diff --git a/source/digits_hits/include/GateToRoot.hh b/source/digits_hits/include/GateToRoot.hh
index cac860dfe..ff4a3562f 100644
--- a/source/digits_hits/include/GateToRoot.hh
+++ b/source/digits_hits/include/GateToRoot.hh
@@ -50,7 +50,7 @@ See LICENSE.md for further details
 
 //OK GND 2022
 #include "GateDigitizerMgr.hh"
-
+#include "GateRunManager.hh"
 /* PY Descourt 08/09/2009 */
 #include "GateActions.hh"
 #include "GateTrack.hh"
@@ -213,18 +213,29 @@ public:
             GateDigitizerMgr* digitizerMgr = GateDigitizerMgr::GetInstance();
 
             if (m_outputFlag) {
+                G4String treeName;
+
             	if( digitizerMgr->m_SDlist.size()==1 )
             	{
+
             		if(m_signlesCommands==0)
             		{
-            		std::string tmp_str = m_collectionName.substr(0, m_collectionName.find("_"));
-            		m_tree = new GateSingleTree(tmp_str);
+
+            			treeName = m_collectionName.substr(0, m_collectionName.find("_"));
+
             		}
             		else
-            			m_tree = new GateSingleTree(m_collectionName);
+            			treeName = m_collectionName;
             	}
             	else
-            		m_tree = new GateSingleTree(m_collectionName);
+            		treeName = m_collectionName;
+
+                G4int runID=GateRunManager::GetRunManager()->GetCurrentRun()->GetRunID();
+            	if(runID>0)
+            		treeName = treeName+"_run"+std::to_string(runID);
+
+
+            	m_tree = new GateSingleTree(treeName);
 
             	m_buffer.SetCCFlag(GetCCFlag());
             	m_tree->Init(m_buffer);
diff --git a/source/digits_hits/src/GateOutputMgr.cc b/source/digits_hits/src/GateOutputMgr.cc
index 174d7fc38..e587b3f32 100644
--- a/source/digits_hits/src/GateOutputMgr.cc
+++ b/source/digits_hits/src/GateOutputMgr.cc
@@ -247,6 +247,8 @@ void GateOutputMgr::RecordEndOfRun(const G4Run* run)
     if ( m_outputModules[iMod]->IsEnabled() )
       m_outputModules[iMod]->RecordEndOfRun(run);
   }
+  m_HCIDs.clear();
+
 }
 //----------------------------------------------------------------------------------
 
diff --git a/source/digits_hits/src/GateToRoot.cc b/source/digits_hits/src/GateToRoot.cc
index 9e975fa0f..44061a3d8 100644
--- a/source/digits_hits/src/GateToRoot.cc
+++ b/source/digits_hits/src/GateToRoot.cc
@@ -98,7 +98,7 @@ ComptonRayleighData &ComptonRayleighData::operator=(const ComptonRayleighData &a
 
 //--------------------------------------------------------------------------
 GateToRoot::GateToRoot(const G4String &name, GateOutputMgr *outputMgr, DigiMode digiMode)
-        : GateVOutputModule(name, outputMgr, digiMode), m_hitBuffers(0) , m_hfile(0), m_treesHit(0),
+        : GateVOutputModule(name, outputMgr, digiMode), m_hitBuffers(0), m_hfile(0), m_treesHit(0),
 		  m_rootHitFlag(digiMode == kruntimeMode), m_rootNtupleFlag(true), m_saveRndmFlag(true),
          m_fileName(" ") // All default output file from all output modules are set to " ".
         // They are then checked in GateApplicationMgr::StartDAQ, using
@@ -249,6 +249,7 @@ void GateToRoot::BookBeginOfRun() {
     GateDigitizerMgr* digitizerMgr = GateDigitizerMgr::GetInstance();
     SetSDlistSize(digitizerMgr->m_SDlist.size() );
 
+
 	   for (G4int i=0; i<GetSDlistSize();i++)
 		{
 			GateRootHitBuffer hitBuffer;
@@ -256,16 +257,32 @@ void GateToRoot::BookBeginOfRun() {
 			m_hitBuffers.push_back(hitBuffer);
 		}
 
