diff --git a/compact/definitions.xml b/compact/definitions.xml
index bf9871adfd1e2d54f74d1501bb202f23b4a3be45..2f6e84c725d9d7452cff6d3985f515ec59634e80 100644
--- a/compact/definitions.xml
+++ b/compact/definitions.xml
@@ -217,6 +217,7 @@
     <constant name="ci_GEM_id"          value="122"/>
     <constant name="ForwardTRD_ID"      value="123"/>
     <constant name="GEMTrackerEndcap_ID" value="124"/>
+    <constant name="GEMTrackerEndcapN_ID" value="125"/>
 
     <comment> 
       =====================================
diff --git a/compact/gem_tracker_endcap.xml b/compact/gem_tracker_endcap.xml
index 7d0604e346d90f4b9a977269a30bff7bbd1c88c9..d545a86a1ab47b3e5ca83b44350683e5ab2fb7f9 100644
--- a/compact/gem_tracker_endcap.xml
+++ b/compact/gem_tracker_endcap.xml
@@ -155,6 +155,96 @@
       </layer>
     </detector>
 
+    <detector
+      id="GEMTrackerEndcapN_ID"
+      name="GEMTrackerEndcapN"
+      type="refdet_GEMTrackerEndcap"
+      readout="GEMTrackerEndcapHits"
+      vis="Argonne_Red"
+      reflect="true">
+      <module name="GEMModule1" vis="Argonne_Process_Blue">
+        <trd x1="GEMTrackerEndcapFoilX1/2.0" x2="GEMTrackerEndcapFoilX2/2.0" z="GEMTrackerEndcapFoilY/2"/>
+        <comment> Going from HV side to readout side</comment>
+        <module_component thickness="0.127 * mm" material="Mylar"/>
+        <module_component thickness="50.0*um" material="Kapton" name="entrance_window"/>
+        <module_component thickness=" 3.0*mm" material="Ar10CO2" name="entrance region" />
+        <module_component thickness="50.0*um" material="Kapton"/>
+        <module_component thickness=" 3.0*um" material="Copper"/>
+        <module_component thickness=" 3.0*mm" material="Ar10CO2" name="drift region"/>
+        <module_component thickness="30.0*um" material="Kapton"  name="gem_foil"/>
+        <module_component thickness=" 3.0*um" material="Copper"  name="gem_foil_Cu"/>
+        <module_component thickness=" 2.0*mm" material="Ar10CO2" name="transfer region I"/>
+        <module_component thickness="30.0*um" material="Kapton"  name="gem_foil"/>
+        <module_component thickness=" 3.0*um" material="Copper"  name="gem_foil_Cu"/>
+        <module_component thickness=" 2.0*mm" material="Ar10CO2" name="transfer region II"/>
+        <module_component thickness="30.0*um" material="Kapton"  name="gem_foil"/>
+        <module_component thickness=" 3.0*um" material="Copper"  name="gem_foil_Cu"/>
+        <module_component thickness=" 2.0*mm" material="Ar10CO2" name="induction region"/>
+        <module_component thickness="30.0*um" material="Kapton"  name="readout"     sensitive="true"/>
+        <module_component thickness=" 3.0*um" material="Copper"  name="readout_Cu"/>
+        <module_component thickness="127.0*um" material="Mylar"/>
+        <module_component thickness="200.0*um" material="Epoxy" sensitive="true" vis="Argonne_Process_Blue"/>
+      </module>
+      <module name="GEMSupportModule1" vis="Argonne_Process_Blue">
+        <trd x1="GEMTrackerEndcapFoilX2/2.0" x2="GEMTrackerEndcapFoilX1/2.0" z="GEMTrackerEndcapFrameBotEdge_width"/>
