Index: phys-services/private/phys-services/I3MediumService.cxx
===================================================================
--- phys-services/private/phys-services/I3MediumService.cxx (revision 80743)
+++ phys-services/private/phys-services/I3MediumService.cxx (working copy)
@@ -48,6 +48,8 @@
 const double I3MediumService::MIN_WAVELENGTH_PRICE = 300.;
 const double I3MediumService::RECO_WAVELENGTH = 380.;
 const double I3MediumService::FP_CMP_TOLERANCE = 1e-6;
+const TString I3MediumService::HISTOPREFIX = "I3Medium";
+unsigned int I3MediumService::instanceNumber_ = 0;


 I3MediumService::I3MediumService()
@@ -56,6 +58,13 @@
        hIntAbsLen_(0), hIntEffScattLen_(0),
        hIceLayerAbsorptivity_(0), hIceLayerInvEffScattLen_(0),
        isBulkice_(true), meanScatCosine_(MEAN_SCATT_COSINE){
+  TString suffix="";
+  suffix+=instanceNumber_;
+  nameAbsHisto_ = HISTOPREFIX+"_Absorptivity_"+suffix;
+  nameInvScatLenHisto_ = HISTOPREFIX+"_InvScatteringLength_"+suffix;
+  nameIntAbsHisto_ = HISTOPREFIX+"_IntAbsorptivity_"+suffix;
+  nameIntInvScatLenHisto_ = HISTOPREFIX+"_IntInvScatteringLength_"+suffix;
+  ++instanceNumber_;
 }


@@ -67,6 +76,13 @@
        hIntAbsLen_(0), hIntEffScattLen_(0),
        hIceLayerAbsorptivity_(0), hIceLayerInvEffScattLen_(0),
        isBulkice_(false), meanScatCosine_(MEAN_SCATT_COSINE){
+  TString suffix="";
+  suffix+=instanceNumber_;
+  nameAbsHisto_ = HISTOPREFIX+"_Absorptivity_"+suffix;
+  nameInvScatLenHisto_ = HISTOPREFIX+"_InvScatteringLength_"+suffix;
+  nameIntAbsHisto_ = HISTOPREFIX+"_IntAbsorptivity_"+suffix;
+  nameIntInvScatLenHisto_ = HISTOPREFIX+"_IntInvScatteringLength_"+suffix;
+  ++instanceNumber_;
    try{
        Configure(properties, histoOutFilename);
    }catch(...){
@@ -123,18 +139,17 @@
      || (RECO_WAVELENGTH > maxwl_)
      || (minwl_ == maxwl_))
        log_fatal("wavelength interval to small");
-
   hIceLayerAbsorptivity_ =
-     new TH2D("hIceLayerAbsorptivity_", "absorptivity",
+      new TH2D(nameAbsHisto_, "absorptivity",
              nlayer_, minz_, maxz_, nwl_, minwl_, maxwl_);
   hIceLayerInvEffScattLen_ =
-     new TH2D("hIceLayerInvEffScattLen_", "inverse eff. scatt. length",
+      new TH2D(nameInvScatLenHisto_, "inverse eff. scatt. length",
              nlayer_, minz_, maxz_, nwl_, minwl_, maxwl_);
   recobinwl_ = hIceLayerAbsorptivity_->GetYaxis()->FindBin(RECO_WAVELENGTH);
-
+
    //////////////////////////////////////////////////////////////
-
-  // fill the scatt. and abs. histo, including unfl/ovfl bins
+
+  // fill the scatt. and abs. histo, including unfl/ovfl bins
    for(unsigned int i = 1; i <= nlayer_; ++i){
     CheckProperties(properties.Layers()[i-1]);
        for(unsigned int j = 1; j <= nwl_; ++j){
@@ -143,7 +158,7 @@
            hIceLayerInvEffScattLen_->SetBinContent(i, j,
                properties.Layers()[i - 1].ScatteringCoefficents().Get()[j - 1]);
        }
-   }
+   }
   for(unsigned int i = 1; i <= nlayer_; ++i){
     hIceLayerInvEffScattLen_->SetBinContent(i, 0,
        hIceLayerInvEffScattLen_->GetBinContent(i, 1));
@@ -201,10 +216,10 @@
   // with fast computation.

   hIntAbsLen_ =
-   new TH2D("hintabslen","integrated abs. length",
+   new TH2D(nameIntAbsHisto_,"integrated abs. length",
        nlayer_, minz_, maxz_, nwl_, minwl_, maxwl_);
   hIntEffScattLen_ =
-   new TH2D("hIntEffScattLen_","integrated eff. scatt. length",
+   new TH2D(nameIntInvScatLenHisto_,"integrated eff. scatt. length",
        nlayer_, minz_, maxz_, nwl_, minwl_, maxwl_);

   for(unsigned int j = 1; j <= nwl_; ++j){ // set to 0 integration the depth unfl bin
Index: phys-services/public/phys-services/I3MediumService.h
===================================================================
--- phys-services/public/phys-services/I3MediumService.h    (revision 80743)
+++ phys-services/public/phys-services/I3MediumService.h    (working copy)
@@ -22,6 +22,7 @@
 #include <string>
 #include <TH1D.h>
 #include <TH2D.h>
+#include <TString.h>

 #include <icetray/I3Logging.h>
 #include <icetray/I3FrameObject.h>
@@ -281,6 +282,8 @@
   const static double MEAN_SCATT_COSINE;
   const static double MIN_WAVELENGTH_PRICE;
   const static double FP_CMP_TOLERANCE;
+  const static TString HISTOPREFIX;
+  static unsigned int instanceNumber_;


   // private copy constructors and assignment
@@ -317,6 +320,10 @@
   double minz_, maxz_, binw_;
   double minwl_, maxwl_, wlstep_;
   int recobinwl_;
+  TString nameAbsHisto_;
+  TString nameInvScatLenHisto_;
+  TString nameIntAbsHisto_;
+  TString nameIntInvScatLenHisto_;

   ////////////////////////////////////////////////////////////////
   // That's Amanda framework stuff