From cdda38ba18d9470907dd1c45b7c043184de1fb0d Mon Sep 17 00:00:00 2001
From: Kolja Kauder <kkauder@gmail.com>
Date: Tue, 2 Apr 2024 15:55:30 -0400
Subject: [PATCH 01/21] First draft of bucketing hits in time

---
 src/algorithms/digi/SiliconTrackerDigi.cc     | 60 +++++++++++--------
 .../digi/SiliconTrackerDigiConfig.h           |  2 +-
 2 files changed, 37 insertions(+), 25 deletions(-)

diff --git a/src/algorithms/digi/SiliconTrackerDigi.cc b/src/algorithms/digi/SiliconTrackerDigi.cc
index daefa12ee2..d8d25496bf 100644
--- a/src/algorithms/digi/SiliconTrackerDigi.cc
+++ b/src/algorithms/digi/SiliconTrackerDigi.cc
@@ -39,12 +39,12 @@ void SiliconTrackerDigi::process(
     auto [raw_hits] = output;
 
     // A map of unique cellIDs with temporary structure RawHit
-    std::unordered_map<std::uint64_t, edm4eic::MutableRawTrackerHit> cell_hit_map;
-
+    std::unordered_map<std::uint64_t, std::vector<edm4eic::MutableRawTrackerHit>> cell_hit_map;
 
     for (const auto& sim_hit : *sim_hits) {
 
         // time smearing
+        // TODO: remove or revisit smearing after time is properly bucketed instead 
         double time_smearing = m_gauss();
         double result_time = sim_hit.getTime() + time_smearing;
         auto hit_time_stamp = (std::int32_t) (result_time * 1e3);
@@ -66,31 +66,43 @@ void SiliconTrackerDigi::process(
             continue;
         }
 
-        if (cell_hit_map.count(sim_hit.getCellID()) == 0) {
-            // This cell doesn't have hits
-            cell_hit_map[sim_hit.getCellID()] = {
+        bool bucket_found = false;
+        if (cell_hit_map.count(sim_hit.getCellID()) == 1) {
+            // Update an existing hit?
+            for (auto& hit : cell_hit_map[sim_hit.getCellID()]) {
+                auto existing_time = hit.getTimeStamp();
+                // TODO: edge cases?
+                if ( hit_time_stamp >= existing_time && hit_time_stamp <= existing_time + m_cfg.timeResolution ) {
+                    // There is already a hit within the same time window
+                    m_log->debug("  Hit already exists in cell ID={}, within the same time bucket. Time stamp: {}, bucket from {} to {}",
+                         sim_hit.getCellID(), hit.getTimeStamp(), existing_time, existing_time + m_cfg.timeResolution);
+                    // sum deposited energy
+                    auto charge = hit.getCharge();
+                    hit.setCharge(charge + (std::int32_t) std::llround(sim_hit.getEDep() * 1e6));
+                    bucket_found = true;
+                    break;
+                } // time bucket found
+            } // loop over existing hits
+        } // cellID found
+
+        if (!bucket_found) {
+            // There is no hit in the same time bucket
+            m_log->debug("  No pre-existing hit in cell ID={} in the same time bucket. Time stamp: {}", 
+                        sim_hit.getCellID(), sim_hit.getTime());
+            cell_hit_map[sim_hit.getCellID()].push_back( 
+                edm4eic::MutableRawTrackerHit{
                 sim_hit.getCellID(),
                 (std::int32_t) std::llround(sim_hit.getEDep() * 1e6),
-                hit_time_stamp  // ns->ps
-            };
-        } else {
-            // There is previous values in the cell
-            auto& hit = cell_hit_map[sim_hit.getCellID()];
-            m_log->debug("  Hit already exists in cell ID={}, prev. hit time: {}", sim_hit.getCellID(), hit.getTimeStamp());
-
-            // keep earliest time for hit
-            auto time_stamp = hit.getTimeStamp();
-            hit.setTimeStamp(std::min(hit_time_stamp, hit.getTimeStamp()));
-
-            // sum deposited energy
-            auto charge = hit.getCharge();
-            hit.setCharge(charge + (std::int32_t) std::llround(sim_hit.getEDep() * 1e6));
-        }
-    }
-
+                hit_time_stamp  // ns->ps <-- TODO: what does this comment mean?!
+            } );
+        } // bucket found
+    } // loop over sim hits
+    
     for (auto item : cell_hit_map) {
-        raw_hits->push_back(item.second);
+        for (auto& hit : item.second) {
+            raw_hits->push_back(hit);
+        }
     }
-}
+} // process
 
 } // namespace eicrecon
diff --git a/src/algorithms/digi/SiliconTrackerDigiConfig.h b/src/algorithms/digi/SiliconTrackerDigiConfig.h
index fb66db252b..fa3d286570 100644
--- a/src/algorithms/digi/SiliconTrackerDigiConfig.h
+++ b/src/algorithms/digi/SiliconTrackerDigiConfig.h
@@ -11,7 +11,7 @@ namespace eicrecon {
     // sub-systems should overwrite their own
     // NB: be aware of thresholds in npsim! E.g. https://github.com/eic/npsim/pull/9/files
     double threshold  = 0 * dd4hep::keV;
-    double timeResolution = 8;   /// TODO 8 of what units??? Same TODO in juggler. Probably [ns]
+    double timeResolution = 8;   /// same unit as sim_hit.getTime, probably [ns]
   };
 
 } // eicrecon

From cb882b9bef2bbe8ee1581aac1cc8488b117e2d70 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Tue, 2 Apr 2024 20:02:12 +0000
Subject: [PATCH 02/21] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 src/algorithms/digi/SiliconTrackerDigi.cc | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/algorithms/digi/SiliconTrackerDigi.cc b/src/algorithms/digi/SiliconTrackerDigi.cc
index d8d25496bf..bc8e8e4fef 100644
--- a/src/algorithms/digi/SiliconTrackerDigi.cc
+++ b/src/algorithms/digi/SiliconTrackerDigi.cc
@@ -44,7 +44,7 @@ void SiliconTrackerDigi::process(
     for (const auto& sim_hit : *sim_hits) {
 
         // time smearing
-        // TODO: remove or revisit smearing after time is properly bucketed instead 
+        // TODO: remove or revisit smearing after time is properly bucketed instead
         double time_smearing = m_gauss();
         double result_time = sim_hit.getTime() + time_smearing;
         auto hit_time_stamp = (std::int32_t) (result_time * 1e3);
@@ -87,9 +87,9 @@ void SiliconTrackerDigi::process(
 
         if (!bucket_found) {
             // There is no hit in the same time bucket
-            m_log->debug("  No pre-existing hit in cell ID={} in the same time bucket. Time stamp: {}", 
+            m_log->debug("  No pre-existing hit in cell ID={} in the same time bucket. Time stamp: {}",
                         sim_hit.getCellID(), sim_hit.getTime());
-            cell_hit_map[sim_hit.getCellID()].push_back( 
+            cell_hit_map[sim_hit.getCellID()].push_back(
                 edm4eic::MutableRawTrackerHit{
                 sim_hit.getCellID(),
                 (std::int32_t) std::llround(sim_hit.getEDep() * 1e6),
@@ -97,7 +97,7 @@ void SiliconTrackerDigi::process(
             } );
         } // bucket found
     } // loop over sim hits
-    
+
     for (auto item : cell_hit_map) {
         for (auto& hit : item.second) {
             raw_hits->push_back(hit);

From ddbcbca827c7496fa065a8c4408c5c0b8deb625f Mon Sep 17 00:00:00 2001
From: Kolja Kauder <kkauder@gmail.com>
Date: Tue, 2 Apr 2024 16:20:43 -0400
Subject: [PATCH 03/21] iwyu

---
 src/algorithms/digi/SiliconTrackerDigi.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/algorithms/digi/SiliconTrackerDigi.cc b/src/algorithms/digi/SiliconTrackerDigi.cc
index bc8e8e4fef..10a40bdad6 100644
--- a/src/algorithms/digi/SiliconTrackerDigi.cc
+++ b/src/algorithms/digi/SiliconTrackerDigi.cc
@@ -8,7 +8,7 @@
 #include <edm4hep/Vector3d.h>
 #include <edm4hep/Vector3f.h>
 #include <fmt/core.h>
-#include <algorithm>
+#include <vector>
 #include <cmath>
 #include <cstdint>
 #include <gsl/pointers>

From 7d9df30298a6b98bd104e2517cbfa960fcf9dbfa Mon Sep 17 00:00:00 2001
From: Kolja Kauder <kkauder@gmail.com>
Date: Tue, 2 Apr 2024 16:22:06 -0400
Subject: [PATCH 04/21] add .DS_STORE to gitignore

