definitions.xml

  <define>
    <constant name="world_side" value="30*m"/>
    <constant name="world_x" value="world_side"/>
    <constant name="world_y" value="world_side"/>
    <constant name="world_z" value="100*m"/>

    <constant name="Pi" value="3.14159265359"/>
    <constant name="mil" value="0.0254*mm"/>
    <constant name="inch" value="2.54*cm"/>

    <documentation>
      ## Detector IDs

      ### Note about ACTS tracking geometry construction

The tracking surfaces need to be structured in a barrel + endcapP + endcapN where 
endcapP/endcapN are the endcaps at positive/negative z values. 
See https://acts.readthedocs.io/en/latest/plugins/dd4hep.html for more details.

The tracking geometry needs to be constructed from cylinders from the inside out. For this reason
each layer needs its own subsystem assembly. This increases the number of top level system IDs. 
For example the silicon tracker needs 3 IDs for each area (endcap+barrel+endcap) and a subassembly for each
layer. Therefore it needs a minimum of 20 IDs. Therefore we will allocate blocks of ~25 for each major subsystem.
Note, future improvements will likely include a more sophisticated ACTS-dd4hep plugin, 
eliminating the need for so many system IDs at construction time.

This barrel/endcap structure needs IDs to be in increasing order going outward. 
The space of IDs for the subassemblies starts at (Subassembly_ID*10+101).

The unused IDs below are saved for future use.
    </documentation>


    <documentation> 

      ### Allocated IDs 

      #### (1-9) Reserved IDs

      - Unused IDs: 1-9 

      #### (10-24) Interaction region beamline 

      - Beampipe ID : 10
      - Unused   IDs: 11-24

    </documentation> 
    <constant name="BeamPipe_ID" value="10"/>
    <constant name="BeamPipeB0_ID" value="11"/>


    <documentation> 
      #### (25-49) Silicon Vertex Tracker

       - SiVertex subsystem  ID: 25 
       - Layer 1 subassembly ID: 26
       - Layer 2 subassembly ID: 27
       - Layer 3 subassembly ID: 28
       - Layer 4 subassembly ID: 29
       - Layer 5 subassembly ID: 30
    </documentation>
    <constant name="VertexBarrel_ID" value="25"/>
    <constant name="VertexBarrelSubAssembly_ID" value="26"/>
    <constant name="VertexEndcapSubAssembly_ID" value="27"/>
    <constant name="VertexEndcapP_ID" value="30"/>
    <constant name="VertexEndcapN_ID" value="40"/>
    
    <documentation>
       - Unused IDs: 31-49
    </documentation>

    <documentation>
      #### (50-74) Silicon Tracker System

      SiTracker subsystem  ID: 50
      Layer 1 subassembly  ID: 51      
      Layer 2 subassembly  ID: 52      
      Layer 3 subassembly  ID: 53
      Layer 4 subassembly  ID: 54
      Layer 5 subassembly  ID: 55
      (56-70) etc...
      Unused IDs: 71-74

    </documentation>

    <constant name="TrackerBarrelSubAssembly_Inner_ID" value="50"/>
    <constant name="TrackerEndcapSubAssembly_Inner_ID" value="51"/>

    <constant name="TrackerBarrelSubAssembly_Outer_ID" value="52"/>
    <constant name="TrackerEndcapSubAssembly_Outer_ID" value="53"/>
    <constant name="OuterTrackingSubAssembly_ID" value="54"/>

    <!--constant name="TrackerSubAssemblyLayer4_ID" value="54"/-->
    <!--constant name="TrackerSubAssemblyLayer5_ID" value="55"/-->

    <constant name="TrackerBarrel_Inner_ID"      value="56"/>
    <constant name="TrackerEndcapP_Inner_ID"     value="57"/>
    <constant name="TrackerEndcapN_Inner_ID"     value="58"/>

    <constant name="TrackerBarrel_Outer_ID"      value="59"/>
    <constant name="TrackerEndcapP_Outer_ID"     value="60"/>
    <constant name="TrackerEndcapN_Outer_ID"     value="61"/>

