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"/>

    <comment>Although not explicit in the EIC design study, the crossing angle is not symmetric.</comment>
    <constant name="CrossingAngle" value="0.025"/>
    <constant name="ionCrossingAngle" value="0.0166667"/>
    <constant name="electronCrossingAngle" value="0.00833333"/>
    <constant name="CrossingSlope" value="0.0166682"/>

    <constant name="Pi" value="3.14159265359"/>

    <constant name="mil" value="0.0254*mm"/>

    <comment>
      ------------
      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.
    </comment>


    <comment> 
      ===================
      (1-9) Reserved IDs
      ===================
      Unused IDs: 1-9 

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

      Beampipe ID : 10
      Unused   IDs: 11-24

    </comment> 
    <constant name="BeamPipe_ID" value="10"/>


    <comment> 
      ===============================
      (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
    </comment>
    <constant name="cb_VTX_Barrel_ID" value="25"/>
    <comment>
      Unused values reserved for vertex:
      constant name="SiVertexSubAssemblyLayer1_ID" value="121"
      constant name="SiVertexSubAssemblyLayer2_ID" value="122"
      constant name="SiVertexSubAssemblyLayer3_ID" value="123"
      constant name="SiVertexSubAssemblyLayer4_ID" value="124"
      constant name="SiVertexSubAssemblyLayer5_ID" value="125"
    </comment>

    <comment>
      ===============================
      (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

    </comment>

    <constant name="SiTrackerSubAssembly_ID" value="50"/>
    <constant name="SiTrackerSubAssemblyLayer1_ID" value="51"/>
    <constant name="SiTrackerSubAssemblyLayer2_ID" value="52"/>
    <constant name="SiTrackerSubAssemblyLayer3_ID" value="53"/>
    <constant name="SiTrackerSubAssemblyLayer4_ID" value="54"/>
    <constant name="SiTrackerSubAssemblyLayer5_ID" value="55"/>

    <constant name="SiTrackerBarrel_Layer1_ID"      value="56"/>
    <constant name="SiTrackerEndcapP_Layer1_ID"     value="57"/>
    <constant name="SiTrackerEndcapN_Layer1_ID"     value="58"/>

    <constant name="SiTrackerBarrel_Layer2_ID"      value="59"/>
    <constant name="SiTrackerEndcapP_Layer2_ID"     value="60"/>
    <constant name="SiTrackerEndcapN_Layer2_ID"     value="61"/>

    <constant name="SiTrackerBarrel_Layer3_ID"      value="62"/>
    <constant name="SiTrackerEndcapP_Layer3_ID"     value="63"/>
    <constant name="SiTrackerEndcapN_Layer3_ID"     value="64"/>

    <constant name="SiTrackerBarrel_Layer4_ID"      value="65"/>
    <constant name="SiTrackerEndcapP_Layer4_ID"     value="66"/>
    <constant name="SiTrackerEndcapN_Layer4_ID"     value="67"/>

    <constant name="SiTrackerBarrel_Layer5_ID"      value="68"/>
    <constant name="SiTrackerEndcapP_Layer5_ID"     value="69"/>
    <constant name="SiTrackerEndcapN_Layer5_ID"     value="70"/>

    <constant name="cb_CTD_Si_ID"                   value="74"/>

    <comment> 
    ===================
    (75-99) Reserved IDs
    ===================

    Unused IDs: 75-89 
    TBD
    </comment>
    <comment> 
    ======================
    (90-99) Barrel PID IDs
    ======================

    DIRC subsystem       ID: 90
    Barrel TRD subsystem ID: 91
    Barrel TOF subsystem ID: 92

    Unused IDs: 93-99 
    </comment>
    <constant name="BarrelDIRC_ID" value="90"/>
    <constant name="BarrelTRD_ID"  value="91"/>
    <constant name="BarrelTOF_ID"  value="92"/>


    <comment> 
      =====================================
      (100-109) Electromagnetic Calorimeter
      =====================================

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

      Unused IDs: 105-109

    </comment>
    <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"/>

    <comment> 
      =====================================
      (110-119) Hadronic Calorimeter
      =====================================

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

      Unused IDs: 115-119
    </comment>
    <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"/>
    <comment> 
      =====================================
      (120-129) (near) Forward reserved
      =====================================

      Forwardtracking ID: 120
      Forward RICH    ID: 121

      Unused IDs: 124-129
    </comment>
    <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"/>

    <comment> 
      =====================================
      (130-139) Backward reserved
      =====================================

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

    </comment>
    <constant name="ce_MRICH_ID"        value="130"/>
    <constant name="ce_GEM_ID"          value="131"/>