---
 .gitignore | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.gitignore b/.gitignore
index 9161794416..ac4a6c34f4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -46,6 +46,8 @@ install/*
 *.out
 *.m_app
 
+# Apple stuff
+.DS_Store
 
 ##### i g n o r i n g   I D E s #####
 

From eaa89ef9176fc8a5faf22890c5cc8433d94657f0 Mon Sep 17 00:00:00 2001
From: kkauder <kkauder@gmail.com>
Date: Wed, 10 Apr 2024 10:34:43 -0400
Subject: [PATCH 05/21] Update src/algorithms/digi/SiliconTrackerDigi.cc

Co-authored-by: Dmitry Kalinkin <dmitry.kalinkin@gmail.com>
---
 src/algorithms/digi/SiliconTrackerDigi.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/algorithms/digi/SiliconTrackerDigi.cc b/src/algorithms/digi/SiliconTrackerDigi.cc
index 10a40bdad6..02177b3ed0 100644
--- a/src/algorithms/digi/SiliconTrackerDigi.cc
+++ b/src/algorithms/digi/SiliconTrackerDigi.cc
@@ -93,7 +93,7 @@ void SiliconTrackerDigi::process(
                 edm4eic::MutableRawTrackerHit{
                 sim_hit.getCellID(),
                 (std::int32_t) std::llround(sim_hit.getEDep() * 1e6),
-                hit_time_stamp  // ns->ps <-- TODO: what does this comment mean?!
+                hit_time_stamp
             } );
         } // bucket found
     } // loop over sim hits

From c35ce0b3e42f8b08ef66077d22ba7034bf283af3 Mon Sep 17 00:00:00 2001
From: kkauder <kkauder@gmail.com>
Date: Wed, 10 Apr 2024 10:35:21 -0400
Subject: [PATCH 06/21] Update src/algorithms/digi/SiliconTrackerDigiConfig.h

Co-authored-by: Dmitry Kalinkin <dmitry.kalinkin@gmail.com>
---
 src/algorithms/digi/SiliconTrackerDigiConfig.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/algorithms/digi/SiliconTrackerDigiConfig.h b/src/algorithms/digi/SiliconTrackerDigiConfig.h
index fa3d286570..db9336beaf 100644
--- a/src/algorithms/digi/SiliconTrackerDigiConfig.h
+++ b/src/algorithms/digi/SiliconTrackerDigiConfig.h
@@ -11,7 +11,7 @@ namespace eicrecon {
     // sub-systems should overwrite their own
     // NB: be aware of thresholds in npsim! E.g. https://github.com/eic/npsim/pull/9/files
     double threshold  = 0 * dd4hep::keV;
-    double timeResolution = 8;   /// same unit as sim_hit.getTime, probably [ns]
+    double timeResolution = 8 * edm4eic::unit::ns;
   };
 
 } // eicrecon

From dc11cb732348aca40cc0681f89c35860ed8f4638 Mon Sep 17 00:00:00 2001
From: Kolja Kauder <kkauder@gmail.com>
Date: Wed, 10 Apr 2024 11:05:30 -0400
Subject: [PATCH 07/21] ignore vscode

---
 .gitignore | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.gitignore b/.gitignore
index ac4a6c34f4..abe552d5b4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -56,6 +56,7 @@ install/*
 
 # The same to vscode
 .vscode/*
+.vscode
 
 # CMake CLion style
 cmake-build-*/

From 077aabfa0e87c550d72415532af49daf695e5f58 Mon Sep 17 00:00:00 2001
From: Kolja Kauder <kkauder@gmail.com>
Date: Wed, 10 Apr 2024 11:13:32 -0400
Subject: [PATCH 08/21] bugfix

---
 src/algorithms/digi/SiliconTrackerDigiConfig.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/algorithms/digi/SiliconTrackerDigiConfig.h b/src/algorithms/digi/SiliconTrackerDigiConfig.h
index db9336beaf..169002fb43 100644
--- a/src/algorithms/digi/SiliconTrackerDigiConfig.h
+++ b/src/algorithms/digi/SiliconTrackerDigiConfig.h
@@ -4,6 +4,8 @@
 #pragma once
 
 #include <DD4hep/DD4hepUnits.h>
+#include <edm4eic/unit_system.h>
+
 
 namespace eicrecon {
 

From d0341050076bc3dccbcfa04507e7124a371be8cb Mon Sep 17 00:00:00 2001
From: Kolja Kauder <kkauder@gmail.com>
Date: Wed, 24 Apr 2024 15:43:38 +0200
Subject: [PATCH 09/21] Updated timeResolution values from digitization
 spreadsheet

---
 src/algorithms/digi/SiliconTrackerDigi.cc     |  1 -
 .../digi/SiliconTrackerDigiConfig.h           |  2 +-
 src/detectors/B0TRK/B0TRK.cc                  |  4 ++--
 src/detectors/BTOF/BTOF.cc                    |  4 ++--
 src/detectors/BTRK/BTRK.cc                    |  5 ++++-
 src/detectors/BVTX/BVTX.cc                    |  5 ++++-
 src/detectors/ECTOF/ECTOF.cc                  |  5 +++--
 src/detectors/ECTRK/ECTRK.cc                  |  5 ++++-
 src/detectors/FOFFMTRK/FOFFMTRK.cc            |  4 ++--
 src/detectors/LOWQ2/LOWQ2.cc                  |  2 +-
 src/detectors/MPGD/MPGD.cc                    | 20 +++++++++----------
 src/detectors/RPOTS/RPOTS.cc                  |  4 ++--
 12 files changed, 35 insertions(+), 26 deletions(-)

diff --git a/src/algorithms/digi/SiliconTrackerDigi.cc b/src/algorithms/digi/SiliconTrackerDigi.cc
index 02177b3ed0..8ac657b684 100644
--- a/src/algorithms/digi/SiliconTrackerDigi.cc
+++ b/src/algorithms/digi/SiliconTrackerDigi.cc
@@ -44,7 +44,6 @@ void SiliconTrackerDigi::process(
     for (const auto& sim_hit : *sim_hits) {
 
         // time smearing
-        // TODO: remove or revisit smearing after time is properly bucketed instead
         double time_smearing = m_gauss();
         double result_time = sim_hit.getTime() + time_smearing;
         auto hit_time_stamp = (std::int32_t) (result_time * 1e3);
diff --git a/src/algorithms/digi/SiliconTrackerDigiConfig.h b/src/algorithms/digi/SiliconTrackerDigiConfig.h
index 169002fb43..d928df5095 100644
--- a/src/algorithms/digi/SiliconTrackerDigiConfig.h
+++ b/src/algorithms/digi/SiliconTrackerDigiConfig.h
@@ -13,7 +13,7 @@ namespace eicrecon {
     // sub-systems should overwrite their own
     // NB: be aware of thresholds in npsim! E.g. https://github.com/eic/npsim/pull/9/files
     double threshold  = 0 * dd4hep::keV;
-    double timeResolution = 8 * edm4eic::unit::ns;
+    double timeResolution = 8 * edm4eic::unit::ns; // Source? This is arbitrary --> however, it should be >0, maybe large, to not distort the fitter by default
   };
 
 } // eicrecon
diff --git a/src/detectors/B0TRK/B0TRK.cc b/src/detectors/B0TRK/B0TRK.cc
index a6f0473391..7468847d7e 100644
--- a/src/detectors/B0TRK/B0TRK.cc
+++ b/src/detectors/B0TRK/B0TRK.cc
@@ -25,7 +25,7 @@ void InitPlugin(JApplication *app) {
         {"B0TrackerRawHits"},
         {
             .threshold = 10.0 * dd4hep::keV,
-            .timeResolution = 8,
+            .timeResolution = 0.015 * dd4hep::ns,
         },
         app
     ));
@@ -36,7 +36,7 @@ void InitPlugin(JApplication *app) {
         {"B0TrackerRawHits"},
         {"B0TrackerRecHits"},
         {
-            .timeResolution = 8,
+            .timeResolution = 0.015 * dd4hep::ns,
         },
         app
     ));
diff --git a/src/detectors/BTOF/BTOF.cc b/src/detectors/BTOF/BTOF.cc
index 113912c8c8..80f0b0ebab 100644
--- a/src/detectors/BTOF/BTOF.cc
+++ b/src/detectors/BTOF/BTOF.cc
@@ -25,7 +25,7 @@ void InitPlugin(JApplication *app) {
         {"TOFBarrelRawHit"},
         {
             .threshold = 6.0 * dd4hep::keV,
-            .timeResolution = 0.025,    // [ns]
+            .timeResolution = 0.02 * dd4hep::ns,
         },
         app
     ));
@@ -36,7 +36,7 @@ void InitPlugin(JApplication *app) {
         {"TOFBarrelRawHit"},    // Input data collection tags
         {"TOFBarrelRecHit"},     // Output data tag
         {
-            .timeResolution = 10,
+            .timeResolution = 0.02 * dd4hep::ns,
         },
         app
     ));         // Hit reco default config for factories
diff --git a/src/detectors/BTRK/BTRK.cc b/src/detectors/BTRK/BTRK.cc
index 18693f5c81..1f6e18e903 100644
--- a/src/detectors/BTRK/BTRK.cc
+++ b/src/detectors/BTRK/BTRK.cc
@@ -25,6 +25,7 @@ void InitPlugin(JApplication *app) {
         {"SiBarrelRawHits"},
         {
             .threshold = 0.54 * dd4hep::keV,
+            .timeResolution = 2000 * dd4hep::ns,
         },
         app
     ));
@@ -35,7 +36,9 @@ void InitPlugin(JApplication *app) {
         "SiBarrelTrackerRecHits",
         {"SiBarrelRawHits"},
         {"SiBarrelTrackerRecHits"},
-        {}, // default config
+        {
+            .timeResolution = 2000 * dd4hep::ns,
+        },
         app
     ));
 
