Ideal Pulse Simulation

As inputs to ideal pulse simulation you should provide

1. LEGEND detector metadata

2. PET input file

3. Environment settings

4. Simulation settings

5. Noise model

Example

detector_metadata_filename = "path/to/legend-detectors/germanium/diodes/V04545A.json"

pet_input_file = "/lfs/l1/legend/detector_char/enr/hades/simulations/legend-g4simple-simulation/simulations/V04545A/am_HS1/top_46r_4z/hdf5/sim-V04545A-am_HS1-top-46r-4z-01.hdf5"

environment_settings = Dict(
    "crystal_temperature_in_K" => 77, 
    "medium" => "vacuum", 
    "dl" => "vendor" # optional, default 0
    "operating_voltage_in_V" => 5000, # optional, default recV from metadata
)

simulation_settings = Dict(
    "method" => "SSD",
    "cached_name" => "test",
    "crystal_metadata_path" => "path/to/legend-detectors/germanium/crystals",
    "time_step" => 2, #ns
    "diffusion" => true,
    "self-repulsion" => true,
    "num_carriers" => 10
)

noise_model = Dict(
    "type" => "sim"
)

pss_table, pss_truth = LegendGeSim.simulate_pulses(detector_metadata_filename, pet_input_file, environment_settings, simulation_settings, noise_model; n_waveforms=100)

The optional variable n_waveforms defines how many waveforms will be simulted based on the given pet file. Not providing the variable will default 0 meaning, simulate all waveforms in the pet input file.

The output: pss_table contains the following fields:

• channel: currently, ID of the contact (1 for p+ contact, 2 for n+ contact)
• ievt: event number
• waveform: waveform in format of RDWaweform from RadiationDetectorSignals.jl. Contains fields time and signal.

pss_truth contains a copy of the information in the pet input file for convenience (to compare)

1. LEGEND detector metadata

To obtain JSONs for all LEGEND detectors you can clone the repository legend-detectors. The JSONs can be found under germanium/diodes. You may also create your custom detector JSON file as long as it follows the LEGEND detector metadata format (see README in diodes/).

2. PET input file

The pet input file contains information on position, energy amd time of the depositions.

Current available formats:

• g4simple output in hdf5 format. The g4simple simulations of HADES characterization data are available on MPIK under /lfs/l1/legend/detector_char/enr/hades/simulations/legend-g4simple-simulation/simulations/. Consult the legend-g4simple-simulation package to simulate your own custom pet input for given detector and source.

• Geant4 output in csv format. See example in legend-testdata under data/ldsim/single-invcoax-th228-geant4.csv

Here we will use an example pet file csv format from LegendTestData corresponding to the Public Inverted Coax.

3. Environemnt settings

See Field Simulation manual for more details

4. Simulation settings

Simulation settings contain settings related to field simulation (see Field Simulation manual) + pulse simulation settings.

Options related to pulse simulation:

• "time_step": time step in nanoseconds, default 1ns
• "diffusion": setting for cloud charge simulation. Default false (point charges)
• "self_repulsion": setting for cloud charge simulation. Default false (point charges)
• "number_of_carriers": setting for cloud charge simulation. Default 1 (point charges)

5. Noise model

At this stage of the simulation, the noise model regards fano noise of the germanium crystal. The options are simply to simulate the noise or not.

If you would like to simulate fano noise, provide

noise_model = Dict( "type" => "sim" )

If you do not want to simulate fano noise, simply do not provide noise_model to to simulate_pulses() (it will default to "type" => "none")