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FT0: update Digitizer signal shape and trigger logic; FV0: update trigger logic in digitizer #15209

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FT0: update Digitizer signal shape and trigger logic; FV0: update trigger logic in digitizer #15209

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6577bc3
FT0: tune signal shape and trigger tunning for MC
Mar 13, 2026
06dbac3
apply clang-format
Mar 16, 2026
0432c88
Update FV0 trigger settings and digitizer logic
Mar 23, 2026
1fe3ee7
FV0: update Digitizer trigger handling
Mar 24, 2026
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5 changes: 3 additions & 2 deletions Detectors/FIT/FT0/base/include/FT0Base/FT0DigParam.h
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Original file line number Diff line number Diff line change
Expand Up @@ -31,8 +31,8 @@ struct FT0DigParam : o2::conf::ConfigurableParamHelper<FT0DigParam> {
float mAmpRecordUp = 15; // to [ns]
float hitTimeOffsetA = 0; ///< hit time offset on the A side [ns]
float hitTimeOffsetC = 0; ///< hit time offset on the C side [ns]
int mtrg_central_trh = 600.; // channels
int mtrg_semicentral_trh = 300.; // channels
int mtrg_central_trh = 1433.; // Tclu
int mtrg_semicentral_trh = 35.; // Tclu units = TCM charge level unit = 16 ADCunits

float mMip_in_V = 7; // MIP to mV
float mPe_in_mip = 0.004; // invserse Np.e. in MIP 1./250.
Expand All @@ -43,6 +43,7 @@ struct FT0DigParam : o2::conf::ConfigurableParamHelper<FT0DigParam> {
float mNoiseVar = 0.1; // noise level
float mNoisePeriod = 1 / 0.9; // GHz low frequency noise period;
short mTime_trg_gate = 153; // #channels as in TCM as in Pilot beams ('OR gate' setting in TCM tab in ControlServer)
short mTime_trg_vertex_gate = 100; // #channels as in TCM as in Pilot beams ('OR gate' setting in TCM tab in ControlServer)
float mAmpThresholdForReco = 5; // only channels with amplitude higher will participate in calibration and collision time: 0.3 MIP
short mTimeThresholdForReco = 1000; // only channels with time below will participate in calibration and collision time

Expand Down
185 changes: 172 additions & 13 deletions Detectors/FIT/FT0/simulation/src/Digitizer.cxx
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,13 @@
#include "CommonConstants/PhysicsConstants.h"
#include "CommonDataFormat/InteractionRecord.h"

#include "DataFormatsFT0/LookUpTable.h"
#include "FT0Base/Constants.h"
#include <map>
#include <array>
#include <regex>
#include <string>

#include "TMath.h"
#include "TRandom.h"
#include <TH1F.h>
Expand All @@ -35,24 +42,84 @@ namespace o2::ft0
template <typename Float>
Float signalForm_i(Float x)
{
using namespace std;
Float const a = -0.45458;
Float const b = -0.83344945;
return x > Float(0) ? -(exp(b * x) - exp(a * x)) / Float(7.8446501) : Float(0);
float p0, p1, p2, p3, p4, p5, p6, p7;
p0 = 1.30853;
p1 = 0.516807;
p2 = 3.36714;
p3 = -1.01206;
p4 = 1.42832;
p5 = 1.1589;
p6 = 1.22019;
p7 = 0.426818;

Double_t val = 0;

if (x > p3) {
Double_t x1 = x - p3;
Double_t arg1 = (log(x1) - p0) / p1;
val += p2 * (1.0 / (x1 * p1 * sqrt(2 * TMath::Pi()))) * exp(-0.5 * arg1 * arg1);
}

if (x > p7) {
Double_t x2 = x - p7;
Double_t arg2 = (log(x2) - p4) / p5;
val += p6 * (1.0 / (x2 * p5 * sqrt(2 * TMath::Pi()))) * exp(-0.5 * arg2 * arg2);
}

return val;
};

