TRAX Introduction


TRAX is a software package to simulate the interaction of ions and electrons on a very basic level ("tracks") with the Monte Carlo method. It is targeted at the simulation in the "low" energy region, important for radiation transport in dosimetric devices and radiation damage to living systems (cells, DNA). Hence its applicability is limited to ions with energies less than a few hundred MeV/u and electrons with less than a few MeV. Photon support might be added in a future release. The lower threshold is given by the available cross sections, at most between 1 and 10 eV.
In contrast to conventional simulation packages which follow more or less the approach of condensed random walk and multiple scattering, as first introduced by M.J.Berger (Meth, Comp. Phys. 1 (1961) ), TRAX handles each basic interaction separately. This offers the opportunity to simulate radiation quantities like W-values, specific energy depositions, ionization distributions, radial and depth dose distributions, energy loss and energy loss straggling and such like from bottom-up instead of requiring them as input data.
On the other hand, the single interaction approach is not very practical for the simulation of large volumes and complex geometries, typically used for high energy physics setups. Although in principle possible, the consumption of CPU resources would be excessive, at least by today's standards.
Due to the long calculation times inherent in most simulation tasks TRAX has been designed as a command-line oriented program, meant to be run mostly in batch mode. Hence TRAX does not come with builtin graphics output and graphical user interfaces, although these features might be added in the future. TRAX is operated by means of an own command and scripting language and outputs its results as ASCII report and data files. Generated track data can also be stored as binary (listmode) files to be analyzed at a later stage.
Last updated: M.Kraemer,
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