legend-pygeom-l200

Warning

This is an early version of the LEGEND-200 geometry implemented with the python-based simulation stack. It is not a drop-in replacement for MaGe, and still under heavy development!

Installation and usage

This package requires a working setup of legend-metadata before usage.

Following a git checkout, the package and its other python dependencies can be installed with:

pip install -e .

If you do not intend to edit the python code in this geometry package, you can omit the -e option.

After installation, the CLI utility legend-pygeom-l200 is provided on your PATH. This CLI utility is the primary way to interact with this package. For now, you can find usage docs by running legend-pygeom-l200 -h.

Runtime configuration

For often-changing details of the geometry are configured using a runtime configuration JSON file. This file is specified using the --config $FILE parameter.

Detailed information about the configurable subsystems is available:

• Calibration system (SIS)

Visualization of the geometry

Visualization with legend-pygeom-l200

Simply use legend-pygeom-l200 -V [...] to visualize the full geometry.

If you want to exclude components from the 3D rendering, append --assemblies=.... Possible values are:

• strings (the whole HPGe array)
• fibers. It is highly recommended to also append the argument --fiber-modules=segmented to avoid rendering all single fibers, if you only need to see the overall shape.
• calibration (calibration tubes and sources, if any)
• top (copper top plate)
• wlsr

Multiple values can be combined with commas. Example: --assemblies=strings,calibration.

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

Visualizing with Geant4/remage (advanced)

The visualization can be exported to Geant4 by using --vis-macro-file=: legend-pygeom-l200 --vis-macro-file=l200-vis.mac l200.gdml [...].

This generated macro does not start any visualization on its own, it just sets the colors. To use it, create a file vis.mac in the same directory:

/run/initialize

/vis/open OGL
/vis/drawVolume lar

/vis/viewer/set/defaultColour black
/vis/viewer/set/background white
/vis/viewer/set/viewpointVector -3 -2 1
/vis/viewer/set/upVector 0 0 1
/vis/viewer/set/rotationStyle freeRotation
/vis/viewer/set/lineSegmentsPerCircle 100

/vis/scene/add/trajectories smooth
/vis/scene/endOfEventAction accumulate

# import the auto-generated visualization attributes from legend-pygeom-l200.
/control/execute l200-vis.mac

and use it with remage remage vis.mac -i -g l200.gdml. It will validate that the given GDML file can be read by Geant4 and show a visualization from it.

It is also possible to use --assemblies= as described above. This will remove any non-specified assembly from the output GDML file. Make sure that you do not overwrite any "production" geometry with this command. Using a file with stripped-down assemblies for a simulation will probably give wrong results.

Adjusting the visualization from python

See the legend-pygeom-tools docs.

Further features (for developers)

Registering detectors for use with remage

See the legend-pygeom-tools docs.

This information can be exported by using --det-macro-file=l200-dets.mac as an additional CLI option. This macro then should be /control/executed in your main macro.

Checking for overlaps

Using --check-overlaps might yield wrong results (it uses the coarsely tessellated volumes also used for visualization); also it is very slow. Using Geant4 to load the generated GDML file will give you correct results.

Create a file called check-overlaps.mac with the following contents:

/RMG/Manager/Logging/LogLevel error
/run/initialize

and use it with remage remage check-overlaps.mac -g $PATH_TO_YOUR_GDML_FILE. It will validate that the given GDML file can be read by Geant4 and that it has no overlaps.