ess.sans.normalization.iofq_norm_wavelength_term#

ess.sans.normalization.iofq_norm_wavelength_term(incident_monitor, transmission_fraction, direct_beam, uncertainties)[source]#

Compute the wavelength-dependent contribution to the denominator term for the I(Q) normalization. Keeping this as a separate function allows us to compute it once during the iterations for finding the beam center, while the solid angle is recomputed for each iteration.

This is basically: incident_monitor * transmission_fraction * direct_beam If the direct beam is not supplied, it is assumed to be 1.

Because the multiplication between the incident_monitor * transmission_fraction (pixel-independent) and the direct beam (potentially pixel-dependent) consists of a broadcast operation which would introduce correlations, variances of the direct beam are dropped or replaced by an upper-bound estimation, depending on the configured mode.

Parameters:

incident_monitor (CleanMonitor[TypeVar(ScatteringRunType, types.SampleRun (int), types.BackgroundRun (int)), types.Incident (int)]) – The incident monitor data (depends on wavelength).
transmission_fraction (TransmissionFraction[TypeVar(ScatteringRunType, types.SampleRun (int), types.BackgroundRun (int))]) – The transmission fraction (depends on wavelength).
direct_beam (types.CleanDirectBeam (types.scipp._scipp.core.DataArray | None)) – The direct beam function (depends on wavelength).
uncertainties (UncertaintyBroadcastMode) – The mode for broadcasting uncertainties. See ess.reduce.uncertainty.UncertaintyBroadcastMode for details.

Returns:

NormWavelengthTerm[TypeVar(ScatteringRunType, types.SampleRun (int), types.BackgroundRun (int))] – Wavelength-dependent term (incident_monitor * transmission_fraction * direct_beam) to be used for the denominator of the SANS I(Q) normalization. Used by iofq_denominator().