diff --git a/SimG4CMS/Muon/interface/MuonSensitiveDetector.h b/SimG4CMS/Muon/interface/MuonSensitiveDetector.h
index 48e721ba32923..746f2fdd65f08 100644
--- a/SimG4CMS/Muon/interface/MuonSensitiveDetector.h
+++ b/SimG4CMS/Muon/interface/MuonSensitiveDetector.h
@@ -20,6 +20,7 @@
 #include "SimG4Core/SensitiveDetector/interface/SensitiveTkDetector.h"
 #include "DataFormats/GeometryVector/interface/LocalPoint.h"
 #include "CondFormats/GeometryObjects/interface/MuonOffsetMap.h"
+#include "FWCore/ParameterSet/interface/ParameterSet.h"
 #include "Geometry/MuonNumbering/interface/MuonGeometryConstants.h"
 
 #include <string>
@@ -41,10 +42,7 @@ class MuonSensitiveDetector : public SensitiveTkDetector, public Observer<const
                                  const MuonOffsetMap*,
                                  const MuonGeometryConstants&,
                                  const SensitiveDetectorCatalog&,
-                                 double ePersistentCutGeV,
-                                 bool allMuonsPersistent,
-                                 bool aPrintHits,
-                                 bool dd4hep,
+                                 edm::ParameterSet const& p,
                                  const SimTrackManager*);
   ~MuonSensitiveDetector() override;
   G4bool ProcessHits(G4Step*, G4TouchableHistory*) override;
@@ -61,6 +59,7 @@ class MuonSensitiveDetector : public SensitiveTkDetector, public Observer<const
 
 private:
   inline Local3DPoint cmsUnits(const Local3DPoint& v) { return Local3DPoint(v.x() * 0.1, v.y() * 0.1, v.z() * 0.1); }
+  bool acceptHit(uint32_t id);
 
   MuonSlaveSD* slaveMuon;
   MuonSimHitNumberingScheme* numbering;
@@ -87,12 +86,17 @@ class MuonSensitiveDetector : public SensitiveTkDetector, public Observer<const
   uint32_t newDetUnitId;
   int theTrackID;
 
-  bool printHits;
+  bool printHits_;
   SimHitPrinter* thePrinter;
 
   //--- SimTracks cuts
-  float ePersistentCutGeV;
-  bool allMuonsPersistent;
+  float ePersistentCutGeV_;
+  bool allMuonsPersistent_;
+
+  // For choice of demo chambers
+  bool haveDemo_;
+  bool demoGEM_;
+  bool demoRPC_;
 
   G4ProcessTypeEnumerator* theG4ProcessTypeEnumerator;
 
diff --git a/SimG4CMS/Muon/plugins/MuonSensitiveDetectorBuilder.cc b/SimG4CMS/Muon/plugins/MuonSensitiveDetectorBuilder.cc
index 6a333a572a10f..182e93fdad271 100644
--- a/SimG4CMS/Muon/plugins/MuonSensitiveDetectorBuilder.cc
+++ b/SimG4CMS/Muon/plugins/MuonSensitiveDetectorBuilder.cc
@@ -35,13 +35,7 @@ class MuonSensitiveDetectorBuilder : public SensitiveDetectorMakerBase {
       : offmap_{nullptr},
         mdc_{nullptr},
         offsetToken_{cc.esConsumes<edm::Transition::BeginRun>()},
-        geomConstantsToken_{cc.esConsumes<edm::Transition::BeginRun>()} {
-    edm::ParameterSet muonSD = p.getParameter<edm::ParameterSet>("MuonSD");
-    ePersistentCutGeV_ = muonSD.getParameter<double>("EnergyThresholdForPersistency") / CLHEP::GeV;  //Default 1. GeV
-    allMuonsPersistent_ = muonSD.getParameter<bool>("AllMuonsPersistent");
-    printHits_ = muonSD.getParameter<bool>("PrintHits");
-    dd4hep_ = p.getParameter<bool>("g4GeometryDD4hepSource");
-  }
+        geomConstantsToken_{cc.esConsumes<edm::Transition::BeginRun>()} {}
 
