KARL - a Monte Carlo model for atomic and molecular processes in the tritium atmosphere of the KATRIN experiment

IF 7.2 2区物理与天体物理 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS Computer Physics Communications Pub Date : 2025-03-17 DOI:10.1016/j.cpc.2025.109580

Christian Sendlinger , Jonas Kellerer , Felix Spanier

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引用次数: 0

Abstract

A new parallelized simulation code is presented, which uses a Monte Carlo method to determine particle spectra in the KATRIN source. Reaction chains are generated from the decay of tritium within the source. The code includes all relevant processes: elastic scattering, ionization, excitation (electric, vibrational, rotational), recombination and various clustering processes. The main emphasis of the code is the calculation of particle spectra and particle densities and currents at specific points within the source. It features a new technique to determine these quantities. It also calculates target fields for the interaction of particles with each other as it is needed for recombination processes.

The code has been designed for the KATRIN experiment but is easily adaptable for other tritium based experiments like Project 8. Geometry and background tritium gas flow can be given as user input.

The code is parallelized using MPI and writes output using HDF5. Input to the simulation is read from a JSON description.

Program summary

Program Title: KARL - KAtrin WGTS electRon and ion spectrum Monte CarLo

CPC Library link to program files: https://doi.org/10.17632/5bj3vwc6rg.1

Licensing provisions: GNU Public License v3

Programming language: C++

External routines/libraries: C++ compiler (tested with g++ 8.2 and 9.4.0), MPI 1.1 (tested with OpenMPI 3.1), HDF5 with support for parallel I/O (tested with version 1.10.0), Blitz++ (tested with version 1.0.2), Jansson (tested with version 2.12 and 2.13)

Nature of problem: In the KATRIN experiment (and other experiments alike that feature large vessels filled with tritium) electrons are created from beta decay. These electrons interact with the ambient gas to produce secondary electrons through ionization. Subsequent processes include excitation, secondary ionization and collisions. The resulting electron and ion differential energy spectrum at various positions is relevant for further plasma analysis, and the current of charged particles to the ends of the experiments is an observable.

Solution method: Semi-classical Monte Carlo.

Additional comments including restrictions and unusual features: The geometry of the experiment is currently limited to the KATRIN experiment, but this may easily be changed. The configuration is stored in JSON files.

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来源期刊

Computer Physics Communications 物理-计算机：跨学科应用

CiteScore

12.10

自引率

3.20%

发文量

287

审稿时长

5.3 months

期刊介绍： The focus of CPC is on contemporary computational methods and techniques and their implementation, the effectiveness of which will normally be evidenced by the author(s) within the context of a substantive problem in physics. Within this setting CPC publishes two types of paper. Computer Programs in Physics (CPiP) These papers describe significant computer programs to be archived in the CPC Program Library which is held in the Mendeley Data repository. The submitted software must be covered by an approved open source licence. Papers and associated computer programs that address a problem of contemporary interest in physics that cannot be solved by current software are particularly encouraged. Computational Physics Papers (CP) These are research papers in, but are not limited to, the following themes across computational physics and related disciplines. mathematical and numerical methods and algorithms; computational models including those associated with the design, control and analysis of experiments; and algebraic computation. Each will normally include software implementation and performance details. The software implementation should, ideally, be available via GitHub, Zenodo or an institutional repository.In addition, research papers on the impact of advanced computer architecture and special purpose computers on computing in the physical sciences and software topics related to, and of importance in, the physical sciences may be considered.