diff --git a/NPSimulation/Core/DetectorConstruction.cc b/NPSimulation/Core/DetectorConstruction.cc
index 123fafb73ecb51c5c70b60a132c18405c64f14c4..a8f4c0ce0cb1137df08da7448b1f99082fc0731b 100644
--- a/NPSimulation/Core/DetectorConstruction.cc
+++ b/NPSimulation/Core/DetectorConstruction.cc
@@ -208,7 +208,7 @@ G4VPhysicalVolume* DetectorConstruction::ReadConfigurationFile(){
     }
 
     else{
-      istd::stringstream oss(LineBuffer);
+      std::stringstream oss(LineBuffer);
       std::string token;
       oss >> token ;
       NPS::VDetector* detector = theFactory->Construct(token);