{

  unsigned int medInd(0);
  Double_t mPar[10];
  //TAG sollte wieder 0 werden sens flag
  mPar[0]=0.;//sensitive volume flag
  mPar[1]=1.;//magnetic field flag
  mPar[2]=30.;//max fiel in kGauss
  mPar[3]=0.1;//maximal angular dev. due to field
  mPar[4]=0.01;//max step allowed (in cm)
  mPar[5]=1.e-5;//max fractional energy loss
  mPar[6]=1.e-3;//boundary crossing accuracy
  mPar[7]=1.e-5;//minimum step
  mPar[8]=0.;//not defined
  mPar[9]=0.;//not defined

  TGeoMaterial *_siliconMat = new TGeoMaterial("siliconMat",28.0855,14.,2.329);
  _siliconMat->SetRadLen(1.);//calc automatically, need this for elemental mats.
  TGeoMedium *_silicon = new TGeoMedium("silicon",medInd++,_siliconMat,mPar);

  TGeoMixture *_airMat = new TGeoMixture("airMat",3);
  _airMat->AddElement(14.01,7.,.78);
  _airMat->AddElement(16.00,8.,.21);
  _airMat->AddElement(39.95,18.,.01);
  _airMat->SetDensity(1.2e-3);
  TGeoMedium *_air = new TGeoMedium("air",medInd++,_airMat,mPar);  

  TGeoMixture *_vacuumMat = new TGeoMixture("vacuumMat",3);
  _vacuumMat->AddElement(14.01,7.,.78);
  _vacuumMat->AddElement(16.00,8.,.21);
  _vacuumMat->AddElement(39.95,18.,.01);
  _vacuumMat->SetDensity(1.2e-15);
  TGeoMedium *_vacuum = new TGeoMedium("vacuum",medInd++,_vacuumMat,mPar);  








}