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Use TOF Utils to subtract BC time to tofSignal #7782

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Merged
shahor02 merged 1 commit into from
Dec 6, 2021
Merged

Use TOF Utils to subtract BC time to tofSignal #7782

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1 change: 0 additions & 1 deletion Detectors/AOD/include/AODProducerWorkflow/AODProducerWorkflowSpec.h
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Original file line number Diff line number Diff line change
Expand Up @@ -290,7 +290,6 @@ class AODProducerWorkflowDPL : public Task
float tofChi2 = -999.f;
float tpcSignal = -999.f;
float trdSignal = -999.f;
float tofSignal = -999.f;
float length = -999.f;
float tofExpMom = -999.f;
float trackEtaEMCAL = -999.f;
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23 changes: 15 additions & 8 deletions Detectors/AOD/src/AODProducerWorkflowSpec.cxx
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Expand Up @@ -53,6 +53,7 @@
#include "SimulationDataFormat/MCTrack.h"
#include "SimulationDataFormat/MCTruthContainer.h"
#include "GPUTPCGMMergedTrackHit.h"
#include "TOFBase/Utils.h"
#include "O2Version.h"
#include "TMath.h"
#include "MathUtils/Utils.h"
Expand Down Expand Up @@ -301,6 +302,7 @@ void AODProducerWorkflowDPL::fillTrackTablesPerCollision(int collisionID,
// normal tracks table
auto contributorsGID = data.getSingleDetectorRefs(trackIndex);
const auto& trackPar = data.getTrackParam(trackIndex);
extraInfoHolder.flags |= trackPar.getPID() << 28;
if (contributorsGID[GIndex::Source::ITS].isIndexSet()) {
int nClusters = itsTracks[contributorsGID[GIndex::ITS].getIndex()].getNClusters();
float chi2 = itsTracks[contributorsGID[GIndex::ITS].getIndex()].getChi2();
Expand All @@ -326,10 +328,9 @@ void AODProducerWorkflowDPL::fillTrackTablesPerCollision(int collisionID,
extraInfoHolder.tofChi2 = tofMatch.getChi2();
const auto& tofInt = tofMatch.getLTIntegralOut();
const float intLen = tofInt.getL();
double timeOrbit = static_cast<int>(tofMatch.getSignal() / o2::constants::lhc::LHCOrbitNS * 1E-3) * o2::constants::lhc::LHCOrbitNS * 1E3;
const float tofSignal = static_cast<float>(o2::tof::Utils::subtractInteractionBC(tofMatch.getSignal() - timeOrbit));
extraInfoHolder.length = intLen;
if (interactionTime > 0) {
extraInfoHolder.tofSignal = static_cast<float>(tofMatch.getSignal() - interactionTime * 1E3);
}
const float mass = o2::constants::physics::MassPionCharged; // default pid = pion
if (tofInt.getTOF(o2::track::PID::Pion) > 0.f) {
const float expBeta = (intLen / (tofInt.getTOF(o2::track::PID::Pion) * cSpeed));
Expand All @@ -339,8 +340,8 @@ void AODProducerWorkflowDPL::fillTrackTablesPerCollision(int collisionID,
const double massZ = o2::track::PID::getMass2Z(trackPar.getPID());
const double energy = sqrt((massZ * massZ) + (extraInfoHolder.tofExpMom * extraInfoHolder.tofExpMom));
const double exp = extraInfoHolder.length * energy / (cSpeed * extraInfoHolder.tofExpMom);
extraInfoHolder.trackTime = static_cast<float>((tofMatch.getSignal() - exp) * 1e-3 - interactionTime); // tof time in \mus, FIXME: account for time of flight to R TOF
extraInfoHolder.trackTimeRes = 200e-3; // FIXME: calculate actual resolution (if possible?)
extraInfoHolder.trackTime = static_cast<float>((tofSignal - exp) * 1e-3); // tof time in ns, taken from the definition of Ruben scaled by 1000 to convert from mus to ns to match the collisionTime
extraInfoHolder.trackTimeRes = 200e-3; // FIXME: calculate actual resolution (if possible?)
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@jgrosseo jgrosseo Dec 3, 2021

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@shahor02 I am in favour of merging this. Unrelated: Don't we have an estimate of the track type already somewhere?