    <constant name="TrackerBarrel_Layer3_ID"      value="62"/>
    <constant name="TrackerEndcapP_Layer3_ID"     value="63"/>
    <constant name="TrackerEndcapN_Layer3_ID"     value="64"/>

    <constant name="TrackerBarrel_Layer4_ID"      value="65"/>
    <constant name="TrackerEndcapP_Layer4_ID"     value="66"/>
    <constant name="TrackerEndcapN_Layer4_ID"     value="67"/>

    <constant name="TrackerBarrel_Layer5_ID"      value="68"/>
    <constant name="TrackerEndcapP_Layer5_ID"     value="69"/>
    <constant name="TrackerEndcapN_Layer5_ID"     value="70"/>

    <documentation>
    #### (75-84) Barrel Tracker IDs

    - MMTrackerBarrel ID: 75
    - RWellTrackerBarrel ID: 76
    - Unused IDs: 77-89

    </documentation>
    <constant name="MMTrackerBarrel_ID" value="75"/>
    <constant name="RWellTrackerBarrel_ID" value="76"/>

    <documentation>
    #### (85-99) Reserved IDs

    - Unused IDs: 85-89 
    TBD
    </documentation>
    <documentation> 
    #### (90-99) Barrel PID IDs

    - DIRC subsystem       ID: 90
    - Barrel TRD subsystem ID: 91
    - Barrel TOF subsystem ID: 92
    - Unused IDs: 93-99
    </documentation>
    <constant name="BarrelDIRC_ID" value="90"/>
    <constant name="BarrelTRD_ID"  value="91"/>
    <constant name="BarrelTOF_ID"  value="92"/>
    <constant name="TOFSubAssembly_ID" value="93"/>

    <documentation> 
      #### (100-109) Electromagnetic Calorimeter

      ECal     subsystem  ID:  100
      Barrel   subassembly ID: 101
      EndcapP  subassembly ID: 102
      EndcapN  subassembly ID: 103
      Crystal  subassembly ID: 104
      Barrel2  subassembly ID: 105

      Unused IDs: 106-109

    </documentation>
    <constant name="ECalSubAssembly_ID" value="100"/>
    <constant name="ECalBarrel_ID"      value="101"/>
    <constant name="ECalEndcapP_ID"     value="102"/>
    <constant name="ECalEndcapN_ID"     value="103"/>
    <constant name="CrystalEndcap_ID"   value="104"/>
    <constant name="ECalBarrel2_ID"     value="105"/>

    <documentation> 
      #### (110-119) Hadronic Calorimeter

      - HCal     subsystem  ID:  110
      - Barrel   subassembly ID: 111
      - EndcapP  subassembly ID: 112
      - EndcapN  subassembly ID: 113

      - Unused IDs: 115-119
    </documentation>
    <constant name="HCalSubAssembly_ID" value="110"/>
    <constant name="HCalBarrel_ID"      value="111"/>
    <constant name="HCalEndcapP_ID"     value="112"/>
    <constant name="HCalEndcapN_ID"     value="113"/>
    <!--constant name="ci_HCAL_id"         value="200"/-->
    <documentation> 
      #### (120-129) (near) Forward reserved

      - Forwardtracking ID: 120
      - Forward RICH    ID: 121

      - Unused IDs: 124-129
    </documentation>
    <constant name="ForwardTracking_ID" value="120"/>
    <constant name="ForwardRICH_ID"     value="121"/>
    <!--constant name="ci_GEM_id"          value="122"/-->
    <constant name="ForwardTRD_ID"      value="123"/>
    <constant name="GEMTrackerEndcapP_ID" value="124"/>
    <constant name="GEMTrackerEndcapN_ID" value="125"/>
    <constant name="ForwardTOF_ID"      value="126"/>
    <constant name="BackwardTOF_ID"      value="127"/>

    <documentation> 
      #### (130-139) Backward reserved

      - Modular RICH ID: 130
      - Electron Endcap GEM tracking ID: 131
      - Unused IDs: 132-139

    </documentation>
    <constant name="MRICH_ID"        value="130"/>
    <!--constant name="ce_GEM_ID"          value="131"/-->

    <documentation> 
      #### (140-149) Central Magnet

      - Solenoid         ID: 140
      - Solenoid support ID: 141
      - Solenoid Yoke    ID: 142

