simtools-generate-simtel-event-data

Generate a reduced dataset of event data from output of telescope simulations.

Processes sim_telarray output files (typically of type ‘.simtel.zst’) and creates reduced datasets containing shower information, array-level parameters, and data about triggered telescopes.

The output consists of an HDF5 or FITS file containing the following tables:

FILE_INFO

Field	Type	Description
file_name	string	Name of the file
file_id	int64	Internal unique identifier for the file
particle_id	int64	PDG particle ID (e.g., 14 for proton)
energy_min	float32	Minimum simulated energy (TeV)
energy_max	float32	Maximum simulated energy (TeV)
viewcone_min	float32	Min viewcone angle (deg)
viewcone_max	float32	Max viewcone angle (deg)
core_scatter_min	float32	Min core scatter radius (m)
core_scatter_max	float32	Max core scatter radius (m)
zenith	float32	Zenith angle (deg)
azimuth	float32	Azimuth angle (deg)
nsb_level	float64	Night sky background level (factor to dark)

SHOWERS

Field	Type	Description
shower_id	int64	Shower identifier
event_id	int64	Event identifier (depends on reuse of showers)
file_id	int64	Internal unique identifier for the file
simulated_energy	float64	Simulated primary energy (TeV)
x_core	float64	Shower core X position on ground (m)
y_core	float64	Shower core Y position on ground (m)
shower_azimuth	float64	Direction of shower azimuth (deg)
shower_altitude	float64	Direction of shower altitude (deg)
area_weight	float64	Weighting factor for sampling area

TRIGGERS

Field	Type	Description
shower_id	int64	Shower identifier
event_id	int64	Event identifier (depends on reuse of showers)
file_id	int64	Internal unique identifier for the file
array_altitude	float64	Altitude of array pointing direction (deg)
array_azimuth	float64	Azimuth of array pointing direction (deg)
telescope_list	string	Comma-separated list of triggered telescopes

Several files generated with this application can be combined into a single dataset using the ‘simtools-merge-tables’ command.

Command line arguments

prefix (str, required)

Path prefix for the input files.

output_file (str, required)

Output file path.

max_files (int, optional, default=100)

Maximum number of input files to process.

print_dataset_information (int, optional, default=0)

Print information about the datasets in the generated reduced event dataset.

Example

Generate a reduced dataset from input files and save the result.

simtools-production-extract-mc-event-data \\
simtools-generate-simtel-event-data \\
    --input 'path/to/input_files/gamma_*dark*.simtel.zst' \\
    --output_file output_file.hdf5 \\
    --max_files 50 \\
    --print_dataset_information 10

To read a reduced event data file, use the following command reading on of the test files:

import h5py

test_file = "tests/resources/proton_za20deg_azm000deg_North_alpha_6.0.0_reduced_event_data.hdf5"

with h5py.File(test_file, "r") as f:
    triggers = f["/TRIGGERS"]
    for row in triggers:
        print({name: row[name] for name in row.dtype.names})