// integrated signal shape function
inline float signalForm_integral(float x)
{
using namespace std;
double const a = -0.45458;
double const b = -0.83344945;
if (x < 0) {
x = 0;
float p0, p1, p2, p3, p4, p5, p6, p7;
p0 = 1.30853;
p1 = 0.516807;
p2 = 3.36714;
p3 = -1.01206;
p4 = 1.42832;
p5 = 1.1589;
p6 = 1.22019;
p7 = 0.426818;
Double_t val = 0;

if (x > p3) {
Double_t x1 = x - p3;
Double_t z1 = (log(x1) - p0) / (sqrt(2) * p1);
val += p2 * 0.5 * (1 + TMath::Erf(z1)); // norm1 * CDF1
}
return -(exp(b * x) / b - exp(a * x) / a) / 7.8446501;

if (x > p7) {
Double_t x2 = x - p7;
Double_t z2 = (log(x2) - p4) / (sqrt(2) * p5);
val += p6 * 0.5 * (1 + TMath::Erf(z2)); // norm2 * CDF2
}

return val;
};
/*
// signal shape function
template <typename Float>
Float signalForm_i(Float x)
{
using namespace std;
Float const a = -0.45458;
Float const b = -0.83344945;
return x > Float(0) ? -(exp(b * x) - exp(a * x)) / Float(7.8446501) : Float(0);
};

// integrated signal shape function
inline float signalForm_integral(float x)
{
using namespace std;
double const a = -0.45458;
double const b = -0.83344945;
if (x < 0) {
x = 0;
}
return -(exp(b * x) / b - exp(a * x) / a) / 7.8446501;
};
*/
// SIMD version of the integrated signal shape function
inline Vc::float_v signalForm_integralVc(Vc::float_v x)
{
Expand Down Expand Up @@ -249,8 +316,64 @@ void Digitizer::storeBC(BCCache& bc,
if (bc.hits.empty()) {
return;
}
// Initialize mapping channelID -> PM hash and PM side (A/C) using FT0 LUT
static bool pmLutInitialized = false;
static std::array<uint8_t, o2::ft0::Constants::sNCHANNELS_PM> mChID2PMhash{};
static std::map<uint8_t, bool> mMapPMhash2isAside; // hashed PM -> is A side

if (!pmLutInitialized) {
std::map<std::string, uint8_t> mapFEE2hash; // module name -> hashed PM id
uint8_t tcmHash = 0;

const auto& lut = o2::ft0::SingleLUT::Instance().getVecMetadataFEE();
auto lutSorted = lut;
std::sort(lutSorted.begin(), lutSorted.end(),
[](const auto& first, const auto& second) { return first.mModuleName < second.mModuleName; });

uint8_t binPos = 0;
for (const auto& lutEntry : lutSorted) {
const auto& moduleName = lutEntry.mModuleName;
const auto& moduleType = lutEntry.mModuleType;
const auto& strChID = lutEntry.mChannelID;

auto [it, inserted] = mapFEE2hash.insert({moduleName, binPos});
if (inserted) {
if (moduleName.find("PMA") != std::string::npos) {
mMapPMhash2isAside.insert({binPos, true});
} else if (moduleName.find("PMC") != std::string::npos) {
mMapPMhash2isAside.insert({binPos, false});
}
++binPos;
}

if (std::regex_match(strChID, std::regex("^[0-9]{1,3}$"))) {
int chID = std::stoi(strChID);
if (chID < o2::ft0::Constants::sNCHANNELS_PM) {
mChID2PMhash[chID] = mapFEE2hash[moduleName];
} else {
LOG(fatal) << "Incorrect LUT entry: chID " << strChID << " | " << moduleName;
}
} else if (moduleType != "TCM") {
LOG(fatal) << "Non-TCM module w/o numerical chID: chID " << strChID << " | " << moduleName;
} else { // TCM
tcmHash = mapFEE2hash[moduleName];
}
}

pmLutInitialized = true;
}

int n_hit_A = 0, n_hit_C = 0, mean_time_A = 0, mean_time_C = 0;
int summ_ampl_A = 0, summ_ampl_C = 0;
int sum_A_ampl = 0, sum_C_ampl = 0;
int nPMTs = mGeometry.NCellsA * 4 + mGeometry.NCellsC * 4;
std::vector<int> sum_ampl_ipmt(nPMTs, 0);
// Per-PM summed charge (like in digits2trgFT0)
std::map<uint8_t, int> mapPMhash2sumAmpl;
for (const auto& entry : mMapPMhash2isAside) {
mapPMhash2sumAmpl.insert({entry.first, 0});
}