+        <module_component thickness="GEMTrackerEndcapFrame_thickness" material="Mylar"/>
+      </module>
+      <module name="GEMSupportModule2" vis="Argonne_Process_Blue">
+        <trd x1="GEMTrackerEndcapFrameSideEdge_width" x2="GEMTrackerEndcapFrameSideEdge_width" z="GEMTrackerEndcapFoilY/2"/>
+        <module_component thickness="4.0*mm" material="Mylar"/>
+      </module>
+      <layer id="1" >
+        <ring vis="Argonne_Red"
+          r="GEMTrackerEndcapFoil_rmin+GEMTrackerEndcapFoilY/2.0"
+          zstart="GEMTrackerEndcap_zmin + 0.5*GEMTrackerEndcapLayer_thickness"
+          nmodules="12" dz="10 * mm" module="GEMModule1" />
+        <ring vis="Argonne_Blue" phi0="15.0*degree"
+          r="GEMTrackerEndcapFoil_rmin+GEMTrackerEndcapFoilY/2.0"
+          zstart="GEMTrackerEndcap_zmin + 0.5*GEMTrackerEndcapLayer_thickness"
+          nmodules="12" dz="0 * mm" module="GEMSupportModule2" />
+      </layer>
+      <layer id="2" >
+        <ring vis="Argonne_Red"
+          r="GEMTrackerEndcapFoil_rmin+GEMTrackerEndcapFoilY/2.0"
+          zstart="GEMTrackerEndcap_zmin+1.5*GEMTrackerEndcapLayer_thickness"
+          nmodules="12" dz="10 * mm" module="GEMModule1" />
+        <ring vis="Argonne_Blue" phi0="15.0*degree"
+          r="GEMTrackerEndcapFoil_rmin+GEMTrackerEndcapFoilY/2.0"
+          zstart="GEMTrackerEndcap_zmin+1.5*GEMTrackerEndcapLayer_thickness"
+          nmodules="12" dz="0 * mm" module="GEMSupportModule2" />
+      </layer>
+      <layer id="3" >
+        <ring vis="Argonne_Red"
+          r="GEMTrackerEndcapFoil_rmin+GEMTrackerEndcapFoilY/2.0"
+          zstart="GEMTrackerEndcap_zmin+2.5*GEMTrackerEndcapLayer_thickness"
+          nmodules="12" dz="10 * mm" module="GEMModule1" />
+        <ring vis="Argonne_Blue" phi0="15.0*degree"
+          r="GEMTrackerEndcapFoil_rmin+GEMTrackerEndcapFoilY/2.0"
+          zstart="GEMTrackerEndcap_zmin+2.5*GEMTrackerEndcapLayer_thickness"
+          nmodules="12" dz="0 * mm" module="GEMSupportModule2" />
+      </layer>
+      <layer id="4" >
+        <ring vis="Argonne_Red"
+          r="GEMTrackerEndcapFoil_rmin+GEMTrackerEndcapFoilY/2.0"
+          zstart="GEMTrackerEndcap_zmin+3.5*GEMTrackerEndcapLayer_thickness"
+          nmodules="12" dz="10 * mm" module="GEMModule1" />
+        <ring vis="Argonne_Blue" phi0="15.0*degree"
+          r="GEMTrackerEndcapFoil_rmin+GEMTrackerEndcapFoilY/2.0"
+          zstart="GEMTrackerEndcap_zmin+3.5*GEMTrackerEndcapLayer_thickness"
+          nmodules="12" dz="0 * mm" module="GEMSupportModule2" />
+      </layer>
+      <layer id="5" >
+        <ring vis="Argonne_Red"
+          r="GEMTrackerEndcapFoil_rmin+GEMTrackerEndcapFoilY/2.0"
+          zstart="GEMTrackerEndcap_zmin+4.5*GEMTrackerEndcapLayer_thickness"
+          nmodules="12" dz="10 * mm" module="GEMModule1" />
+        <ring vis="Argonne_Blue" phi0="15.0*degree"
+          r="GEMTrackerEndcapFoil_rmin+GEMTrackerEndcapFoilY/2.0"
+          zstart="GEMTrackerEndcap_zmin+4.5*GEMTrackerEndcapLayer_thickness"
+          nmodules="12" dz="0 * mm" module="GEMSupportModule2" />
+      </layer>
+    </detector>
+
   </detectors>
 