      - Unused IDs: 143-149

    </documentation>
    <constant name="Solenoid_ID"             value="140"/>
    <constant name="SolenoidSupport_ID"      value="141"/>
    <constant name="SolenoidYoke_ID"         value="142"/>

    <documentation> 
      #### (150-169) Far Forward  Detectors

      - Forward Roman Pot     ID: 150
      - Forward B0 Tracker    ID: 151
      - Zero Degree Cal. Ecal ID: 160
      - Zero Degree Cal. Hcal ID: 161

      TODO: A lot of the  repeated ID's below should be pushed into a single detector
    </documentation>
    <constant name="B0Tracker_Station_1_ID"          value="150"/>
    <constant name="B0Tracker_Station_2_ID"          value="151"/>
    <constant name="B0Tracker_Station_3_ID"          value="152"/>
    <constant name="B0Tracker_Station_4_ID"          value="153"/>
    <constant name="B0Preshower_Station_1_ID"        value="154"/>
	  <constant name="ForwardRomanPot_Station_1_ID"    value="155"/>
    <constant name="ForwardRomanPot_Station_2_ID"    value="156"/>
	  <constant name="ForwardOffMTracker_station_1_ID" value="159"/>
    <constant name="ForwardOffMTracker_station_2_ID" value="160"/>
    <constant name="ForwardOffMTracker_station_3_ID" value="161"/>
    <constant name="ForwardOffMTracker_station_4_ID" value="162"/>
    <comment> TODO naming consistency </comment>
    <constant name="ffi_ZDC_ECAL_ID"                 value="163"/>
    <constant name="ffi_ZDC_HCAL_ID"                 value="164"/>

    <documentation> 
      #### (170-189) Forward Beamline Magnets
    </documentation>

    <documentation> 
      #### (190-199) Backward Beamline Magnets
    </documentation>

    <documentation>
## Detector Definition Parameters 

## Constant naming convention

SubSystemNameFurtherDescriptor_quantity

Examples: 
 - TrackerBarrelInside_length
 - EcalEndcapP_rmin
 - MRichFresnelLens_thickness

### Naming Barrel and Endcaps

 - **Barrel**
 - **EndcapP**
   - Postive Endcap (+z direction)
   - This is the ion beam side
 - **EndcapN**
   - Negative Endcap (-z direction) 
   - This is the electron beam side
       
## Parameter nomenclature

 - "rmin", "rmax", "thickness" all refer to the radial direction.
 - "zmin", "zmax", "length", "offset" all refer to the z direction.
 - Positive and Negative are  "EndcapP" and "EndcapN", respectively.
 - All values are positive (except offsets, which are positive in the hadron direction, i.e. towards EndCapP).
     When refering to a negative endcap z position, the values are
     also positive then negated when required. (Many endcap constructions are mirrored, 
     hence a postive value.)
 - We will try to keep the subsystem component name first and the parameter after an "_" (eg, EcalBarrel_length").

    </documentation>

    <documentation>
      ## Solenoid Magnet Parameters

      When changing here, also change the include file in athena.xml.
    </documentation>

    <comment>Solenoid option</comment>
    <constant name="Solenoid_length"           value="3840.0*mm"/>
    <constant name="Solenoid_rmin"             value="1600.0*mm"/>
    <constant name="Solenoid_thickness"        value="640*mm"/>
    <constant name="Solenoid_offset"           value="10*mm"/>

    <comment>Helmholtz option</comment>
    <comment>
    <constant name="Solenoid_length"           value="3840.0*mm"/>
    <constant name="Solenoid_rmin"             value="1655.0*mm"/> <!-- Larger inner bore radius -->
    <constant name="Solenoid_thickness"        value="640*mm"/>
    <constant name="Solenoid_offset"           value="10*mm"/>
    </comment>

    <constant name="Solenoid_rmax"             value="Solenoid_rmin + Solenoid_thickness"/>
    <constant name="SolenoidBarrel_rmin"       value="Solenoid_rmin"/>
    <constant name="SolenoidBarrel_length"     value="Solenoid_length"/>
    <constant name="SolenoidBarrel_zmax"       value="Solenoid_length/2.0"/>


    <documentation level="0">
      ## Key Central Detector Parameters

      These are needed here to compute the dependent parameters.


