diff --git a/Simulation/DetSimMixing/src/BackgroundEvent.hh b/Simulation/DetSimMixing/src/BackgroundEvent.hh
index c6a8bea9ed6b55b14749aaf960f447b06742829f..4b3547bb66cb349056e479d3dedc18e575555cba 100644
--- a/Simulation/DetSimMixing/src/BackgroundEvent.hh
+++ b/Simulation/DetSimMixing/src/BackgroundEvent.hh
@@ -40,7 +40,7 @@ struct BackgroundEvent {
         kMUON = 6, // 100 ns // from Xiaolong Wang
         kNSubDetType
     };
-    std::vector<double> subdet2twindow = {200, 200, 34000, 1000, 150, 1000, 100}; // key is subdet, value is time window.
+    std::vector<double> subdet2twindow = {200, 30, 34000, 30, 150, 1000, 100}; // key is subdet, value is time window.
     std::vector<std::vector<std::string>> subdet2colnames = {
         {"VXD"},
         {"ITK"},
diff --git a/Simulation/DetSimMixing/src/DetSimMixingAlg.hh b/Simulation/DetSimMixing/src/DetSimMixingAlg.hh
index d50c9b3f17332f1992a0a47e27a0b92c33117d6f..054372c92ab87bebc405eace90262a615a76df52 100644
--- a/Simulation/DetSimMixing/src/DetSimMixingAlg.hh
+++ b/Simulation/DetSimMixing/src/DetSimMixingAlg.hh
@@ -112,9 +112,9 @@ private:
     // Time window for VXD, ITK, TPC, OTK, ECAL, HCAL, MUON
     // Only the hits between [-T, T] ns are loaded
     Gaudi::Property<double> m_vxd_time_window{this, "VXDTimeWindow", 200.0, "The time window for VXD in ns"};
-    Gaudi::Property<double> m_itk_time_window{this, "ITKTimeWindow", 200.0, "The time window for ITK in ns"};
+    Gaudi::Property<double> m_itk_time_window{this, "ITKTimeWindow", 30.0, "The time window for ITK in ns"};
     Gaudi::Property<double> m_tpc_time_window{this, "TPCTimeWindow", 34000.0, "The time window for TPC in ns"};
-    Gaudi::Property<double> m_otk_time_window{this, "OTKTimeWindow", 1000.0, "The time window for OTK in ns"};
+    Gaudi::Property<double> m_otk_time_window{this, "OTKTimeWindow", 30.0, "The time window for OTK in ns"};
     Gaudi::Property<double> m_ecal_time_window{this, "EcalTimeWindow", 150.0, "The time window for ECAL in ns"};
     Gaudi::Property<double> m_hcal_time_window{this, "HcalTimeWindow", 1000.0, "The time window for HCAL in ns"};
     Gaudi::Property<double> m_muon_time_window{this, "MuonTimeWindow", 100.0, "The time window for MUON in ns"};