diff --git a/src/programs/Simulation/HDGeant/hdgeant_f.F b/src/programs/Simulation/HDGeant/hdgeant_f.F
index 7357a770b..99abcec4f 100644
--- a/src/programs/Simulation/HDGeant/hdgeant_f.F
+++ b/src/programs/Simulation/HDGeant/hdgeant_f.F
@@ -8,7 +8,7 @@ SUBROUTINE HDGEANT
       implicit none
       real q,hq
       integer ispace,hspace
-      parameter (ispace=5000000)
+      parameter (ispace=8000000)
       parameter (hspace=5000000)
       common /gcbank/ q(ispace)
       common /pawc/ hq(hspace)