diff --git a/CMakeLists.txt b/CMakeLists.txt
index cbfa09b..18149ac 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -24,11 +24,11 @@ if(NOT Geant4_shared_FOUND)
   message(FATAL_ERROR "CaTS must use shared libraries")
 endif()
 
-find_package(Boost REQUIRED COMPONENTS timer)
-if(NOT BOOST_FOUND)
-message(STATUS "${name} BOOST package not found. --> ${name} disabled")
-  return()
-endif()
+#find_package(Boost REQUIRED COMPONENTS timer)
+#if(NOT BOOST_FOUND)
+#message(STATUS "${name} BOOST package not found. --> ${name} disabled")
+#  return()
+#endif()
 
 
 option(WITH_ROOT "Build example with ROOT" ON)
@@ -95,8 +95,10 @@ file(GLOB evtdata ${PROJECT_SOURCE_DIR}/data/*)
 file(GLOB runscripts ${PROJECT_SOURCE_DIR}/scripts/run.sh  ${PROJECT_SOURCE_DIR}/scripts/check.sh)
 
 add_executable(${name} ${name}.cc ${sources} ${headers})
-target_compile_definitions( ${name} PRIVATE WITH_G4OPTICKS WITH_ROOT)
-target_link_libraries(${name}  CaTSClassesDict Opticks::G4OK ${Geant4_LIBRARIES} ${ROOT_LIBRARIES} Boost::timer )
+#target_compile_definitions( ${name} PRIVATE WITH_G4OPTICKS WITH_ROOT)
+#target_link_libraries(${name}  CaTSClassesDict Opticks::G4OK ${Geant4_LIBRARIES} ${ROOT_LIBRARIES} Boost::timer )
+#target_link_libraries(${name}  CaTSClassesDict ${Geant4_LIBRARIES} ${ROOT_LIBRARIES} )
+target_link_libraries(${name}  ${Geant4_LIBRARIES} )
 
 if(WITH_ROOT)
 add_executable(readPhotonHits readPhotonHits.cc  ${sources} ${headers})
diff --git a/CaTS.cc b/CaTS.cc
index 78469e4..6d31c53 100644
--- a/CaTS.cc
+++ b/CaTS.cc
@@ -50,7 +50,8 @@
 #include "CaTS_Version.hh"
 #include "ActionInitialization.hh"
 #include "DetectorConstruction.hh"
-#include "OpNoviceDetectorConstruction.hh"
+// Compilation error - file not found
+// #include "OpNoviceDetectorConstruction.hh" 
 #include "PhysicsConfigurator.hh"
 #include "ConfigurationManager.hh"
 // Geant4 headers:
@@ -126,7 +127,9 @@ int main(int argc, char** argv) {
 
 
 
+#ifdef WITH_G4OPTICKS
     OPTICKS_LOG(argc, argv);
+#endif
     G4VModularPhysicsList* phys = PhysicsConfigurator::getInstance()->Construct(physicsconf);
     G4String DumpFilename = gdmlfile + "_G4";
     G4cout << "**********************************************************" << G4endl;
diff --git a/include/ConfigurationManager.hh b/include/ConfigurationManager.hh
index f6bcb99..68666ac 100644
--- a/include/ConfigurationManager.hh
+++ b/include/ConfigurationManager.hh
@@ -127,9 +127,23 @@ public:
 #endif  
     void Print();
 
-    inline void setEnable_verbose(bool enable_verbose) {
-        this->enable_verbose = enable_verbose;
+// Clang Compilation warning
+// /Users/ivana/work/packages/geant4/geant4-dev/examples/extended/CaTS/include/ConfigurationManager.hh:130:40: warning: declaration shadows a field of 'ConfigurationManager' [-Wshadow]
+//     inline void setEnable_verbose(bool enable_verbose) {
+//                                        ^
+// /Users/ivana/work/packages/geant4/geant4-dev/examples/extended/CaTS/include/ConfigurationManager.hh:68:10: note: previous declaration is here
+//     bool enable_verbose; // switch on/off diagnostic printouts
+//          ^
+    // inline void setEnable_verbose(bool enable_verbose) {
+    //     this->enable_verbose = enable_verbose;
+    // };  
+    inline void setEnable_verbose(bool value) {
+        enable_verbose = value;
     };
+    // BETTER When using examples guideline, data membre starts with 'f':
+    // inline void setEnable_verbose(bool enable_verbose) {
+    //     fenable_verbose = enable_verbose;
+    // };
 