    <comment> 
      =====================================
      (140-149) Central Magnet
      =====================================

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

      Unused IDs: 143-149

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

    <comment> 
      =====================================
      (150-169) Far Forward  Detectors
      =====================================

      Forward Roman Pot  ID: 150
      Forward B0 Tracker ID: 151
      Zero Degree Cal.   ID: 160

    </comment>
    <constant name="B0Tracker_ID"        value="150"/>
    <constant name="ForwardRomanPotA_ID" value="155"/>
    <constant name="ForwardRomanPotB_ID" value="156"/>
    <constant name="ForwardRomanPotC_ID" value="157"/>
    <constant name="ffi_ZDC_ID"          value="160"/>

    <comment> 
      =====================================
      (170-189) Forward Beamline Magnets
      =====================================
    </comment>

    <comment> 
      =====================================
      (190-199) Backward Beamline Magnets
      =====================================
    </comment>

    <comment>
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      Detector Definition Parameters 
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

      ## 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. 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").
           TODO: fix parameter naming to be uniform in the above convention.

    </comment>

    <comment>
      ==========================
      Solenoid Magnet Parameters
      ==========================
    </comment>

    <constant name="Solenoid_length"           value="7000.0*mm"/>
    <constant name="Solenoid_rmin"             value="3000.0*mm"/>
    <constant name="Solenoid_thickness"        value="400*mm"/>
    <constant name="Solenoid_offset"           value="600.0*mm"/>

    <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"/>


    <comment>
      --------------------------------
      Key Central Detector Parameters
      --------------------------------

      These are needed here to compute the dependent parameters.
    </comment>

    <constant name="ForwardRICH_length"       value="1.1*m"/>
    <constant name="ForwardTRD_length"        value="20.0*cm"/>
    <constant name="ForwardTOF_length" value="10.0*cm"/>
    
    <constant name="BackwardCherenkovLength"   value="15.0*cm"/>
    <constant name="BackwardTOFLength"         value="10.0*cm"/>

    <comment> Total length of PID detectors above</comment>
    <constant name="ForwardPIDLength"    value="ForwardRICH_length + ForwardTRD_length + ForwardTOF_length"/>
    <constant name="BackwardPIDLength"   value="BackwardCherenkovLength + BackwardTOFLength"/>

    <comment> Barrel PID thicknesses</comment>
    <constant name="BarrelExtraPIDThickness"  value="25.0 * cm"/>
    <constant name="BarrelTRDThickness"  value="25.0 * cm"/>
    <constant name="BarrelTOFThickness"  value="1.0 * cm"/>

    <comment>
      ============================
      Tracking Detector Parameters
      ============================
    </comment>

    <comment>
      -------------------------
      GEM Tracker Parameters
      -------------------------
    </comment>
    <constant name="ForwardTrackingGEMLength" value="30.0*cm"/>

    <comment>
      -------------------------
      Vertex Tracker Parameters
      -------------------------
    </comment>
    <constant name="VertexTrackerInnerRadius"       value="30.0*mm"/>
    <constant name="VertexTrackerOuterRadius"       value="90.0*mm"/>
    <constant name="VertexTrackerOuterBarrelLength" value="400.0*mm"/>

    
    <constant name="cb_VTX_Barrel_rmin"   value="33.0*mm"/>
    <constant name="cb_VTX_Barrel_rmax"   value="165.0*mm"/>
    <constant name="cb_VTX_Barrel_length" value="740.0*mm"/>

    <constant name="cb_VTX_Barrel_x_pos"   value="0.0*mm"/>
    <constant name="cb_VTX_Barrel_y_pos"   value="0.0*mm"/>
    <constant name="cb_VTX_Barrel_z_pos"   value="0.0*mm"/>

    <constant name="cb_VTX_Barrel_layer"   value="6"/>
    <comment>
      --------------------------
      Silicon Tracker Parameters
      --------------------------
    </comment>
    <constant name="SiliconTrackerInnerRadius"       value="95.0*mm"/>
    <constant name="SiliconTrackerInnerBarrelLength" value="300.0*mm"/>
    <constant name="SiliconTrackerOuterRadius"       value="Solenoid_rmax/3.0"/>
    <constant name="SiliconTrackerOuterBarrelLength" value="Solenoid_length/2.5"/>
    <constant name="SiliconTrackerOuterBarrel_zmax"  value="SiliconTrackerOuterBarrelLength/2.0"/>

    <comment>
      Central tracking boundaries

      The central tracking detectors are assumed to be symmtric about the origin.
      