diff --git a/src/detectors/BVTX/BVTX.cc b/src/detectors/BVTX/BVTX.cc
index 4c60d8d240..78d9f59edf 100644
--- a/src/detectors/BVTX/BVTX.cc
+++ b/src/detectors/BVTX/BVTX.cc
@@ -25,6 +25,7 @@ void InitPlugin(JApplication *app) {
         {"SiBarrelVertexRawHits"},
         {
             .threshold = 0.54 * dd4hep::keV,
+            .timeResolution = 2000 * dd4hep::ns,
         },
         app
     ));
@@ -34,7 +35,9 @@ void InitPlugin(JApplication *app) {
         "SiBarrelVertexRecHits",
         {"SiBarrelVertexRawHits"},
         {"SiBarrelVertexRecHits"},
-        {}, // default config
+        {
+            .timeResolution = 2000 * dd4hep::ns,
+        }, 
         app
     ));
 
diff --git a/src/detectors/ECTOF/ECTOF.cc b/src/detectors/ECTOF/ECTOF.cc
index e26a1caf63..6189af957f 100644
--- a/src/detectors/ECTOF/ECTOF.cc
+++ b/src/detectors/ECTOF/ECTOF.cc
@@ -25,7 +25,8 @@ void InitPlugin(JApplication *app) {
       {"TOFEndcapRawHits"},
       {
         .threshold = 6.0 * dd4hep::keV,
-        .timeResolution = 0.025,
+        .timeResolution = 0.02 * dd4hep::ns,
+
       },
       app
     ));
@@ -36,7 +37,7 @@ void InitPlugin(JApplication *app) {
       {"TOFEndcapRawHits"},     // Input data collection tags
       {"TOFEndcapRecHits"},     // Output data tag
       {
-        .timeResolution = 0.025,
+        .timeResolution = 0.02 * dd4hep::ns,
       },
       app
     ));
diff --git a/src/detectors/ECTRK/ECTRK.cc b/src/detectors/ECTRK/ECTRK.cc
index 621e665c53..58f575c6b0 100644
--- a/src/detectors/ECTRK/ECTRK.cc
+++ b/src/detectors/ECTRK/ECTRK.cc
@@ -25,6 +25,7 @@ void InitPlugin(JApplication *app) {
         {"SiEndcapTrackerRawHits"},
         {
             .threshold = 0.54 * dd4hep::keV,
+            .timeResolution = 2000 * dd4hep::ns,
         },
         app
     ));
@@ -34,7 +35,9 @@ void InitPlugin(JApplication *app) {
         "SiEndcapTrackerRecHits",
         {"SiEndcapTrackerRawHits"},
         {"SiEndcapTrackerRecHits"},
-        {}, // default config
+        {
+            .timeResolution = 2000 * dd4hep::ns,
+        },
         app
     ));
 
diff --git a/src/detectors/FOFFMTRK/FOFFMTRK.cc b/src/detectors/FOFFMTRK/FOFFMTRK.cc
index 4fea2aa927..d3aed24d83 100644
--- a/src/detectors/FOFFMTRK/FOFFMTRK.cc
+++ b/src/detectors/FOFFMTRK/FOFFMTRK.cc
@@ -28,7 +28,7 @@ void InitPlugin(JApplication *app) {
         {"ForwardOffMTrackerRawHits"},
         {
             .threshold = 10.0 * dd4hep::keV,
-            .timeResolution = 8,
+            .timeResolution = 0.015 * dd4hep::ns,
         },
         app
     ));
@@ -38,7 +38,7 @@ void InitPlugin(JApplication *app) {
         {"ForwardOffMTrackerRawHits"},
         {"ForwardOffMTrackerRecHits"},
         {
-            .timeResolution = 8,
+            .timeResolution = 0.015 * dd4hep::ns,
         },
         app
     ));
diff --git a/src/detectors/LOWQ2/LOWQ2.cc b/src/detectors/LOWQ2/LOWQ2.cc
index 361b780d5f..8027276cee 100644
--- a/src/detectors/LOWQ2/LOWQ2.cc
+++ b/src/detectors/LOWQ2/LOWQ2.cc
@@ -31,7 +31,7 @@ extern "C" {
          {"TaggerTrackerRawHits"},
          {
            .threshold = 1.5 * dd4hep::keV,
-           .timeResolution = 2 * dd4hep::ns,
+           .timeResolution = 0.195 * dd4hep::ns,
          },
          app
     ));
diff --git a/src/detectors/MPGD/MPGD.cc b/src/detectors/MPGD/MPGD.cc
index 8cb695596c..b252d16d13 100644
--- a/src/detectors/MPGD/MPGD.cc
+++ b/src/detectors/MPGD/MPGD.cc
@@ -25,7 +25,7 @@ void InitPlugin(JApplication *app) {
         {"MPGDBarrelRawHits"},
         {
             .threshold = 0.25 * dd4hep::keV,
-            .timeResolution = 10,
+            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz) 
         },
         app
     ));
@@ -36,7 +36,7 @@ void InitPlugin(JApplication *app) {
         {"MPGDBarrelRawHits"},     // Input data collection tags
         {"MPGDBarrelRecHits"},     // Output data tag
         {
-            .timeResolution = 10,
+            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
         },
         app
     ));
@@ -48,7 +48,7 @@ void InitPlugin(JApplication *app) {
         {"MPGDDIRCRawHits"},
         {
             .threshold = 0.25 * dd4hep::keV,
-            .timeResolution = 10,
+            .timeResolution = 10, // no information in the digitization spreadsheet!
         },
         app
     ));
@@ -59,7 +59,7 @@ void InitPlugin(JApplication *app) {
         {"MPGDDIRCRawHits"},    // Input data collection tags
         {"MPGDDIRCRecHits"},    // Output data tag
         {
-            .timeResolution = 10,
+            .timeResolution = 10, // no information in the digitization spreadsheet!
         },
         app
     ));
@@ -72,7 +72,7 @@ void InitPlugin(JApplication *app) {
         {"OuterMPGDBarrelRawHits"},
         {
             .threshold = 0.25 * dd4hep::keV,
-            .timeResolution = 10,
+            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
         },
         app
     ));
@@ -83,7 +83,7 @@ void InitPlugin(JApplication *app) {
         {"OuterMPGDBarrelRawHits"},     // Input data collection tags
         {"OuterMPGDBarrelRecHits"},     // Output data tag
         {
-            .timeResolution = 10,
+            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
         },
         app
     ));
@@ -95,7 +95,7 @@ void InitPlugin(JApplication *app) {
         {"BackwardMPGDEndcapRawHits"},
         {
             .threshold = 0.25 * dd4hep::keV,
-            .timeResolution = 10,
+            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
         },
         app
     ));
@@ -106,7 +106,7 @@ void InitPlugin(JApplication *app) {
         {"BackwardMPGDEndcapRawHits"},     // Input data collection tags
         {"BackwardMPGDEndcapRecHits"},     // Output data tag
         {
-            .timeResolution = 10,
+            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
         },
         app
     ));
@@ -118,7 +118,7 @@ void InitPlugin(JApplication *app) {
         {"ForwardMPGDEndcapRawHits"},
         {
             .threshold = 0.25 * dd4hep::keV,
-            .timeResolution = 10,
+            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
         },
         app
     ));
@@ -129,7 +129,7 @@ void InitPlugin(JApplication *app) {
         {"ForwardMPGDEndcapRawHits"},     // Input data collection tags
         {"ForwardMPGDEndcapRecHits"},     // Output data tag
         {
-            .timeResolution = 10,
+            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
         },
         app
     ));
diff --git a/src/detectors/RPOTS/RPOTS.cc b/src/detectors/RPOTS/RPOTS.cc
index 89c85215af..bad6f71876 100644
--- a/src/detectors/RPOTS/RPOTS.cc
+++ b/src/detectors/RPOTS/RPOTS.cc
@@ -28,7 +28,7 @@ void InitPlugin(JApplication *app) {
         {"ForwardRomanPotRawHits"},
         {
             .threshold = 10.0 * dd4hep::keV,
-            .timeResolution = 8,
+            .timeResolution = 0.015 * dd4hep::ns,
         },
         app
     ));
@@ -38,7 +38,7 @@ void InitPlugin(JApplication *app) {
         {"ForwardRomanPotRawHits"},
         {"ForwardRomanPotRecHits"},
         {
-            .timeResolution = 8,
+            .timeResolution = 0.015 * dd4hep::ns,
         },
         app
     ));

