diff --git a/src/Parameters.cc b/src/Parameters.cc
index e8f8123..5e5155a 100644
--- a/src/Parameters.cc
+++ b/src/Parameters.cc
@@ -1,56 +1,56 @@
 /**
  *  \authors   The HEJ collaboration (see AUTHORS for details)
  *  \date      2019
  *  \copyright GPLv2 or later
  */
 #include "HEJ/Parameters.hh"
 
 #include <sstream>
 #include <iostream>
 
 namespace HEJ {
 
   namespace {
     void replace(
         std::string & str,
         char to_replace, std::string const & replacement
     ) {
       for( auto pos = str.find(to_replace); pos != str.npos;
           pos = str.find(to_replace, pos)
       ){
         str.replace(pos, 1, replacement);
         pos += replacement.size();
       }
     }
 
     // remove "special" characters from scale name
     // so that we can more easily use it as part of a file name
     std::string sanitise_scalename(std::string scalename) {
-      replace(scalename, '/', "-over-");
-      replace(scalename, '*', "-times-");
-      replace(scalename, ' ', "-");
+      replace(scalename, '/', "_over_");
+      replace(scalename, '*', "_times_");
+      replace(scalename, ' ', "_");
       return scalename;
     }
   }
 
   std::string to_string(ParameterDescription const & p) {
     // use ostringstream over std::to_string to remove trailing 0s
     std::ostringstream stream;
     stream << "\\mu_r = ";
     if(p.mur_factor != 1.) stream << p.mur_factor << '*';
     stream << p.scale_name << ", "
       "\\mu_f = ";
     if(p.muf_factor != 1.) stream << p.muf_factor << '*';
     stream << p.scale_name;
     return stream.str();
   }
 
   std::string to_simple_string(ParameterDescription const & p) {
     // use ostringstream over std::to_string to remove trailing 0s
     std::ostringstream stream;
     stream << "Scale_" << sanitise_scalename(p.scale_name)
       << "_MuR" << p.mur_factor << "_MuF" << p.muf_factor;
     return stream.str();
   }
 
 }