Geometry options

geometry options are both available in the CLI interface and the config file interface. Provided CLI options override the values from the config file.

Important

Always use fiber_modules: detailed (in the config file) or --fiber-modules detailed (on CLI) for optical simulations.

The simplified geometry has a different (and certainly wrong) light-guiding efficiency - it is only suitable for visualisation or simulations not requiring full optical physics.

example config (not the default values!):

# select parts of the geometry to be built.
assemblies:
  - fibers
  - strings

# Select the fiber shroud model, either coarse segments or single fibers.
fiber_modules: detailed # or "segmented"

# Select the PMT configuration of the muon veto.
pmt_config: LEGEND200 # or "GERDA"

# If true, build from public testdata only.
public_geom: false

# if false, replace all asymmetric HPGe detectors with symmetric variants.
# this might be necessary to have better post-processing support.
allow_cylindrical_asymmetry: false

Assemblies

The list of assemblies provided in the assemblies config option or the --assemblies CLI option can be either:

  • a list of assemblies to build: strings,calibration will build the argon cryostat (this is always bullt), the HPGe strings and the calibration system only.

  • a list of operations modifying the default assembly list: +watertank will build all default assemblies (i.e. the argon cryostat and anything in it), and dd also the muon veto watertank.

Specifying assemblies in the config file works similarly, but requires the list to be passed as an actual JSON/YAML list instead of a comma-delimited string.

Supported assembly options are:

  • strings (the whole HPGe array)

  • fibers (fiber modules and holding structure)

  • calibration (calibration tubes and sources, if any have been configured))

  • top (copper top plate)

  • wlsr (wavelength-shifting reflector in the center of the cryostat)

  • watertank (water Čerenkov muon veto, off by default)

The cryostat and LAr volumes are always part of the output.