From 680eca540c5fac87fdada2bba6ee0c0cf335f3c0 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Thu, 2 May 2024 18:38:58 +0000
Subject: [PATCH 10/21] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 src/algorithms/digi/SiliconTrackerDigi.cc | 2 +-
 src/detectors/BVTX/BVTX.cc                | 2 +-
 src/detectors/MPGD/MPGD.cc                | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/algorithms/digi/SiliconTrackerDigi.cc b/src/algorithms/digi/SiliconTrackerDigi.cc
index 0b3f2fe485..78a8181baa 100644
--- a/src/algorithms/digi/SiliconTrackerDigi.cc
+++ b/src/algorithms/digi/SiliconTrackerDigi.cc
@@ -122,7 +122,7 @@ void SiliconTrackerDigi::process(
         } //hits
     } // cell_hit_map
 
-    
+
 } // process
 
 } // namespace eicrecon
diff --git a/src/detectors/BVTX/BVTX.cc b/src/detectors/BVTX/BVTX.cc
index 12a7e09ea1..fa6cb42147 100644
--- a/src/detectors/BVTX/BVTX.cc
+++ b/src/detectors/BVTX/BVTX.cc
@@ -42,7 +42,7 @@ void InitPlugin(JApplication *app) {
         {"SiBarrelVertexRecHits"},
         {
             .timeResolution = 2000 * dd4hep::ns,
-        }, 
+        },
         app
     ));
 
diff --git a/src/detectors/MPGD/MPGD.cc b/src/detectors/MPGD/MPGD.cc
index fe3ba83090..6393ebb513 100644
--- a/src/detectors/MPGD/MPGD.cc
+++ b/src/detectors/MPGD/MPGD.cc
@@ -30,7 +30,7 @@ void InitPlugin(JApplication *app) {
         },
         {
             .threshold = 0.25 * dd4hep::keV,
-            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz) 
+            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
         },
         app
     ));

From 21178292ebfe9af0a9b2fc26afb293cd4d2d2897 Mon Sep 17 00:00:00 2001
From: Kolja Kauder <kkauder@gmail.com>
Date: Thu, 2 May 2024 15:21:13 -0400
Subject: [PATCH 11/21] Allow prepopulation of cellhitMap for MAPS

---
 src/algorithms/digi/SiliconTrackerDigi.cc     | 27 ++++++++++++++++---
 .../digi/SiliconTrackerDigiConfig.h           |  3 ++-
 src/detectors/BTRK/BTRK.cc                    |  1 +
 src/detectors/BVTX/BVTX.cc                    |  1 +
 src/detectors/ECTRK/ECTRK.cc                  |  1 +
 5 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/src/algorithms/digi/SiliconTrackerDigi.cc b/src/algorithms/digi/SiliconTrackerDigi.cc
index 0b3f2fe485..2191325f4b 100644
--- a/src/algorithms/digi/SiliconTrackerDigi.cc
+++ b/src/algorithms/digi/SiliconTrackerDigi.cc
@@ -44,9 +44,29 @@ void SiliconTrackerDigi::process(
 
     auto hit_time_stamp_err = (std::int32_t) (m_cfg.timeResolution * 1e3);
 
+    // Some detectors have a steady pulse of hits - generate empty time buckets for those
+    // Conundrum: We can't know the number of buckets without knowing the timeSlice length
+    // Assuming this is only used for MAPS, and that the time slice length is <= 1ms,
+    // we need at most 1ms / 2000ns = 500 buckets
+    // Let's use 1000, and pad with over and underflow to allow smearing out of range
+    if ( m_cfg.prepopulate ) {
+        for (auto cell : cell_hit_map) {
+            auto& hits = cell.second;
+            for (int i = -1; i <= 1001; i++) {
+                hits.push_back(
+                    edm4eic::MutableRawTrackerHit{
+                    cell.first,
+                    0,
+                    0
+                } );
+            }
+        }
+    }
     for (const auto& sim_hit : *sim_hits) {
 
         // time smearing
+        // Note: In the current setup, we can have hits outside the time slice
+        // Up to the analyzer to decide what to do with them
         double time_smearing = m_gauss();
         double result_time = sim_hit.getTime() + time_smearing;
         auto hit_time_stamp = (std::int32_t) (result_time * 1e3);
@@ -91,7 +111,6 @@ void SiliconTrackerDigi::process(
             m_log->debug("  No pre-existing hit in cell ID={} in the same time bucket. Time stamp: {}",
                         sim_hit.getCellID(), sim_hit.getTime());
 
-
             // Create a new hit
             cell_hit_map[sim_hit.getCellID()].push_back(
                 edm4eic::MutableRawTrackerHit{
@@ -102,12 +121,12 @@ void SiliconTrackerDigi::process(
         } // bucket found
     } // loop over sim hits
 
-    for (auto item : cell_hit_map) {
-        for (auto& hit : item.second) {
+    for (auto cell : cell_hit_map) {
+        for (auto& hit : cell.second) {
             raw_hits->push_back(hit);
 
             for (const auto& sim_hit : *sim_hits) {
-                if (item.first == sim_hit.getCellID()) {
+                if (cell.first == sim_hit.getCellID()) {
                     // set association
                     auto hitassoc = associations->create();
                     hitassoc.setWeight(1.0);
diff --git a/src/algorithms/digi/SiliconTrackerDigiConfig.h b/src/algorithms/digi/SiliconTrackerDigiConfig.h
index d928df5095..6a6630cd96 100644
--- a/src/algorithms/digi/SiliconTrackerDigiConfig.h
+++ b/src/algorithms/digi/SiliconTrackerDigiConfig.h
@@ -13,7 +13,8 @@ namespace eicrecon {
     // sub-systems should overwrite their own
     // NB: be aware of thresholds in npsim! E.g. https://github.com/eic/npsim/pull/9/files
     double threshold  = 0 * dd4hep::keV;
-    double timeResolution = 8 * edm4eic::unit::ns; // Source? This is arbitrary --> however, it should be >0, maybe large, to not distort the fitter by default
+    double timeResolution = 2000 * edm4eic::unit::ns; // Source for 8? This is arbitrary --> however, it should be >0, maybe large, to not distort the fitter by default. Choosing 2us for now.
+    bool prepopulate = false; // prepopulate cellHit map with empty hits, for MAPS
   };
 
 } // eicrecon
diff --git a/src/detectors/BTRK/BTRK.cc b/src/detectors/BTRK/BTRK.cc
index dc9159c5b9..f0d054ba31 100644
--- a/src/detectors/BTRK/BTRK.cc
+++ b/src/detectors/BTRK/BTRK.cc
@@ -31,6 +31,7 @@ void InitPlugin(JApplication *app) {
         {
             .threshold = 0.54 * dd4hep::keV,
             .timeResolution = 2000 * dd4hep::ns,
+            .prepopulate = true, // for MAPS, initialize digitization with a "pulse" of empty hits
         },
         app
     ));
diff --git a/src/detectors/BVTX/BVTX.cc b/src/detectors/BVTX/BVTX.cc
index 12a7e09ea1..f5ce5d6d2f 100644
--- a/src/detectors/BVTX/BVTX.cc
+++ b/src/detectors/BVTX/BVTX.cc
@@ -31,6 +31,7 @@ void InitPlugin(JApplication *app) {
         {
             .threshold = 0.54 * dd4hep::keV,
             .timeResolution = 2000 * dd4hep::ns,
+            .prepopulate = true, // for MAPS, initialize digitization with a "pulse" of empty hits
         },
         app
     ));
diff --git a/src/detectors/ECTRK/ECTRK.cc b/src/detectors/ECTRK/ECTRK.cc
index 36feb881da..893446dccf 100644
--- a/src/detectors/ECTRK/ECTRK.cc
+++ b/src/detectors/ECTRK/ECTRK.cc
@@ -31,6 +31,7 @@ void InitPlugin(JApplication *app) {
         {
             .threshold = 0.54 * dd4hep::keV,
             .timeResolution = 2000 * dd4hep::ns,
+            .prepopulate = true, // for MAPS, initialize digitization with a "pulse" of empty hits
         },
         app
     ));