    </comment>
    <constant name="CentralTracking_rmax"    value="SiliconTrackerOuterRadius"/>
    <constant name="CentralTracking_length"  value="SiliconTrackerOuterBarrelLength + ForwardTrackingGEMLength"/>

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


    <comment>
      -------------------------------
      Central Barrel Tracker - Global
      -------------------------------

      The cb_CTD_* parameters can probably be moved to the detector specific xml file.
    </comment>
    <constant name="cb_CTD_rmin"   value="SiliconTrackerInnerRadius + 70.0 * mm"/>
    <constant name="cb_CTD_rmax"   value="SiliconTrackerOuterRadius"/>
    <constant name="cb_CTD_zmax"   value="SiliconTrackerOuterBarrel_zmax"/>
    <constant name="cb_CTD_length" value="SiliconTrackerOuterBarrelLength"/>

    <comment>
      ------------
      Calorimeters
      ------------
      ======================
      Calorimeter Parameters
      ======================

    </comment>
    <comment>
      Ecal and Hcal Barrel/Endcap 
    </comment>

    <constant name="ExtraHcalEndcapP_length"   value="0.0*cm"/>
    <constant name="ExtraHcalEndcapN_length"   value="0.0*cm"/>
    <constant name="SolenoidYokeEndcapP_zmin"  value="Solenoid_length/2.0 + Solenoid_offset+ExtraHcalEndcapP_length"/>
    <constant name="SolenoidYokeEndcapN_zmin"  value="Solenoid_length/2.0 - Solenoid_offset+ExtraHcalEndcapN_length"/>

    <constant name="EcalBarrel_rmin"            value="SiliconTrackerOuterRadius + BarrelExtraPIDThickness + 5.0 * mm"/>
    <constant name="HcalBarrel_rmax"            value="Solenoid_rmin - 10.0 *cm "/>
    <constant name="Barrel_TotalCalThickness"   value="HcalBarrel_rmax - EcalBarrel_rmin"/>
    <constant name="CalBarrelDivider"           value="0.5"/> <comment> Ecal and Hcal have the same thickness </comment>

    <constant name="EcalBarrel_TotalThickness"  value="Barrel_TotalCalThickness * CalBarrelDivider"/>
    <constant name="HcalBarrel_TotalThickness"  value="Barrel_TotalCalThickness * (1.0 - CalBarrelDivider)"/>

    <constant name="EcalBarrelLength"           value="CentralTracking_length + BackwardPIDLength"/>
    <constant name="EcalBarrel_offset"          value="(CentralTracking_length -(CentralTracking_length+BackwardPIDLength))/2.0"/>

    <constant name="EcalEndcapP_zmin"           value="CentralTracking_length/2.0 + ForwardPIDLength"/>
    <constant name="EcalEndcapN_zmin"           value="CentralTracking_length/2.0 + BackwardPIDLength"/>

    <constant name="BarrelLength"               value="SiliconTrackerOuterBarrelLength + ForwardPIDLength + BackwardPIDLength"/>
    <constant name="Barrel_offset"              value="(EcalEndcapP_zmin-EcalEndcapN_zmin)/2.0"/>

    <constant name="EndcapPTotalCal_length"  value="(SolenoidYokeEndcapP_zmin - 0.0 * mm) - (EcalEndcapP_zmin + 20.0 * mm)"/>
    <constant name="EndcapNTotalCal_length"  value="(SolenoidYokeEndcapN_zmin - 0.0 * mm) - (EcalEndcapN_zmin + 20.0 * mm)"/>

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

    <constant name="EcalEndcapP_length" value="EndcapPTotalCal_length * EndcapP_CalDivide"/>
    <constant name="EcalEndcapN_length" value="EndcapNTotalCal_length * EndcapN_CalDivide"/>

    <constant name="HcalEndcapP_length" value="EndcapPTotalCal_length * (1.0 - EndcapP_CalDivide)"/>
    <constant name="HcalEndcapN_length" value="EndcapNTotalCal_length * (1.0 - EndcapN_CalDivide)"/>

    <comment> These need to be set in sync with the forward and backward  detectors </comment>
    <constant name="EcalEndcapP_rmin"                      value="200.0*mm"/>
    <constant name="EcalEndcapN_rmin"                      value="300.0*mm"/>

    <constant name="HcalEndcapP_rmin"                      value="EcalEndcapP_rmin"/>
    <constant name="HcalEndcapN_rmin"                      value="EcalEndcapN_rmin"/>

    <comment>
      -------------------------
      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.

