TRAX Data Evaluation


Although TRAX scores the various particle interactions and energy depositions on a volume-by-volume basis, specific physical problems might require dedicated analysis. To support this, a couple of evaluation procedures and associated commands are provided which read listmode data files and output evaluated results as ASCII data files in gd plotting format.

Depth dose profiles

Depth dose profiles are 1-dimensional projections of the dose distribution generated by particles emitted from a point source in a fixed direction.
See the evaladose command.

Crossers, starters, stoppers, insiders

This procedure is not yet fully implemented!
Its intended purpose is the evaluation of the number of ionizations volume-by-volume as well as the energy deposited by particles
See the evalcrossers command.

Microdosimetric distributions

These are specific energy, z, and lineal energy deposition, y, calculated as a function of the radial distance from the primary ion path. Both depend on the size (diameter) of the sensitive volume as well as on its shape (cylinder, sphere).
Additionally, sort of an "inactivation" cross section is calculated assuming a threshold (minimum number of ionizations) for lethal damage.
See the evalmdose command.

Emission spectra

These are single differential energy and angular distributions, as well as double differential energy distributions with the angle as a parameter. The spectra are build from the energy and flight direction of particles leaving a volume, e.g. a thin foil.
See the evalout command.

Radial dose distribution

This is a 1-dimensional dose distribution assuming cylindrical symmetry around an ion path, averaged along the z-axis. It is obtained as an ionization as well as an energy deposition distribution. The first one is closer to most experiments since they "see" only ionizations, not excitations. The calculated ionization dose, however, needs to be multiplied with a global W-value (in keV) to be comparable with experiments (which measure in Gy).
See the evalrdose command.

Cylindrical (r-z) dose distributions

This is a 2-dimensional dose distribution assuming cylindrical symmetry around an ion path. It is obtained as an ionization as well as an energy deposition distribution. The first one is closer to most experiments since they "see" only ionizations, not excitations. The calculated ionization dose, however, needs to be multiplied with a global W-value (in keV) to be comparable with experiments (which measure in Gy).
See the evalrzdose command.

Spherical dose distributions

This is a 1-dimensional dose distribution assuming spherical symmetry around a point source, averaged along the polar and azimuth angles. It is obtained as an ionization as well as an energy deposition distribution. The first one is closer to most experiments since they "see" only ionizations, not excitations. The calculated ionization dose, however, needs to be multiplied with a global W-value (in keV) to be comparable with experiments (which measure in Gy).
See the evalsphere command.

Time-energy spectra

For this evaluation electron energy spectra are taken corresponding to specified intervals of time-of-flight of the electrons. Should give some info on the time evolution. However, I don't know if the information is reasonable (i.e. it has never been verified against experiments) nor do I know if it's useful at all.
See the evaltespec command.

Volume specific energy spectra

For each volume the energy deposition spectra are generated (volume mode). This corresponds more to a classical detector simulation.
See the evalvolespc command.

Line track pictures

These are the well-known "track" pictures. They are derived in a multi-pass evaluation from listmode data necessarily resident on some file. Output are the flight paths of electrons, coloured according to their residual energy.
See the linetrack command.

Point track pictures

With these pictures tracks are represented as symbols for the points of interactions. Different symbols are used for the different types of interactions, as described in the gd header lines.
Different colours are used for the different particle types: Additionally the local energy deposition is written as an additional column, which might be used as a varying symbol size.
See the pointtrack command.

Radical Evaluation

This is the way TRAX currently handles radiation chemistry. Physics events such as ionization, excitation and cutoff produce chemical species (radicals and ions) by dissociation of the struck target molecules. These species are collected in a separate internal table until the end of the physics simulation. On end-of-run they are followed up by a separate chemical simulation comprising diffusion and reaction. The chemical simulation eventually yields G-values over time, species track snapshots and species radial distributions.
See the evalrcal command.

User Specific Evaluation

In addition to the builtin hardcoded evaluation functions, a mechanism is provided for user supplied evaluation functions. These require an external C function coded, compiled and linked according to TRAX standards.
See the evalusr command.
Last updated: M.Kraemer
$Id: traxeval.html,v 1.7 2019/03/17 22:57:50 kraemer Exp $