   void beginRun(const edm::EventSetup& es) final {
     edm::ESHandle<MuonOffsetMap> mom = es.getHandle(offsetToken_);
@@ -55,8 +49,7 @@ class MuonSensitiveDetectorBuilder : public SensitiveDetectorMakerBase {
                                           const edm::ParameterSet& p,
                                           const SimTrackManager* man,
                                           SimActivityRegistry& reg) const final {
-    auto sd = std::make_unique<MuonSensitiveDetector>(
-        iname, offmap_, *mdc_, clg, ePersistentCutGeV_, allMuonsPersistent_, printHits_, dd4hep_, man);
+    auto sd = std::make_unique<MuonSensitiveDetector>(iname, offmap_, *mdc_, clg, p, man);
     SimActivityRegistryEnroller::enroll(reg, sd.get());
     return sd;
   }
diff --git a/SimG4CMS/Muon/src/MuonSensitiveDetector.cc b/SimG4CMS/Muon/src/MuonSensitiveDetector.cc
index cf22fe9e8436e..b00b0aca9e327 100644
--- a/SimG4CMS/Muon/src/MuonSensitiveDetector.cc
+++ b/SimG4CMS/Muon/src/MuonSensitiveDetector.cc
@@ -9,6 +9,10 @@
 #include "SimG4CMS/Muon/interface/SimHitPrinter.h"
 #include "SimDataFormats/TrackingHit/interface/UpdatablePSimHit.h"
 #include "DataFormats/GeometryVector/interface/GlobalPoint.h"
+#include "DataFormats/MuonDetId/interface/MuonSubdetId.h"
+#include "DataFormats/MuonDetId/interface/GEMDetId.h"
+#include "DataFormats/MuonDetId/interface/ME0DetId.h"
+#include "DataFormats/MuonDetId/interface/RPCDetId.h"
 
 #include "SimG4CMS/Muon/interface/MuonG4Numbering.h"
 #include "Geometry/MuonNumbering/interface/MuonGeometryConstants.h"
@@ -36,10 +40,7 @@ MuonSensitiveDetector::MuonSensitiveDetector(const std::string& name,
                                              const MuonOffsetMap* offmap,
                                              const MuonGeometryConstants& constants,
                                              const SensitiveDetectorCatalog& clg,
-                                             double aEPersistentCutGeV,
-                                             bool aAllMuonsPersistent,
-                                             bool aPrintHits,
-                                             bool dd4hep,
+                                             edm::ParameterSet const& p,
                                              const SimTrackManager* manager)
     : SensitiveTkDetector(name, clg),
       thePV(nullptr),
@@ -47,15 +48,23 @@ MuonSensitiveDetector::MuonSensitiveDetector(const std::string& name,
       theDetUnitId(0),
       newDetUnitId(0),
       theTrackID(0),
-      printHits(aPrintHits),
       thePrinter(nullptr),
-      ePersistentCutGeV(aEPersistentCutGeV),
-      allMuonsPersistent(aAllMuonsPersistent),
       theManager(manager) {
   // Here simply create 1 MuonSlaveSD for the moment
   //
+  bool dd4hep = p.getParameter<bool>("g4GeometryDD4hepSource");
+  edm::ParameterSet muonSD = p.getParameter<edm::ParameterSet>("MuonSD");
+  printHits_ = muonSD.getParameter<bool>("PrintHits");
+  ePersistentCutGeV_ = muonSD.getParameter<double>("EnergyThresholdForPersistency") / CLHEP::GeV;  //Default 1. GeV
+  allMuonsPersistent_ = muonSD.getParameter<bool>("AllMuonsPersistent");
+  haveDemo_ = muonSD.getParameter<bool>("HaveDemoChambers");
+  demoGEM_ = muonSD.getParameter<bool>("UseDemoHitGEM");
+  demoRPC_ = muonSD.getParameter<bool>("UseDemoHitRPC");
+
 #ifdef EDM_ML_DEBUG
-  edm::LogVerbatim("MuonSim") << "create MuonSubDetector " << name << " with dd4hep flag " << dd4hep;
+  edm::LogVerbatim("MuonSim") << "create MuonSubDetector " << name << " with dd4hep flag " << dd4hep
+                              << " Flags for Demonstration chambers " << haveDemo_ << " for GEM " << demoGEM_
+                              << " for RPC " << demoRPC_;
 #endif
   detector = new MuonSubDetector(name);
 
