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How To Run CREME96
Before you start CREME96 calculations, you should know the answers to these questions:
- What is the orbit of your satellite?
- What kind of radiation environment are you designing for? The typical "quiescent" environment which prevails most of the time? Or do you want to consider extreme cases, ie., solar particle ("flare") events and (if your orbit is inside Earth's magnetic field) geomagnetic storms?
- How much shielding does the satellite provide between your system and the external space radiation environment?
In addition, if you want to calculate single-event effect (SEE) rates:
- What are your devices' characteristics? What are the ground-test data on your devices' single event effect (SEE) cross-sections, both due to proton-induced recoils and due to direct-ionization?
If you've got answers to these questions, you're ready to make calculations.
The CREME96 program suite consists of eight primary modules, not all of which are needed for each calculation. The names and functions of these modules (as well as the input/output files -- explained below) are summarized in the following table:
CREME96 Primary Program Modules
| Module | What it does | Input Files | Output Files |
|---|---|---|---|
| GTRN | Evaluates geomagnetic shielding. | None | *.gtf ; *.gt#, #=1-X |
| TRP | Evaluates trapped proton fluxes. | None | *.trp; *.tr#, #=1-X |
| FLUX | Evaluates the ionizing radiation environment at the external surface of the spacecraft. | *.gtf or *.gt#; *.trp; all optional | *.flx |
| TRANS | Transports nuclear fluxes through the spacecraft shielding | *.flx (or *.tfx); *.shd (optional) | *.tfx |
| LETSPEC | Calculates Linear Energy Transfer (LET) spectra. | *.tfx (or *.flx) | *.let; (*.dlt optional) |
| HUP | Evaluates direct-ionization ("heavy-ion") -induced SEEs | *.let | *.hup |
| PUP | Evaluates proton-induced SEEs | *.tfx (or *.flx) | *.pup |
| DOSE | Evaluates dose due to non-trapped particles (GCRs, SEPs) | *.tfx (or *.flx) | *.dse |
Note: If you are interested in geosynchronous or interplanetary orbits, you do not need to run GTRN or TRP. (See GTRN for more advice.) In these cases, begin your calculations with FLUX.
For example, if you wanted to calculate the direct-ionization induced SEE rate on an interplanetary mission, you would run the CREME96 programs in this order:
FLUX, TRANS, LETSPEC, then HUP
If you wanted to calculate the direct-ionization SEE rate in a low-Earth orbit, you would run:
GTRN, FLUX, TRANS, LETSPEC, then HUP
If you wanted to calculate the trapped-proton-induced SEE rate in a low-Earth orbit, you would run:
TRP, TRANS, then PUP
(However, you should always evaluate both proton-induced and direct-ionization induced SEE rates for Earth orbits.)
The CREME96 modules are accessed from the creme96 portlet. The modular structure of CREME96 should enable you to calculate more efficiently. For example, once you've done the FLUX calculation for the orbit and environment you're interested in, you can use it as the input for many different TRANS calculations, which differ in the amount of shielding. Once you've completed the TRANS (and LETSPEC) calculations, their results can serve as the starting point for many different PUP (and HUP) calculations.
On each module's User Inputs Page, you will see a help button linking to hyperlinked documents. These hyperlinks provide a tutorial on what you need to know to run the CREME96 codes. Please take the time to read these hyperlinks, at least on your first time through the modules. Please pay special attention to the hyperlinks denoted IMPORTANT ADVICE.
As shown in the above table, data are transferred between the CREME96 modules via intermediate data files. You specify the rootname for these files, but the filename extensions, which identify the type of file and are required by the CREME96 software, are added automatically by the code. See rootname for suggestions about naming your files.
