Resolve "ERICH service material"

compact/display.xml

@@ -113,6 +113,8 @@
     <vis name="MRICH_lens_vis" ref="AnlGray" showDaughters="true" visible="true" />
     <vis name="MRICH_mirror_vis"  ref="AnlGray" showDaughters="true" visible="true" />
 
+    <vis name="RICHServiceVis"  ref="AnlGray" showDaughters="true" visible="true" />
+
   </display>
 
     <comment>

compact/display_geoviewer.xml

@@ -102,6 +102,7 @@
     <vis name="MRICH_lens_vis" ref="AnlGray" showDaughters="true" visible="true" />
     <vis name="MRICH_mirror_vis"  ref="AnlGray" showDaughters="true" visible="true" />
 
+    <vis name="RICHServiceVis"  ref="AnlGray" showDaughters="true" visible="true" />
 
     <comment>
       Deprecated values used for IP6 vis

compact/erich.xml

@@ -155,6 +155,10 @@
   rmax="ERICH_rmax  - 4*cm"
   />
 
+<services>
+  <comment> SJJ: random standin for readout + electronics + cooling @FIXME </comment>
+  <component name="aluminum" thickness="10*mm" vis="RICHServiceVis" material="Aluminum"/>
+</services>
 
 </sensors>
 </detector>

src/ERich_geo.cpp

@@ -3,93 +3,99 @@
 //  Author: C. Dilks
 //----------------------------------
 
-#include <XML/Helper.h>
-#include "TMath.h"
-#include "TString.h"
-#include "GeometryHelpers.h"
-#include "Math/Point2D.h"
-#include "DDRec/Surface.h"
-#include "DDRec/DetectorData.h"
-#include "DD4hep/OpticalSurfaces.h"
 #include "DD4hep/DetFactoryHelper.h"
+#include "DD4hep/OpticalSurfaces.h"
 #include "DD4hep/Printout.h"
+#include "DDRec/DetectorData.h"
+#include "DDRec/Surface.h"
+#include "GeometryHelpers.h"
+#include "Math/Point2D.h"
+#include "TMath.h"
+#include "TString.h"
+#include <XML/Helper.h>
 
 using namespace dd4hep;
 using namespace dd4hep::rec;
 
 // create the detector
-static Ref_t createDetector(Detector& desc, xml::Handle_t handle, SensitiveDetector sens) {
+static Ref_t createDetector(Detector& desc, xml::Handle_t handle, SensitiveDetector sens)
+{
   xml::DetElement detElem = handle;
-  std::string detName = detElem.nameStr();
-  int detID = detElem.id();
+  std::string     detName = detElem.nameStr();
+  int             detID   = detElem.id();
 
-  DetElement det(detName, detID);
-  xml::Component dims = detElem.dimensions();
+  DetElement            det(detName, detID);
+  xml::Component        dims    = detElem.dimensions();
   OpticalSurfaceManager surfMgr = desc.surfaceManager();
 