      ### PID Detector Region Parameters
    </documentation>

    <constant name="ForwardPID_length"            value="180.0*cm"/>
    <constant name="ForwardTracking_length"       value="5.0*cm"/>
    <constant name="ForwardPID_rmin1"             value="Beampipe_rmax + 80*mm"/>
    <constant name="ForwardPID_rmin2"             value="19.0*cm"/>
    
    <!--constant name="BackwardPID_rmax"             value="83.65*cm"/-->
    <constant name="BackwardPID_rmax"             value="95.*cm"/>
    <constant name="BackwardPID_length"           value="40.0*cm"/>
    <constant name="BackwardTracking_length"      value="5.0*cm"/>
    <constant name="BackwardTOF_length"           value="0.0*cm"/>

    <comment> Note: PID has space for DIRC, ExtraSpace has room for other detectors past the PID</comment>
    <constant name="BarrelPIDThickness"           value="10.0 * cm"/>
    <constant name="BarrelExtraSpaceThickness"    value="7.0 * cm"/>


    <documentation>
     Service gaps in FW direction (before endcapP ECAL) and BW direction (before endcapN HCAL)
    </documentation>
    <constant name="ForwardServiceGap_length"     value="10.0*cm"/>
    <constant name="BackwardServiceGap_length"    value="10.0*cm"/>

    <documentation>
      ## Tracking Detector Parameters

      Generic tracking space allocations
    </documentation>

    <documentation>
      ## Vertex Tracker Parameters
    </documentation>
    <constant name="VertexTrackerBarrel_rmin"   value="Beampipe_rmax + 1.0*mm"/>
    <constant name="VertexTrackerBarrel_rmax"   value="200.0*mm"/>
    <constant name="VertexTrackerBarrel_length" value="300.0*mm"/>
    <constant name="VertexTrackerBarrel_zmax"   value="VertexTrackerBarrel_length/2.0"/>

    <constant name="VertexTrackerEndcapP_rmax"  value="VertexTrackerBarrel_rmax"/>
    <constant name="VertexTrackerEndcapN_rmax"  value="VertexTrackerBarrel_rmax"/>

    <constant name="VertexTrackerEndcapP_rmin"  value="Beampipe_rmax + 5.0*mm"/>
    <constant name="VertexTrackerEndcapN_rmin"  value="Beampipe_rmax + 5.0*mm"/>

    <constant name="VertexTrackerEndcapP_zmax"  value="300.0*mm"/>
    <constant name="VertexTrackerEndcapN_zmax"  value="300.0*mm"/>

    <documentation>
      ### Vertex Tracking Region
    </documentation>
    <constant name="VertexTrackingRegion_length" value="VertexTrackerEndcapP_zmax + VertexTrackerEndcapN_zmax "/>
    <constant name="VertexTrackingRegion_zmax"   value="VertexTrackerEndcapP_zmax"/>
    <constant name="VertexTrackingRegion_rmax"   value="VertexTrackerBarrel_rmax"/>

    <documentation>
      ### Tracker Detector Parameters
      TrackerBarrel_rmax: also the rmin for the barrel PID system (DIRC)
    </documentation>

    <constant name="TrackerBarrel_rmin"         value="VertexTrackingRegion_rmax"/>
    <constant name="TrackerBarrel_rmax"         value="BackwardPID_rmax"/> 
    <constant name="TrackerBarrel_thickness"    value="TrackerBarrel_rmax-TrackerBarrel_rmin"/>

    <constant name="TrackerBarrel_length"       value="VertexTrackingRegion_length + 2000.0*mm"/>
    <constant name="TrackerBarrelInside_length" value="VertexTrackingRegion_length"/>
    <constant name="TrackerBarrelInside_zmax"   value="TrackerBarrelInside_length/2.0"/>
    <constant name="TrackerBarrel_zmax"    value="TrackerBarrel_length/2.0"/>

