Elements Included in FLUX Ionizing-Radiation Environment Calculations

You must specify the range of elements to be included in your FLUX calculations of the external space ionizing-radiation environment.

By default, this range is set at:

• minimum atomic number: Z = 1 (protons)
• maximum atomic number: Z = 28 (nickel)

For the large majority of SEE applications, this range is adequate: cosmic rays and solar energetic particles with Z > 28 are very rare and generally may be neglected.

However, for SEE rate calculations:

• in devices with high thresholds (effective LET > 15 MeV-cm²/mg);
• for applications demanding very low SEE rates (< 10^-8 SEEs/bit/day);
• in low-Earth, low-inclination orbits, where the usual source of high LET particles (low-energy Fe group nuclei) is geomagnetically excluded;

you should consider increasing the maximum atomic number to Z=92. But please note that including Z > 28 elements in your calculations may significantly slow down the nuclear transport code TRANS.