   // attributes -----------------------------------------------------------
   // - vessel
-  double  vesselLength     =  dims.attr<double>(_Unicode(length));
-  double  vesselZmin       =  dims.attr<double>(_Unicode(zmin));
-  double  vesselZmax       =  dims.attr<double>(_Unicode(zmax));
-  double  vesselRmin0      =  dims.attr<double>(_Unicode(rmin0));
-  double  vesselRmin1      =  dims.attr<double>(_Unicode(rmin1));
-  double  vesselRmax0      =  dims.attr<double>(_Unicode(rmax0));
-  double  vesselRmax1      =  dims.attr<double>(_Unicode(rmax1));
-  int     nSectors         =  dims.attr<int>(_Unicode(nsectors));
-  double  wallThickness    =  dims.attr<double>(_Unicode(wall_thickness));
-  double  windowThickness  =  dims.attr<double>(_Unicode(window_thickness));
-  auto    vesselMat        =  desc.material(detElem.attr<std::string>(_Unicode(material)));
-  auto    gasvolMat        =  desc.material(detElem.attr<std::string>(_Unicode(gas)));
-  auto    vesselVis        =  desc.visAttributes(detElem.attr<std::string>(_Unicode(vis_vessel)));
-  auto    gasvolVis        =  desc.visAttributes(detElem.attr<std::string>(_Unicode(vis_gas)));
+  double vesselLength    = dims.attr<double>(_Unicode(length));
+  double vesselZmin      = dims.attr<double>(_Unicode(zmin));
+  double vesselZmax      = dims.attr<double>(_Unicode(zmax));
+  double vesselRmin0     = dims.attr<double>(_Unicode(rmin0));
+  double vesselRmin1     = dims.attr<double>(_Unicode(rmin1));
+  double vesselRmax0     = dims.attr<double>(_Unicode(rmax0));
+  double vesselRmax1     = dims.attr<double>(_Unicode(rmax1));
+  int    nSectors        = dims.attr<int>(_Unicode(nsectors));
+  double wallThickness   = dims.attr<double>(_Unicode(wall_thickness));
+  double windowThickness = dims.attr<double>(_Unicode(window_thickness));
+  auto   vesselMat       = desc.material(detElem.attr<std::string>(_Unicode(material)));
+  auto   gasvolMat       = desc.material(detElem.attr<std::string>(_Unicode(gas)));
+  auto   vesselVis       = desc.visAttributes(detElem.attr<std::string>(_Unicode(vis_vessel)));
+  auto   gasvolVis       = desc.visAttributes(detElem.attr<std::string>(_Unicode(vis_gas)));
   // - radiator (applies to aerogel and filter)
-  auto    radiatorElem        =  detElem.child(_Unicode(radiator));
-  double  radiatorRmin        =  radiatorElem.attr<double>(_Unicode(rmin));
-  double  radiatorRmax        =  radiatorElem.attr<double>(_Unicode(rmax));
-  double  radiatorPhiw        =  radiatorElem.attr<double>(_Unicode(phiw));
-  double  radiatorPitch       =  radiatorElem.attr<double>(_Unicode(pitch));
-  double  radiatorFrontplane  =  radiatorElem.attr<double>(_Unicode(frontplane));
+  auto   radiatorElem       = detElem.child(_Unicode(radiator));
+  double radiatorRmin       = radiatorElem.attr<double>(_Unicode(rmin));
+  double radiatorRmax       = radiatorElem.attr<double>(_Unicode(rmax));
+  double radiatorPhiw       = radiatorElem.attr<double>(_Unicode(phiw));
+  double radiatorPitch      = radiatorElem.attr<double>(_Unicode(pitch));
+  double radiatorFrontplane = radiatorElem.attr<double>(_Unicode(frontplane));
   // - aerogel
-  auto    aerogelElem       =  radiatorElem.child(_Unicode(aerogel));
-  auto    aerogelMat        =  desc.material(aerogelElem.attr<std::string>(_Unicode(material)));