int vertex_time;
const auto& params = FT0DigParam::Instance();
int first = digitsCh.size(), nStored = 0;
Expand Down Expand Up @@ -297,6 +420,10 @@ void Digitizer::storeBC(BCCache& bc,
if (is_time_in_signal_gate) {
chain |= (1 << o2::ft0::ChannelData::EEventDataBit::kIsCFDinADCgate);
chain |= (1 << o2::ft0::ChannelData::EEventDataBit::kIsEventInTVDC);
// Sum channel charge per PM (similar logic as in digits2trgFT0)
if (ipmt < o2::ft0::Constants::sNCHANNELS_PM) {
mapPMhash2sumAmpl[mChID2PMhash[static_cast<uint8_t>(ipmt)]] += static_cast<int>(amp);
}
}
digitsCh.emplace_back(ipmt, smeared_time, int(amp), chain);
nStored++;
Expand All @@ -308,6 +435,8 @@ void Digitizer::storeBC(BCCache& bc,
continue;
}

sum_ampl_ipmt[ipmt] += amp;

if (is_A_side) {
n_hit_A++;
summ_ampl_A += amp;
Expand All @@ -318,17 +447,47 @@ void Digitizer::storeBC(BCCache& bc,
mean_time_C += smeared_time;
}
}

for (size_t i = 0; i < sum_ampl_ipmt.size(); i++) {
sum_ampl_ipmt[i] = sum_ampl_ipmt[i] >> 3;
if (i < 4 * mGeometry.NCellsA) {
sum_A_ampl += sum_ampl_ipmt[i];
} else {
sum_C_ampl += sum_ampl_ipmt[i];
}
}

// Sum over PMs (using per-PM map) for debug/monitoring
int sum_PM_ampl_debug = 0;
int sum_PM_ampl_A_debug = 0;
int sum_PM_ampl_C_debug = 0;
for (const auto& entry : mapPMhash2sumAmpl) {
int pmAmpl = (entry.second >> 3);
sum_PM_ampl_debug += pmAmpl;
auto itSide = mMapPMhash2isAside.find(entry.first);
if (itSide != mMapPMhash2isAside.end()) {
if (itSide->second) {
sum_PM_ampl_A_debug += pmAmpl;
} else {
sum_PM_ampl_C_debug += pmAmpl;
}
}
}
LOG(debug) << "Sum PM amplitude (LUT-based): total=" << sum_PM_ampl_debug
<< " A-side=" << sum_PM_ampl_A_debug
<< " C-side=" << sum_PM_ampl_C_debug;

Bool_t is_A, is_C, isVertex, is_Central, is_SemiCentral = 0;
is_A = n_hit_A > 0;
is_C = n_hit_C > 0;
is_Central = summ_ampl_A + summ_ampl_C >= params.mtrg_central_trh;
is_SemiCentral = summ_ampl_A + summ_ampl_C >= params.mtrg_semicentral_trh;
is_Central = sum_PM_ampl_A_debug + sum_PM_ampl_C_debug >= 2 * params.mtrg_central_trh;
is_SemiCentral = sum_PM_ampl_A_debug + sum_PM_ampl_C_debug >= 2 * params.mtrg_semicentral_trh && !is_Central;
uint32_t amplA = is_A ? summ_ampl_A * 0.125 : -5000; // sum amplitude A side / 8 (hardware)
uint32_t amplC = is_C ? summ_ampl_C * 0.125 : -5000; // sum amplitude C side / 8 (hardware)
int timeA = is_A ? mean_time_A / n_hit_A : -5000; // average time A side
int timeC = is_C ? mean_time_C / n_hit_C : -5000; // average time C side
vertex_time = (timeC - timeA) * 0.5;
isVertex = is_A && is_C && (vertex_time > -params.mTime_trg_gate && vertex_time < params.mTime_trg_gate);
isVertex = is_A && is_C && (vertex_time > -params.mTime_trg_vertex_gate && vertex_time < params.mTime_trg_vertex_gate);
LOG(debug) << " A " << is_A << " timeA " << timeA << " mean_time_A " << mean_time_A << " n_hit_A " << n_hit_A << " C " << is_C << " timeC " << timeC << " mean_time_C " << mean_time_C << " n_hit_C " << n_hit_C << " vertex_time " << vertex_time;
Triggers triggers;
bool isLaser = false;
Expand Down
4 changes: 4 additions & 0 deletions Detectors/FIT/FV0/simulation/include/FV0Simulation/FV0DigParam.h
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Expand Up @@ -69,6 +69,10 @@ struct FV0DigParam : o2::conf::ConfigurableParamHelper<FV0DigParam> {
uint8_t defaultChainQtc = 0x48; // only 2 flags are set by default in simulation: kIsCFDinADCgate and kIsEventInTVDC
float mAmpThresholdForReco = 24; // only channels with amplitude higher will participate in calibration and collision time
short mTimeThresholdForReco = 1000; // only channels with time below will participate in calibration and collision time
int NchannelsLevel = 8; // trigger Nchannels paramter
float InnerRingsChargeLevel = 0; // InnerRingsChargeLevel, Tclu
float OuterRingsChargeLevel = 0; // TcluOuterRingsChargeLevel, Tclu
float ChargeLevel = 10; // ChargeLevel, Tclu