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@shahor02 shahor02 Dec 6, 2021

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@jgrosseo sorry, just saw the question. If you are asking whether we do reco-time PID: no, for that the TPC would need to provide a dedx -> PID algorithm.

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@jgrosseo jgrosseo Dec 6, 2021

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@shahor02 I wrote track type but mean track time resolution (sorry for this; and that's why I made the comment here).
So do you already have a track time resolution (even course based on the type of track)?

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@shahor02 shahor02 Dec 6, 2021

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Not for ITS-TPC-TOF tracks: they are somewhat special since their time is given by the TOF signal stored in the match info (while the kinematic comes from ITS-TPC). In the

AliceO2/DataFormats/Detectors/GlobalTracking/include/DataFormatsGlobalTracking/RecoContainerCreateTracksVariadic.h

Lines 169 to 170 in ce3e745

const float timeErr = 0.010f; // assume 10 ns error FIXME
if (creator(tracksTPCTRD[gidx.getIndex()], {i, GTrackID::TPCTRDTOF}, timeTOFMUS, timeErr)) {
a 10 ns error is assigned (which is surely an overkill but is much more precise that the ITS-TPC time errors), but AOD producer does not use this method, since it relias on the vertex->tracks attachments tables.

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@jgrosseo jgrosseo Dec 6, 2021

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I think we should propagate these values into the AOD (even if you mark them as "overkill" for now). All this info should be available in the AOD converter, so it just requires adjusting the code, right?

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@jgrosseo jgrosseo Dec 7, 2021

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TrackTime contains here the track time estimate based on TOF (absolute wrt BC). We do not talk about the estimated time with a momentum and particle hypothesis. Do we talk about the same thing?

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@jgrosseo jgrosseo Dec 7, 2021

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@jgrosseo for tracks with TRD the error corresponds to the nominal triggered BC duration (i.e. a few 100 ps), for ITS-TPC tracks: uncertainty in matching point Z / vdrift.

Can we add this to the AOD producer already?

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@noferini noferini Dec 7, 2021

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I see. A deltat (t_tof - t_track) is avaliable with the matching info.
For the resolution we depend on the track time precision which is available with the track.
Is this what you need?

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@shahor02 shahor02 Dec 7, 2021

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@jgrosseo

We do not talk about the estimated time with a momentum and particle hypothesis. Do we talk about the same thing?

Does this matter if we speak about the uncertainty?

Can we add this to the AOD producer already?

Do you mean to fill extraInfoHolder.trackTime and extraInfoHolder.trackTimeRes for all tracks types?

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@jgrosseo jgrosseo Dec 7, 2021 •
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Do you mean to fill extraInfoHolder.trackTime and extraInfoHolder.trackTimeRes for all tracks types?

Yes!

}
if (src == GIndex::Source::TPCTRD || src == GIndex::Source::ITSTPCTRD) {
const auto& trdOrig = data.getTrack<o2::trd::TrackTRD>(src, contributorsGID[src].getIndex());
Expand Down Expand Up @@ -1106,11 +1107,17 @@ void AODProducerWorkflowDPL::run(ProcessingContext& pc)
auto caloCellsCursor = caloCellsBuilder.cursor<o2::aod::Calos>();
auto caloCellsTRGTableCursor = caloCellsTRGTableBuilder.cursor<o2::aod::CaloTriggers>();

std::unique_ptr<o2::steer::MCKinematicsReader> mcReader;
if (mUseMC) {
mcReader = std::make_unique<o2::steer::MCKinematicsReader>("collisioncontext.root");
std::unique_ptr<o2::steer::MCKinematicsReader> mcReader = std::make_unique<o2::steer::MCKinematicsReader>("collisioncontext.root");
if (!o2::tof::Utils::hasFillScheme()) {
LOG(debug) << "FOUND " << mcReader->getDigitizationContext()->getEventRecords().size()
<< " records" << mcReader->getDigitizationContext()->getEventParts().size() << " parts";
o2::BunchFilling bcf = mcReader->getDigitizationContext()->getBunchFilling();
std::bitset<3564> bs = bcf.getBCPattern();
for (int i = 0; i < bs.size(); i++) {
if (bs.test(i)) {
o2::tof::Utils::addInteractionBC(i);
}
}
}

std::map<uint64_t, int> bcsMap;
Expand Down