-  auto    aerogelVis        =  desc.visAttributes(aerogelElem.attr<std::string>(_Unicode(vis)));
-  double  aerogelThickness  =  aerogelElem.attr<double>(_Unicode(thickness));
+  auto   aerogelElem      = radiatorElem.child(_Unicode(aerogel));
+  auto   aerogelMat       = desc.material(aerogelElem.attr<std::string>(_Unicode(material)));
+  auto   aerogelVis       = desc.visAttributes(aerogelElem.attr<std::string>(_Unicode(vis)));
+  double aerogelThickness = aerogelElem.attr<double>(_Unicode(thickness));
   // - filter
-  auto    filterElem       =  radiatorElem.child(_Unicode(filter));
-  auto    filterMat        =  desc.material(filterElem.attr<std::string>(_Unicode(material)));
-  auto    filterVis        =  desc.visAttributes(filterElem.attr<std::string>(_Unicode(vis)));
-  double  filterThickness  =  filterElem.attr<double>(_Unicode(thickness));
+  auto   filterElem      = radiatorElem.child(_Unicode(filter));
+  auto   filterMat       = desc.material(filterElem.attr<std::string>(_Unicode(material)));
+  auto   filterVis       = desc.visAttributes(filterElem.attr<std::string>(_Unicode(vis)));
+  double filterThickness = filterElem.attr<double>(_Unicode(thickness));
   // - sensor module
-  auto    sensorElem       =  detElem.child(_Unicode(sensors)).child(_Unicode(module));
-  auto    sensorMat        =  desc.material(sensorElem.attr<std::string>(_Unicode(material)));
-  auto    sensorVis        =  desc.visAttributes(sensorElem.attr<std::string>(_Unicode(vis)));
-  auto    sensorSurf       =  surfMgr.opticalSurface(sensorElem.attr<std::string>(_Unicode(surface)));
-  double  sensorSide       =  sensorElem.attr<double>(_Unicode(side));
-  double  sensorGap        =  sensorElem.attr<double>(_Unicode(gap));
-  double  sensorThickness  =  sensorElem.attr<double>(_Unicode(thickness));
+  auto   sensorElem      = detElem.child(_Unicode(sensors)).child(_Unicode(module));
+  auto   sensorMat       = desc.material(sensorElem.attr<std::string>(_Unicode(material)));
+  auto   sensorVis       = desc.visAttributes(sensorElem.attr<std::string>(_Unicode(vis)));
+  auto   sensorSurf      = surfMgr.opticalSurface(sensorElem.attr<std::string>(_Unicode(surface)));
+  double sensorSide      = sensorElem.attr<double>(_Unicode(side));
+  double sensorGap       = sensorElem.attr<double>(_Unicode(gap));
+  double sensorThickness = sensorElem.attr<double>(_Unicode(thickness));
   // - sensor plane
-  auto    sensorPlaneElem        =  detElem.child(_Unicode(sensors)).child(_Unicode(plane));
-  double  sensorPlaneFrontplane  =  sensorPlaneElem.attr<double>(_Unicode(frontplane));
-  double  sensorPlaneRmin        =  sensorPlaneElem.attr<double>(_Unicode(rmin));
-  double  sensorPlaneRmax        =  sensorPlaneElem.attr<double>(_Unicode(rmax));
+  auto   sensorPlaneElem       = detElem.child(_Unicode(sensors)).child(_Unicode(plane));
+  double sensorPlaneFrontplane = sensorPlaneElem.attr<double>(_Unicode(frontplane));
+  double sensorPlaneRmin       = sensorPlaneElem.attr<double>(_Unicode(rmin));
+  double sensorPlaneRmax       = sensorPlaneElem.attr<double>(_Unicode(rmax));
   // - debugging switches
-  int   debug_optics_mode  =  detElem.attr<int>(_Unicode(debug_optics));
+  int debug_optics_mode = detElem.attr<int>(_Unicode(debug_optics));
 