@@ -81,12 +90,12 @@ MuonSensitiveDetector::MuonSensitiveDetector(const std::string& name,
   numbering = new MuonSimHitNumberingScheme(detector, constants);
   g4numbering = new MuonG4Numbering(constants, offmap, dd4hep);
 
-  if (printHits) {
+  if (printHits_) {
     thePrinter = new SimHitPrinter("HitPositionOSCAR.dat");
   }
 
   edm::LogVerbatim("MuonSim") << " of type " << sdet << " <" << GetName() << "> EnergyThresholdForPersistency(GeV) "
-                              << ePersistentCutGeV / CLHEP::GeV << " allMuonsPersistent: " << allMuonsPersistent;
+                              << ePersistentCutGeV_ / CLHEP::GeV << " allMuonsPersistent: " << allMuonsPersistent_;
 
   theG4ProcessTypeEnumerator = new G4ProcessTypeEnumerator;
 }
@@ -122,7 +131,13 @@ bool MuonSensitiveDetector::ProcessHits(G4Step* aStep, G4TouchableHistory* ROhis
 
   if (aStep->GetTotalEnergyDeposit() > 0.) {
     newDetUnitId = setDetUnitId(aStep);
-
+#ifdef EDM_ML_DEBUG
+    G4VPhysicalVolume* vol = aStep->GetPreStepPoint()->GetTouchable()->GetVolume(0);
+    std::string namx = static_cast<std::string>(vol->GetName());
+    std::string name = namx.substr(0, 2);
+    if (name == "RE")
+      edm::LogVerbatim("MuonSim") << "DETID " << namx << " " << RPCDetId(newDetUnitId);
+#endif
     if (newHit(aStep)) {
       saveHit();
       createHit(aStep);
@@ -223,7 +238,7 @@ void MuonSensitiveDetector::createHit(const G4Step* aStep) {
   // Make track persistent
   int thePID = std::abs(theTrack->GetDefinition()->GetPDGEncoding());
   //---VI - in parameters cut in energy is declared but applied to momentum
-  if (thePabs > ePersistentCutGeV || (thePID == 13 && allMuonsPersistent)) {
+  if (thePabs > ePersistentCutGeV_ || (thePID == 13 && allMuonsPersistent_)) {
     TrackInformation* info = cmsTrackInformation(theTrack);
     info->storeTrack(true);
   }
@@ -290,13 +305,15 @@ void MuonSensitiveDetector::updateHit(const G4Step* aStep) {
 
 void MuonSensitiveDetector::saveHit() {
   if (theHit) {
-    if (printHits) {
-      thePrinter->startNewSimHit(detector->name());
-      thePrinter->printId(theHit->detUnitId());
-      thePrinter->printLocal(theHit->entryPoint(), theHit->exitPoint());
+    if (acceptHit(theHit->detUnitId())) {
+      if (printHits_) {
+        thePrinter->startNewSimHit(detector->name());
+        thePrinter->printId(theHit->detUnitId());
+        thePrinter->printLocal(theHit->entryPoint(), theHit->exitPoint());
+      }
+      // hit is included into hit collection
+      slaveMuon->processHits(*theHit);
     }
-    // hit is included into hit collection
-    slaveMuon->processHits(*theHit);
     delete theHit;
     theHit = nullptr;
   }
@@ -336,3 +353,41 @@ Local3DPoint MuonSensitiveDetector::FinalStepPositionVsParent(const G4Step* curr
 
