Resolve "Bethe-Bloch threshold"

Closes #83 (closed)

src/Structure/ParticleMatterInteraction.cpp

@@ -154,7 +154,7 @@ void ParticleMatterInteraction::print(std::ostream& os) const {
  
     if ( Attributes::getString(itsAttr[TYPE]) != "BEAMSTRIPPING" ) {
         os << "* MATERIAL       " << Attributes::getString(itsAttr[MATERIAL]) << '\n';
-        os << "* LOWENERGYTHR   " << Attributes::getString(itsAttr[LOWENERGYTHR]) << " GeV" << '\n';
+        os << "* LOWENERGYTHR   " << Attributes::getReal(itsAttr[LOWENERGYTHR]) << " GeV" << '\n';
     }
 
     os << "* ********************************************************************************** " << std::endl;