diff --git a/compact/definitions.xml b/compact/definitions.xml
index aa898adf3bbf4feb1f7da8b1bab1ab7a6907b6ce..3fe95f89954f30abf6adbd5a929c1abc47e0da19 100644
--- a/compact/definitions.xml
+++ b/compact/definitions.xml
@@ -435,11 +435,12 @@ Examples:
 
     <comment> Global PID regions with suballocations for TOF and RICH detectors </comment>
     <constant name="ForwardPIDRegion_zmin"        value="CentralTrackingRegionP_zmax" />
-    <constant name="ForwardPIDRegion_length"      value="120.0*cm" />
+    <constant name="ForwardPIDRegion_length"      value="155.0*cm" />
+    <constant name="ForwardPIDRegion_rmax"        value="180.0*cm" />
 
     <comment> Forward TOF region currenlty empty for future upgrades </comment>
     <constant name="ForwardTOFRegion_zmin"        value="ForwardPIDRegion_zmin" />
-    <constant name="ForwardTOFRegion_length"      value="20.0*cm" />
+    <constant name="ForwardTOFRegion_length"      value="35.0*cm" />
     <constant name="ForwardTOFRegion_rmax"        value="CentralTrackingRegion_rmax" />
     <constant name="ForwardTOFRegion_tan"         value="CentralTrackingRegionP_tan" />
 
@@ -491,6 +492,11 @@ Service gaps in FW direction (before endcapP ECAL) and BW direction (before endc
     <constant name="ForwardServiceGap_zmin"       value="ForwardPIDRegion_zmin + ForwardInnerEndcapRegion_length"/>
     <constant name="ForwardServiceGap_zmax"       value="ForwardServiceGap_zmin + ForwardServiceGap_length"/>
 
+    <comment> Radial service gap between dRICH and HcalBarrel </comment>
+    <constant name="ForwardServiceGap_thickness"  value="15.0*cm"/>
+    <constant name="ForwardServiceGap_rmin"       value="ForwardPIDRegion_rmax"/>
+    <constant name="ForwardServiceGap_rmax"       value="ForwardServiceGap_rmin + ForwardServiceGap_thickness"/>
+
     <constant name="BackwardServiceGap_length"    value="10.0 * cm"/>
     <constant name="BackwardServiceGap_zmin"      value="320.0 * cm"/> <!-- FIXME hardcoded -->
     <constant name="BackwardServiceGap_zmax"      value="BackwardServiceGap_zmin + BackwardServiceGap_length"/>
@@ -557,7 +563,7 @@ Service gaps in FW direction (before endcapP ECAL) and BW direction (before endc
     <constant name="HcalEndcapN_rmin"     value="max((HcalEndcapN_zmin + HcalEndcapN_length) * tan(abs(CrossingAngle)) + 22.25 * mm, 11 * cm)"/>
 
     <constant name="HcalBarrel_thickness" value="88.0*cm"/> <!-- ref: ECCE proposal -->
-    <constant name="HcalBarrel_rmin"      value="182*cm"/> <!-- ref: ECCE proposal -->
+    <constant name="HcalBarrel_rmin"      value="ForwardServiceGap_rmax"/>
     <constant name="HcalBarrel_rmax"      value="HcalBarrel_rmin + HcalBarrel_thickness"/>
     <constant name="HcalBarrelForward_zmax"  value="ForwardServiceGap_zmin"/>
     <constant name="HcalBarrelBackward_zmax" value="BackwardServiceGap_zmin"/>
diff --git a/compact/drich.xml b/compact/drich.xml
index 4b125ac2cbb104e2b9c03b147b15a40f009083e8..c98d41301f7d33363cff28faf98d432a7b341b09 100644
--- a/compact/drich.xml
+++ b/compact/drich.xml
@@ -3,19 +3,20 @@
 
 <define>
 <!-- vessel (=snout+tank) geometry -->
-<constant name="DRICH_zmin"               value="ForwardRICHRegion_zmin"/> <!-- vessel front -->
-<constant name="DRICH_Length"             value="ForwardRICHRegion_length"/>  <!-- overall vessel length (including snout) -->
-<constant name="DRICH_rmin0"              value="ForwardRICHRegion_zmin * ForwardRICHRegion_tan1"/>  <!-- bore radius at dRICh vessel frontplane -->
-<constant name="DRICH_rmin1"              value="(ForwardRICHRegion_zmin + ForwardRICHRegion_length) * ForwardRICHRegion_tan2"/>  <!-- bore radius at dRICh vessel backplane -->
+<constant name="DRICH_Length"             value="ForwardRICHRegion_length"/>  <!-- overall vessel length -->
+<constant name="DRICH_zmin"               value="ForwardRICHRegion_zmin"/>
+<constant name="DRICH_zmax"               value="DRICH_zmin + DRICH_Length"/>
+<constant name="DRICH_rmin0"              value="DRICH_zmin * ForwardRICHRegion_tan1"/>  <!-- bore radius at dRICh entrance -->
+<constant name="DRICH_rmin1"              value="DRICH_zmax * ForwardRICHRegion_tan2"/>  <!-- bore radius at dRICh exit -->
 <constant name="DRICH_wall_thickness"     value="0.5*cm"/>  <!-- thickness of radial walls -->
 <constant name="DRICH_window_thickness"   value="0.1*cm"/>  <!-- thickness of entrance and exit walls -->
-<!-- tank geometry: cylinder, holding the majority of detector components -->
-<constant name="DRICH_rmax2"              value="HcalBarrel_rmin-2*cm"/>  <!-- cylinder radius, near maximal to fit HCal barrel inner polygon -->
 <!-- snout geometry: cone with front radius rmax0 and back radius of rmax1 -->
+<constant name="DRICH_rmax0"              value="95.0*cm"/>
 <constant name="DRICH_SnoutLength"        value="20.0*cm"/>
-<constant name="DRICH_SnoutSlope"         value="DRICH_rmax2 / (DRICH_zmin + DRICH_Length)"/>
-<constant name="DRICH_rmax0"              value="DRICH_SnoutSlope * DRICH_zmin"/>
-<constant name="DRICH_rmax1"              value="DRICH_SnoutSlope * ( DRICH_zmin + DRICH_SnoutLength)"/>
+<constant name="DRICH_SnoutSlope"         value="DRICH_rmax0 / DRICH_zmin"/> <!-- TODO: increase slope to allow more space for aerogel cones ? -->
+<constant name="DRICH_rmax1"              value="DRICH_rmax0 + DRICH_SnoutLength * DRICH_SnoutSlope"/>
+<!-- tank geometry: cylinder, holding the majority of detector components -->
+<constant name="DRICH_rmax2"              value="ForwardPIDRegion_rmax"/>  <!-- cylinder radius -->
 <!-- additional parameters -->
 <constant name="DRICH_aerogel_thickness"  value="4.0*cm"/>  <!-- aerogel thickness -->
 <constant name="DRICH_sensor_size"        value="25.8*mm"/> <!-- sensor side length -->