```

_____ _____ ____ _____ ____ _____ _

| __ | __ \ / __ | __ \ / __ \ / ____| /\ | |

| |) | |) | | | | |) | | | | (_ / \ | |

| __/| _ /| | | | _/| | | |__ \ / /\ \ | |

| | | | \ | || | | | || |_) / _ | |____

|| || _\_/|| _/|_// _____|

_ _ ___ ___

| | | | / _ \ ( )

| || | | _/ | |

| .,| ___| _)

| |

|_|

```

PROPOSAL

PROPOSAL (Propagator with optimal precision and optimized speed for all leptons) is presented as a public tool for propagating leptons and gamma rays through media. Up-to-date cross sections for ionization, bremsstrahlung, photonuclear interactions, electron pair production, Landau–Pomeranchuk–Migdal and Ter-Mikaelian effects, muon and tau decay, as well as Molière scattering are implemented for different parametrizations. The full Paper can be found here. Recent improvements are documented here.

PROPOSAL is developed and tested on macOS, Linux and Windows: Continuous integration is set up on GitHub actions testing PROPOSAL on gcc, clang and Visual Studio.

PROPOSAL is now a C++14 library using pybind11 Python bindings!

Requirements

• CMake 3.9 or higher (to build the tests CMake 3.10 is required)
• C++14 compatible compiler (for gcc: version 5 and later; for clang: version 3.4 and later)

Furthermore, you either need the package manager

• conan

which will provide all dependencies that are necessary for PROPOSAL or you need to provide these dependencies by your own. For more information, see here.

Installation

If you are only interested in using PROPOSAL as a python library, the easiest way to install it should be using

pip install proposal

Advanced install and compiling instructions, especially if you want to use PROPOSAL as a C++ library, are found in install.

Usage

Usage in Python

If you want to learn how to use PROPOSAL in Python, we recommend to look at the jupyter notebooks provided in the examples folder. A good starting point is the Propagator jupyter notebook.

For a short demonstration, look at the following snippet: It will create data you can use to show the distribution of muon ranges and the number of interactions in ice.

```python import proposal as pp

mudef = pp.particle.MuMinusDef() prop = pp.Propagator( particledef=mudef, pathtoconfigfile="path/to/config.json" )

initstate = pp.particle.ParticleState() initstate.energy = 1e9 # initial energy in MeV initstate.position = pp.Cartesian3D(0, 0, 0) initstate.direction = pp.Cartesian3D(0, 0, 1)

mu_length = []

for i in range(1000): track = prop.propagate(init_state)

mu_length.append(track.track_propagated_distances()[-1] / 100)

```

Note that you need to provide a path to a valid configuration file. The parameters of the given configuration file are described here.

For a detailed explanation on how this snippet works, look at the Propagator jupyter notebook!

Usage as a C++ library

PROPOSAL is built as a library, which means you can include this project in your own C++ project by including the header files. The following snippet uses the configuration to propagate muons and stores the muon ranges. The parameters of the configuration file are described here.

```c++

include "PROPOSAL/PROPOSAL.h"

using namespace PROPOSAL;

int main(){ auto mudef = MuMinusDef(); Propagator prop(mudef, "path/to/config.json");

Cartesian3D position(0, 0, 0);
Cartesian3D direction(0, 0, 1);
auto energy = 1e8; // MeV
auto init_state = ParticleState(position, direction, energy, 0., 0.);

std::vector<double> ranges;

for (int i = 0; i < 10; i++)
{
    auto track = prop.Propagate(init_state, 50000); // distance to propagate in cm

    ranges.push_back(track.back().propagated_distance);
}

// ... Do stuff with ranges, e.g. plot histogram

} ```

To see an example on how to run this script with PROPOSAL using CMake, see here.

Issues

When you encounter any errors or misunderstandings, you can always create an issue here on GitHub. Furthermore, you may always contact us with your questions via Jean-Marco Alameddine, Jan Soedingrekso, Alexander Sandrock.

License

This software may be modified and distributed under the terms of a modified LGPL License. See the LICENSE for details of the LGPL License.

Modifications of the LGPL License:

1. The user shall acknowledge the use of PROPOSAL by citing the following reference:

   J.H. Koehne et al. Comput.Phys.Commun. 184 (2013) 2070-2090 DOI: 10.1016/j.cpc.2013.04.001

2. The user should report any bugs/errors or improvements to the current maintainer of PROPOSAL.

How to cite PROPOSAL?

If you use PROPOSAL, please cite the PROPOSAL paper

bibtex @article{koehne2013proposal, title ={PROPOSAL: A tool for propagation of charged leptons}, author = {Koehne, Jan-Hendrik and Frantzen, Katharina and Schmitz, Martin and Fuchs, Tomasz and Rhode, Wolfgang and Chirkin, Dmitry and Tjus, J Becker}, journal = {Computer Physics Communications}, volume = {184}, number = {9}, pages = {2070--2090}, year = {2013}, doi = {10.1016/j.cpc.2013.04.001} } and our zenodo entry of the version you use bibtex @misc{dunsch_2020_1484180, author = {Alameddine, Jean-Marco and Dunsch, Mario and Bollmann, Lars and Fuchs, Tomasz and Gutjahr, Pascal and Koehne, Jan-Hendrik and Kopper, Claudio and Krings, Kai and Kuo, Chung-Yun and Menne, Thorben and Noethe, Maximilian and Olivas, Alex and Rhode, Wolfgang and Sackel, Maximilian and Sandrock, Alexander and Schneider, Austin and Soedingrekso, Jan and van Santen, Jacob}, title = {tudo-astroparticlephysics/PROPOSAL: Zenodo}, month = mar, year = 2020, doi = {10.5281/zenodo.1484180}, url = {https://doi.org/10.5281/zenodo.1484180} } and if you want to cite the latest improvements bibtex @article{dunsch_2018_proposal_improvements, title = {Recent Improvements for the Lepton Propagator PROPOSAL}, author = {Dunsch, Mario and Soedingrekso, Jan and Sandrock, Alexander and Meier, Max and Menne, Thorben and Rhode, Wolfgang}, journal = {Computer Physics Communications}, volume = {242}, pages = {132--144}, year = {2019}, eprint = {1809.07740}, eprinttype = {arXiv}, eprintclass = {hep-ph}, doi = {10.1016/j.cpc.2019.03.021} }

Developers and Maintainers

Jan Soedingrekso, Alexander Sandrock, Jean-Marco Alameddine

Former Developers and Maintainers

Jan-Hendrik Koehne, Tomasz Fuchs, Mario Dunsch, Maximilian Sackel

Acknowledgment

This work was created as part of the project C3 of the SFB876.