scippneutron.absorption.base.compute_transmission_map#

scippneutron.absorption.base.compute_transmission_map(sample_shape, sample_material, beam_direction, wavelength, detector_position, quadrature_kind='medium')[source]#

Computes transmission probability of single-scattered neutrons.

Computes the probability that a neutron is transmitted to detector_position given that it travelled in beam_direction and scattered incoherently a single time when passing through the sample.

\[C(\mathbf{p}, \lambda) = \int_{Sample} \exp{(-\mu(\lambda) L(\mathbf{p}, \mathbf{x}))} \ d\mathbf{x}\]

where \(L\) is the length of the path through the sample, \(\mu\) is the material dependent attenuation factor, and \(\mathbf{p}\) is the detector_position.

Parameters:

  • sample_shape (SampleShape) – The size and shape of the sample.

  • sample_material (Material) – The sample material, this parameter determines the absorption and scattering coefficients.

  • beam_direction (Variable) – The direction of the incoming beam.

  • wavelength (Variable) – An array of wavelengths for which to evaluate the transmission fraction.

  • detector_position (Variable) – An array of vectors representing the scattering directions where the transmission fraction is evaluated.

  • quadrature_kind (Union[Literal['cheap', 'medium', 'expensive'], Any], default: 'medium') – What kind of quadrature to use. A denser quadrature makes the result more accurate but takes longer to compute. What options exists depend on the sample shape.

Returns:

DataArray – the transmission fraction as a function of detector_position and wavelength