   <readouts>
diff --git a/compact/mm_tracker_barrel.xml b/compact/mm_tracker_barrel.xml
index 483b8914f37322832ad7cde97ae183f244b7e9cd..aef3c89d8dc7cdfe7a38210991de6511cd3dca3e 100644
--- a/compact/mm_tracker_barrel.xml
+++ b/compact/mm_tracker_barrel.xml
@@ -3,13 +3,17 @@
   <comment>Micromegas tracker barrel</comment>        
 
   <define>
+
+    <constant name="MMTrackerBarrel_thickness" value="TrackerBarrel_rmax - TrackerBarrel_rmax"/>
+    <constant name="MMTrackerBarrel_NLayers" value="5"/>
+    <constant name="MMTrackerBarrel_delta" value="MMTrackerBarrel_thickness/MMTrackerBarrel_NLayers"/>
+
     <constant name="MMTrackerBarrelLayer1_rmin"          value="800.0 * mm"/>
     <constant name="MMTrackerBarrelLayer1_length"        value="100.0 * mm"/>
     <constant name="MMTrackerBarrelLayer1_thickness"     value="10.0 * mm"/>
     <constant name="MMTrackerBarrel_NZModules"           value="floor(BarrelTracking_length/MMTrackerBarrelLayer1_length)"/>
     <constant name="MMTrackerBarrelModulesTotal_length"  value="MMTrackerBarrel_NZModules*MMTrackerBarrelLayer1_length"/>
 
-
   </define>
 
   <limits>
@@ -25,9 +29,9 @@
     <detector id="MMTrackerBarrel_ID" name="MMTrackerBarrel" type="refdet_MMTrackerBarrel" readout="MMTrackerBarrelHits">
       <module name="Module1" vis="Argonne_Gold">
         <module_envelope
-          rmin="MMTrackerBarrelLayer1_rmin"
+          rmin="TrackerBarrel_rmax"
           length="MMTrackerBarrelLayer1_length"
-          thickness="MMTrackerBarrelLayer1_thickness" phi="90*degree" />
+          thickness="MMTrackerBarrel_delta" phi="90*degree" />
         <module_component thickness="1.0*mm" material="PEEK" sensitive="false">
           <position x="0" />
         </module_component>
diff --git a/reference_detector.xml b/reference_detector.xml
index c04c3e60bff8c53fc0c7d1056f8bc9ad9306076a..137966a474c6363dc4ccc2cba8926ed98b9d4c2e 100644
--- a/reference_detector.xml
+++ b/reference_detector.xml
@@ -120,7 +120,6 @@
   <include ref="compact/forward_trd.xml"/>
   <include ref="compact/vertex_tracker.xml"/>
   <include ref="compact/gem_tracker_endcap.xml"/>
-  <include ref="compact/mm_tracker_barrel.xml"/>
 
   <include ref="compact/B0_tracker.xml"/>
   <include ref="compact/forward_offM_tracker.xml"/>
@@ -129,10 +128,11 @@
   <include ref="eic/forward_ion_beamline.xml"/>
   <include ref="compact/hcal.xml"/>
   <include ref="compact/forward_rich.xml"/>
+  <include ref="compact/cb_CTD_Si.xml"/>
 
   <!--
+  <include ref="compact/mm_tracker_barrel.xml"/>
   <include ref="compact/ci_GEM.xml"/>
-  <include ref="compact/cb_CTD_Si.xml"/>
   <include ref="compact/cb_VTX_Barrel.xml"/>
   <include ref="compact/ci_HCAL.xml"/>
   <include ref="compact/roman_pots.xml"/>