Introduction#

Kassiopeia is a software package for the purpose of tracking particles in complex geometries and electromagnetic fields. It was originally developed for the simulation of the KATRIN experiment, but was designed to be extremely flexible and has broad applicability to systems with similar problems.

It is primarily of interest for examining the behavior of particles in electrostatic and magnetostatic systems at relatively low energy scales (<100keV). It also provides a mechanism to incorporate scattering interactions with dilute gases and offers specialized treatment of electron transport in silicon baseddetectors.

The Kasper framework#

The Kassiopeia software relies upon three separate, but concurrently distributed libraries. These are Kommon, KGeoBag and KEMField.

  • Kommon contains a collection of commonly used and very basic utilities which are used by the other three packages. It also contains a unique system for parsing and constructing objects from an XML file.

  • KGeoBag is the library responsible for geometric calculations. It models an experiment’s physical geometry using a boundary representation (B-REP) method, and is also entrusted with answering navigation queries as well as generating the mesh used by the boundary element method (BEM).

  • KEMField handles all of the field related tasks. These include solving the Laplace boundary value problem using a bounary element method (BEM), solving for the field at arbitrary locations from charges and currents, and constructing field maps for fast evaluation. Kassiopeia incorporates these three libraries in order to solve the equation of motion of a particle and deal with any stochastic interactions to which it might be subjected.

Extending Functionality#

Using Kassiopeia and its associated libraries can involve varying levels of complexity, depending on the end users needs. If the pre-existing features of Kassiopeia are sufficient, no additional code is needed and a simulation can be configured entirely through a plain text XML file. If a user needs a physics process which is not yet incorporated (e.g scattering on neon), it is relatively straightforward to create and include a new module for this process.

Furthermore, the object oriented approach of Kassiopeia provides a clear path for advanced users who wish to use certain specific features in their own novel applications. Code contributions that extend Kassiopeia’s functionality can be submitted through GitHub and are always welcome.

Supported operating systems and hardware requirements#

Kassiopeia is supported and intended to run on systems running either Linux or MacOS X. Currently, it has been compiled and tested to run on fresh installations of the Linux distributions Fedora 31 and Ubuntu 20.04 LTS. It is also expected to compile and run on other Linux distributions, however this has not been tested, and the steps needed to compile Kassiopeia may deviate from what is outlined here.