     inline bool isEnable_verbose() const {
         return enable_verbose;
diff --git a/include/DRCalorimeterHit.hh b/include/DRCalorimeterHit.hh
index 04dad75..2b34f81 100644
--- a/include/DRCalorimeterHit.hh
+++ b/include/DRCalorimeterHit.hh
@@ -115,6 +115,10 @@ public:
     unsigned int GetNceren() const;
     void SetEm_Edep(double em_Edep);
     double GetEm_Edep() const;
+// Clang warning
+// /Users/ivana/work/packages/geant4/geant4-dev/examples/extended/CaTS/include/DRCalorimeterHit.hh:118:5: warning: extra ';' inside a class [-Wextra-semi]
+//     ;
+//     ^
     ;
 
 private:
diff --git a/include/DetectorConstruction.hh b/include/DetectorConstruction.hh
index 42112ec..ba71b27 100644
--- a/include/DetectorConstruction.hh
+++ b/include/DetectorConstruction.hh
@@ -56,20 +56,24 @@ class DetectorConstruction : public G4VUserDetectorConstruction {
 public:
 
     DetectorConstruction(G4String fname);
-    virtual ~DetectorConstruction();
+    ~DetectorConstruction() override;
+    // Prefer deleted functions to private undefined ones.
+    DetectorConstruction & operator=(const DetectorConstruction &right) = delete;
+    DetectorConstruction(const DetectorConstruction&) = delete;
+
     void ReadGDML();
-    G4VPhysicalVolume* Construct();
-    virtual void ConstructSDandField();
+    // Prefer to declare virtual functions with override,
+    // virtual keyword can be then ommitted
+    G4VPhysicalVolume* Construct() override;
+    void ConstructSDandField() override;
     void UpdateGeometry();
 
 private:
-    DetectorConstruction & operator=(const DetectorConstruction &right);
-    DetectorConstruction(const DetectorConstruction&);
-
     G4String gdmlFile;
-    G4GDMLParser *parser;
-    ColorReader* fReader;
-    bool verbose;
+    // Data members were not initialized
+    G4GDMLParser* parser{nullptr};
+    ColorReader* fReader{nullptr};
+    bool verbose{false};
 };
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.....
 #endif
diff --git a/include/PrimaryGeneratorAction.hh b/include/PrimaryGeneratorAction.hh
index 30d8bcb..8abfdf1 100644
--- a/include/PrimaryGeneratorAction.hh
+++ b/include/PrimaryGeneratorAction.hh
@@ -61,7 +61,7 @@ private:
     G4String currentGeneratorName;
     std::map<G4String, G4VPrimaryGenerator*> gentypeMap;
     PrimaryGeneratorActionMessenger* gunMessenger;
-    static PrimaryGeneratorAction* instance;
+    // static PrimaryGeneratorAction* instance;
 
 public:
     PrimaryGeneratorAction();
@@ -71,7 +71,8 @@ public:
     void SetGenerator(G4String genname);
     G4VPrimaryGenerator* GetGenerator() const;
     G4String GetGeneratorName() const;
-    static PrimaryGeneratorAction* getInstance();
+    // Not needed; if used, should be thread local
+    // static PrimaryGeneratorAction* getInstance();
 };
 // ====================================================================
 // inline functions
diff --git a/include/RadiatorSD.hh b/include/RadiatorSD.hh
index 2af82d0..e6faf58 100644
--- a/include/RadiatorSD.hh
+++ b/include/RadiatorSD.hh
@@ -53,6 +53,7 @@
 class G4Step;
 class G4HCofThisEvent;
 class G4MaterialPropertiesTable;
+class G4PhysicsOrderedFreeVector;
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
 class RadiatorSD : public G4VSensitiveDetector {
@@ -66,29 +67,33 @@ public:
     virtual void EndOfEvent(G4HCofThisEvent* hitCollection);
 
