diff --git a/analysis/common/analysis_tree_converter/CbmRecEventHeaderConverter.cxx b/analysis/common/analysis_tree_converter/CbmRecEventHeaderConverter.cxx
index f7c9a2efd4df951c98925ca1b73277c4954474f0..e692aa893483026b5c18ea8db718af9780edc219 100644
--- a/analysis/common/analysis_tree_converter/CbmRecEventHeaderConverter.cxx
+++ b/analysis/common/analysis_tree_converter/CbmRecEventHeaderConverter.cxx
@@ -25,7 +25,6 @@ void CbmRecEventHeaderConverter::Init()
   auto* ioman = FairRootManager::Instance();
   assert(ioman != nullptr);
   cbm_header_      = (FairMCEventHeader*) ioman->GetObject("MCEventHeader.");
-  cbm_prim_vertex_ = (CbmVertex*) ioman->GetObject("PrimaryVertex.");
   cbm_sts_tracks_  = (TClonesArray*) ioman->GetObject("StsTrack");
   cbm_psd_hits_    = (TClonesArray*) ioman->GetObject("PsdHit");
   fTimeSlice       = static_cast<CbmTimeSlice*>(ioman->GetObject("TimeSlice."));
@@ -62,8 +61,9 @@ void CbmRecEventHeaderConverter::Init()
 void CbmRecEventHeaderConverter::ProcessData(CbmEvent* event)
 {
   if (event) { cbm_prim_vertex_ = event->GetVertex(); }
-
-  if (!cbm_prim_vertex_) { throw std::runtime_error("No fPrimVtx"); }
+  if (!cbm_prim_vertex_) {
+    throw std::runtime_error("No event vertex in CbmEvent");
+  }
 
   rec_event_header_->SetVertexPosition3({cbm_prim_vertex_->GetX(), cbm_prim_vertex_->GetY(), cbm_prim_vertex_->GetZ()});
   rec_event_header_->SetField(float(cbm_prim_vertex_->GetChi2() / cbm_prim_vertex_->GetNDF()), ivtx_chi2_);
diff --git a/analysis/common/analysis_tree_converter/CbmRecEventHeaderConverter.h b/analysis/common/analysis_tree_converter/CbmRecEventHeaderConverter.h
index cc4d053ca7d158f36d5f3975ce09ed0ef25efe1f..660023b21703473667b7b83f9260b10fda86a39f 100644
--- a/analysis/common/analysis_tree_converter/CbmRecEventHeaderConverter.h
+++ b/analysis/common/analysis_tree_converter/CbmRecEventHeaderConverter.h
@@ -30,11 +30,11 @@ private:
 
   AnalysisTree::EventHeader* rec_event_header_ {nullptr};
 
-  TClonesArray* cbm_psd_hits_ {nullptr};
+  TClonesArray* cbm_psd_hits_{nullptr};      ///< non-owning pointer
   TClonesArray* cbm_sts_tracks_ {nullptr};   ///< non-owning pointer
   FairMCEventHeader* cbm_header_ {nullptr};  ///< non-owning pointer
   CbmVertex* cbm_prim_vertex_ {nullptr};     ///< non-owning pointer
-  CbmTimeSlice* fTimeSlice {nullptr};
+  CbmTimeSlice* fTimeSlice{nullptr};         ///< non-owning pointer
 
   int ivtx_chi2_ {AnalysisTree::UndefValueInt};
   int iEpsd_ {AnalysisTree::UndefValueInt};
diff --git a/analysis/common/analysis_tree_converter/CbmStsTracksConverter.cxx b/analysis/common/analysis_tree_converter/CbmStsTracksConverter.cxx
index 6a3e4371b2ea9c6de0e20129ec10a453e1cb688e..1c54eaf2996f201c8d0079b1f5baa4fe4e74b9ed 100644
--- a/analysis/common/analysis_tree_converter/CbmStsTracksConverter.cxx
+++ b/analysis/common/analysis_tree_converter/CbmStsTracksConverter.cxx
@@ -49,7 +49,6 @@ void CbmStsTracksConverter::InitInput()
 {
   auto* ioman = FairRootManager::Instance();
 
-  cbm_prim_vertex_ = (CbmVertex*) ioman->GetObject("PrimaryVertex.");
   cbm_sts_tracks_  = (TClonesArray*) ioman->GetObject("StsTrack");
   cbm_sts_match_   = (TClonesArray*) ioman->GetObject("StsTrackMatch");
 
@@ -134,6 +133,9 @@ float CbmStsTracksConverter::ExtrapolateToVertex(CbmStsTrack* sts_track, Analysi
 
 void CbmStsTracksConverter::ReadVertexTracks(CbmEvent* event)
 {
+  if (event) {
+    cbm_prim_vertex_ = event->GetVertex();
+  }
   assert(cbm_prim_vertex_ && cbm_sts_tracks_);
 
   vtx_tracks_->ClearChannels();
diff --git a/analysis/common/analysis_tree_converter/CbmStsTracksConverter.h b/analysis/common/analysis_tree_converter/CbmStsTracksConverter.h
index b28dbe74763215c27cceeac6ec2a456ef8a4262b..3726ab95dde28dafad1c0b1902585b799119abc5 100644
--- a/analysis/common/analysis_tree_converter/CbmStsTracksConverter.h
+++ b/analysis/common/analysis_tree_converter/CbmStsTracksConverter.h
@@ -56,7 +56,7 @@ private:
   TClonesArray* cbm_sts_tracks_ {nullptr};  ///< non-owning pointer
   TClonesArray* cbm_sts_match_ {nullptr};   ///< non-owning pointer
 
-  CbmMCDataManager* cbm_mc_manager_ {nullptr};
+  CbmMCDataManager* cbm_mc_manager_{nullptr};  ///< non-owning pointer
 
   bool is_write_kfinfo_ {true};
   bool is_reproduce_cbmkfpf_ {true};