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"/>
    <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="UNUSED"          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="UNUSED"          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>
    <constant name="Solenoid_length"           value="3840.0*mm"/>
    <constant name="Solenoid_rmin"             value="1655.0*mm"/> <comment> Larger inner bore radius </comment>
    <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="SolenoidForward_zmax"      value="Solenoid_length/2. + Solenoid_offset"/>
    <constant name="SolenoidBackward_zmax"      value="Solenoid_length/2. - Solenoid_offset"/>
    <constant name="SolenoidBarrel_rmin"       value="Solenoid_rmin"/>
    <constant name="SolenoidBarrel_length"     value="Solenoid_length"/>

    <documentation>
      ## Tracking Detector Parameters

    </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="95.*cm"/> 
    <constant name="TrackerBarrel_thickness"    value="TrackerBarrel_rmax-TrackerBarrel_rmin"/>

    <constant name="TrackerBarrel_length"       value="VertexTrackingRegion_length + 1150.0*mm"/>
    <constant name="TrackerBarrel_zmax"         value="TrackerBarrel_length/2.0"/>
    <constant name="TrackerBarrelInside_length" value="VertexTrackingRegion_length"/>
    <constant name="TrackerBarrelInside_zmax"   value="TrackerBarrelInside_length/2.0"/>
    <constant name="TrackerEndcapP_length"      value="925.0*mm"/>
    <constant name="TrackerEndcapN_length"      value="495.0*mm"/>

    <documentation level="0">
### PID Detector Region Parameters
    </documentation>

    <constant name="ForwardPID_length"            value="145.0*cm"/>
    <constant name="ForwardPID_rmin1"             value="Beampipe_rmax + 90*mm"/>
    <constant name="ForwardPID_rmin2"             value="18.0*cm"/>

    <constant name="BackwardPID_length"           value="40.0*cm"/>
    <constant name="BackwardPID_rmax"             value="TrackerBarrel_rmax"/>

    <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 level="0">
### Extra tracking region behind the endcap PID system
    </documentation>
    <constant name="ForwardTracking_length"       value="5.0*cm"/>
    <constant name="BackwardTracking_length"      value="8.0*cm"/>

    <documentation>
## Service gaps

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>
## Central tracking and PID detector boundaries
    </documentation>
    <constant name="CentralTracking_rmax"        value="TrackerBarrel_rmax"/>
    <constant name="CentralTracking_length"      value="TrackerBarrel_length + TrackerEndcapP_length + TrackerEndcapN_length"/>

    <constant name="BackwardPID_zmin" value="TrackerBarrel_length/2. + TrackerEndcapN_length"/>
    <constant name="ForwardPID_zmin" value="TrackerBarrel_length/2. + TrackerEndcapP_length"/>
    <constant name="BackwardTracking_zmin" value="BackwardPID_zmin + BackwardPID_length"/>
    <constant name="ForwardTracking_zmin" value="ForwardPID_zmin + ForwardPID_length"/>

    <comment> These are used by ddsim </comment>
    <constant name="tracker_region_rmax"   value="CentralTracking_rmax"/>
    <constant name="tracker_region_zmax"   value="max(BackwardPID_zmin, ForwardPID_zmin)"/>

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

  <documentation level="3">
## Calorimeter Parameters
  </documentation>
    <constant name="CaloSides"                      value="12"/>

    <constant name="EcalEndcapP_zmin"               value="ForwardPID_zmin + ForwardInnerEndcap_length + ForwardServiceGap_length"/>
    <constant name="EcalEndcapP_length"             value="40*cm"/>
    <constant name="EcalEndcapP_rmin"               value="200.0*mm"/>
    <constant name="EcalEndcapP_rmax"               value="Solenoid_rmax "/>

    <constant name="EcalEndcapN_zmin"               value="max(BackwardPID_zmin + BackwardInnerEndcap_length, SolenoidBackward_zmax)"/>
    <constant name="EcalEndcapN_length"             value="60*cm"/>
    <constant name="EcalEndcapN_rmin"               value="max((EcalEndcapN_zmin + EcalEndcapN_length) * tan(abs(CrossingAngle)) + 12.5 * mm, 5*cm)"/>
    <constant name="EcalEndcapN_rmax"               value="TrackerBarrel_rmax"/>

    <constant name="EcalBarrelEnvelope_thickness"      value="40.0*cm"/>
    <constant name="EcalBarrel_rmin"                value="CentralTracking_rmax + BarrelPIDThickness + BarrelExtraSpaceThickness"/>
    <constant name="EcalBarrelForward_length"       value="-21*cm"/>
    <constant name="EcalBarrelForward_zmax"         value="ForwardPID_zmin + EcalBarrelForward_length"/>
    <constant name="EcalBarrelBackward_zmax"        value="BackwardPID_zmin + BackwardInnerEndcap_length + EcalEndcapN_length"/>
    <constant name="EcalBarrel_length"              value="EcalBarrelForward_zmax + EcalBarrelBackward_zmax"/>
    <constant name="EcalBarrel_offset"              value="(EcalBarrelForward_zmax - EcalBarrelBackward_zmax)/2.0"/>


  <documentation level="3">
## Special DIRC parameters (depend on the ECAL setup)
  </documentation>
    <constant name="DIRCReadout_length"         value="30*cm"/>
    <constant name="DIRCForward_length"         value="0*cm"/>
    <constant name="DIRCForward_zmax"           value="ForwardPID_zmin + DIRCForward_length"/>
    <constant name="DIRCBackward_zmax"          value="BackwardPID_zmin + BackwardInnerEndcap_length + EcalEndcapN_length + DIRCReadout_length"/>
    <constant name="DIRC_length"                value="DIRCForward_zmax + DIRCBackward_zmax"/>
    <constant name="DIRC_offset"                value="(DIRCForward_zmax - DIRCBackward_zmax)/2"/>
    <constant name="DIRC_rmin"                  value="TrackerBarrel_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="HcalEndcapP_length"   value="120.0*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)"/>

    <constant name="HcalEndcapN_zmin"     value="DIRCBackward_zmax + BackwardServiceGap_length"/>
    <constant name="HcalEndcapN_length"   value="105.0*cm"/>
    <comment> HcalEndcapN 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="HcalBarrel_length"    value="HcalEndcapP_zmin + HcalEndcapN_zmin "/>

  </define>