   // if debugging optics, override some settings
   bool debug_optics = debug_optics_mode > 0;
-  if(debug_optics) {
-    printout(WARNING,"ERich_geo","DEBUGGING ERICH OPTICS");
-    switch(debug_optics_mode) {
-      case 1: vesselMat = aerogelMat = filterMat = sensorMat = gasvolMat = desc.material("VacuumOptical"); break;
-      case 2: vesselMat = aerogelMat = filterMat = sensorMat = desc.material("VacuumOptical"); break;
-      default: printout(FATAL,"ERich_geo","UNKNOWN debug_optics_mode"); return det;
+  if (debug_optics) {
+    printout(WARNING, "ERich_geo", "DEBUGGING ERICH OPTICS");
+    switch (debug_optics_mode) {
+    case 1:
+      vesselMat = aerogelMat = filterMat = sensorMat = gasvolMat = desc.material("VacuumOptical");
+      break;
+    case 2:
+      vesselMat = aerogelMat = filterMat = sensorMat = desc.material("VacuumOptical");
+      break;
+    default:
+      printout(FATAL, "ERich_geo", "UNKNOWN debug_optics_mode");
+      return det;
     };
     aerogelVis = sensorVis;
     gasvolVis = vesselVis = desc.invisible();
   };
 
-
   // BUILD VESSEL //////////////////////////////////////
   /* - `vessel`: aluminum enclosure, the mother volume of the eRICh
    * - `gasvol`: gas volume, which fills `vessel`; all other volumes defined below
@@ -97,36 +103,34 @@ static Ref_t createDetector(Detector& desc, xml::Handle_t handle, SensitiveDetec
    */
 
   // tank solids
-  Cone vesselTank(
-      vesselLength/2.0,
-      vesselRmin1,
-      vesselRmax1,
-      vesselRmin0,
-      vesselRmax0
-      );
-  Cone gasvolTank(
-      vesselLength/2.0 - windowThickness,
-      vesselRmin1 + wallThickness,
-      vesselRmax1 - wallThickness,
-      vesselRmin0 + wallThickness,
-      vesselRmax0 - wallThickness
-      );
+  Cone vesselTank(vesselLength / 2.0, vesselRmin1, vesselRmax1, vesselRmin0, vesselRmax0);
+  Cone gasvolTank(vesselLength / 2.0 - windowThickness, vesselRmin1 + wallThickness, vesselRmax1 - wallThickness,
+                  vesselRmin0 + wallThickness, vesselRmax0 - wallThickness);
 
   //  extra solids for `debug_optics` only
-  Box vesselBox(1001,1001,1001);
-  Box gasvolBox(1000,1000,1000);
+  Box vesselBox(1001, 1001, 1001);
+  Box gasvolBox(1000, 1000, 1000);
 
   // choose vessel and gasvol solids (depending on `debug_optics_mode` (0=disabled))
   Solid vesselSolid, gasvolSolid;
-  switch(debug_optics_mode) {
-    case 0:  vesselSolid=vesselTank;   gasvolSolid=gasvolTank;   break; // `!debug_optics`
-    case 1:  vesselSolid=vesselBox;    gasvolSolid=gasvolBox;    break;
-    case 2:  vesselSolid=vesselBox;    gasvolSolid=gasvolTank;   break;
+  switch (debug_optics_mode) {
+  case 0:
+    vesselSolid = vesselTank;
+    gasvolSolid = gasvolTank;
+    break; // `!debug_optics`
+  case 1:
+    vesselSolid = vesselBox;
+    gasvolSolid = gasvolBox;
+    break;
+  case 2:
+    vesselSolid = vesselBox;
+    gasvolSolid = gasvolTank;
+    break;
   };
 
   // volumes
   Volume vesselVol(detName, vesselSolid, vesselMat);
-  Volume gasvolVol(detName+"_gas", gasvolSolid, gasvolMat);
+  Volume gasvolVol(detName + "_gas", gasvolSolid, gasvolMat);
   vesselVol.setVisAttributes(vesselVis);
   gasvolVol.setVisAttributes(gasvolVis);
 
@@ -137,82 +141,80 @@ static Ref_t createDetector(Detector& desc, xml::Handle_t handle, SensitiveDetec
   //   the z-direction to be in the proper ATHENA-integration location
   // - these reference positions are for the frontplane and backplane of the vessel,
   //   with respect to the vessel origin position
-  auto originFront = Position(0., 0.,  vesselLength/2.0 );
-  auto originBack =  Position(0., 0., -vesselLength/2.0 );
-
+  auto originFront = Position(0., 0., vesselLength / 2.0);
+  auto originBack  = Position(0., 0., -vesselLength / 2.0);
 
   // sensitive detector type
   sens.setType("photoncounter");
 
-
   // SECTOR LOOP //////////////////////////////////
-  for(int isec=0; isec<nSectors; isec++) {
+  for (int isec = 0; isec < nSectors; isec++) {
 
     // debugging filters, limiting the number of sectors
-    //if( debug_optics && isec!=0) continue;
+    // if( debug_optics && isec!=0) continue;
 
     // sector rotation about z axis
-    double sectorRotation = isec * 360/nSectors * degree;
-    std::string secName = "sec" + std::to_string(isec);
-
+    double      sectorRotation = isec * 360 / nSectors * degree;
+    std::string secName        = "sec" + std::to_string(isec);
 
