diff --git a/macro/reco/reco_ts.C b/macro/reco/reco_ts.C
index e520b169d94ecab63c2005abbd702c95d689118a..ea0cebc743deb64122323809161f4842fb639518 100644
--- a/macro/reco/reco_ts.C
+++ b/macro/reco/reco_ts.C
@@ -65,6 +65,7 @@ void reco_ts(TString tsaFile = "", TString outFile = "")
// TODO: Would need a small up-to-date default input file; the one distributed with
// the code is outdated.
+
// ----- Default file names ---------------------------------------------
if (tsaFile.IsNull()) tsaFile = srcDir + "/input/mcbm_run399_first20Ts";
TString inFile = tsaFile + ".tsa";
@@ -121,6 +122,13 @@ void reco_ts(TString tsaFile = "", TString outFile = "")
// ------------------------------------------------------------------------
+ // ----- Event QA -----------------------------------------------------
+ auto eventQa = std::make_unique<CbmTaskDigiEventQa>();
+ LOG(info) << myName << ": Added task " << eventQa->GetName();
+ run->AddTask(eventQa.release());
+ // ------------------------------------------------------------------------
+
+
// ----- Logger settings ----------------------------------------------
FairLogger::GetLogger()->SetLogScreenLevel(logLevel.Data());
FairLogger::GetLogger()->SetLogVerbosityLevel(logVerbosity.Data());
diff --git a/reco/tasks/CMakeLists.txt b/reco/tasks/CMakeLists.txt
index dd87b3a51de4bf5eee4813a1e30b2dc18cd07808..7d98de2467e7d82c137bfb90a86f20ceb3bf3e22 100644
--- a/reco/tasks/CMakeLists.txt
+++ b/reco/tasks/CMakeLists.txt
@@ -13,6 +13,7 @@ set(SRCS
CbmReco.cxx
CbmSourceTs.cxx
CbmTaskBuildEvents.cxx
+CbmTaskDigiEventQa.cxx
CbmTaskMakeRecoEvents.cxx
CbmTaskTriggerDigi.cxx
CbmTaskUnpack.cxx
diff --git a/reco/tasks/CbmRecoTasksLinkDef.h b/reco/tasks/CbmRecoTasksLinkDef.h
index 9d2dbacc5b1bc63f4f357949980a9a098d3508d1..ac0ef949083e0ac7e4329d9aca8f1a5c0ea99b88 100644
--- a/reco/tasks/CbmRecoTasksLinkDef.h
+++ b/reco/tasks/CbmRecoTasksLinkDef.h
@@ -15,6 +15,7 @@
#pragma link C++ class CbmRecoConfig + ;
#pragma link C++ class CbmSourceTs + ;
#pragma link C++ class CbmTaskBuildEvents + ;
+#pragma link C++ class CbmTaskDigiEventQa + ;
#pragma link C++ class CbmTaskMakeRecoEvents + ;
#pragma link C++ class CbmTaskTriggerDigi + ;
#pragma link C++ class CbmTaskUnpack + ;
diff --git a/reco/tasks/CbmTaskDigiEventQa.cxx b/reco/tasks/CbmTaskDigiEventQa.cxx
new file mode 100644
index 0000000000000000000000000000000000000000..c775574f50cf303637df45dfbe138bb06e387604
--- /dev/null
+++ b/reco/tasks/CbmTaskDigiEventQa.cxx
@@ -0,0 +1,144 @@
+/* Copyright (C) 2022 GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
+ SPDX-License-Identifier: GPL-3.0-only
+ Authors: Volker Friese [committer] */
+
+#include "CbmTaskDigiEventQa.h"
+
+#include "CbmDigiBranchBase.h"
+#include "CbmDigiManager.h"
+#include "CbmDigiTimeslice.h"
+#include "CbmModuleList.h"
+
+#include <FairLogger.h>
+#include <FairRunOnline.h>
+
+#include <TH1F.h>
+#include <THttpServer.h>
+#include <TStopwatch.h>
+
+#include <cassert>
+#include <iomanip>
+#include <iostream>
+
+using namespace std;
+