    <documentation>
      `TrackerBarrelForwardPadding` and `TrackerBarrelBackwardPadding` compensate for the asymmetry of the setup
    </documentation>
    <constant name="TrackerBarrelForwardPadding" value="25.0*cm"/>
    <constant name="TrackerBarrelBackwardPadding" value="7.5*cm"/>
 

    <comment> Deprecated
    constant name="SiliconTrackerInnerRadius"       value="TrackerBarrel_rmin"
    constant name="SiliconTrackerInnerBarrelLength" value="TrackerBarrelInner_length"
    constant name="SiliconTrackerOuterRadius"       value="TrackerBarrel_rmax"
    constant name="SiliconTrackerOuterBarrelLength" value="TrackerBarrelOuter_length"
    constant name="SiliconTrackerOuterBarrel_zmax"  value="TrackerBarrelOuter_length/2.0"
    TrackerBarrelOuter_length  -> TrackerBarrel_length
    TrackerBarrelInner_length  -> TrackerBarrelInside_length
    </comment>

    <documentation>
## Central tracking and PID detector boundaries

The central tracking detectors are assumed to be symmtric about the origin.
      
    </documentation>
    <constant name="BarrelTracking_length"       value="TrackerBarrel_length"/>
    <constant name="BarrelTracking_rmax"         value="TrackerBarrel_rmax"/>
    <constant name="BarrelTracking_zmax"         value="BarrelTracking_length/2.0"/>

    <constant name="BarrelTrackingAndPID_length" value="BarrelTracking_length"/>
    <constant name="BarrelTrackingAndPID_rmax"   value="BarrelTracking_rmax   + BarrelPIDThickness"/>

    <constant name="CentralTracking_length"      value="BarrelTracking_length + TrackerBarrelForwardPadding + TrackerBarrelBackwardPadding"/>
    <constant name="CentralTracking_rmax"        value="TrackerBarrel_rmax"/>
    <constant name="CentralTrackingHalfN_length" value="BarrelTracking_length/2. + TrackerBarrelBackwardPadding"/>
    <constant name="CentralTrackingHalfP_length" value="BarrelTracking_length/2. + TrackerBarrelForwardPadding"/>

    <comment> These are used by ddsim </comment>
    <constant name="tracker_region_rmax"   value="CentralTracking_rmax"/>
    <constant name="tracker_region_zmax"   value="CentralTracking_length/2.0"/>

    <comment> Total length of the endcap detectors</comment>
    <constant name="BackwardInnerEndcap_length"    value="BackwardPID_length + BackwardTracking_length"/>
    <constant name="ForwardInnerEndcap_length"     value="ForwardPID_length + ForwardTracking_length"/>

  <documentation level="3">
## Calorimeter Parameters

### Note on paramaeterization 

The HCal Barrel is outside of the solenoid magnet.  However,
there is an option to add some HCal barrel inside the magnet but this
is turned off below.

The space for the calorimeters inside the solenoid is assumed to be fixed by 
the solenoid inner diameter/length and by the central tracking and PID outer diameter/length.

### Endcaps

The extra endcap lengths are for offsetting the outside endcap surface (zmax) from the
end of the solenoid coils.

  </documentation>

    <comment> these offesets could be implemented differently for clarity. </comment>
    <constant name="EcalEndcapPSolenoid_offset" value="800.0*mm" />
    <constant name="EcalEndcapNSolenoid_offset" value="-100.0*mm" />

    <constant name="EndcapPExtra_length"    value="40.0*cm"/>
    <constant name="EndcapNExtra_length"    value="0.0*cm"/>

    <constant name="SolenoidYokeEndcapP_zmin"  value="Solenoid_length/2.0 + Solenoid_offset + EndcapPExtra_length"/>
    <constant name="SolenoidYokeEndcapN_zmin"  value="Solenoid_length/2.0 - Solenoid_offset + EndcapNExtra_length"/>

    <constant name="EcalBarrel_rmin"            value="BarrelTrackingAndPID_rmax + BarrelExtraSpaceThickness"/>
    <constant name="Barrel_rmax"                value="Solenoid_rmin - 1.0 *cm "/>
    <constant name="Barrel_TotalCalThickness"   value="Barrel_rmax - EcalBarrel_rmin"/>