     // BUILD RADIATOR //////////////////////////////////////
 
     // solid and volume: create aerogel and filter sectors
-    Tube aerogelSolid(radiatorRmin, radiatorRmax, aerogelThickness/2, -radiatorPhiw/2.0, radiatorPhiw/2.0);
-    Tube filterSolid( radiatorRmin, radiatorRmax, filterThickness/2,  -radiatorPhiw/2.0, radiatorPhiw/2.0);
-    Volume aerogelVol( detName+"_aerogel_"+secName, aerogelSolid, aerogelMat );
-    Volume filterVol(  detName+"_filter_"+secName,  filterSolid,  filterMat );
+    Tube   aerogelSolid(radiatorRmin, radiatorRmax, aerogelThickness / 2, -radiatorPhiw / 2.0, radiatorPhiw / 2.0);
+    Tube   filterSolid(radiatorRmin, radiatorRmax, filterThickness / 2, -radiatorPhiw / 2.0, radiatorPhiw / 2.0);
+    Volume aerogelVol(detName + "_aerogel_" + secName, aerogelSolid, aerogelMat);
+    Volume filterVol(detName + "_filter_" + secName, filterSolid, filterMat);
     aerogelVol.setVisAttributes(aerogelVis);
     filterVol.setVisAttributes(filterVis);
 
     // aerogel placement and surface properties
     // TODO [low-priority]: define skin properties for aerogel and filter
-    auto radiatorPos = Position(0., 0., radiatorFrontplane-0.5*aerogelThickness) + originFront;
-    auto aerogelPV = gasvolVol.placeVolume(aerogelVol,
-          RotationZ(sectorRotation) // rotate about beam axis to sector
-        * Translation3D(radiatorPos.x(), radiatorPos.y(), radiatorPos.z()) // re-center to originFront
-        * RotationY(radiatorPitch) // change polar angle to specified pitch
-        );
+    auto radiatorPos = Position(0., 0., radiatorFrontplane - 0.5 * aerogelThickness) + originFront;
+    auto aerogelPV   = gasvolVol.placeVolume(
+        aerogelVol,
+        RotationZ(sectorRotation)                                              // rotate about beam axis to sector
+            * Translation3D(radiatorPos.x(), radiatorPos.y(), radiatorPos.z()) // re-center to originFront
+            * RotationY(radiatorPitch) // change polar angle to specified pitch
+    );
     DetElement aerogelDE(det, Form("aerogel_de%d", isec), isec);
     aerogelDE.setPlacement(aerogelPV);
-    //SkinSurface aerogelSkin(desc, aerogelDE, Form("mirror_optical_surface%d", isec), aerogelSurf, aerogelVol);
-    //aerogelSkin.isValid();
+    // SkinSurface aerogelSkin(desc, aerogelDE, Form("mirror_optical_surface%d", isec), aerogelSurf, aerogelVol);
+    // aerogelSkin.isValid();
 
     // filter placement and surface properties
-    if(!debug_optics) {
-      auto filterPV = gasvolVol.placeVolume(filterVol,
-            RotationZ(sectorRotation) // rotate about beam axis to sector
-          * Translation3D(radiatorPos.x(), radiatorPos.y(), radiatorPos.z()) // re-center to originFront
-          * RotationY(radiatorPitch) // change polar angle
-          * Translation3D(0., 0., -(aerogelThickness+filterThickness)/2.) // move to aerogel backplane
-          );
+    if (!debug_optics) {
+      auto filterPV = gasvolVol.placeVolume(
+          filterVol,
+          RotationZ(sectorRotation)                                               // rotate about beam axis to sector
+              * Translation3D(radiatorPos.x(), radiatorPos.y(), radiatorPos.z())  // re-center to originFront
+              * RotationY(radiatorPitch)                                          // change polar angle
+              * Translation3D(0., 0., -(aerogelThickness + filterThickness) / 2.) // move to aerogel backplane
+      );
       DetElement filterDE(det, Form("filter_de%d", isec), isec);
       filterDE.setPlacement(filterPV);
-      //SkinSurface filterSkin(desc, filterDE, Form("mirror_optical_surface%d", isec), filterSurf, filterVol);
-      //filterSkin.isValid();
+      // SkinSurface filterSkin(desc, filterDE, Form("mirror_optical_surface%d", isec), filterSurf, filterVol);
+      // filterSkin.isValid();
     };
 