   return ConvertToLocal3DPoint(localCoordinates);
 }
+
+bool MuonSensitiveDetector::acceptHit(uint32_t id) {
+  if (id == 0) {
+#ifdef EDM_ML_DEBUG
+    edm::LogVerbatim("MuonSim") << "DetId " << id << " Flag " << false;
+#endif
+    return false;
+  }
+  bool flag(true);
+  if (haveDemo_) {
+    int subdet = DetId(id).subdetId();
+    if (subdet == MuonSubdetId::GEM) {
+      if (GEMDetId(id).station() == 2)
+        flag = demoGEM_;
+    } else if (subdet == MuonSubdetId::RPC) {
+      if ((RPCDetId(id).region() != 0) && (RPCDetId(id).ring() == 1) && (RPCDetId(id).station() > 2))
+        flag = demoRPC_;
+    }
+  }
+#ifdef EDM_ML_DEBUG
+  int subdet = DetId(id).subdetId();
+  if (subdet == MuonSubdetId::RPC)
+    edm::LogVerbatim("MuonSim") << "DetId " << std::hex << id << std::dec << " RPC " << RPCDetId(id) << " Flag "
+                                << flag;
+  else if (subdet == MuonSubdetId::GEM)
+    edm::LogVerbatim("MuonSim") << "DetId " << std::hex << id << std::dec << " GEM " << GEMDetId(id) << " Flag "
+                                << flag;
+  else if (subdet == MuonSubdetId::ME0)
+    edm::LogVerbatim("MuonSim") << "DetId " << std::hex << id << std::dec << " " << ME0DetId(id) << " Flag " << flag;
+  else if (subdet == MuonSubdetId::CSC)
+    edm::LogVerbatim("MuonSim") << "DetId " << std::hex << id << std::dec << " CSC Flag " << flag;
+  else if (subdet == MuonSubdetId::DT)
+    edm::LogVerbatim("MuonSim") << "DetId " << std::hex << id << std::dec << " DT Flag " << flag;
+  else
+    edm::LogVerbatim("MuonSim") << "DetId " << std::hex << id << std::dec << " Unknown Flag " << flag;
+#endif
+  return flag;
+}
diff --git a/SimG4Core/Application/python/g4SimHits_cfi.py b/SimG4Core/Application/python/g4SimHits_cfi.py
index b5f6c6e3c51bd..127fa6f7c1a3e 100644
--- a/SimG4Core/Application/python/g4SimHits_cfi.py
+++ b/SimG4Core/Application/python/g4SimHits_cfi.py
@@ -327,7 +327,10 @@
     MuonSD = cms.PSet(
         EnergyThresholdForPersistency = cms.double(1.0),
         PrintHits = cms.bool(False),
-        AllMuonsPersistent = cms.bool(True)
+        AllMuonsPersistent = cms.bool(True),
+        UseDemoHitRPC = cms.bool(False),
+        UseDemoHitGEM = cms.bool(False),
+        HaveDemoChambers = cms.bool(True)
     ),
     CaloSD = cms.PSet(
         common_heavy_suppression,
@@ -668,4 +671,7 @@
 from Configuration.Eras.Modifier_phase2_common_cff import phase2_common
 phase2_common.toModify(g4SimHits,
                        OnlySDs = ['ZdcSensitiveDetector', 'TotemT2ScintSensitiveDetector', 'TotemSensitiveDetector', 'RomanPotSensitiveDetector', 'PLTSensitiveDetector', 'MuonSensitiveDetector', 'MtdSensitiveDetector', 'BCM1FSensitiveDetector', 'EcalSensitiveDetector', 'CTPPSSensitiveDetector', 'HGCalSensitiveDetector', 'BSCSensitiveDetector', 'CTPPSDiamondSensitiveDetector', 'FP420SensitiveDetector', 'BHMSensitiveDetector', 'HFNoseSensitiveDetector', 'HGCScintillatorSensitiveDetector', 'CastorSensitiveDetector', 'CaloTrkProcessing', 'HcalSensitiveDetector', 'TkAccumulatingSensitiveDetector'],
-                       LHCTransport = False ) 
+                       LHCTransport = False, 
+                       MuonSD = dict( 
+                       HaveDemoChambers = False ) 
+)