From 27d2ae6e933931e3dfa418cbed5d42266a6c8fc5 Mon Sep 17 00:00:00 2001
From: Kolja Kauder <kkauder@gmail.com>
Date: Tue, 7 May 2024 08:45:07 -0400
Subject: [PATCH 12/21] use uncertainty = resolution/2; TODO text added

---
 src/algorithms/digi/SiliconTrackerDigi.cc | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/algorithms/digi/SiliconTrackerDigi.cc b/src/algorithms/digi/SiliconTrackerDigi.cc
index 4d0141377a..77e9a59156 100644
--- a/src/algorithms/digi/SiliconTrackerDigi.cc
+++ b/src/algorithms/digi/SiliconTrackerDigi.cc
@@ -93,7 +93,7 @@ void SiliconTrackerDigi::process(
             for (auto& hit : cell_hit_map[sim_hit.getCellID()]) {
                 auto existing_time = hit.getTimeStamp();
                 // TODO: edge cases?
-                if ( hit_time_stamp >= existing_time - hit_time_stamp_err && hit_time_stamp <= existing_time + hit_time_stamp_err ) {
+                if ( hit_time_stamp >= existing_time - 0.5*hit_time_stamp_err && hit_time_stamp <= existing_time + 0.5*hit_time_stamp_err ) {
                     // There is already a hit within the same time window
                     m_log->debug("  Hit already exists in cell ID={}, within the same time bucket. Time stamp: {}, bucket from {} to {}",
                          sim_hit.getCellID(), hit.getTimeStamp(), existing_time - hit_time_stamp_err, existing_time + hit_time_stamp_err);
@@ -112,6 +112,13 @@ void SiliconTrackerDigi::process(
                         sim_hit.getCellID(), sim_hit.getTime());
 
             // Create a new hit
+            // Note: time uncertainty in the TrackerHitReconstruction is set independently
+            // It would probably be better to move it into the RawTrackerHit class
+            // (same for spatial uncertainty, actually)
+            // Note 2: It's possible to not fall into a bucket but still be close enough to one or 
+            // more that uncertainties overlap. Cannot be avoided in the current setup.
+            // It could lead to ambiguity which bucket is chosen for a third hit in this area.
+            // In reality, this is probably more like dead time; revisit later.
             cell_hit_map[sim_hit.getCellID()].push_back(
                 edm4eic::MutableRawTrackerHit{
                 sim_hit.getCellID(),

From 49d4ee47d0a7a0185a18d8fa00a198c29f469291 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Tue, 7 May 2024 12:45:20 +0000
Subject: [PATCH 13/21] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 src/algorithms/digi/SiliconTrackerDigi.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/algorithms/digi/SiliconTrackerDigi.cc b/src/algorithms/digi/SiliconTrackerDigi.cc
index 77e9a59156..c58f5321fd 100644
--- a/src/algorithms/digi/SiliconTrackerDigi.cc
+++ b/src/algorithms/digi/SiliconTrackerDigi.cc
@@ -115,7 +115,7 @@ void SiliconTrackerDigi::process(
             // Note: time uncertainty in the TrackerHitReconstruction is set independently
             // It would probably be better to move it into the RawTrackerHit class
             // (same for spatial uncertainty, actually)
-            // Note 2: It's possible to not fall into a bucket but still be close enough to one or 
+            // Note 2: It's possible to not fall into a bucket but still be close enough to one or
             // more that uncertainties overlap. Cannot be avoided in the current setup.
             // It could lead to ambiguity which bucket is chosen for a third hit in this area.
             // In reality, this is probably more like dead time; revisit later.

From 6267e03fee2fe7785912d5de9834cdc436976ea6 Mon Sep 17 00:00:00 2001
From: Kolja Kauder <kkauder@gmail.com>
Date: Fri, 17 May 2024 12:03:42 -0400
Subject: [PATCH 14/21] Added integration window, updated time resolution for
 silicon hits

---
 src/detectors/B0TRK/B0TRK.cc       |  7 +++++--
 src/detectors/BTOF/BTOF.cc         |  7 +++++--
 src/detectors/BTRK/BTRK.cc         |  7 +++++--
 src/detectors/BVTX/BVTX.cc         |  7 +++++--
 src/detectors/ECTOF/ECTOF.cc       |  7 +++++--
 src/detectors/ECTRK/ECTRK.cc       |  7 +++++--
 src/detectors/FOFFMTRK/FOFFMTRK.cc |  7 +++++--
 src/detectors/LOWQ2/LOWQ2.cc       | 13 ++++++++-----
 src/detectors/MPGD/MPGD.cc         | 28 ++++++++++++++++++++--------
 src/detectors/RPOTS/RPOTS.cc       | 13 ++++++++-----
 10 files changed, 71 insertions(+), 32 deletions(-)

diff --git a/src/detectors/B0TRK/B0TRK.cc b/src/detectors/B0TRK/B0TRK.cc
index 464ad081ca..9a57681357 100644
--- a/src/detectors/B0TRK/B0TRK.cc
+++ b/src/detectors/B0TRK/B0TRK.cc
@@ -19,6 +19,8 @@ void InitPlugin(JApplication *app) {
     using namespace eicrecon;
 
     // Digitization
+    auto B0TrackerTimeResolution    =   0.02 * dd4hep::ns; // 15-20 ps
+    auto B0TrackerIntegrationWindow =  0.750 * dd4hep::ns; // 750 ps shaping time
     app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
         "B0TrackerRawHits",
         {
@@ -30,7 +32,8 @@ void InitPlugin(JApplication *app) {
         },
         {
             .threshold = 10.0 * dd4hep::keV,
-            .timeResolution = 0.015 * dd4hep::ns,
+            .timeResolution = B0TrackerTimeResolution,
+            .integrationWindow = B0TrackerIntegrationWindow,
         },
         app
     ));
@@ -41,7 +44,7 @@ void InitPlugin(JApplication *app) {
         {"B0TrackerRawHits"},
         {"B0TrackerRecHits"},
         {
-            .timeResolution = 0.015 * dd4hep::ns,
+            .timeResolution = B0TrackerTimeResolution,
         },
         app
     ));
diff --git a/src/detectors/BTOF/BTOF.cc b/src/detectors/BTOF/BTOF.cc
index 2fd687a85e..d4c09238d8 100644
--- a/src/detectors/BTOF/BTOF.cc
+++ b/src/detectors/BTOF/BTOF.cc
@@ -19,6 +19,8 @@ void InitPlugin(JApplication *app) {
     using namespace eicrecon;
 
     // Digitization
+    auto BTOFBarrelTimeResolution    = 0.02 * dd4hep::ns; // 20 ps bin width
+    auto BTOFBarrelIntegrationWindow =  5.0 * dd4hep::ns; // shaping time
     app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
         "TOFBarrelRawHit",
         {
@@ -30,7 +32,8 @@ void InitPlugin(JApplication *app) {
         },
         {
             .threshold = 6.0 * dd4hep::keV,
-            .timeResolution = 0.02 * dd4hep::ns,
+            .timeResolution = BTOFBarrelTimeResolution,
+            .integrationWindow = BTOFBarrelIntegrationWindow,
         },
         app
     ));
@@ -41,7 +44,7 @@ void InitPlugin(JApplication *app) {
         {"TOFBarrelRawHit"},    // Input data collection tags
         {"TOFBarrelRecHit"},     // Output data tag
         {
-            .timeResolution = 0.02 * dd4hep::ns,
+            .timeResolution = BTOFBarrelTimeResolution,
         },
         app
     ));         // Hit reco default config for factories
diff --git a/src/detectors/BTRK/BTRK.cc b/src/detectors/BTRK/BTRK.cc
index f0d054ba31..b1bd0e377a 100644
--- a/src/detectors/BTRK/BTRK.cc
+++ b/src/detectors/BTRK/BTRK.cc
@@ -19,6 +19,8 @@ void InitPlugin(JApplication *app) {
     using namespace eicrecon;
 
