data

This module contains both the Data class and the MeasurementBase class. In a reflectometry measurement, the experimental data corresponds to the reflected intensity as a function of scattering vector Q. In a typical diffractometer, Q is a virtual axis, calculated geometrically from various motor positions. The Data class takes care of these conversions, exposing q, theta, intensity, reflectivity, and energy.

The MeasurementBase class defines a simple class that is Data, but that also has metadata.

Module Contents

Classes

Data	The base class of all Islatu objects that contain data.
MeasurementBase	All measurements derive from this class.

API

class data.Data(intensity, intensity_e, energy, theta=None, q_vectors=None)

The base class of all Islatu objects that contain data.

Attributes:

intensity:

A numpy array containing intensities in this dataset.

intensity_e:

A numpy array containing the corresponding errors in intensity.

theta:

A numpy array containing the probe particle’s angle of incidence at each intensity.

q_vectors:

A numpy array containing the magnitude of the probe particle’s scattering vector for each intensity value.

energy:

The energy of the probe particle used to acquire this data. This is necessary to swap between theta and q.

Args:

intensity:

A numpy array of the intensities in this dataset.

intensity_e:

The errors on the intensities.

energy:

The energy of the probe particle used to acquire this data.

theta:

A numpy array containing the probe particle’s angle of incidence at each intensity. NOTE: only one of theta/q needs to be provided.

q_vectors:

A numpy array containing the magnitude of the probe particle’s scattering vector for each intensity value. NOTE: only one of theta/q needs to be provided.

Initialization

property reflectivity: numpy.array

Returns the intensity, normalized such that the maximum value of the intensity is equal to 1. To acquire

property reflectivity_e: numpy.array

Returns the errors on the intensity, divided by the maximum value of the intensity array.

property reflectivity_nonorm: numpy.array

Returns the intensity, unnormalised

property reflectivity_e_nonorm: numpy.array

Returns the errors on the intensity, unnormalised

property q_vectors: numpy.array

Returns self._q if this instance of Data was generated from q-data. Otherwise, converts from self._theta to q.

property theta: numpy.array

Returns self._theta if this instance of Data was generate from th-data. Otherwise, converts from scattered q to theta.

_theta_to_q(theta, energy) → numpy.array

Calculates the scattering vector Q from diffractometer theta.

Args:

theta (str):

Array of theta values to be converted.

energy (float):

Energy of the incident probe particle.

_q_to_theta(q_values, energy) → numpy.array

Calculates the diffractometer theta from scattering vector Q.

Args:

theta (str):

Array of theta values to be converted.

energy (float):

Energy of the incident probe particle.

remove_data_points(indices)

Convenience method for the removal of a specific data point by its index.

Args:

indices:

The indices to be removed.

class data.MeasurementBase(intensity, intensity_e, energy, metadata, theta=None, q=None)

Bases: data.Data

All measurements derive from this class.

Attrs:

metadata:

The metadata relevant to this measurement.

Initialization