    <constant name="EcalBarrel_TotalThickness"  value="40.0*cm"/>

    <constant name="EcalEndcapP_zmin"           value="CentralTrackingHalfP_length + ForwardInnerEndcap_length + ForwardServiceGap_length"/>
    <constant name="EcalEndcapN_zmin"           value="max(CentralTrackingHalfN_length+ BackwardInnerEndcap_length, SolenoidYokeEndcapN_zmin)"/>

    <constant name="BarrelLength"               value="BarrelTrackingAndPID_length" />
    <constant name="Barrel_offset"              value="(EcalEndcapP_zmin-EcalEndcapN_zmin)/2.0" />


    <documentation>
      ### Ecal  Endcaps
    </documentation>

    <comment>
      Unused, TBD
    </comment>
    <constant name="EndcapPTotalCal_length"  value="(SolenoidYokeEndcapP_zmin + EcalEndcapPSolenoid_offset) - (EcalEndcapP_zmin)"/>
    <constant name="EndcapNTotalCal_length"  value="(SolenoidYokeEndcapN_zmin + EcalEndcapNSolenoid_offset) - (EcalEndcapN_zmin)"/>

    <!--constant name="EndcapP_CalDivide"          value="0.8"/> <comment> 0.5 means Ecal and Hcal have the same thickness </comment-->
    <!--constant name="EndcapN_CalDivide"          value="1.0"/> <comment> 0.5 means Ecal and Hcal have the same thickness </comment-->

    <!--constant name="EcalEndcapP_length" value="EndcapPTotalCal_length * EndcapP_CalDivide"/-->
    <constant name="EcalEndcapP_length" value="40*cm"/>
    <!--constant name="EcalEndcapN_length" value="EndcapNTotalCal_length * EndcapN_CalDivide"/-->
    <constant name="EcalEndcapN_length" value="60*cm"/>


    <documentation>
EcalEndcapP_rmin and EcalEndcapN_rmin need to be set in sync with the forward and backward detectors.
    </documentation>
    <constant name="EcalEndcapP_rmin"                      value="200.0*mm"/>
    <constant name="EcalEndcapN_rmin"                      value="max((EcalEndcapN_zmin + EcalEndcapN_length) * tan(abs(CrossingAngle)) + 12.5 * mm, 5*cm)"/>
    <constant name="EcalEndcapN_rmax"                      value="BarrelTracking_rmax"/>

    <documentation>
      ## EM Calorimeter Parameters

       ### Note about Calormieter parameterization.
      
The logic goes like this: 
1. The space for the calorimeter is fixed via parameterization above.
2. The layer thicknesses are fixed (first parameters below)
3. From the space/thickness the number of layers is computed.

    </documentation>
    <constant name="CaloSides"                  value="12"/>
      
    <documentation>
      Calorimeter slice material thicknesses
    </documentation>
    <constant name="EcalSiliconThickness"       value="9.00 * mm" />
    <constant name="EcalCopperThickness"        value="0.05 * mm" />
    <constant name="EcalKaptonThickness"        value="0.30 * mm" />
    <constant name="EcalAir1Thickness"          value="0.33 * mm" />
    <constant name="EcalAir2Thickness"          value="0.25 * mm" />
    <constant name="EcalThinTungstenThickness"  value="2.50 * mm" />
    <constant name="EcalThickTungstenThickness" value="5.00 * mm" />
      
    <comment> Layer Thickness  </comment>
    <constant name="EcalLayer1_thickness"
        value="EcalSiliconThickness + EcalCopperThickness + EcalKaptonThickness + EcalAir1Thickness"/>
    <constant name="EcalLayer2_thickness"   
        value="EcalThinTungstenThickness + EcalAir2Thickness + EcalSiliconThickness + EcalCopperThickness + EcalKaptonThickness + EcalAir1Thickness"/>
    <constant name="EcalLayer3_thickness"   
        value="EcalThickTungstenThickness + EcalAir2Thickness + EcalSiliconThickness + EcalCopperThickness + EcalKaptonThickness + EcalAir1Thickness"/>
      
