diff --git a/compact/LGC.xml b/compact/LGC.xml
index 3e237649bad19606265a8cc29d871dd03c7b7f29..d020b1a5acb034f68a3a574c24e0f953d42c5811 100644
--- a/compact/LGC.xml
+++ b/compact/LGC.xml
@@ -3,7 +3,7 @@
 <readouts>
   <readout name="LightGasCherenkovHits">
     <segmentation type="CartesianGridXY" grid_size_x="3*mm" grid_size_y="3*mm" />
-    <id>system:6,sector:11,mirror:4,module:10,x:32:-16,y:-16</id>
+    <id>system:6,sector:12,mirror:4,module:10,x:32:-16,y:-16</id>
   </readout>
 </readouts>
 
diff --git a/solid.xml b/solid.xml
index 6fbf19b2de85ff6c7e994f5fe8d4ca0cc7f1e31b..2745de418b33de2347ca0be0d6999ad668b53179 100644
--- a/solid.xml
+++ b/solid.xml
@@ -60,6 +60,11 @@
 
   <surfaces>
     <comment> For the values of "finish", model and type, see TGeoOpticalSurface.h !  </comment>
+    <opticalsurface name="MirrorOpticalSurface" finish="polished" model="glisur" type="dielectric_metal" value="0">
+      <property name="REFLECTIVITY" ref="REFLECTIVITY_mirror"/>
+      <property name="RINDEX"       coldim="2" values="1.034*eV  1.5   4.136*eV  1.5"/>
+      <!--<property name="EFFICIENCY"   ref="EFFICIENCY0x8b77240"/>-->
+    </opticalsurface>
     <opticalsurface name="PMTOpticalSurface" finish="polished" model="glisur" type="dielectric_dielectric" value="0">
       <property name="RINDEX"       coldim="2" values="1.034*eV  1.5   4.136*eV  1.5"/>
       <!--<property name="EFFICIENCY"   ref="EFFICIENCY0x8b77240"/>-->
@@ -72,7 +77,7 @@
   </surfaces>
 
 
-  <include ref="compact/fields.xml"/>
+      <!--<include ref="compact/fields.xml"/>-->
 
   <detectors>
     <!--<include ref="compact/LAEC.xml"/>
diff --git a/src/GasCherenkov_geo.cpp b/src/GasCherenkov_geo.cpp
index de9ba9bc4c1af47505308f6c0c12eb64542bb7cc..894947aa9a5357190acf3c92d534dfa3923ed917 100644
--- a/src/GasCherenkov_geo.cpp
+++ b/src/GasCherenkov_geo.cpp
@@ -98,8 +98,8 @@ static Ref_t createDetector(Detector& desc, xml::Handle_t handle, SensitiveDetec
         Volume v_mir("vol_mirror_" + std::to_string(i), IntersectionSolid(mir_cutout, mir_shell, mir_trans), mmat);
         auto   mir_trans2 = Transform3D(Position(mloc.x(), mloc.y(), mloc.z()))*RotationZYX(mrot.z(), mrot.y(), mrot.x());
         PlacedVolume pv_mir = v_sector.placeVolume(v_mir, mir_trans2);
-        DetElement   de_mir(det, "de_mirror" + std::to_string(i) + "_shape", 1);
-        pv_mir.addPhysVolID("mirror", 1);
+        DetElement de_mir(det, "de_mirror" + std::to_string(i), i);
+        pv_mir.addPhysVolID("mirror", i);
         de_mir.setPlacement(pv_mir);
         sens.setType("photoncounter");
         v_mir.setSensitiveDetector(sens);
@@ -107,13 +107,14 @@ static Ref_t createDetector(Detector& desc, xml::Handle_t handle, SensitiveDetec
         // optical surface
         SkinSurface mirrorBorder_Surf(desc, de_mir, "LGCmirror", mirrorSurf, v_mir);
         mirrorBorder_Surf.isValid();
+        i++;
     }
 
     // sectors
     double sector_angle = 2.*M_PI / nsec;
     for (int isec = 1; isec <= nsec; isec++) {
         auto pv = v_tank.placeVolume(v_sector, Transform3D(RotationZ((isec - 1) * sector_angle)));
-        pv.addPhysVolID("sector" + std::to_string(isec), isec);
+        pv.addPhysVolID("sector", isec);
         auto amod = (isec == 1 ? de_sector : de_sector.clone("de_sector" + std::to_string(isec), isec));
         amod.setPlacement(pv);
         det.add(amod);