 private:
-    G4int materialIndex;
-    const G4Material* aMaterial;
-    G4MaterialPropertiesTable* aMaterialPropertiesTable;
-    //
-    // properties related to Scintillation
-    //
-    G4MaterialPropertyVector* Fast_Intensity;
-    G4MaterialPropertyVector* Slow_Intensity;
-    G4double YieldRatio; // slowerRatio,
-    G4double FastTimeConstant; // TimeConstant,
-    G4double SlowTimeConstant; //slowerTimeConstant,
-    G4ScintillationType ScintillationType;
-    //
-    // properties related to Cerenkov
-    //
-    G4MaterialPropertyVector* Rindex;
-    G4PhysicsOrderedFreeVector* CerenkovAngleIntegrals;
-    const G4PhysicsTable* thePhysicsTable;
-    G4double Pmin{0};
-    G4double Pmax{0};
-    G4double dp{0};
-    G4double nMax{0};
-    bool first{true};
+// Clang warning
+// /Users/ivana/work/packages/geant4/geant4-dev/examples/extended/CaTS/include/RadiatorSD.hh:70:11: warning: private field 'materialIndex' is not used [-Wunused-private-field]
+//     G4int materialIndex;
+//           ^
+    // G4int materialIndex;
+    // const G4Material* aMaterial;
+    // G4MaterialPropertiesTable* aMaterialPropertiesTable;
+    // //
+    // // properties related to Scintillation
+    // //
+    // G4MaterialPropertyVector* Fast_Intensity;
+    // G4MaterialPropertyVector* Slow_Intensity;
+    // G4double YieldRatio; // slowerRatio,
+    // G4double FastTimeConstant; // TimeConstant,
+    // G4double SlowTimeConstant; //slowerTimeConstant,
+    // G4ScintillationType ScintillationType;
+    // //
+    // // properties related to Cerenkov
+    // //
+    // G4MaterialPropertyVector* Rindex;
+    // G4PhysicsOrderedFreeVector* CerenkovAngleIntegrals;
+    // const G4PhysicsTable* thePhysicsTable;
+    // G4double Pmin{0};
+    // G4double Pmax{0};
+    // G4double dp{0};
+    // G4double nMax{0};
+    // bool first{true};
     bool verbose{false};
     int tCphotons{0};
     int tSphotons{0};
diff --git a/include/lArTPCSD.hh b/include/lArTPCSD.hh
index fbce707..33d131b 100644
--- a/include/lArTPCSD.hh
+++ b/include/lArTPCSD.hh
@@ -53,6 +53,8 @@
 class G4Step;
 class G4HCofThisEvent;
 class G4MaterialPropertiesTable;
+// Missinf - compilation error
+class G4PhysicsOrderedFreeVector;
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
 class lArTPCSD : public G4VSensitiveDetector {
diff --git a/src/CalorimeterHit.cc b/src/CalorimeterHit.cc
index 709249a..fed9b02 100644
--- a/src/CalorimeterHit.cc
+++ b/src/CalorimeterHit.cc
@@ -71,19 +71,21 @@ CalorimeterHit::~CalorimeterHit() = default;
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 CalorimeterHit::CalorimeterHit(const CalorimeterHit& right)
 : G4VHit() {
-    this->id = right.id;
-    this->Edep = right.Edep;
-    this->em_Edep = right.em_Edep;
-    this->time = right.time;
-    this->position = right.position;
+    // No need to call class member functions via this->
+    id = right.id;
+    Edep = right.Edep;
+    em_Edep = right.em_Edep;
+    time = right.time;
+    position = right.position;
 }
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 const CalorimeterHit& CalorimeterHit::operator=(const CalorimeterHit& right) {
-    this->id = right.id;
-    this->Edep = right.Edep;
-    this->em_Edep = right.em_Edep;
-    this->time = right.time;
-    this->position = right.position;
+    // No need to call class member functions via this->
+    id = right.id;
+    Edep = right.Edep;
+    em_Edep = right.em_Edep;
+    time = right.time;
+    position = right.position;
     return *this;
 }
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
diff --git a/src/CalorimeterSD.cc b/src/CalorimeterSD.cc
index 8b44dae..370953f 100644
--- a/src/CalorimeterSD.cc
+++ b/src/CalorimeterSD.cc
@@ -74,15 +74,16 @@ void CalorimeterSD::Initialize(G4HCofThisEvent* hce) {
 }
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 G4bool CalorimeterSD::ProcessHits(G4Step* aStep, G4TouchableHistory*) {
-    double edep = aStep->GetTotalEnergyDeposit() / CLHEP::MeV;
+    // auto can be used for all results from retrieving functions
+    auto edep = aStep->GetTotalEnergyDeposit() / CLHEP::MeV;
     if (edep == 0.) return false;
-    double time = aStep->GetPreStepPoint()->GetGlobalTime() / CLHEP::ns;
-    const G4VTouchable* touch = aStep->GetPreStepPoint()->GetTouchable();
-    G4ThreeVector cellpos = touch->GetTranslation();
-    unsigned int ID = aStep->GetPreStepPoint()->GetPhysicalVolume()->GetCopyNo();
+    auto time = aStep->GetPreStepPoint()->GetGlobalTime() / CLHEP::ns;
+    auto touch = aStep->GetPreStepPoint()->GetTouchable();
+    auto cellpos = touch->GetTranslation();
+    auto ID = aStep->GetPreStepPoint()->GetPhysicalVolume()->GetCopyNo();
     //std::cout<<"ID:  "<<ID<<"  Edep:  "<< edep<<std::endl;
-    G4Track* theTrack = aStep->GetTrack();
-    G4String particleType = theTrack->GetDefinition()->GetParticleName();
+    auto theTrack = aStep->GetTrack();
+    auto particleType = theTrack->GetDefinition()->GetParticleName();
     //
     //  check if this cell has been hit before
     //fCalorimeterHitsCollection
diff --git a/src/ColorReader.cc b/src/ColorReader.cc
index 0410a6d..6e53dee 100644
--- a/src/ColorReader.cc
+++ b/src/ColorReader.cc
@@ -57,9 +57,9 @@ ColorReader::ColorReader()
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
 ColorReader::~ColorReader() {
-    std::map<G4String, G4VisAttributes*>::iterator pos;
-    for (pos = fAttribs.begin(); pos != fAttribs.end(); pos++) {
-        delete pos->second;
+    // Range based for loop (C++11) + structured bindings (C++17)
+    for ( auto [name, attribute] : fAttribs ) {
+       delete attribute;    
     }
 }
 