+// ----- Constructor -----------------------------------------------------
+CbmTaskDigiEventQa::CbmTaskDigiEventQa() : FairTask("DigiEventQa") {}
+// ---------------------------------------------------------------------------
+
+
+// ----- Destructor ------------------------------------------------------
+CbmTaskDigiEventQa::~CbmTaskDigiEventQa() {}
+// ---------------------------------------------------------------------------
+
+
+// ----- Execution -------------------------------------------------------
+void CbmTaskDigiEventQa::Exec(Option_t*)
+{
+
+ // --- Timer and counters
+ TStopwatch timer;
+ timer.Start();
+ double sumT = 0.;
+ double sumTsq = 0.;
+ double sumNumDigis = 0.;
+ double sumNumDigisSq = 0.;
+ size_t numEvents = 0;
+ size_t numDigis = 0;
+
+ // --- Event loop
+ for (const auto& event : *fEvents) {
+ numEvents++;
+ double numDigisEvt = double(event.fData.fSts.fDigis.size());
+ sumNumDigis += numDigisEvt;
+ sumNumDigisSq += numDigisEvt * numDigisEvt;
+ for (const auto& digi : event.fData.fSts.fDigis) {
+ numDigis++;
+ const double tDigi = digi.GetTime() - event.fTime;
+ fHistDigiTime->Fill(tDigi);
+ sumT += tDigi;
+ sumTsq += tDigi * tDigi;
+ }
+ }
+
+ // --- First and second moments of digi times and digi numbers
+ double tMean = sumT / double(numDigis);
+ double tSqMean = sumTsq / double(numDigis);
+ double tRms = sqrt(tSqMean - tMean * tMean);
+ double numDigisMean = sumNumDigis / double(numEvents);
+ double numDigisSqMean = sumNumDigisSq / double(numEvents);
+ double numDigisRms = sqrt(numDigisSqMean - numDigisMean * numDigisMean);
+
+ // --- Timeslice log
+ timer.Stop();
+ fExecTime += timer.RealTime();
+ stringstream logOut;
+ logOut << setw(15) << left << GetName() << " [";
+ logOut << fixed << setw(8) << setprecision(1) << right << timer.RealTime() * 1000. << " ms] ";
+ logOut << "TS " << fNumTs << ", events " << numEvents << ", digis " << numDigis << ", digis per event ("
+ << numDigisMean << " +- " << numDigisRms << ")"
+ << ", digi time (" << tMean << " +- " << tRms << ") ns";
+ LOG(info) << logOut.str();
+
+ // --- Run statistics
+ fNumTs++;
+ fNumEvents += numEvents;
+ fNumDigis += numDigis;
+
+
+ // See: macro/run/run_unpack_online.C
+ // See : recp/detectors/sts/unpack/CbmStsUnpackMonitor
+}
+// ----------------------------------------------------------------------------
+
+
+// ----- End-of-timeslice action ------------------------------------------
+void CbmTaskDigiEventQa::Finish()
+{
+ std::cout << std::endl;
+ LOG(info) << "=====================================";
+ LOG(info) << GetName() << ": Run summary";
+ LOG(info) << "Timeslices : " << fNumTs;
+ LOG(info) << "Events : " << fNumEvents;
+ LOG(info) << "Digis : " << fNumDigis;
+ LOG(info) << "Exec time : " << fixed << setprecision(2) << 1000. * fExecTime / double(fNumTs) << " ms / TS";
+ LOG(info) << "Digi times : entries " << fHistDigiTime->GetEntries() << ", mean " << fHistDigiTime->GetMean()
+ << ", stddev " << fHistDigiTime->GetStdDev();
+ LOG(info) << "=====================================";
+ fHistDigiTime->Write();
+}