O2ParamDef(FV0DigParam, "FV0DigParam");
};
Expand Down
36 changes: 20 additions & 16 deletions Detectors/FIT/FV0/simulation/src/Digitizer.cxx
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Expand Up @@ -38,8 +38,8 @@ void Digitizer::clear()
void Digitizer::init()
{
LOG(info) << "init";
mNBins = FV0DigParam::Instance().waveformNbins; //Will be computed using detector set-up from CDB
mBinSize = FV0DigParam::Instance().waveformBinWidth; //Will be set-up from CDB
mNBins = FV0DigParam::Instance().waveformNbins; // Will be computed using detector set-up from CDB
mBinSize = FV0DigParam::Instance().waveformBinWidth; // Will be set-up from CDB
mNTimeBinsPerBC = std::lround(o2::constants::lhc::LHCBunchSpacingNS / mBinSize); // 1920 bins/BC

for (Int_t detID = 0; detID < Constants::nFv0Channels; detID++) {
Expand Down Expand Up @@ -149,8 +149,8 @@ void Digitizer::process(const std::vector<o2::fv0::Hit>& hits,

createPulse(mipFraction, hit.GetTrackID(), hitTime, hit.GetPos().R(), cachedIR, nCachedIR, detId);

} //while loop
} //hitloop
} // while loop
} // hitloop
}

void Digitizer::createPulse(float mipFraction, int parID, const double hitTime, const float hitR,
Expand Down Expand Up @@ -200,7 +200,7 @@ void Digitizer::createPulse(float mipFraction, int parID, const double hitTime,
}
added[ir] = true;
}
///Add MC labels to BCs for those contributed to the PMT signal
/// Add MC labels to BCs for those contributed to the PMT signal
for (int ir = 0; ir < nCachedIR; ir++) {
if (added[ir]) {
auto bcCache = getBCCache(cachedIR[ir]);
Expand Down Expand Up @@ -238,6 +238,8 @@ void Digitizer::storeBC(const BCCache& bc,
int8_t nTotFiredCells = 0;
int8_t nTrgFiredCells = 0; // number of fired cells, that follow additional trigger conditions (time gate)
int totalChargeAllRing = 0;
int totalChargeInnerRing = 0;
int totalChargeOuterRing = 0;
int32_t avgTime = 0;
double nSignalInner = 0;
double nSignalOuter = 0;
Expand Down Expand Up @@ -285,8 +287,10 @@ void Digitizer::storeBC(const BCCache& bc,
avgTime += iCfdZero;
if (iPmt < 24) {
nSignalInner++;
totalChargeInnerRing += iTotalCharge;
} else {
nSignalOuter++;
totalChargeOuterRing += iTotalCharge;
}
}
}
Expand All @@ -300,24 +304,24 @@ void Digitizer::storeBC(const BCCache& bc,
} else {
avgTime = o2::fit::Triggers::DEFAULT_TIME;
}
///Triggers for FV0
bool isA, isAIn, isAOut, isCen, isSCen;
/// Triggers for FV0
bool isA, isNchannels, isAIn, isAOut, isTotalCharge;
isA = nTrgFiredCells > 0;
isAIn = nSignalInner > 0; // ring 1,2 and 3
isAOut = nSignalOuter > 0; // ring 4 and 5
isCen = totalChargeAllRing > FV0DigParam::Instance().adcChargeCenThr;
isSCen = totalChargeAllRing > FV0DigParam::Instance().adcChargeSCenThr;
isNchannels = nTrgFiredCells > FV0DigParam::Instance().NchannelsLevel;
isAIn = nSignalInner > FV0DigParam::Instance().NchannelsLevel; // ring 1,2 and 3
isAOut = nSignalOuter > FV0DigParam::Instance().NchannelsLevel; // ring 4 and 5
isTotalCharge = 0.125 * totalChargeAllRing > 2 * FV0DigParam::Instance().ChargeLevel;

