drich.xml

<?xml version="1.0" encoding="UTF-8"?>
<lccdd>

<define>
<!-- vessel (=snout+tank) geometry -->
<constant name="DRICH_zmin"               value="ForwardPIDRegion_zmin"/> <!-- vessel front -->
<constant name="DRICH_Length"             value="ForwardPIDRegion_length"/>  <!-- overall vessel length (including snout) -->
<constant name="DRICH_rmin0"              value="ForwardPIDRegion_zmin * ForwardPIDRegion_tan1"/>  <!-- bore radius at dRICh vessel frontplane -->
<constant name="DRICH_rmin1"              value="(ForwardPIDRegion_zmin + ForwardPIDRegion_length) * ForwardPIDRegion_tan2"/>  <!-- bore radius at dRICh vessel backplane -->
<constant name="DRICH_wall_thickness"     value="0.5*cm"/>  <!-- thickness of radial walls -->
<constant name="DRICH_window_thickness"   value="0.1*cm"/>  <!-- thickness of entrance and exit walls -->
<!-- tank geometry: cylinder, holding the majority of detector components -->
<constant name="DRICH_rmax2"              value="HcalBarrel_rmin-10*cm"/>  <!-- cylinder radius, near maximal to fit HCal barrel inner polygon -->
<!-- snout geometry: cone with front radius rmax0 and back radius of rmax1 -->
<constant name="DRICH_SnoutLength"        value="4.0*cm"/>
<constant name="DRICH_SnoutSlope"         value="DRICH_rmax2 / (DRICH_zmin + DRICH_Length)"/>
<constant name="DRICH_rmax0"              value="DRICH_SnoutSlope * DRICH_zmin"/>
<constant name="DRICH_rmax1"              value="DRICH_SnoutSlope * ( DRICH_zmin + DRICH_SnoutLength)"/>
<!-- additional parameters -->
<constant name="DRICH_aerogel_thickness"  value="4.0*cm"/>  <!-- aerogel thickness -->
<constant name="DRICH_sensor_size"        value="48.0*mm"/> <!-- sensor side length -->
<constant name="DRICH_sensor_thickness"   value="35.0*mm"/> <!-- sensor thickness -->
<constant name="DRICH_num_px"             value="16"/> <!-- number of pixels along one side of the sensor -->
<!-- debugging switches -->
<comment>
- `DRICH_debug_optics`:  1 = all components become vacuum, except for mirrors; test opticalphotons from IP
                         2 = all components become vacuum, except for mirrors and `gasvol`, test charged particles from IP
                         0 = off
- `DRICH_debug_mirror`:  1 = draw full mirror shape for single sector; 0 = off
- `DRICH_debug_sensors`: 1 = draw full sensor sphere for a single sector; 0 = off
</comment>
<constant name="DRICH_debug_optics"  value="0"/>
<constant name="DRICH_debug_mirror"  value="0"/>
<constant name="DRICH_debug_sensors" value="0"/>
</define>


<detectors>


<!-- /detectors/detector -->
<documentation level="10">
### dRICh: ***d***ual ***R***ing ***I***maging ***Ch***erenkov detector
</documentation>
<detector
  id="ForwardRICH_ID"
  name="DRICH"
  type="athena_DRICH"
  readout="DRICHHits"
  gas="C2F6_DRICH"
  material="Aluminum"
  vis_vessel="DRICH_vessel_vis"
  vis_gas="DRICH_gas_vis"
  debug_optics="DRICH_debug_optics"
  >


<!-- /detectors/detector/dimensions -->
<documentation level="10">
#### Vessel
- the dRICh vessel is composed of two parts:
  - tank: cylindrical region containing most of the detector components
  - snout: conical region at the front of the vessel, containing the aerogel
- dimensions:
  - `zmin`: z-position of vessel front plane
  - `length`: overall z-length of the full vessel
  - `snout_length`: length of cone-shaped snout region, housing aerogel
  - `rmin0` and `rmin1`: bore radius at front plane and back plane, respectively
  - `rmax0` and `rmax1`: outer radius of snout at front plane and snout-back (tank-front) plane, respectively
  - `rmax2`: outer radius of tank, the main cylindrical vessel volume
  - `nsectors`: number of azimuthal sectors
  - `wall_thickness`: thickness of radial walls
  - `window_thickness`: thickness of entrance and exit disks
</documentation>
<dimensions
  zmin="DRICH_zmin"
  length="DRICH_Length"
  snout_length="DRICH_SnoutLength"
  rmin0="DRICH_rmin0"
  rmin1="DRICH_rmin1"
  rmax0="DRICH_rmax0"
  rmax1="DRICH_rmax1"
  rmax2="DRICH_rmax2"
  nsectors="6"
  wall_thickness="DRICH_wall_thickness"
  window_thickness="DRICH_window_thickness"
  />


<!-- /detectors/detector/radiator -->
<documentation level="10">
#### Radiator
- radiator is defined in a wedge of azimuthal space, composed of aerogel and a
  filter; the filter is applied to the back of the aerogel, so that it separates
  the aerogel and gas radiators
- dimensions:
  - `frontplane`: front of the aerogel, w.r.t. front plane of the vessel envelope
  - `rmin` and `rmax`: inner and outer radius (at the front plane; radial bounds are conical)
  - `phiw`: azimuthal width of wedge
  - `thickness`: radiator thickness, defined separately for aerogel and filter
  - `pitch`: controls the angle of the radiator (0=vertical)
</documentation>
<radiator
  rmin="DRICH_rmin0 + DRICH_wall_thickness + 0.2*cm"
  rmax="DRICH_rmax0 - DRICH_wall_thickness - 0.2*cm"
  phiw="60*degree"
  frontplane="DRICH_window_thickness + 0.5*DRICH_aerogel_thickness"
  pitch="0*degree"
  >
  <aerogel
    material="Aerogel_DRICH"
    vis="DRICH_aerogel_vis"
    thickness="DRICH_aerogel_thickness"
    />
  <filter
    material="Acrylic_DRICH"
    vis="DRICH_filter_vis"
    thickness="0.3*mm"
    />
</radiator>