+// ----------------------------------------------------------------------------
+
+
+// ----- Initialisation ---------------------------------------------------
+InitStatus CbmTaskDigiEventQa::Init()
+{
+ // --- Get FairRootManager instance
+ FairRootManager* ioman = FairRootManager::Instance();
+ assert(ioman);
+
+ std::cout << std::endl;
+ LOG(info) << "==================================================";
+ LOG(info) << GetName() << ": Initialising...";
+
+ // --- Input data
+ fEvents = ioman->InitObjectAs<const std::vector<CbmDigiEvent>*>("DigiEvent");
+ if (!fEvents) {
+ LOG(error) << GetName() << ": No input branch DigiEvent!";
+ return kFATAL;
+ }
+ LOG(info) << "--- Found branch DigiEvent";
+
+ // --- Histograms
+ fHistDigiTime = new TH1F("hDigiTime", "Digi time in event", 100, -50., 50.);
+ THttpServer* server = FairRunOnline::Instance()->GetHttpServer();
+ if (server) server->Register("DigiTime", fHistDigiTime);
+
+ LOG(info) << "==================================================";
+ std::cout << std::endl;
+
+ return kSUCCESS;
+}
+// ----------------------------------------------------------------------------
+
+ClassImp(CbmTaskDigiEventQa)
diff --git a/reco/tasks/CbmTaskDigiEventQa.h b/reco/tasks/CbmTaskDigiEventQa.h
new file mode 100644
index 0000000000000000000000000000000000000000..6a5d60ebf8128e3a334625391a96f7c85cb748d8
--- /dev/null
+++ b/reco/tasks/CbmTaskDigiEventQa.h
@@ -0,0 +1,69 @@
+/* Copyright (C) 2022 GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
+ SPDX-License-Identifier: GPL-3.0-only
+ Authors: Volker Friese [committer] */
+
+#ifndef CBMTASKDIGIEVENTQA_H
+#define CBMTASKDIGIEVENTQA_H 1
+
+#include "CbmDefs.h"
+#include "CbmDigiEvent.h"
+
+#include <FairTask.h>
+
+#include <vector>
+
+#include "EventBuilder.h"
+
+class CbmDigiManager;
+class TH1F;
+
+/** @class CbmTaskDigiEventQa
+ ** @brief QA task class for digi events produced by the event builder
+ ** @author Volker Friese <v.friese@gsi.de>
+ ** @since 15.03.2022
+ **/
+class CbmTaskDigiEventQa : public FairTask {
+
+public:
+ /** @brief Constructor **/
+ CbmTaskDigiEventQa();
+
+
+ /** @brief Copy constructor (disabled) **/
+ CbmTaskDigiEventQa(const CbmTaskDigiEventQa&) = delete;
+
+
+ /** @brief Destructor **/
+ virtual ~CbmTaskDigiEventQa();
+
+
+ /** @brief Task execution **/
+ virtual void Exec(Option_t* opt);
+
+
+ /** @brief Finish timeslice **/
+ virtual void Finish();
+
+
+ /** @brief Assignment operator (disabled) **/
+ CbmTaskDigiEventQa& operator=(const CbmTaskDigiEventQa&) = delete;
+
+
+private: // methods
+ /** @brief Task initialisation **/
+ virtual InitStatus Init();
+
+
+private: // members
+ const std::vector<CbmDigiEvent>* fEvents = nullptr; //! Input data (events)
+ size_t fNumTs = 0; ///< Number of processed timeslices
+ size_t fNumEvents = 0; ///< Number of analysed events
+ size_t fNumDigis = 0; ///< Number of analysed digis
+ double fExecTime = 0.; ///< Execution time [s]
+ TH1F* fHistDigiTime = nullptr; //!
+
+
+ ClassDef(CbmTaskDigiEventQa, 1);
+};
+
+#endif /* CBMTASKDIGIEVENTQA_H */