celeritas::inp::GeantSd Struct Reference

Control options for Geant4 sensitive detector integration. More...

#include <Scoring.hh>

Public Types
using	SetVolume = std::unordered_set< G4LogicalVolume const * >
	Provide either a set of labels or a set of pointers to Geant4 objects.
using	SetString = std::unordered_set< std::string >
using	VariantSetVolume = std::variant< SetVolume, SetString >
using	PointAttrs = EnumArray< StepPoint, GeantSdStepPointAttributes >

Public Attributes
bool	ignore_zero_deposition {true}
	Skip steps that do not deposit energy locally.
bool	energy_deposition {true}
	Save energy deposition.
bool	step_length {true}
	Save physical step length.
bool	track {true}
	Create a track with the dynamic particle type and post-step data.
PointAttrs	points
	Options for saving and converting beginning- and end-of-step data.
VariantSetVolume	force_volumes
	Manually list LVs that don't have an SD on the master thread.
VariantSetVolume	skip_volumes
	List LVs that should not have automatic hit mapping.

Detailed Description

Control options for Geant4 sensitive detector integration.

By default, Celeritas connects to Geant4 sensitive detectors so that it reconstructs full-fidelity hits with all available step information.

• By default, steps that do not deposit energy do not generate any hits.
• To improve performance and memory usage, determine what quantities (time, position, direction, touchable, ...) are required by your setup's sensitive detectors and set all other attributes to false.
• Reconstructing the full geometry status using touchable step option is the most expensive detector option. Disable it unless your SDs require (e.g.) the volume's copy number to locate a detector submodule.
• Some reconstructed track attributes (such as post-step material) are currently never set because they are rarely used in practice. Contact the Celeritas team or submit a pull request to add this functionality.

Various attributes on the step, track, and pre/post step points may be available depending on the selected options.

• Disabling track will leave G4Step::GetTrack as nullptr .
• Enabling track will set the Charge attribute on the pre-step.
• Requested post-step data including GlobalTime, Position, KineticEnergy, and MomentumDirection will be copied to the Track when the combination of options is enabled.
• Some pre-step properties (Material and MaterialCutsCouple, and sensitive detector) are always updated. Post-step values for those are not set.
• Track and Parent IDs will never be a valid value since Celeritas track counters are independent from Geant4 track counters. Similarly, special Geant4 user-defined UserInformation and AuxiliaryTrackInformation are never set.

The force_volumes option can be used for unusual cases (i.e., when using a custom run manager) that do not define SDs on the "master" thread. Similarly, the skip_volumes option allows optimized GPU-defined SDs to be used in place of a Geant4 callback. For both options, the FindVolumes helper function can be used to determine LV pointers from the volume names.

Todo:

For improved granularity in models with duplicate names, we could add a vector of Label to VariantSetVolume .

change from unordered_set to set for better reproducibility in serialized output

The pre- and post-step attributes can be set with:

sd.points[StepPoint::pre].global_time = true;
sd.points[StepPoint::post].touchable = false;

See also

celeritas::GeantSd

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The documentation for this struct was generated from the following file:

• Scoring.hh