    </comment>
    <constant name="CaloSides"                  value="12"/>
      
    <comment>Material Thickness</comment>
    <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"/>


    <comment>
      -------------------------------
      Hadronic Calorimeter Parameters
      -------------------------------
    </comment>
    <constant name="HcalBarrel_rmin"          value="EcalBarrel_rmax"/>
    <constant name="HcalBarrelAvailThickness" value="HcalBarrel_rmax - HcalBarrel_rmin"/>
    <constant name="HcalBarrelLength"         value="Solenoid_length + ExtraHcalEndcapP_length + ExtraHcalEndcapN_length- HcalEndcapP_length- HcalEndcapN_length - 10*cm"/>
                                                                     
    <constant name="HcalEndcapP_zmin"          value="SolenoidYokeEndcapP_zmin - HcalEndcapP_length "/>
    <constant name="HcalEndcapN_zmin"          value="SolenoidYokeEndcapN_zmin - HcalEndcapN_length "/>

    <comment> Material Thickness </comment>
    <constant name="HcalSteelThickness"       value="1.89 * cm"/>
    <constant name="HcalPyrexThickness"       value="1.10 * mm"/>
    <constant name="HcalRPCGasThickness"      value="1.20 * mm"/>
    <constant name="HcalG10Thickness"         value="3.00 * mm"/>
    <constant name="HcalAirThickness"         value="1.60 * mm"/>

    <comment> Single Layer Thickness (for both barrel and endcap)</comment>
    <constant name="HcalSingleLayerThickness"
      value="HcalSteelThickness + (2 * HcalPyrexThickness) + HcalRPCGasThickness + HcalG10Thickness + HcalAirThickness"/>

    <comment> Hcal Barrel Layers and computed Thickness </comment>
    <constant name="HcalBarrelLayer_NRepeat" value="floor(HcalBarrelAvailThickness / HcalSingleLayerThickness)"/>
    <constant name="HcalBarrelThickness" value="HcalBarrelLayer_NRepeat * HcalSingleLayerThickness"/>

    <comment> Hcal Endcap Layers and computed Thickness </comment>
    <constant name="HcalEndcapPLayer_NRepeat" value="floor(HcalEndcapP_length / HcalSingleLayerThickness)"/>
    <constant name="HcalEndcapNLayer_NRepeat" value="floor(HcalEndcapN_length / HcalSingleLayerThickness)"/>
    <constant name="HcalEndcapP_thickness" value="HcalEndcapPLayer_NRepeat * HcalSingleLayerThickness"/>
    <constant name="HcalEndcapN_thickness" value="HcalEndcapNLayer_NRepeat * HcalSingleLayerThickness"/>

    <comment>
      ----------------------
      Zero Degree Parameters
      ----------------------
    </comment>
    <comment> BeamLines: IP6 </comment>
    <constant name="ffi_ZDC_z_pos"         value="3800.0 * cm"/>
    <constant name="ffi_ZDC_x_pos"         value="ffi_ZDC_z_pos * ionCrossingAngle"/> <comment> original value="90.0 * cm" </comment>
    <constant name="ffi_ZDC_y_pos"         value="0.0 * cm"/>
    <constant name="ffi_ZDC_rotateX_angle" value="0.0 * rad"/>
    <constant name="ffi_ZDC_rotateY_angle" value="-0.0125 * rad"/>
    <constant name="ffi_ZDC_rotateZ_angle" value="0.0 * rad"/>

    <comment> BeamLines: IP8 </comment>
    <!--
    <constant name="ffi_ZDC_x_pos"     value="127.0 * cm"/>
    <constant name="ffi_ZDC_y_pos"         value="0.0 * cm"/>
    <constant name="ffi_ZDC_z_pos"         value="3600.0 * cm"/>
    <constant name="ffi_ZDC_rotateX_angle" value="0.0 * rad"/>
    <constant name="ffi_ZDC_rotateY_angle" value="-0.025 * rad"/>
    <constant name="ffi_ZDC_rotateZ_angle" value="0.0 * rad"/>
    -->

    <comment> Global parameters </comment>
    <constant name="ffi_ZDC_width"             value="60.0 * cm"/>
    <constant name="ffi_ZDC_thickness"         value="200.0 * cm"/>
    <comment> Original Global parameters </comment>     
    <!--
    <constant name="ffi_ZDC_thickness"         value="250.0 * cm"/>
    -->     
    <constant name="ffi_ZDC_ECAL_thickness"    value="30.0 * cm"/>
    <constant name="ffi_ZDC_ECAL_inner_radius" value="0.0 * cm"/>
    <constant name="ffi_ZDC_ECAL_outer_radius" value="60.0 * cm"/>
    <constant name="ffi_ZDC_ECAL_width"        value="5.0 * cm"/>
    <constant name="ffi_ZDC_ECAL_gap"          value="5.0 * mm"/>
    <constant name="ffi_ZDC_ECAL_ntower"       value="10"/>
    <comment> Original number of towers parameter  </comment> 
    <!--
    <constant name="ffi_ZDC_ECAL_ntower"       value="20"/>
    -->

