digit with key: " << key << "  ROF: " << roFr << "  row: " << row << "  col: " << col << "  charge: " << nEleROF;
       pd->charge += nEleROF;
-      if (pd->labelRef.label == lbl) { // don't store the same label twice
+      pd->toa = std::min(pd->toa, toaROF); /// in case of two hits on the same digit in the same ROF, get the first ToA
+      if (pd->labelRef.label == lbl) {     // don't store the same label twice
         continue;
       }
       ExtraDig* extra = getExtraDigBuffer(roFr);

Detectors/Upgrades/ALICE3/TRKFT3/common/simulation/src/TRKFT3SimulationLinkDef.h

@@ -23,5 +23,7 @@
 #pragma link C++ class o2::conf::ConfigurableParamHelper < o2::trkft3::DPLDigitizerParam < o2::detectors::DetID::TRK>> + ;
 #pragma link C++ class o2::trkft3::DPLDigitizerParam < o2::detectors::DetID::FT3> + ;
 #pragma link C++ class o2::conf::ConfigurableParamHelper < o2::trkft3::DPLDigitizerParam < o2::detectors::DetID::FT3>> + ;
+#pragma link C++ class o2::trkft3::PreDigit + ;
+#pragma link C++ class o2::trkft3::PreDigitLabelRef + ;
 
 #endif