   }; // END SECTOR LOOP //////////////////////////
 
-
-
   // BUILD SENSORS ///////////////////////
 
   // solid and volume: single sensor module
-  Box sensorSolid(sensorSide/2., sensorSide/2., sensorThickness/2.);
-  Volume sensorVol(detName+"_sensor", sensorSolid, sensorMat);
+  Box    sensorSolid(sensorSide / 2., sensorSide / 2., sensorThickness / 2.);
+  Volume sensorVol(detName + "_sensor", sensorSolid, sensorMat);
   sensorVol.setVisAttributes(sensorVis);
 
   // sensitivity
-  if(!debug_optics) sensorVol.setSensitiveDetector(sens);
+  if (!debug_optics)
+    sensorVol.setSensitiveDetector(sens);
 
   // sensor plane positioning: we want |`sensorPlaneFrontplane`| to be the distance between the
   // aerogel backplane (i.e., aerogel/filter boundary) and the sensor active surface (e.g, photocathode)
-  double sensorZpos = radiatorFrontplane - aerogelThickness + sensorPlaneFrontplane - 0.5*sensorThickness;
-  auto sensorPlanePos = Position(0., 0., sensorZpos) + originFront; // reference position
+  double sensorZpos     = radiatorFrontplane - aerogelThickness + sensorPlaneFrontplane - 0.5 * sensorThickness;
+  auto   sensorPlanePos = Position(0., 0., sensorZpos) + originFront; // reference position
   // miscellaneous
-  int imod=0; // module number
+  int    imod    = 0;           // module number
   double tBoxMax = vesselRmax1; // sensors will be tiled in tBox, within annular limits
 
   // SENSOR MODULE LOOP ------------------------
@@ -221,34 +223,37 @@ static Ref_t createDetector(Detector& desc, xml::Handle_t handle, SensitiveDetec
    * - loop over positive-x positions; for each, place the corresponding negative-x sensor too
    * - nested similar loop over y positions
    */
-  double sx,sy;
-  for(double usx=0; usx<=tBoxMax; usx+=sensorSide+sensorGap) {
-    for(int sgnx=1; sgnx>=(usx>0?-1:1); sgnx-=2) {
-      for(double usy=0; usy<=tBoxMax; usy+=sensorSide+sensorGap) {
-        for(int sgny=1; sgny>=(usy>0?-1:1); sgny-=2) {
+  double sx, sy;
+  for (double usx = 0; usx <= tBoxMax; usx += sensorSide + sensorGap) {
+    for (int sgnx = 1; sgnx >= (usx > 0 ? -1 : 1); sgnx -= 2) {
+      for (double usy = 0; usy <= tBoxMax; usy += sensorSide + sensorGap) {
+        for (int sgny = 1; sgny >= (usy > 0 ? -1 : 1); sgny -= 2) {
 
           // sensor (x,y) center
-          sx = sgnx*usx;
-          sy = sgny*usy;
+          sx = sgnx * usx;
+          sy = sgny * usy;
 
           // annular cut
-          if(std::hypot(sx,sy)<sensorPlaneRmin || std::hypot(sx,sy)>sensorPlaneRmax) continue;
+          if (std::hypot(sx, sy) < sensorPlaneRmin || std::hypot(sx, sy) > sensorPlaneRmax)
+            continue;
 
           // placement (note: transformations are in reverse order)
-          auto sensorPV = gasvolVol.placeVolume(sensorVol,Transform3D(
-                Translation3D(sensorPlanePos.x(), sensorPlanePos.y(), sensorPlanePos.z()) // move to reference position
-              * Translation3D(sx, sy, 0.) // move to grid position
-              ));
+          auto sensorPV = gasvolVol.placeVolume(
+              sensorVol, Transform3D(Translation3D(sensorPlanePos.x(), sensorPlanePos.y(),
+                                                   sensorPlanePos.z()) // move to reference position
+                                     * Translation3D(sx, sy, 0.)       // move to grid position
+                                     ));
 
