diff --git a/sim/detectors/sts/CbmStsDigitize.cxx b/sim/detectors/sts/CbmStsDigitize.cxx
index f918b05609478c546f5fc84c6f79447d1e372577..c9619a01ff233704b21219b78dea2b4e19a12fdf 100644
--- a/sim/detectors/sts/CbmStsDigitize.cxx
+++ b/sim/detectors/sts/CbmStsDigitize.cxx
@@ -820,7 +820,7 @@ void CbmStsDigitize::SetProcesses(CbmStsELoss eLossModel, Bool_t useLorentzShift
     return;
   }
 
-  fParSim->SetProcesses(eLossModel, useLorentzShift, useDiffusion, useCrossTalk);
+  fUserParSim->SetProcesses(eLossModel, useLorentzShift, useDiffusion, useCrossTalk);
 }
 // -------------------------------------------------------------------------