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Particle Interaction and Propagation

The Lepton Propagator PROPOSAL

PROPOSAL (PRopagator with Optimal Precision and Optimal Speed for All Leptons) is a Monte Carlo simulation library written in C++ with Python bindings. The original design goal was to provide a performant and accurate simulation of high-energy muons traveling long distances through media. This is necessary for large volume detectors such as neutrino telescopes or other subsurface experiments dealing with an atmospheric muon background.

PROPOSAL is currently used for muon propagation and decay and Taus in the IceCube and RNO simulation chain. It is used in the CORSIKA 8 air shower simulation software to calculate the electromagnetic component consisting of electron/positron and high-energy photon propagation.

More information about PROPOSAL can be found on GitHub.

Cherenkov light created by an iron-induced air shower © Maximilian Nöthe​/​TU Dortmund
Cherenkov light of a 10 TeV iron shower on the ground. The colors represent the secondary particles of the shower that excited Emisson of Cherenkov light: red for electrons/positrons, green for muons, blue for heavier particles. Simulation with CORSIKA 7 and the IACT/Atmo extension.


The software framework CORSIKA (COsmic Ray SImulations for KAscade) was developed for the simulation of complex atmospheric particle cascades induced by cosmic rays up to the highest energies. Due to the complexity of the simulation with tens of thousands of particles and billions of photons, the computation time for a single cascade can be up to several hours or even days. With several million cumulative CPU hours per year, even small improvements can significantly reduce costs and enable better or new simulations.

While the long-standing and successful CORSIKA7 is technically aging, work is currently underway on a completely renewed CORSIKA8. This version will be written in C++ and will use state-of-the-art technical methods such as Python bindings and high parallel execution. We are working on CORSIKA in Dortmund in the course of the Collaborative Research Center SFB876 (Provision of Information by Resource Constrained Data Analysis) with different methods to reduce time and energy consumption.

Location & approach

The campus of the Technical University of Dortmund is located near the freeway junction Dortmund West, where the Sauerland line A45 crosses the Ruhr expressway B1/A40. The Dortmund-Eichlinghofen exit on the A45 leads to the South Campus, the Dortmund-Dorstfeld exit on the A40 leads to the North Campus. The university is signposted at both exits.

The "Dortmund Universität" S-Bahn station is located directly on the North Campus. From there, the S-Bahn line S1 runs every 20 or 30 minutes to Dortmund main station and in the opposite direction to Düsseldorf main station via Bochum, Essen and Duisburg. In addition, the university can be reached by bus lines 445, 447 and 462. Timetable information can be found on the homepage of the Rhine-Ruhr transport association, and DSW21 also offer an interactive route network map.

One of the landmarks of the TU Dortmund is the H-Bahn. Line 1 runs every 10 minutes between Dortmund Eichlinghofen and the Technology Center via Campus South and Dortmund University S, while Line 2 commutes every 5 minutes between Campus North and Campus South. It covers this distance in two minutes.