<!-- /detectors/detector/mirror -->
<documentation level="10">
#### Spherical mirror
- spherical mirrors are built from spherical patches, and positioned near the
  vessel back plane, separately for each sector
- dimensions:
  - `backplane`: the position of the maximum z-plane intersected by the sphere,
    w.r.t. the back plane of vessel envelope
  - `rmin` and `rmax`: polar angle boundaries
  - `phiw`: azimuthal width of one sector
  - `thickness` is the radial thickness of the mirror; note that `backplane` is given for the 
    reflective mirror surface, the inner radius of the sphere
  - `focus_tune*` are tuning parameters for the focal region:
    - `focus_tune_z` and `focus_tune_x` will move the focal region, with respect
      to the sensor sphere center (i.e., set both to zero for focus at the sensor sphere center
      (ignoring spherical aberrations effects))
- other settings:
  - `debug`: set to 1 so draw reference sphere instead, view with y-clipping
</documentation>
<mirror
  material="Acrylic_DRICH"
  surface="MirrorSurface_DRICH"
  vis="DRICH_mirror_vis"
  backplane="DRICH_window_thickness + 1.0*cm"
  rmin="DRICH_rmin1 + DRICH_wall_thickness - 1.0*cm"
  rmax="DRICH_rmax2 - DRICH_wall_thickness - 1.0*cm"
  phiw="59.5*degree"
  thickness="0.2*cm"
  focus_tune_x="30.0*cm"
  focus_tune_z="-40.0*cm"
  debug="DRICH_debug_mirror"
  />

<!-- /detectors/detector/sensors -->
<documentation level="10">
#### Sensors
</documentation>
<sensors>


<!-- /detectors/detector/sensors/module -->
<documentation level="10">
##### Sensor module
- based on [Hamamatsu H13700 MAPMT](https://www.hamamatsu.com/us/en/product/type/H13700/index.html):
  - not ideal for a magnetic field, SiPM matrix would be better
  - effective area: 48.5x48.5 mm
  - enclosure size: 52x52 mm
  - 16x16 channel matrix (cf. readout segmentation below)
  - pixel size: 3x3 mm
- dimensions:
  - `side`: side length of the square module
  - `thickness`: thickness of the sensor module
  - `gap`: provides room between the squares, to help prevent them from overlapping
  - note: the value of `side` will determine how many sensors there are, since the
    sensor placement algorithm will try to place as many as it can in the specified
    spherical patch below
</documentation>
<module
  material="Silicon"
  surface="SensorSurface_DRICH"
  vis="DRICH_sensor_vis"
  side="DRICH_sensor_size"
  thickness="DRICH_sensor_thickness"
  gap="0.5*(52-48)*mm + 2*mm"
  />


<!-- /detectors/detector/sensors/{sphere,sphericalpatch} -->
<documentation level="10">
##### Sensor sphere
- sensors will be placed on a sphere, using a "disco ball" tiling algorithm; each
  sector has its own sensor sphere
  - sphere dimensions:
    - `centerx` and `centerz`: sphere center, defined w.r.t. vessel front plane,
      for the sector on +x axis
    - `radius`: radius of the sensor sphere
  - other settings:
    - `debug`: set to 1 so draw reference sphere instead, view with y-clipping
- sensors will be limited to a patch of the sphere
  - patch dimensions:
    - `phiw`: defines half the angle between the azimuthal boundaries
    - `rmin` and `rmax`: radial cut boundaries
    - `zmin`: z-plane cut
</documentation>
<sphere
  centerz="-55.0 * cm"
  centerx="DRICH_rmax2 - 35.0*cm"
  radius="85.0 * cm"
  debug="DRICH_debug_sensors"
  />
<sphericalpatch
  phiw="18*degree"
  rmin="DRICH_rmax1 + 5.0*cm"
  rmax="DRICH_rmax2 - 5.0*cm"
  zmin="DRICH_SnoutLength + 5.0*cm"
  />


</sensors>
</detector>
</detectors>


<documentation level="10">
#### Readout
- segmentation: square matrix of pixels
  - `grid_size_x,y`: size of each sensor, but note we must divide sensor size
    by 1 less than the number of pixels, to account for fenceposting
  - `offset_x,y`: specified such that the `x` and `y` indicators are unsigned
- indicators and `cellID` bits:

  | indicator | offset | length |
  |-----------|--------|--------|
  | dRICh ID  | 0      | 8      |
  | sector    | 8      | 3      |
  | sensor    | 11     | 12     |
  | x pixel   | 23     | 16     |
  | y pixel   | 39     | 16     |

</documentation>
<readouts>
  <readout name="DRICHHits">
    <segmentation
      type="CartesianGridXY"
      grid_size_x="DRICH_sensor_size/(DRICH_num_px-1)"
      grid_size_y="DRICH_sensor_size/(DRICH_num_px-1)"
      offset_x="-DRICH_sensor_size/2.0"
      offset_y="-DRICH_sensor_size/2.0"
      />
    <id>system:8,sector:3,module:12,x:23:16,y:16</id>
  </readout>
</readouts>


</lccdd>