STK SEET Radiation Models

• APEXRAD - radiation models based on data collected by the APEX Space Radiation Dosimeter behind shielding thicknesses of 4.29, 82.5, 232.5 and 457.5 mil Al
• CRRES - flux models based on the CRRESELE and CRRESPRO models and supported at discrete electron and proton energies based on data collected by the Combined Release and Radiation Effects Satellite (CRRES) instrumentation:
  • the High Energy Electron Fluxmeter (HEEF) instrument (for omni-directional electron flux).
  • the PROTEL proton telescope (for omni-directional proton flux).
• CRRESRAD - radiation models based on data collected by the Combined Release and Radiation Effects Satellite (CRRES) Space Radiation Dosimeter for radiation dosages behind shielding thicknesses of 82.5, 232.5, 457.5 and 886.5 mil Al.
• NASA - flux models based on NASA AE-8 radiation belt maps for electron flux for energies between 0.04 and 7.0 MeV, and NASA AP-8 radiation belt maps for proton flux (energies between 0.1 and 400 MeV).
• Irene - a new set of models for the fluxes of radiation belt and plasma particles in near-Earth space for use in space system design, mission planning, and other applications of climatological specification.
• Radiation Only - radiation models behind shielding thicknesses of 82.5, 232.5, and 457.5 mil Al based on
• data collected by the CRRES Space Radiation Dosimeter for radiation dosages.
• data collected by the APEX Space Radiation Dosimeter for dosages.

In Radiation Only mode, computations default to the APEXRAD radiation models but will use CRRESRAD outside the APEXRAD range of validity.

APEXRAD and CRRESSRAD do not specifically compute proton or electron fluxes or provide constituent dosage rate and dose information, only combined information from all constituent sources.

Specifies which dose-rate data set to use:

• High LET (1 - 10 MeV dosage, primarily from protons)
• Low LET (0.05 - 1 MeV, primarily from electrons, bremsstrahlung, with some high energy protons)
• Total - both High LET and Low LET

Linear energy transfer (LET) is the energy lost by an ion and deposited into the target material per unit distance along the ion’s path. This option only affects CRRESRAD and APEXRAD models.

Select from a pre-defined list of material specimen types, assumed to be a small-volume of material under Aluminum shielding of specified thickness. This option is effective when operating with the CRRES and NASA computational modes for arbitrary proton and electron incident spectra and used for dose computations from the SHIELDOSE-2 radiation-transport model. The default detector type is Silicon.

• Finite slab - The detector is embedded in one side a planar slab of Aluminum shielding material, and is irradiated through the slab from the other side.
• Semi-infinite slab - The detector has the same geometry as the finite slab, except that the Aluminum shielding material has no boundary behind the irradiated surface (thereby enclosing the detector material).
• Spherical - The detector is embedded at the center of a solid sphere of Aluminum and irradiated from all directions.

Specifies the time step for sampling (of dose rate from raditation-dose databases, or of fluence versus energy from the flux-model databases) that goes into dose computations.

Specifies the default time step used by data providers reporting radiation-dose output. When graphing or reporting from the Report & Graph Manager Page, this value can be overridden by specifying Step Size under Time Properties.

If selected, nuclear attenuation due to local charged secondary energy deposition is used for dose computations from the SHIELDOSE-2 radiation-transport model. This option is effective when operating in the CRRES and NASA computational modes for arbitrary proton and electron incident spectra.

If selected, the effect of neutrons will be included in nuclear attenuation. This option is effective only when the Use Nuclear Attenuation option is active.

If selected, the field model used for computing indices into the radiation model databases is set to use the fixed epochs and external field models from which those databases were constructed, as recommended in [Heynderickx, 1996].

• APEXRAD - 1996, no external field
• CRRES models - 1985, Olsen-Pfitzer quiet external field
• NASAELE and NASAPRO at solar min - 1962, no external field
• NASAPRO at solar max - 1970, no external field

All cases use the IGRF/DGRF main-field model with the corresponding epoch coefficients.

This switch is only available if the “Set magnetic field epoch to Mode’s reference epoch” switch has been selected. If selected, the method of [Heynderickx, 1996] is used to shift the relative location of the effect of the SAA on the magnetic field computation.

• Static Value - a user-input value representing a 15-day average of the standard Ap geomagnetic activity index
• Use Flux File - source data based on published Ap tables

This option only affects CRRESELE and APEXRAD models.

Specify up to 70 different Aluminum shielding thicknesses as needed. This option is effective when operating with the CRRES and NASA computational modes for arbitrary proton and electron incident spectra and used for dose computations from the SHIELDOSE-2 radiation-transport model.