+
+
 	  for (size_t i=0; i< GetSDlistSize();i++)
 	  {
    		GateHitTree *treeHit;
+
+   		G4String treeName ;
+
    		if (digitizerMgr->m_SDlist.size() ==1 ) // keep the old name "Hits" if there is only one collection
-   			treeHit = new GateHitTree("Hits");
+   		{
+   				treeName = "Hits";
+   		}
    		else
-   			treeHit = new GateHitTree("Hits_"+digitizerMgr->m_SDlist[i]->GetName());
+   				treeName = "Hits_"+digitizerMgr->m_SDlist[i]->GetName();
+
+   		G4int runID=GateRunManager::GetRunManager()->GetCurrentRun()->GetRunID();
+   		if(runID>0)
+   			treeName = treeName+"_run"+std::to_string(runID);
+
+   		treeHit = new GateHitTree(treeName);
+
    		treeHit->Init(m_hitBuffers[i]);
    		m_treesHit.push_back(treeHit);
-   	    }
+
+
+   	  }
 
     // v. cuplov - optical photons
 	for (size_t i=0; i< digitizerMgr->m_SDlist.size();i++)
@@ -335,6 +352,7 @@ void GateToRoot::RecordBeginOfAcquisition() {
     if (nVerboseLevel > 1)
         G4cout << " GateToRoot::RecordBeginOfAcquisition()  Tracking Mode " << int(theMode) << Gateendl;
 
+
     // PY. Descourt 11/12/2008
     // NORMAL OR DETECTOR MODE
     if ((theMode == TrackingMode::kBoth) || (theMode == TrackingMode::kDetector)) {
@@ -367,6 +385,7 @@ void GateToRoot::RecordBeginOfAcquisition() {
                 m_hfile = new TFile((m_fileName + ".root").c_str(), "RECREATE", "ROOT file with histograms");
                 // v. cuplov
 
+
                 break;
             case kofflineMode:
                 // In DigiGate mode, we first check that the file does not exist. If it does, we abort as we want to make sure the ROOT file is not overwritten by accident
@@ -411,6 +430,9 @@ void GateToRoot::RecordBeginOfAcquisition() {
         }
         //! We book histos and ntuples only once per acquisition
         BookBeginOfAquisition();
+        //BookBeginOfRun();
+
+
 
 
         return;
@@ -633,6 +655,7 @@ void GateToRoot::RecordBeginOfRun(const G4Run *) {
       }
       }*/
 
+
    if (nVerboseLevel > 2)
         G4cout << "GateToRoot::RecordBeginOfRun\n";
        BookBeginOfRun();
@@ -655,7 +678,8 @@ void GateToRoot::RecordEndOfRun(const G4Run *) {
 
     nbPrimaries -= 1.; // Number of primaries increase too much at each end of run !
 
-
+    m_hitBuffers.clear();
+    m_treesHit.clear();
 }
 //--------------------------------------------------------------------------
 
@@ -765,6 +789,9 @@ void GateToRoot::RecordEndOfEvent(const G4Event *event) {
     //OK GND 2022
     std::vector<GateHitsCollection*> CHC_vector = GetOutputMgr()->GetHitCollections();
 
+
+    G4int runID=GateRunManager::GetRunManager()->GetCurrentRun()->GetRunID();
+
     for (size_t i=0; i<CHC_vector.size();i++ )//HC_vector.size()
     {
     	GateHitsCollection* CHC = CHC_vector[i];
@@ -787,13 +814,14 @@ void GateToRoot::RecordEndOfEvent(const G4Event *event) {
 							<< ">    Particls PDG code : " << PDGEncoding << Gateendl;
 
 				if (aHit->GoodForAnalysis()) {
-					m_hitBuffers[i].Fill(aHit);
+						 m_hitBuffers[i].Fill(aHit);
+
 					if (nVerboseLevel > 1)
 						G4cout << "GateToRoot::RecordEndOfEvent : m_treeHit->Fill\n";
 
-
 					if (m_rootHitFlag) m_treesHit[i]->Fill();
 
+
 				}
 			}