Array calibration#

Here we describe the configuration parameters of the relative throughput calibration using reconstructed shower energies tool.

event_filters: a dictionary with the event selection filters. The keys are the name of the filters while the values are the thresholds. Currently implemented are:
min_gammaness: used to select gamma-like showers.
min_energy: the minimum energy.
max_distance_asymmetry: used to select equidistant events.
reconstruction_algorithm: name of the reconstruction algorithm.
throughput_normalization: a FloatTelescopeParameter that sets the overall telescope throughput normalization. Dependingon the use case scenario, it could reflect the absolute optical throughput measured by the muon rings / illuminator, if we want to compare or complement these methods. Alternatively it could get an arbitrary number, e.g. one that sets the average throughput to 1, if the user wants to ‘flat-field’ the array. Finally it could be set to 1, if we want to identify outlier telescopes or study the aging.
reference_telescopes: an IntTelescopeParameter that sets the ID of the telescopes whose throughput kept fixed during the intercalibration minimization.
max_impact_distance: a FloatTelescopeParameter that sets the maximum distance between the telescopes and a shower core in meters. The maximum distance between the telescopes in pair should not exceed the sum of these values for the telescopes in pair.

CalculateCrossCalibration:
  event_filters: {"min_gammaness": 0.5,
  "min_energy": 0.0 GeV,
  "max_distance_asymmetry": 0.05
}
  reconstruction_algorithm: "RandomForest"
  RelativeThroughputFitter:
    throughput_normalization:
      - [type, 'MST*', 1.0]
      - [type, 'SST*', 1.0]
    reference_telescopes:
      - [type, 'MST*', 5]
      - [type, 'SST*', 37]
  PairFinder:
    max_impact_distance:
      - [type, 'LST*', 125.0]
      - [type, 'MST*', 125.0]
      - [type, 'SST*', 225.0]

The tool produces a new hdf5 file with the two following tables:

/dl2/monitoring/inter_calibration

Where the inter-calibration results are stored. The table has the following fields:

Column Name	Type \| Description
`size_type`	numpy.str	Telescope type (LST, MST, SST).
`tel_id`	numpy.int64	Telescope ID.
`value`	numpy.float64	Relative telescope throughput.
`error`	numpy.float64	Relative telescope throughput uncertainty.

/dl2/monitoring/cross_calibration

where the results of cross-calibration are stored.

Column Name	Type	Description
`type_a`	numpy.str	Telescope type 1 (LST, MST, SST).
`type_b`	numpy.str	Telescope type 1 (LST, MST, SST).
`ratio`	numpy.float64	Throughput scaling ratio between different types.
`error`	numpy.float64	Throughput scaling ratio uncertainty.

Array calibration#

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