PEMtk: the Photoelectron Metrology Toolkit

(aka Quantum Metrology with Photoelectrons platform data & analysis layer: the unifiying layer (glue) for the platform)

Currently, the platform is under development, based on methods developed over the last 10+ years of reasearch in this area. On the theory side, work is based around ePolyScat, and a set of python packages have already been developed; on the experimental side, the plan is to update existing Matlab codes for Velocity Map Imaging (VMI) experiments and analysis routines (and rewrite/unify in python). The real foundation, and glue, for the platform will be the Photoelectron metrology toolkit (PEMtk), which will provide the unifying data platform, and analysis routines. In the future, it is hoped that this platform will be extended to other theoretical and experimental methods, but continue to provide a useful, unifying, platform.

For now, see

QM Platform schematic

QM Platform schematic

Currently implemented


Currently (dev version) only from source + local pip install

Using pip

git clone
pip install -e PEMtk

Or from (from clone dir)

python install


  • The repo can be passed directly to pip, e.g. pip install git+, see notes in the pip docs.

  • Note that pip -e is for ‘editable’, and requires the source dir to remain, but the installation is also editable, see notes here. Alternatively, use pip install <path_to_local_pkg>.


  • Further fitting methodology & code developments.

  • Integrated data handling class(es).

  • Image processing.

  • Image simulation.

  • More versatile plotting routines.

  • Interfaces for various experimental platforms.


If you make use of PEMtk in your research, please cite it.

Cite the software directly via the Github repository for the software:

  title = {Photoelectron Metrology Toolkit (PEMtk)},
  author = {Hockett, Paul},
  url = {},
  howpublished = {\url{}},
  author={Hockett, Paul},
  commit = {aca9bc06bee4ab16dbe3d30a5b1e1b5604f975c5}

(For specific releases and commits, see

… or the upcoming Topical Review: Extracting Molecular Frame Photoionization Dynamics from Experimental Data (2022) paper (to be published in J. Phys. B) which includes discussion and numerical demos using the software (currently available via Authorea or as an arXiv preprint):

  title = {Topical Review: Extracting Molecular Frame Photoionization Dynamics from Experimental Data},
  author = {Hockett, Paul and Makhija, Varun},
  year = {2022},
  month = sep,
  eid = {arXiv:2209.04301},
  eprint = {2209.04301},
  eprinttype = {arxiv},
  primaryclass = {physics, physics:quant-ph},
  publisher = {arXiv},
  doi = {10.48550/arXiv.2209.04301},
  url = {},
  archiveprefix = {arXiv},


(Citation styles for software from StackExchange.)