    <comment> EM Barrel N Layer; same number of layers for EcalThin and EcalThick</comment>
    <constant name="EcalBarrelLayers" 
        value="floor((EcalBarrel_TotalThickness - EcalLayer1_thickness) / (EcalLayer2_thickness + EcalLayer3_thickness))"/>
    <constant name="EcalBarrelLayer1_NRepeat"       value="1"/>
    <constant name="EcalBarrelLayer2_NRepeat"       value="EcalBarrelLayers"/>
    <constant name="EcalBarrelLayer3_NRepeat"       value="EcalBarrelLayers"/>

    <comment> EM Barrel Thickness </comment>
    <constant name="EcalBarrelThickness"
        value="EcalBarrelLayer1_NRepeat*EcalLayer1_thickness + EcalBarrelLayer2_NRepeat * EcalLayer2_thickness + EcalBarrelLayer3_NRepeat * EcalLayer3_thickness"/>
    <constant name="EcalBarrel_rmax"            value="EcalBarrel_rmin + EcalBarrelThickness"/>

    <comment> EM Endcap N Layer; same number of layers for EcalThin and EcalThick </comment>
    <constant name="EcalEndcapPLayers" 
        value="floor((EcalEndcapP_length - EcalLayer1_thickness) / (EcalLayer2_thickness + EcalLayer3_thickness))"/>
    <constant name="EcalEndcapNLayers" 
        value="floor((EcalEndcapN_length - EcalLayer1_thickness) / (EcalLayer2_thickness + EcalLayer3_thickness))"/>
    <constant name="EcalEndcapPLayer1_NRepeat"      value="1"/>
    <constant name="EcalEndcapNLayer1_NRepeat"      value="1"/>
    <constant name="EcalEndcapPLayer2_NRepeat"      value="EcalEndcapPLayers"/>
    <constant name="EcalEndcapPLayer3_NRepeat"      value="EcalEndcapPLayers"/>
    <constant name="EcalEndcapNLayer2_NRepeat"      value="EcalEndcapNLayers"/>
    <constant name="EcalEndcapNLayer3_NRepeat"      value="EcalEndcapNLayers"/>

    <comment> EM Endcap Thickness </comment>
    <!--constant name="EcalEndcapPThickness"        
        value="EcalEndcapPLayer1_NRepeat*EcalLayer1_thickness + EcalEndcapPLayer2_NRepeat*EcalLayer2_thickness + EcalEndcapPLayer3_NRepeat*EcalLayer3_thickness "/-->
    <!--constant name="EcalEndcapNThickness"        
        value="EcalEndcapNLayer1_NRepeat*EcalLayer1_thickness + EcalEndcapNLayer2_NRepeat*EcalLayer2_thickness + EcalEndcapNLayer3_NRepeat*EcalLayer3_thickness"/-->

    <constant name="EcalBarrel_length"           value="CentralTracking_length + BackwardInnerEndcap_length + EcalEndcapN_length"/>
    <constant name="EcalBarrel_offset"          value="(CentralTracking_length - EcalBarrel_length)/2.0"/>


    <comment> Special DIRC parameters (depend on the ECAL setup) </comment>
    <constant name="DIRCReadout_length"         value="30*cm" />
    <constant name="DIRC_length"                value="max(CentralTracking_length + BackwardInnerEndcap_length + EcalEndcapN_length, EcalBarrel_length) + DIRCReadout_length"/>
		<constant name="DIRCExtra_offset"           value="-5*cm"/>
    <constant name="DIRC_offset"                value="(CentralTracking_length - DIRC_length) / 2 - DIRCExtra_offset"/>
    <constant name="DIRCForward_zmax"           value="DIRC_length/2. + DIRC_offset"/>
    <constant name="DIRCBackward_zmax"          value="DIRC_length/2. - DIRC_offset"/>
    <constant name="DIRC_rmin"                  value="BarrelTracking_rmax"/>
    <constant name="DIRC_rmax"                  value="DIRC_rmin + BarrelPIDThickness"/>

