diff --git a/Processes/CONEXSourceCut/CONEXSourceCut.cc b/Processes/CONEXSourceCut/CONEXSourceCut.cc
index 078d6d014f20043007770109adbb33bd717a5c30..dcedc52598df9015d9398c9c8341b411114f30bb 100644
--- a/Processes/CONEXSourceCut/CONEXSourceCut.cc
+++ b/Processes/CONEXSourceCut/CONEXSourceCut.cc
@@ -122,7 +122,7 @@ void CONEXSourceCut::addParticle(int egs_pid, HEPEnergyType energy,
   conex::cxoptl_.dptl[1 - 1] = v;
   conex::cxoptl_.dptl[3 - 1] = w;
 
-  int n = 0, i = 0;
+  int n = 1, i = 1;
   conex::cegs4_(n, i);
 }