The idea is to define the atmosphere specification in a robust way, which is both future proof and misinterpretation-proof. The main characteristics of the format are:
#578Si380Al242Fe CO_2 N Ar
Note: you can use materials available in the Geant4 NIST material database. Leave out the prefix “G4_$. If your gas molecule is not available, you can specify it as an artificial mixture. For example, SO2 would be 50.05% Sulfur and 49.95% Oxygen (in terms of mass fraction). The error of this approximation is discussed here.
Column nr | Name | Long Name | Unit | Range | Type, Notation |
---|---|---|---|---|---|
0 | alt_low | altitude at bottom of the layer | km | 0- | %12e |
1 | alt_high | altitude at top of the layer | km | 0- | %12e |
2 | phi_low | azimuth angle start | rad | 0-6.2831853 | %12e |
3 | phi_high | azimuth angle stop | rad | 0-6.2831853 | %12e |
4 | theta_low | polar angle start | rad | 0-3.14159265 | %12e |
5 | theta_high | polar angle stop | rad | 0-3.14159265 | %12e |
6 | SDID | (0=core,1=crust), 2,3,… | 0-666 | %4i | |
7 | Temperature | K | 0- | %12e | |
8 | Density | $\rm{g}/\rm{cm}^3$ | 0- | %12e | |
9 | Pressure | hPa | 0- | %12e | |
10 | Soil | Mass fraction of soil | $\%\,(\rm{kg}/\rm{kg})$ | 0-1.0 | %12e |
11 | $\rm{CO_2}$ | Mass fraction of CO2 | $\%\,(\rm{kg}/\rm{kg})$ | 0-1.0 | %12e |
12 | $\rm{N_2}$ | Mass fraction of N2 | $\%\,(\rm{kg}/\rm{kg})$ | 0-1.0 | %12e |
13 | $\rm{Ar}$ | Mass fraction of Ar | $\%\,(\rm{kg}/\rm{kg})$ | 0-1.0 | %12e |
The gdml files are created using the psf2gdml.py script. Note that the .psf files offers advantages for human use, since it is much easier to read. 1)