    <documentation>
      ## Hadronic Calorimeter Parameters
    </documentation>

    <constant name="HcalEndcapP_zmin"          value="max(EcalEndcapP_zmin + EcalEndcapP_length, Solenoid_length / 2.0 + Solenoid_offset) "/>
    <!--constant name="HcalEndcapN_zmin"          value="max(EcalEndcapN_zmin + EcalEndcapN_length, Solenoid_length / 2.0 - Solenoid_offset) "/-->
    <comment> Hard coded for now, but we really need to fix the parametrization...</comment>
    <comment> Note: we can go up to 350cm here for 1m thick hcal</comment>
    <constant name="HcalEndcapN_zmin"          value="DIRCBackward_zmax + BackwardServiceGap_length"/>

    <constant name="HcalEndcapP_length"   value="120.0*cm"/>
    <constant name="HcalEndcapN_length"   value="105.0*cm"/>

    <comment> HcalEndcapP needs to clear the expanding beampipe with 2 * crossing angle + its radius of BeampipeOD / 2</comment>
    <constant name="HcalEndcapP_rmin"     value="max((HcalEndcapP_zmin + HcalEndcapP_length) * tan(2.0 * abs(CrossingAngle)) + BeampipeOD / 2.0, 15 * cm)"/>
    <comment> HcalEndcapP needs to clear the straight beampipe with 1 * crossing angle + its radius of 22.25 mm </comment>
    <constant name="HcalEndcapN_rmin"     value="max((HcalEndcapN_zmin + HcalEndcapN_length) * tan(abs(CrossingAngle)) + 22.25 * mm, 11 * cm)"/>

    <constant name="HcalBarrel_thickness" value="100.0*cm "/>
    <constant name="HcalBarrel_rmin"      value="Solenoid_rmax"/>
    <constant name="HcalBarrel_rmax"      value="HcalBarrel_rmin + HcalBarrel_thickness"/>

    <constant name="HcalBarrelAvailThickness" value="HcalBarrel_thickness"/>

    <constant name="HcalBarrelLength"          value="HcalEndcapP_zmin + HcalEndcapN_zmin "/>

    <documentation>
      #### Material Thickness 
    </documentation>
    <constant name="HcalBarrelSteelThickness"        value="2.0 * cm"/>
    <constant name="HcalBarrelPolystyreneThickness"  value="0.5 * cm"/>
    <constant name="HcalEndcapNSteelThickness"       value="HcalBarrelSteelThickness"/>
    <constant name="HcalEndcapNPolystyreneThickness" value="HcalBarrelPolystyreneThickness"/>
    <constant name="HcalEndcapPSteelThickness"       value="HcalBarrelSteelThickness"/>
    <constant name="HcalEndcapPPolystyreneThickness" value="0.3 * cm"/>

    <documentation>
      - Hcal Barrel Layers and computed Thickness
    </documentation>
    <constant name="HcalBarrelSingleLayerThickness"
             value="HcalBarrelSteelThickness + HcalBarrelPolystyreneThickness"/>
    <constant name="HcalBarrelLayer_NRepeat" value="floor(HcalBarrelAvailThickness / HcalBarrelSingleLayerThickness)"/>
    <constant name="HcalBarrelThickness" value="HcalBarrelLayer_NRepeat * HcalBarrelSingleLayerThickness"/>

    <documentation>
      - Hcal Endcap P Layers and computed Thickness
    </documentation>
    <constant name="HcalEndcapNSingleLayerThickness"
             value="HcalEndcapNSteelThickness + HcalEndcapNPolystyreneThickness"/>
    <constant name="HcalEndcapNLayer_NRepeat" value="floor(HcalEndcapN_length / HcalEndcapNSingleLayerThickness)"/>
    <constant name="HcalEndcapN_thickness" value="HcalEndcapNLayer_NRepeat * HcalEndcapNSingleLayerThickness"/>

    <documentation>
      - Hcal Endcap P Layers and computed Thickness
    </documentation>
    <constant name="HcalEndcapPSingleLayerThickness"
             value="HcalEndcapPSteelThickness + HcalEndcapPPolystyreneThickness"/>
    <constant name="HcalEndcapPLayer_NRepeat" value="floor(HcalEndcapP_length / HcalEndcapPSingleLayerThickness)"/>
    <constant name="HcalEndcapP_thickness" value="HcalEndcapPLayer_NRepeat * HcalEndcapPSingleLayerThickness"/>


  </define>