diff --git a/Interface/Parameter.cc b/Interface/Parameter.cc
--- a/Interface/Parameter.cc
+++ b/Interface/Parameter.cc
@@ -1,107 +1,159 @@
 // -*- C++ -*-
 //
 // Parameter.cc is a part of ThePEG - Toolkit for HEP Event Generation
 // Copyright (C) 1999-2011 Leif Lonnblad
 //
 // ThePEG is licenced under version 2 of the GPL, see COPYING for details.
 // Please respect the MCnet academic guidelines, see GUIDELINES for details.
 //
 //
 // This is the implementation of the non-inlined, non-templated member
 // functions of the ParameterBase class.
 //
 
 #include "InterfacedBase.h"
 #include "Parameter.h"
 #include "Parameter.xh"
 
 namespace ThePEG {
 
 ParameterBase::~ParameterBase() {}
 
 string ParameterBase::exec(InterfacedBase & i, string action,
 			   string arguments) const  {
   if ( action == "get" ) {
     return get(i);
   }
   else if ( action == "min" ) {
     return minimum(i);
   }
   else if ( action == "max" ) {
     return maximum(i);
   }
   else if ( action == "def" ) {
     return def(i);
   }
   else if ( action == "setdef" ) {
     if ( objectDefaults(i).find(name()) == objectDefaults(i).end() )
       setDef(i);
     else
       set(i, objectDefaults(i)[name()]);
   }
   else if ( action == "set" || action == "newdef" ) {
     set(i, arguments);
     if ( action == "newdef" ) objectDefaults(i)[name()] = get(i);
   } else if ( action == "notdef" ) {
     string deflt = def(i);
     if ( objectDefaults(i).find(name()) != objectDefaults(i).end() )
       deflt = objectDefaults(i)[name()];
     else if ( !hasDefault ) return "";
     if ( deflt != get(i) ) return get(i) + " (" + deflt + ")";
   }
   else
     throw InterExUnknown(*this, i);
   return "";
 }
 
 string ParameterBase::fullDescription(const InterfacedBase & ib) const {
   string min = minimum(ib);
   if ( min.empty() ) min = "-inf";
   string max = maximum(ib);
   if ( max.empty() ) max = "inf";
   
   return InterfaceBase::fullDescription(ib) + get(ib) + '\n' +
     min + '\n' + def(ib) + '\n' + max + '\n';
 }
 
 ParExGetUnknown::ParExGetUnknown(const InterfaceBase & i,
 				 const InterfacedBase & o, const char * s) {
   theMessage << "Could not get the " << s << " value of parameter \""
 	     << i.name() << "\" for the object \"" << o.name()
 	     << "\" because the get function threw an unknown exception.";
   severity(setuperror);
 }
 
 }
 
 namespace {
   const std::map<std::string, ThePEG::Energy> 
   energymapping = {
   	{"GeV",ThePEG::GeV},
   	{"MeV",ThePEG::MeV}
   };
+
+  const std::map<std::string, ThePEG::Energy2> 
+  energy2mapping = {
+  	{"GeV2",ThePEG::GeV2},
+  	{"MeV2",ThePEG::MeV2}
+  };
+
+  const std::map<std::string, ThePEG::Length> 
+  lengthmapping = {
+  	{"mm",ThePEG::mm},
+  	{"millimeter",ThePEG::mm}
+  };
 }
 
 template <>
 void ThePEG::ParameterTBase<ThePEG::Energy>::
 checkUnitConsistency(string suffix) const {
   // for now, we don't require units to be specified
   if ( suffix.empty() ) return;
 
 
   const auto requestedUnit = energymapping.find(suffix);
   if ( requestedUnit != energymapping.end()
        && requestedUnit->second == unit() ) 
     return; // all is fine
   else
     Throw<InterfaceException>()
       << name() 
       << ": the unit suffix " << suffix << " does not match the unit\n"
       << "specified in the parameter definition (" << unit()/GeV << " GeV).\n\n"
       << "To proceed, fix the unit suffix in the input file.\n\n"
       << Exception::setuperror;      
 }
 
+template <>
+void ThePEG::ParameterTBase<ThePEG::Energy2>::
+checkUnitConsistency(string suffix) const {
+  // for now, we don't require units to be specified
+  if ( suffix.empty() ) return;
+
+
+  const auto requestedUnit = energy2mapping.find(suffix);
+  if ( requestedUnit != energy2mapping.end()
+       && requestedUnit->second == unit() ) 
+    return; // all is fine
+  else
+    Throw<InterfaceException>()
+      << name() 
+      << ": the unit suffix " << suffix << " does not match the unit\n"
+      << "specified in the parameter definition (" << unit()/GeV2 << " GeV2).\n\n"
+      << "To proceed, fix the unit suffix in the input file.\n\n"
+      << Exception::setuperror;      
+}
+
+template <>
+void ThePEG::ParameterTBase<ThePEG::Length>::
+checkUnitConsistency(string suffix) const {
+  // for now, we don't require units to be specified
+  if ( suffix.empty() ) return;
+
+
+  const auto requestedUnit = lengthmapping.find(suffix);
+  if ( requestedUnit != lengthmapping.end()
+       && requestedUnit->second == unit() ) 
+    return; // all is fine
+  else
+    Throw<InterfaceException>()
+      << name() 
+      << ": the unit suffix " << suffix << " does not match the unit\n"
+      << "specified in the parameter definition (" << unit()/mm << " mm).\n\n"
+      << "To proceed, fix the unit suffix in the input file.\n\n"
+      << Exception::setuperror;      
+}
+
 #ifdef ThePEG_TEMPLATES_IN_CC_FILE
 #include "Parameter.tcc"
 #endif