           // generate LUT for module number -> sensor position, for readout mapping tests
-          //printf("%d %f %f\n",imod,sensorPV.position().x(),sensorPV.position().y());
+          // printf("%d %f %f\n",imod,sensorPV.position().x(),sensorPV.position().y());
 
           // properties
           sensorPV.addPhysVolID("module", imod);
-          DetElement sensorDE(det, Form("sensor_de_%d", imod), 10000*imod); // TODO: what is this 10000?
+          DetElement sensorDE(det, Form("sensor_de_%d", imod), 10000 * imod); // TODO: what is this 10000?
           sensorDE.setPlacement(sensorPV);
-          if(!debug_optics) {
-            SkinSurface sensorSkin(desc, sensorDE, "sensor_optical_surface", sensorSurf, sensorVol); // TODO: 3rd arg needs `imod`?
+          if (!debug_optics) {
+            SkinSurface sensorSkin(desc, sensorDE, "sensor_optical_surface", sensorSurf,
+                                   sensorVol); // TODO: 3rd arg needs `imod`?
             sensorSkin.isValid();
           };
 
@@ -259,18 +264,44 @@ static Ref_t createDetector(Detector& desc, xml::Handle_t handle, SensitiveDetec
     };
   };
   // END SENSOR MODULE LOOP ------------------------
-
+  //
+  // Add service material if desired
+  if (detElem.child("sensors").hasChild("services")) {
+    xml_comp_t x_service = detElem.child("sensors").child(_Unicode(services));
+    Assembly   service_vol("services");
+    service_vol.setVisAttributes(desc, x_service.visStr());
+
+    // Compute service total thickness from components
+    double     total_thickness = 0;
+    xml_coll_t ci(x_service, _Unicode(component));
+    for (ci.reset(), total_thickness = 0.0; ci; ++ci) {
+      total_thickness += xml_comp_t(ci).thickness();
+    }
+
+    int    ncomponents   = 0;
+    double thickness_sum = -total_thickness / 2.0;
+    for (xml_coll_t ci(x_service, _Unicode(component)); ci; ++ci, ncomponents++) {
+      xml_comp_t x_comp    = ci;
+      double     thickness = x_comp.thickness();
+      Tube       c_tube{sensorPlaneRmin, sensorPlaneRmax, thickness};
+      Volume     c_vol{_toString(ncomponents, "component%d"), c_tube, desc.material(x_comp.materialStr())};
+      c_vol.setVisAttributes(desc, x_comp.visStr());
+      service_vol.placeVolume(c_vol, Position(0, 0, thickness_sum + thickness / 2.0));
+      thickness_sum += thickness;
+    }
+    gasvolVol.placeVolume(service_vol,
+                          Transform3D(Translation3D(sensorPlanePos.x(), sensorPlanePos.y(),
+                                                    sensorPlanePos.z() - sensorThickness - total_thickness)));
+  }
 
   // place gas volume
-  PlacedVolume gasvolPV = vesselVol.placeVolume(gasvolVol,Position(0, 0, 0));
-  DetElement gasvolDE(det, "gasvol_de", 0);
+  PlacedVolume gasvolPV = vesselVol.placeVolume(gasvolVol, Position(0, 0, 0));
+  DetElement   gasvolDE(det, "gasvol_de", 0);
   gasvolDE.setPlacement(gasvolPV);
 
   // place mother volume (vessel)
-  Volume motherVol = desc.pickMotherVolume(det);
-  PlacedVolume vesselPV = motherVol.placeVolume(vesselVol,
-      Position(0, 0, vesselZmin) - originFront
-      );
+  Volume       motherVol = desc.pickMotherVolume(det);
+  PlacedVolume vesselPV  = motherVol.placeVolume(vesselVol, Position(0, 0, vesselZmin) - originFront);
   vesselPV.addPhysVolID("system", detID);
   det.setPlacement(vesselPV);