     // Digitization
+    auto BTRKBarrelTimeResolution    = 2000 * dd4hep::ns;
+    auto BTRKBarrelIntegrationWindow = 2000 * dd4hep::ns; // shaping time
     app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
         "SiBarrelRawHits",
         {
@@ -30,7 +32,8 @@ void InitPlugin(JApplication *app) {
         },
         {
             .threshold = 0.54 * dd4hep::keV,
-            .timeResolution = 2000 * dd4hep::ns,
+            .timeResolution = BTRKBarrelTimeResolution,
+            .integrationWindow = BTRKBarrelIntegrationWindow,
             .prepopulate = true, // for MAPS, initialize digitization with a "pulse" of empty hits
         },
         app
@@ -43,7 +46,7 @@ void InitPlugin(JApplication *app) {
         {"SiBarrelRawHits"},
         {"SiBarrelTrackerRecHits"},
         {
-            .timeResolution = 2000 * dd4hep::ns,
+            .timeResolution = BTRKBarrelTimeResolution,
         },
         app
     ));
diff --git a/src/detectors/BVTX/BVTX.cc b/src/detectors/BVTX/BVTX.cc
index b7ca9d7bb4..e05c4d8e9f 100644
--- a/src/detectors/BVTX/BVTX.cc
+++ b/src/detectors/BVTX/BVTX.cc
@@ -19,6 +19,8 @@ void InitPlugin(JApplication *app) {
     using namespace eicrecon;
 
     // Digitization
+    auto SiBarrelVertexTimeResolution    = 2000 * dd4hep::ns;
+    auto SiBarrelVertexIntegrationWindow = 2000 * dd4hep::ns;
     app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
         "SiBarrelVertexRawHits",
         {
@@ -30,7 +32,8 @@ void InitPlugin(JApplication *app) {
         },
         {
             .threshold = 0.54 * dd4hep::keV,
-            .timeResolution = 2000 * dd4hep::ns,
+            .timeResolution    = SiBarrelVertexTimeResolution,
+            .integrationWindow = SiBarrelVertexIntegrationWindow,
             .prepopulate = true, // for MAPS, initialize digitization with a "pulse" of empty hits
         },
         app
@@ -42,7 +45,7 @@ void InitPlugin(JApplication *app) {
         {"SiBarrelVertexRawHits"},
         {"SiBarrelVertexRecHits"},
         {
-            .timeResolution = 2000 * dd4hep::ns,
+            .timeResolution = SiBarrelVertexTimeResolution,
         },
         app
     ));
diff --git a/src/detectors/ECTOF/ECTOF.cc b/src/detectors/ECTOF/ECTOF.cc
index aee4a41152..ec776393cf 100644
--- a/src/detectors/ECTOF/ECTOF.cc
+++ b/src/detectors/ECTOF/ECTOF.cc
@@ -19,6 +19,8 @@ void InitPlugin(JApplication *app) {
     using namespace eicrecon;
 
     // Digitization
+    auto TOFEndcapTimeResolution    =  20.0 * dd4hep::ns; // 20 ps bin width
+    auto TOFEndcapIntegrationWindow =   5.0 * dd4hep::ns; // shaping time
     app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
       "TOFEndcapRawHits",
       {
@@ -29,7 +31,8 @@ void InitPlugin(JApplication *app) {
       },
       {
         .threshold = 6.0 * dd4hep::keV,
-        .timeResolution = 0.02 * dd4hep::ns,
+        .timeResolution = TOFEndcapTimeResolution,
+        .integrationWindow = TOFEndcapIntegrationWindow,
 
       },
       app
@@ -41,7 +44,7 @@ void InitPlugin(JApplication *app) {
       {"TOFEndcapRawHits"},     // Input data collection tags
       {"TOFEndcapRecHits"},     // Output data tag
       {
-        .timeResolution = 0.02 * dd4hep::ns,
+        .timeResolution = TOFEndcapTimeResolution,
       },
       app
     ));
diff --git a/src/detectors/ECTRK/ECTRK.cc b/src/detectors/ECTRK/ECTRK.cc
index 893446dccf..225e65f8f9 100644
--- a/src/detectors/ECTRK/ECTRK.cc
+++ b/src/detectors/ECTRK/ECTRK.cc
@@ -19,6 +19,8 @@ void InitPlugin(JApplication *app) {
     using namespace eicrecon;
 
     // Digitization
+    auto SiEndcapTrackerTimeResolution    = 2000. * dd4hep::ns;
+    auto SiEndcapTrackerIntegrationWindow = 2000. * dd4hep::ns;
     app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
         "SiEndcapTrackerRawHits",
         {
@@ -30,7 +32,8 @@ void InitPlugin(JApplication *app) {
         },
         {
             .threshold = 0.54 * dd4hep::keV,
-            .timeResolution = 2000 * dd4hep::ns,
+            .timeResolution = SiEndcapTrackerTimeResolution,
+            .integrationWindow = SiEndcapTrackerIntegrationWindow,
             .prepopulate = true, // for MAPS, initialize digitization with a "pulse" of empty hits
         },
         app
@@ -42,7 +45,7 @@ void InitPlugin(JApplication *app) {
         {"SiEndcapTrackerRawHits"},
         {"SiEndcapTrackerRecHits"},
         {
-            .timeResolution = 2000 * dd4hep::ns,
+            .timeResolution = SiEndcapTrackerTimeResolution,
         },
         app
     ));
diff --git a/src/detectors/FOFFMTRK/FOFFMTRK.cc b/src/detectors/FOFFMTRK/FOFFMTRK.cc
index 68a84a0293..7b0c7ab505 100644
--- a/src/detectors/FOFFMTRK/FOFFMTRK.cc
+++ b/src/detectors/FOFFMTRK/FOFFMTRK.cc
@@ -22,6 +22,8 @@ void InitPlugin(JApplication *app) {
     MatrixTransferStaticConfig recon_cfg;
 
         //Digitized hits, especially for thresholds
+        auto ForwardOffMTrackerTimeResolution    = 0.015 * dd4hep::ns; // 15-20 ps
+        auto ForwardOffMTrackerIntegrationWindow = 0.750 * dd4hep::ns; // 750 ps shaping time
         app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
         "ForwardOffMTrackerRawHits",
         {
@@ -33,7 +35,8 @@ void InitPlugin(JApplication *app) {
         },
         {
             .threshold = 10.0 * dd4hep::keV,
-            .timeResolution = 0.015 * dd4hep::ns,
+            .timeResolution = ForwardOffMTrackerTimeResolution,
+            .integrationWindow = ForwardOffMTrackerIntegrationWindow,
         },
         app
     ));
@@ -43,7 +46,7 @@ void InitPlugin(JApplication *app) {
         {"ForwardOffMTrackerRawHits"},
         {"ForwardOffMTrackerRecHits"},
         {
-            .timeResolution = 0.015 * dd4hep::ns,
+            .timeResolution = ForwardOffMTrackerTimeResolution,
         },
         app
     ));
diff --git a/src/detectors/LOWQ2/LOWQ2.cc b/src/detectors/LOWQ2/LOWQ2.cc
index e539c3d4f2..d679cd3640 100644
--- a/src/detectors/LOWQ2/LOWQ2.cc
+++ b/src/detectors/LOWQ2/LOWQ2.cc
@@ -28,18 +28,21 @@ extern "C" {
     using namespace eicrecon;
 
     // Digitization of silicon hits
+    auto TaggerTrackerTimeResolution    = 0.195 * dd4hep::ns;
+    auto TaggerTrackerIntegrationWindow = 5.0   * dd4hep::ns;
     app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
          "TaggerTrackerRawHits",
          {
-           "TaggerTrackerHits"
+            "TaggerTrackerHits"
          },
          {
-           "TaggerTrackerRawHits",
-           "TaggerTrackerHitAssociations"
+            "TaggerTrackerRawHits",
+            "TaggerTrackerHitAssociations"
          },
          {
-           .threshold = 1.5 * dd4hep::keV,
-           .timeResolution = 0.195 * dd4hep::ns,
+            .threshold = 1.5 * dd4hep::keV,
+            .timeResolution = TaggerTrackerTimeResolution,
+            .integrationWindow = TaggerTrackerIntegrationWindow,
          },
          app
     ));
diff --git a/src/detectors/MPGD/MPGD.cc b/src/detectors/MPGD/MPGD.cc
index 6393ebb513..df119f1be2 100644
--- a/src/detectors/MPGD/MPGD.cc
+++ b/src/detectors/MPGD/MPGD.cc
@@ -19,6 +19,8 @@ void InitPlugin(JApplication *app) {
     using namespace eicrecon;
 
