Flat-plate sample self-absorption correction#

Summary#

Correct angle-dependent self-absorption for a transmission-normalized flat sample.

Metadata#

Module ID: FlatPlateSelfAbsorptionCorrection
Module path: /home/runner/work/MoDaCor/MoDaCor/src/modacor/modules/technique_modules/scattering/flat_plate_self_absorption_correction.py
Module version: 20260905.1
Keywords: sample, self absorption, flat plate, transmission

Required data keys#

signal
CosAlpha

Modifies#

signal: signal, uncertainties

Required arguments#

with_processing_keys
transmission_source

Default configuration#

{
  "correction_key": "flat_plate_self_absorption",
  "cos_alpha_key": "CosAlpha",
  "minimum_attenuation_factor": 1e-12,
  "minimum_cos_alpha": 1e-12,
  "transmission_source": null,
  "transmission_uncertainties_sources": {},
  "transmission_units_source": null,
  "with_processing_keys": [
    "sample"
  ]
}

Argument specification#

Argument	Type	Required	Default	Dependency role	Description
`correction_key`	str	No	flat_plate_self_absorption	-	BaseData key used to store the relative attenuation factor.
`cos_alpha_key`	str	No	CosAlpha	-	BaseData key containing cos(2theta) for the sample exit angle.
`minimum_attenuation_factor`	int or float	No	1e-12	-	Lower allowed relative attenuation factor before division.
`minimum_cos_alpha`	int or float	No	1e-12	-	Lower numerical clip for positive exit-angle cosines.
`transmission_source`	str	Yes	-	-	IoSources key for the sample transmission factor.
`transmission_uncertainties_sources`	dict	No	{}	-	Mapping of uncertainty names to IoSources keys for sample transmission.
`transmission_units_source`	str or NoneType	No	-	-	Optional IoSources key for transmission units.
`with_processing_keys`	list	Yes	[“sample”]	-	ProcessingData keys whose signal should be corrected.

Notes#

For s=1/cos(2theta), x=(s-1) ln(T), the relative attenuation is expm1(x)/x. The expression is the depth integral for scattering generated uniformly through a plate and is not the same as transmission through a separate downstream attenuator.