Resolution Functions

Python library for working with resolution functions of inelastic neutron scattering (INS) instruments. This package exists to centralise all things related to resolution of INS instruments and make it easier to work with. It pools related code from existing projects, namely AbINS and PyChop, as well as implementing code published in literature. The main purposes are:

1. Provide one, central place implementing various models for INS instruments (resolution functions)
2. Provide a simple way to obtain the broadening at a given frequency, for a given instrument and settings
3. (in progress) Provide a way to apply broadening to a spectrum

Quick Start

The package can be installed with pip (see Installation). To start, import the main Instrument class and get the instrument object of your choice:

>>> from resolution_functions import Instrument
>>> tosca = Instrument('TOSCA')
>>> tosca
Instrument(name='TOSCA', version='TOSCA', models=['AbINS', 'book', 'vision'])

To get the resolution function, call the get_resolution_function method, which returns a callable that can be called to get the broadening at specified frequencies. However, you will need to know which model you want to use, as well as any model-specific parameters.

>>> # The available models for a given instrument can be queried:
>>> tosca.available_models
['AbINS', 'book', 'vision']
>>> # There are multiple ways of querying the model-specific parameters, but the most comprehensive is
>>> tosca.get_model_signature('book')
<Signature (model_name: Optional[str] = 'book', *, detector_bank: Literal['Backward', 'Forward'] = 'Backward', _)>
>>> # Now we can get the resolution function
>>> book = tosca.get_resolution_function('book', detector_bank='Forward')
>>> book
<resolution_functions.models.tosca_book.ToscaBookModel object at 0x000000000>
>>> book(100)
0.81802604002035
>>> import numpy as np
>>> book(np.array([100, 200, 300]))
array([0.81802604, 1.34222267, 1.88255039])

Installation

This package can be installed using pip, though it is not yet on PyPI, so it has to be installed directly from GitHub:

pip install git+https://github.com/pace-neutrons/resolution_functions.git

or from a local copy:

git clone https://github.com/pace-neutrons/resolution_functions.git
pip install resolution_functions