Sources

To generate the intensities and energies of the xrays, a source needs to be instantiated.

Source Class

Purpose

This class is a template for all the sources. It is not meant to be used directly, as it is an abstract class.

Properties

The attributes of this abstract class are immutable and are set at the time of instantiation.

num_energies: (double) The number of energies that the source will generate.

Functions

source(num_energies)

This is the constructor for the source class. It sets the number of energies that the source will generate.

Parameters:: num_energies (double) – The number of energies that the source will generate.
Returns:: source – A source object.
Return type:: source

Abstract Methods

Note: all ranges referred to are semi open intervals, i.e. [min_energy, max_energy).

get_energies(obj, range)

This method is meant to be overridden by the child classes. It should return the energies of the xrays that the source will generate within each range provided.

Parameters:: range (Nx2 double) – A vector with N rows of [min_energy, max_energy) indicating the range of energies that the source should generate.
Returns:: energies – The energies from the source in the given range. If the source is not able to generate the energies in the range, it should error, or give a valid energy with a zero fluence. It is up to the user to give the correct sensor to the source.
Return type:: 1xN double

get_fluences(obj, range, ypixels)

This method is meant to be overridden by the child classes. It should return the fluences of the xrays that the source will generate within each range provided and at each pixel.

Parameters:

range (Nx2 double) – A vector with N rows of [min_energy, max_energy) indicating the range of energies that the source should generate.
ypixels (1xM double) – The index of the pixels in the y direction.

Returns:

fluences – The fluences in units of photons/cm^2 at 1m. (Use the units library to ensure the conversion is correct) for each pixel index and energy range.

Return type:

MxN double

get_nrj_range(obj)

This method is meant to be overridden by the child classes. It should return the range of energies that the source will generate.

Returns:

min (double) – the minimum energy that the source will generate.
max (double) – the maximum energy that the source will generate.

Single Energy Source

Purpose

This is a subclass of the source class. It represents a source that generates a single energy.

Properties

All the properties from the source class are inherited and also the following:

energy: (double) The energy of the xray that the source will generate.

Functions

single_energy(energy)

This is the constructor for the single_energy class. It sets the energy of the xray that the source will generate.

Parameters:: energy (double) – The energy of the xray that the source will generate.
Returns:: single_energy – A single_energy object.
Return type:: single_energy

Methods

single_energy.get_energies(obj, range)

This method returns a list of energies of the xrays, independent of the range. If the energy is not within the range, we use a fluence of 0.

Parameters:: range (Nx2 double) – A vector with N rows of [min_energy, max_energy) indicating the range of energies that the source should generate.
Returns:: energies – a list with every element being the energy of the xray, independent of the range.
Return type:: 1xN double

single_energy.get_fluences(obj, range)

This method returns the fluence of the xray if it is within the range. If it is not, it returns 0.

Parameters:: range (Nx2 double) – A vector with N rows of [min_energy, max_energy) indicating the range of energies that the source should generate.
Returns:: fluences – a list with the fluence being \(1\times10^6\) if the energy is within the range, and 0 if it is not.
Return type:: 1xN double

single_energy.get_nrj_range(obj)

This method returns the range of energies that the source will generate. It is the same as the energy of the xray \(\pm 1\) keV.

Returns:

min (double) – The energy of the xray minus 1 keV.
max (double) – The energy of the xray plus 1 keV.

Source from Spectrum File

Purpose

This is a subclass of the source class. It represents a source that generates the xrays from a spectrum file. The spectrum file is expected to be in the format produced by the SpekPy library. The following code is an example of how to generate a spectrum file:

import spekpy as sp

s = sp.Spek(kvp=80,th=12, dk=1) # Generate a spectrum (80 kV, 12 degree tube angle)
s.filter('Al', 4.0) # Filter by 4 mm of Al

s.export_spectrum('spectrum.spk') # Export the spectrum to a file

At the moment, the code is limited in producing different fluences at different angles. This is a limitation of the code and not the library. In the future, it is expected that the code will have an algorithm to calculate the fluences at different angles.

Properties

All the properties from the source class are inherited and also the following:

ebins: (Nx1 double) The energy bins of the spectrum file.

fluences: (Nx1 double) The fluences of the spectrum file.

Functions

source_fromfile(file)

This is the constructor for the source_fromfile class. It reads the spectrum file and sets the energy bins and fluences.

Parameters:: file (string) – The path to the spectrum file.
Returns:: source_fromfile – A source_fromfile object.
Return type:: source_fromfile

Methods

source_fromfile.get_energies(obj, range)

This method returns the energies of the xrays if they are within the range. If they are not, it errors, as it is up to the user to give the correct sensor to the source.

Parameters:: range (Nx2 double) – A vector with N rows of [min_energy, max_energy) indicating the range of energies that the source should generate.
Returns:: energies - The weighted mean of the energies within the range.
Return type:: 1xN double

source_fromfile.get_fluences(obj, range, ypixels)

This method returns the fluences of the xrays if they are within the range. If they are not, it returns 0. This function is independent of the pixel index.

Parameters:

range (Nx2 double) – A vector with N rows of [min_energy, max_energy) indicating the range of energies that the source should generate.
ypixels (1xM double) – The index of the pixels in the y direction.

Returns:

fluences – The sum of the fluences of the xrays within the range in units of photons/cm^2 at 1m. (This function uses the units library to ensure the conversion is correct). As the fluences are independent of the pixel index, the fluences are the same for all pixels.

Return type:

MxN double

source_fromfile.get_nrj_range(obj)

This method returns the range of energies that the source will generate. It is the same as the energy bins of the spectrum file.

Returns:

min (double) – The minimum energy bin of the spectrum file.
max (double) – The maximum energy bin of the spectrum file.