diff --git a/src/InteractionSD.cc b/src/InteractionSD.cc
index 0562527..66c4809 100644
--- a/src/InteractionSD.cc
+++ b/src/InteractionSD.cc
@@ -66,8 +66,10 @@ InteractionSD::InteractionSD(G4String name)
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
 InteractionSD::~InteractionSD() {
-    if (fFirstInter) delete fFirstInter;
-    if (fOtherInter) delete fOtherInter;
+// - No need to test pointer before calling delete:
+//   if pointer is 0, delete call has no effect
+    delete fFirstInter;
+    delete fOtherInter;
 }
 
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
diff --git a/src/PrimaryGeneratorAction.cc b/src/PrimaryGeneratorAction.cc
index bbae160..1396b9a 100644
--- a/src/PrimaryGeneratorAction.cc
+++ b/src/PrimaryGeneratorAction.cc
@@ -53,12 +53,12 @@
 // Project headers:
 #include "PrimaryGeneratorAction.hh"
 #include "PrimaryGeneratorActionMessenger.hh"
-PrimaryGeneratorAction* PrimaryGeneratorAction::instance = 0;
-//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
-PrimaryGeneratorAction* PrimaryGeneratorAction::getInstance() {
-    if (instance == 0) instance = new PrimaryGeneratorAction();
-    return instance;
-}
+// PrimaryGeneratorAction* PrimaryGeneratorAction::instance = 0;
+// //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
+// PrimaryGeneratorAction* PrimaryGeneratorAction::getInstance() {
+//     if (instance == 0) instance = new PrimaryGeneratorAction();
+//     return instance;
+// }
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 PrimaryGeneratorAction::PrimaryGeneratorAction() {
     const char* filename = "pythia_event.data";
@@ -78,14 +78,15 @@ PrimaryGeneratorAction::PrimaryGeneratorAction() {
     gunMessenger = new PrimaryGeneratorActionMessenger(this);
     currentGenerator = gentypeMap["particleGun"];
     currentGeneratorName = "particleGun";
-    instance = this;
+    // instance = this;
 }
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 PrimaryGeneratorAction::~PrimaryGeneratorAction() {
     delete gunMessenger;
-    for (std::map<G4String, G4VPrimaryGenerator*>::iterator ii = gentypeMap.begin(); ii != gentypeMap.end(); ++ii) {
-        delete (*ii).second;
-        gentypeMap.erase((*ii).first);
+    // Range based for loop (C++11) + structured bindings (C++17)
+    for (auto [genType, generator] : gentypeMap ) {
+        delete generator;
+        gentypeMap.erase(genType);
     }
 }
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
diff --git a/src/StackingAction.cc b/src/StackingAction.cc
index b5edea5..517d996 100644
--- a/src/StackingAction.cc
+++ b/src/StackingAction.cc
@@ -55,7 +55,8 @@
 #include "G4VProcess.hh"
 #include "G4ClassificationOfNewTrack.hh"
 #include "G4PhysicalConstants.hh"
-#include "G4PhysicsOrderedFreeVector.hh"
+// Compilation error: 'G4PhysicsOrderedFreeVector.hh' file not found
+// #include "G4PhysicsOrderedFreeVector.hh"
 #include "G4Material.hh" 
 #include "G4MaterialPropertyVector.hh"
 #include "g4analysis.hh"