     // Digitization
+    auto MPGDBarrelTimeResolution    =  20.0 * dd4hep::ns; // 1 / (50 MHz)
+    auto MPGDBarrelIntegrationWindow = 500.0 * dd4hep::ns; // shaping time
     app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
         "MPGDBarrelRawHits",
         {
@@ -30,7 +32,8 @@ void InitPlugin(JApplication *app) {
         },
         {
             .threshold = 0.25 * dd4hep::keV,
-            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
+            .timeResolution = MPGDBarrelTimeResolution,
+            .integrationWindow = MPGDBarrelIntegrationWindow,
         },
         app
     ));
@@ -41,12 +44,14 @@ void InitPlugin(JApplication *app) {
         {"MPGDBarrelRawHits"},     // Input data collection tags
         {"MPGDBarrelRecHits"},     // Output data tag
         {
-            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
+            .timeResolution = MPGDBarrelTimeResolution,
         },
         app
     ));
 
     // Digitization
+    auto OuterMPGDBarrelTimeResolution    =  20.0 * dd4hep::ns; // 1 / (50 MHz)
+    auto OuterMPGDBarrelIntegrationWindow = 500.0 * dd4hep::ns; // shaping time
     app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
         "OuterMPGDBarrelRawHits",
         {
@@ -58,7 +63,8 @@ void InitPlugin(JApplication *app) {
         },
         {
             .threshold = 0.25 * dd4hep::keV,
-            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
+            .timeResolution = OuterMPGDBarrelTimeResolution,
+            .integrationWindow = OuterMPGDBarrelIntegrationWindow,
         },
         app
     ));
@@ -69,12 +75,14 @@ void InitPlugin(JApplication *app) {
         {"OuterMPGDBarrelRawHits"},     // Input data collection tags
         {"OuterMPGDBarrelRecHits"},     // Output data tag
         {
-            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
+            .timeResolution = OuterMPGDBarrelTimeResolution,
         },
         app
     ));
 
     // Digitization
+    auto BackwardMPGDEndcapTimeResolution    =  20.0 * dd4hep::ns; // 1 / (50 MHz)
+    auto BackwardMPGDEndcapIntegrationWindow = 500.0 * dd4hep::ns; // shaping time
     app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
         "BackwardMPGDEndcapRawHits",
         {
@@ -86,7 +94,8 @@ void InitPlugin(JApplication *app) {
         },
         {
             .threshold = 0.25 * dd4hep::keV,
-            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
+            .timeResolution = BackwardMPGDEndcapTimeResolution,
+            .integrationWindow = BackwardMPGDEndcapIntegrationWindow,
         },
         app
     ));
@@ -97,12 +106,14 @@ void InitPlugin(JApplication *app) {
         {"BackwardMPGDEndcapRawHits"},     // Input data collection tags
         {"BackwardMPGDEndcapRecHits"},     // Output data tag
         {
-            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
+            .timeResolution = BackwardMPGDEndcapTimeResolution,
         },
         app
     ));
 
     // Digitization
+    auto ForwardMPGDEndcapTimeResolution    =  20.0 * dd4hep::ns; // 1 / (50 MHz)
+    auto ForwardMPGDEndcapIntegrationWindow = 500.0 * dd4hep::ns; // shaping time
     app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
         "ForwardMPGDEndcapRawHits",
         {
@@ -114,7 +125,8 @@ void InitPlugin(JApplication *app) {
         },
         {
             .threshold = 0.25 * dd4hep::keV,
-            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
+            .timeResolution = ForwardMPGDEndcapTimeResolution,
+            .integrationWindow = ForwardMPGDEndcapIntegrationWindow,
         },
         app
     ));
@@ -125,7 +137,7 @@ void InitPlugin(JApplication *app) {
         {"ForwardMPGDEndcapRawHits"},     // Input data collection tags
         {"ForwardMPGDEndcapRecHits"},     // Output data tag
         {
-            .timeResolution = 20 * dd4hep::ns, // 1 / (50 MHz)
+            .timeResolution = ForwardMPGDEndcapTimeResolution,
         },
         app
     ));
diff --git a/src/detectors/RPOTS/RPOTS.cc b/src/detectors/RPOTS/RPOTS.cc
index a37428ec89..9d30add179 100644
--- a/src/detectors/RPOTS/RPOTS.cc
+++ b/src/detectors/RPOTS/RPOTS.cc
@@ -22,18 +22,21 @@ void InitPlugin(JApplication *app) {
     MatrixTransferStaticConfig recon_cfg;
 
         //Digitized hits, especially for thresholds
+        auto ForwardRomanPotTimeResolution    = 0.015 * dd4hep::ns; // 15-20 ps
+        auto ForwardRomanPotIntegrationWindow = 0.750 * dd4hep::ns; // 750 ps shaping time
         app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
         "ForwardRomanPotRawHits",
         {
-          "ForwardRomanPotHits"
+            "ForwardRomanPotHits"
         },
         {
-          "ForwardRomanPotRawHits",
-          "ForwardRomanPotHitAssociations"
+            "ForwardRomanPotRawHits",
+            "ForwardRomanPotHitAssociations"
         },
         {
             .threshold = 10.0 * dd4hep::keV,
-            .timeResolution = 0.015 * dd4hep::ns,
+            .timeResolution = ForwardRomanPotTimeResolution,
+            .integrationWindow = ForwardRomanPotIntegrationWindow,
         },
         app
     ));
@@ -43,7 +46,7 @@ void InitPlugin(JApplication *app) {
         {"ForwardRomanPotRawHits"},
         {"ForwardRomanPotRecHits"},
         {
-            .timeResolution = 0.015 * dd4hep::ns,
+            .timeResolution = ForwardRomanPotTimeResolution,
         },
         app
     ));

From 79d867dc9eb293d3a66d05a7577a030c9d5d9734 Mon Sep 17 00:00:00 2001
From: Kolja Kauder <kkauder@gmail.com>
Date: Tue, 21 May 2024 13:50:10 -0400
Subject: [PATCH 15/21] timeResolution is a double

---
 src/algorithms/tracking/TrackerHitReconstructionConfig.h  | 3 ++-
 src/factories/tracking/TrackerHitReconstruction_factory.h | 3 +--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/algorithms/tracking/TrackerHitReconstructionConfig.h b/src/algorithms/tracking/TrackerHitReconstructionConfig.h
index 35d81adbe4..0e1c06f97c 100644
--- a/src/algorithms/tracking/TrackerHitReconstructionConfig.h
+++ b/src/algorithms/tracking/TrackerHitReconstructionConfig.h
@@ -2,9 +2,10 @@
 // Copyright (C) 2022 Whitney Armstrong, Sylvester Joosten, Wouter Deconinck, Dmitry Romanov
 
 #pragma once
+#include <edm4eic/unit_system.h>
 
 namespace eicrecon {
     struct TrackerHitReconstructionConfig {
-        float timeResolution = 10;
+    double timeResolution    = 2000 * edm4eic::unit::ns; // It should be >0, maybe large, to not distort the fitter by default. Choosing 2us for now.
     };
 }
diff --git a/src/factories/tracking/TrackerHitReconstruction_factory.h b/src/factories/tracking/TrackerHitReconstruction_factory.h
index ad59096931..eb27b57d1a 100644
--- a/src/factories/tracking/TrackerHitReconstruction_factory.h
+++ b/src/factories/tracking/TrackerHitReconstruction_factory.h
@@ -7,7 +7,6 @@
 #include "services/geometry/dd4hep/DD4hep_service.h"
 #include "extensions/jana/JOmniFactory.h"
 
-
 namespace eicrecon {
 
 class TrackerHitReconstruction_factory :
@@ -18,7 +17,7 @@ public JOmniFactory<TrackerHitReconstruction_factory, TrackerHitReconstructionCo
     PodioInput<edm4eic::RawTrackerHit> m_raw_hits_input {this};
     PodioOutput<edm4eic::TrackerHit> m_rec_hits_output {this};
 
-    ParameterRef<float> m_timeResolution {this, "timeResolution", config().timeResolution};
+    ParameterRef<double> m_timeResolution {this, "timeResolution", config().timeResolution};
 
     Service<DD4hep_service> m_geoSvc {this};
 

From 0e377fb2f22f8d6bf1832b3a1c4defddb3373ff3 Mon Sep 17 00:00:00 2001
From: Kolja Kauder <kkauder@gmail.com>
Date: Tue, 21 May 2024 13:51:25 -0400
Subject: [PATCH 16/21] WS Cleanup

