Merge pull request #47480 from CMSTrackerDPG/LoweredSiPixelL1ClusterThreshold_from-CMSSW_15_1_X_2025-02-28-1100

Lowered cluster charge threshold for pixel L1

Author: cmsbuild

Configuration/Eras/python/Era_Run3_2025_cff.py

@@ -3,5 +3,6 @@
 from Configuration.Eras.Era_Run3_2024_cff import Run3_2024
 from Configuration.Eras.Modifier_run3_GEM_2025_cff import run3_GEM_2025
 from Configuration.Eras.Modifier_stage2L1Trigger_2025_cff import stage2L1Trigger_2025
+from Configuration.Eras.Modifier_run3_SiPixel_2025_cff import run3_SiPixel_2025
 
-Run3_2025 = cms.ModifierChain(Run3_2024, run3_GEM_2025, stage2L1Trigger_2025)
+Run3_2025 = cms.ModifierChain(Run3_2024, run3_GEM_2025, stage2L1Trigger_2025, run3_SiPixel_2025)

Configuration/Eras/python/Modifier_run3_SiPixel_2025_cff.py

@@ -0,0 +1,5 @@
+import FWCore.ParameterSet.Config as cms
+
+# This modifier is for SiPixel-specific changes
+
+run3_SiPixel_2025 =  cms.Modifier()

Configuration/StandardSequences/python/Eras.py

@@ -100,6 +100,7 @@ def __init__(self):
                            'run2_HF_2017', 'run2_HCAL_2017', 'run2_HEPlan1_2017', 'run2_HB_2018','run2_HE_2018',
                            'run3_HB', 'run3_HFSL', 'run3_common', 'run3_RPC',
                            'phase1Pixel', 'run3_GEM', 'run2_GEM_2017',
+                           'run3_SiPixel_2025',
                            'run2_CSC_2018',
                            'phase2_common', 'phase2_tracker',
                            'phase2_muon', 'phase2_GEM', 'phase2_GE0',

RecoLocalTracker/SiPixelClusterizer/python/SiPixelClusterizer_cfi.py

@@ -27,6 +27,12 @@
   ClusterThreshold_L1     = 4000
 )
 
+# lowered L1 cluster charge threshold to cope with reduced charge collection efficiency in the sensor caused by radiation damage
+from Configuration.Eras.Modifier_run3_SiPixel_2025_cff import run3_SiPixel_2025
+run3_SiPixel_2025.toModify(siPixelClusters,
+  ClusterThreshold_L1 = 2000
+)
+
 # Need these until phase2 pixel templates are used
 from Configuration.Eras.Modifier_phase2_tracker_cff import phase2_tracker
 from SimTracker.SiPhase2Digitizer.phase2TrackerDigitizer_cfi import PixelDigitizerAlgorithmCommon

RecoLocalTracker/SiPixelClusterizer/python/siPixelClustersPreSplitting_cff.py

@@ -1,6 +1,7 @@
 import FWCore.ParameterSet.Config as cms
 from HeterogeneousCore.AlpakaCore.functions import *
 from Configuration.Eras.Modifier_run3_common_cff import run3_common
+from Configuration.Eras.Modifier_run3_SiPixel_2025_cff import run3_SiPixel_2025
 from Configuration.ProcessModifiers.alpaka_cff import alpaka
 
 # HIon Modifiers
@@ -44,6 +45,10 @@ def _addProcessCalibTrackerAlpakaES(process):
     VCaltoElectronOffset    = 0,
     VCaltoElectronOffset_L1 = 0)
 
+(alpaka & run3_SiPixel_2025).toModify(siPixelClustersPreSplittingAlpaka,
+    # lowered L1 cluster charge threshold to cope with reduced charge collection efficiency in the sensor caused by radiation damage
+    clusterThreshold_layer1 = 2000)
+
 from RecoLocalTracker.SiPixelClusterizer.siPixelPhase2DigiToCluster_cfi import siPixelPhase2DigiToCluster as _siPixelPhase2DigiToCluster
 
 # for phase2 no pixel raw2digi is available at the moment