Triggers triggers;
const int unusedCharge = o2::fit::Triggers::DEFAULT_AMP;
const int unusedTime = o2::fit::Triggers::DEFAULT_TIME;
const int unusedZero = o2::fit::Triggers::DEFAULT_ZERO;
const bool unusedBitsInSim = false; // bits related to laser and data validity
const bool bitDataIsValid = true;
triggers.setTriggers(isA, isAIn, isAOut, isCen, isSCen, nTrgFiredCells, (int8_t)unusedZero,
triggers.setTriggers(isA, isAIn, isAOut, isTotalCharge, isNchannels, nTrgFiredCells, (int8_t)unusedZero,
(int32_t)(0.125 * totalChargeAllRing), (int32_t)unusedCharge, (int16_t)avgTime, (int16_t)unusedTime, unusedBitsInSim, unusedBitsInSim, bitDataIsValid);
digitsBC.emplace_back(first, nTotFiredCells, bc, triggers, mEventId - 1);
digitsTrig.emplace_back(bc, isA, isAIn, isAOut, isCen, isSCen);
digitsTrig.emplace_back(bc, isA, isAIn, isAOut, isTotalCharge, isNchannels);
for (auto const& lbl : bc.labels) {
labels.addElement(nBC, lbl);
}
Expand All @@ -342,8 +346,8 @@ Int_t Digitizer::SimulateLightYield(Int_t pmt, Int_t nPhot) const
//---------------------------------------------------------------------------
Float_t Digitizer::IntegrateCharge(const ChannelDigitF& pulse) const
{
int const chargeIntMin = FV0DigParam::Instance().isIntegrateFull ? 0 : (FV0DigParam::Instance().avgCfdTimeForMip - 6.0) / mBinSize; //Charge integration offset (cfd mean time - 6 ns)
int const chargeIntMax = FV0DigParam::Instance().isIntegrateFull ? mNTimeBinsPerBC : (FV0DigParam::Instance().avgCfdTimeForMip + 14.0) / mBinSize; //Charge integration offset (cfd mean time + 14 ns)
int const chargeIntMin = FV0DigParam::Instance().isIntegrateFull ? 0 : (FV0DigParam::Instance().avgCfdTimeForMip - 6.0) / mBinSize; // Charge integration offset (cfd mean time - 6 ns)
int const chargeIntMax = FV0DigParam::Instance().isIntegrateFull ? mNTimeBinsPerBC : (FV0DigParam::Instance().avgCfdTimeForMip + 14.0) / mBinSize; // Charge integration offset (cfd mean time + 14 ns)
if (chargeIntMin < 0 || chargeIntMin > mNTimeBinsPerBC || chargeIntMax > mNTimeBinsPerBC) {
LOG(fatal) << "invalid indicess: chargeInMin=" << chargeIntMin << " chargeIntMax=" << chargeIntMax;
}
Expand Down Expand Up @@ -400,7 +404,7 @@ float Digitizer::getDistFromCellCenter(UInt_t cellId, double hitx, double hity)
double a = -(y0 - pCell->y) / (x0 - pCell->x);
double b = 1;
double c = -(y0 - a * x0);
//Return the distance from hit to this line
// Return the distance from hit to this line
return (a * hitx + b * hity + c) / TMath::Sqrt(a * a + b * b);
}

Expand Down
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