Westcott g-factor

Python package for calculating Westcott g-factors, which adjust thermal-neutron capture cross sections for non-1/v behavior at low energies. These are important in Neutron Activation Analysis (NAA) and Prompt Gamma-ray Activation Analysis (PGAA) when measuring nuclei that have low-energy resonances in their cross sections. Code calculates g-factors for Maxwellian neutron energy distributions and individual neutron source spectra, when available. A reference article describing this project is available on the arXiv [1].

Building and installation

This project can be built and installed by running the pip command in a Unix terminal:

$ pip install westcott

Alternatively, because this project is also maintained on GitHub, it can be installed by cloning the repository and running the installation script at the terminal command line of the project directory as described in README on the landing page.

Testing

A suite of Python modules containing unit tests has been developed for this project. These unit tests are distributed with the project on GitHub. This project has been successfully built and tested against multiple virtual Python environments from Python-3.6 to Python-3.13. To run the suite and ensure they work with the local Python environment, run tox in the project directory where the tox.ini file is also located:

$ tox -r

This project has the following Python-package dependencies: numpy, scipy, pandas, and pytest. The session is automatically started after building against the required Python environment.

Running the software

Following installation, the westcott scripts can be ran from any location by importing the library and making an instance of the Westcott class:

$ python

>>> import westcott
>>> gw = westcott.Westcott()

Various Jupyter Notebooks are also distributed with the project on GitHub. These Jupyter Notebooks can be used to demonstrate workflows and methods for interacting with the functionality available to the library.

Docstrings

All westcott classes and methods have supporting docstrings. Please refer to the individual dosctrings for more information on any particular function including how to use it. The dosctrings for each method generally have the following structure:

• A short explanation of the function.
• A list and description of arguments that need to be passed to the function.
• The return value of the function.
• Exceptions that may be raised.
• An example(s) invoking use of the function.

To retrieve a list of all available methods simply execute the following command in a Python interpreter:

>>> help(gw)

Or, to retrieve the docstring for a particular method, e.g., the callable gw_Maxwellian to calculate the g-factor assuming a Maxwellian spectrum:

>>> help(gw.gw_Maxwellian)

References

[1] D.A. Matters, A.M. Hurst, T. Kawano, "Westcott g Factors Extended to Arbitrary Neutron Energy Spectra", Atomic Data and Nuclear Data Tables 170 (2026) 101807; https://doi.org/10.1016/j.adt.2026.101807