1. Cosmic Ray Backgrounds • Creme96 Studies • Crème Description (old stuff) • Creme96 vs AMS (old stuff) • Conversations with Allan Tylka and Limitations of Creme96 (new stuff). • What we might have to do (new stuff). Tom Diehl 08/20/2003

2. CREME96 • See https://creme96.nrl.navy.mil • Generate spectra of Cosmic Rays using .TRP for trapped radiation and .FLX for interplanetary radiation. • I used solar flare “average” for the trapped radiation. • The product of each of these is an average flux (# per second) in the orbit. • Orbital Parameters • Perigee 10,000 km, Apogee 100,000 km, inclination 26.3 deg. • I sent email to the codemaster (Allan Tylka) of CREME96 asking him to change the upper limit of the apogee.

3. CREME96 vs AMS • Generate a table of proton fluences for comparison with the AMS data. • KEY: • CREME96 interplanetary protons • CREME96 trapped protons • AMS data (interplanetary protons) • Spectra agree pretty well in the region both are available.

4. Limitations of Creme96 • Then I heard from Tylka. He said: • The Trapped radiation is irrelevant at the high parts of the SNAP orbit (we know that) • He thought they’d been generous in going to 100,000 km. • He expressed concern about the accuracy of the integration for long-period orbits and about the “lack of precession terms” in Creme96 • Reading between the lines “long-period” means period compared with 7 days. • But our orbit precesses once a year, if I understand what it means to have fixed perigee over LBNL. • I wrote back, explaining what we want to do. After all, the 150,000 km limit and the integration time are artificial limits that we can be overcome for our use.

5. Further thoughts • Allan Tylka might help us get Creme96 adjusted to our needs. He might not. • If he doesn’t, we could reweight the TRP calculation by 42/72 and reweight the FLX calculation by 1/1 (no change). • Further improvement requires getting into generating our own orbital calculation.

6. Summary and Promises • The CREME96 program provides cosmic ray fluences • The CREME96 fluences match closely with AMS data in range of overlapped energy. • Limitations in the orbital parameters need to be addressed by CREME96 people if we are to do this most precisely, though we have a fairly easy way to make an approximating correction.