    <comment>
      -----------------------
      Gaseous RICH Parameters
      -----------------------
    </comment>
    <constant name="ForwardRICH_zmin"  value="SiliconTrackerOuterBarrel_zmax + 1 * cm"/>
    <constant name="ForwardRICH_rmin"  value="15 * cm"/>
    <constant name="ForwardRICH_rmax0"  value="SiliconTrackerOuterRadius"/>
    <constant name="ForwardRICH_rmax1"  value="EcalBarrel_rmin"/>
    <constant name="ForwardRICH_rmax2"  value="SolenoidBarrel_rmin-2*cm"/>
    <constant name="ForwardRICHDepth" value="0.9*m"/>


    <comment>
      --------------------------
      Forward Tracker Parameters
      --------------------------
    </comment>

    <comment>
      --------------------------
      Forward ECal Parameters
      --------------------------
    </comment>

    <comment>
      --------------------------
      Forward HCal Parameters
      --------------------------
    </comment>


    <comment>
      --------------------------
      ce_MRICH Parameters
      --------------------------
    </comment>
    <constant name="ce_MRICHRMin"   value="15*cm"/>
    <constant name="ce_MRICHRMax"   value="100*cm"/>
    <constant name="ce_MRICHLength" value="BackwardCherenkovLength"/>
    <constant name="ce_MRICHZMin"   value="-EcalEndcapN_zmin+ce_MRICHLength"/>


    <comment>
      ------------------
      ce_GEM Parameters
      ------------------
    </comment>
    <constant name="ce_GEM_rmin"            value="10.0 * cm"/> <comment> temporary number. Need beampipe radius  </comment>
    <!--<constant name="ce_GEM_rmin"        value="0.0 * cm"/>-->
    <constant name="ce_GEM_rmax"            value="HcalEndcapN_rmin + 8.0 * cm"/> <comment> temporary number to avoid overlaps  </comment>
    <!--<constant name="ce_GEM_rmax"        value="45.0 * cm + 50.0 * cm"/>-->
    <constant name="ce_GEM_length"          value="30.0 * cm"/>
    <constant name="ce_GEM_x_pos"           value="0.0 * cm"/>
    <constant name="ce_GEM_y_pos"           value="0.0 * cm"/>
    <constant name="ce_GEM_z_pos"           value="-Solenoid_length/2.0 + ce_GEM_length/2.0"/>
    <constant name="ce_GEM_layer"           value="8"/>
    <constant name="ce_GEM_layer_thickness" value="1.0 * cm"/>

    <comment>
      --------------------------
      Central Ion HCal Parameters
      --------------------------
    </comment>
    <constant name="ci_HCAL_rin"     value="90 * cm"/><comment> Orginally 0, changed to not overlap solenoid </comment>
    <constant name="ci_HCAL_rout"    value="300 * cm"/>
    <constant name="ci_HCAL_sizez"   value="160 * cm"/>
    <constant name="ci_HCAL_shiftz"  value="5 * cm"/>
    <constant name="ci_HCAL_posz"    value="0 * cm"/>
   
    <constant name="ci_HCAL_nlayers"       value="20"/>
    <constant name="ci_HCAL_lay_rin"       value="ci_HCAL_rin"/> <comment> Orginally 80cm, changed to not overlap solenoid </comment>
    <constant name="ci_HCAL_lay_rout"      value="ci_HCAL_rout - 1 * cm"/>
    <constant name="ci_HCAL_lay_thickness" value="2* cm"/>
    <constant name="ci_HCAL_lay_gapz"      value="2* cm"/>

    <comment>
      --------------------------
      Central Ion GEM Parameters
      --------------------------
    </comment>
    <constant name="ci_GEM_rin"     value="10 * cm"/>
    <constant name="ci_GEM_rout"    value="95 * cm"/>
    <constant name="ci_GEM_sizez"   value="30 * cm"/>
    <constant name="ci_GEM_shiftz"  value="0 * cm"/>
    <constant name="ci_GEM_posz"    value="0 * cm"/>
    <constant name="ci_GEM_posx"    value="0 * cm"/>
    <constant name="ci_GEM_nlayers" value="8"/>

  </define>