---
 src/detectors/BTRK/BTRK.cc | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/detectors/BTRK/BTRK.cc b/src/detectors/BTRK/BTRK.cc
index b1bd0e377a..6c6aea7fed 100644
--- a/src/detectors/BTRK/BTRK.cc
+++ b/src/detectors/BTRK/BTRK.cc
@@ -1,7 +1,5 @@
 // Copyright 2022, Dmitry Romanov
 // Subject to the terms in the LICENSE file found in the top-level directory.
-//
-//
 
 #include <Evaluator/DD4hepUnits.h>
 #include <JANA/JApplication.h>
@@ -38,8 +36,7 @@ void InitPlugin(JApplication *app) {
         },
         app
     ));
-
-
+    
     // Convert raw digitized hits into hits with geometry info (ready for tracking)
     app->Add(new JOmniFactoryGeneratorT<TrackerHitReconstruction_factory>(
         "SiBarrelTrackerRecHits",

From 9ebdc110df6a2da779725cd2e2f237bcebc0a696 Mon Sep 17 00:00:00 2001
From: Kolja Kauder <kkauder@gmail.com>
Date: Tue, 21 May 2024 13:53:06 -0400
Subject: [PATCH 17/21] Added integrationWindow parameter

---
 src/algorithms/digi/SiliconTrackerDigiConfig.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/algorithms/digi/SiliconTrackerDigiConfig.h b/src/algorithms/digi/SiliconTrackerDigiConfig.h
index 6a6630cd96..456aa32235 100644
--- a/src/algorithms/digi/SiliconTrackerDigiConfig.h
+++ b/src/algorithms/digi/SiliconTrackerDigiConfig.h
@@ -13,7 +13,8 @@ namespace eicrecon {
     // sub-systems should overwrite their own
     // NB: be aware of thresholds in npsim! E.g. https://github.com/eic/npsim/pull/9/files
     double threshold  = 0 * dd4hep::keV;
-    double timeResolution = 2000 * edm4eic::unit::ns; // Source for 8? This is arbitrary --> however, it should be >0, maybe large, to not distort the fitter by default. Choosing 2us for now.
+    double timeResolution    = 2000 * edm4eic::unit::ns; // Source for 8? This is arbitrary --> however, it should be >0, maybe large, to not distort the fitter by default. Choosing 2us for now.
+    double integrationWindow = 2000 * edm4eic::unit::ns; // Source for 8? This is arbitrary --> however, it should be >0, maybe large, to not distort the fitter by default. Choosing 2us for now.
     bool prepopulate = false; // prepopulate cellHit map with empty hits, for MAPS
   };
 

From ab22a197d9980845561a2e7a45e088502399ca4a Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Tue, 21 May 2024 17:53:18 +0000
Subject: [PATCH 18/21] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 src/detectors/BTRK/BTRK.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/detectors/BTRK/BTRK.cc b/src/detectors/BTRK/BTRK.cc
index 6c6aea7fed..0cd2c53ca5 100644
--- a/src/detectors/BTRK/BTRK.cc
+++ b/src/detectors/BTRK/BTRK.cc
@@ -36,7 +36,7 @@ void InitPlugin(JApplication *app) {
         },
         app
     ));
-    
+
     // Convert raw digitized hits into hits with geometry info (ready for tracking)
     app->Add(new JOmniFactoryGeneratorT<TrackerHitReconstruction_factory>(
         "SiBarrelTrackerRecHits",

From 5bc417126984f67b48fe55ce0e054c256f70f5c8 Mon Sep 17 00:00:00 2001
From: Kolja Kauder <kkauder@gmail.com>
Date: Tue, 25 Jun 2024 10:47:30 -0400
Subject: [PATCH 19/21] Digitzing with resolution and integration time

---
 src/algorithms/digi/SiliconTrackerDigi.cc | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/algorithms/digi/SiliconTrackerDigi.cc b/src/algorithms/digi/SiliconTrackerDigi.cc
index c58f5321fd..52f4267cf9 100644
--- a/src/algorithms/digi/SiliconTrackerDigi.cc
+++ b/src/algorithms/digi/SiliconTrackerDigi.cc
@@ -31,6 +31,9 @@ void SiliconTrackerDigi::init(std::shared_ptr<spdlog::logger>& logger) {
     };
 }
 
+// Logic: timeResolution is the smearing of the time.
+// Smeared time marks the beginning of a bucket. If another hit falls within the same bucket,
+// the energy is summed up. If not, a new hit is created.
 
 void SiliconTrackerDigi::process(
     const SiliconTrackerDigi::Input& input,
@@ -42,7 +45,7 @@ void SiliconTrackerDigi::process(
     // A map of unique cellIDs with temporary structure RawHit
     std::unordered_map<std::uint64_t, std::vector<edm4eic::MutableRawTrackerHit>> cell_hit_map;
 
-    auto hit_time_stamp_err = (std::int32_t) (m_cfg.timeResolution * 1e3);
+    auto bucket_width = (std::int32_t) (m_cfg.integrationWindow * 1e3);
 
     // Some detectors have a steady pulse of hits - generate empty time buckets for those
     // Conundrum: We can't know the number of buckets without knowing the timeSlice length
@@ -62,11 +65,9 @@ void SiliconTrackerDigi::process(
             }
         }
     }
+    
     for (const auto& sim_hit : *sim_hits) {
-
         // time smearing
-        // Note: In the current setup, we can have hits outside the time slice
-        // Up to the analyzer to decide what to do with them
         double time_smearing = m_gauss();
         double result_time = sim_hit.getTime() + time_smearing;
         auto hit_time_stamp = (std::int32_t) (result_time * 1e3);
@@ -93,10 +94,10 @@ void SiliconTrackerDigi::process(
             for (auto& hit : cell_hit_map[sim_hit.getCellID()]) {
                 auto existing_time = hit.getTimeStamp();
                 // TODO: edge cases?
-                if ( hit_time_stamp >= existing_time - 0.5*hit_time_stamp_err && hit_time_stamp <= existing_time + 0.5*hit_time_stamp_err ) {
+                if ( hit_time_stamp >= existing_time && hit_time_stamp <= existing_time + bucket_width ) {
                     // There is already a hit within the same time window
                     m_log->debug("  Hit already exists in cell ID={}, within the same time bucket. Time stamp: {}, bucket from {} to {}",
-                         sim_hit.getCellID(), hit.getTimeStamp(), existing_time - hit_time_stamp_err, existing_time + hit_time_stamp_err);
+                         sim_hit.getCellID(), hit.getTimeStamp(), existing_time, existing_time + bucket_width);
                     // sum deposited energy
                     auto charge = hit.getCharge();
                     hit.setCharge(charge + (std::int32_t) std::llround(sim_hit.getEDep() * 1e6));

From 474b95495ab52c181a73a832f5262c8007b42e35 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Tue, 25 Jun 2024 15:47:06 +0000
Subject: [PATCH 20/21] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 src/algorithms/digi/SiliconTrackerDigi.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/algorithms/digi/SiliconTrackerDigi.cc b/src/algorithms/digi/SiliconTrackerDigi.cc
index 7df9d304a1..7c1cc87cba 100644
--- a/src/algorithms/digi/SiliconTrackerDigi.cc
+++ b/src/algorithms/digi/SiliconTrackerDigi.cc
@@ -62,7 +62,7 @@ void SiliconTrackerDigi::process(
             }
         }
     }
-    
+
     for (const auto& sim_hit : *sim_hits) {
         // time smearing
         double time_smearing = m_gauss();

From 09b1f4917fc299c0ad83cb3afa87393e0062f94d Mon Sep 17 00:00:00 2001
From: kkauder <kkauder@gmail.com>
Date: Tue, 25 Jun 2024 15:55:57 -0400
Subject: [PATCH 21/21] Update src/detectors/LOWQ2/LOWQ2.cc

Co-authored-by: Simon Gardner <simon.gardner@glasgow.ac.uk>
---
 src/detectors/LOWQ2/LOWQ2.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/detectors/LOWQ2/LOWQ2.cc b/src/detectors/LOWQ2/LOWQ2.cc
index 99b7e553f7..7cc71cad72 100644
--- a/src/detectors/LOWQ2/LOWQ2.cc
+++ b/src/detectors/LOWQ2/LOWQ2.cc
@@ -36,7 +36,7 @@ extern "C" {
 
     // Digitization of silicon hits
     auto TaggerTrackerTimeResolution    = 0.195 * dd4hep::ns;
-    auto TaggerTrackerIntegrationWindow = 5.0   * dd4hep::ns;
+    auto TaggerTrackerIntegrationWindow = 25.0   * dd4hep::ns;
     app->Add(new JOmniFactoryGeneratorT<SiliconTrackerDigi_factory>(
          "TaggerTrackerRawHits",
          {