Cosmic Ray Backgrounds

1
Cosmic Ray Backgrounds

• Three components
• Galactic cosmics
• Primary Protons and heavier elements
• Van Allen Belts
• Low energy electrons and protons
• Solar Flare Events
• More protons
• Creme96 vs AMS Spectra

Tom Diehl 08/6/2003
2
Spectra Added So Far

• AMS Result for Near Earth Orbit
• Space Shuttle _at_ altitude 380 km
• Above the atmosphere but below the Van Allen
  belts
• 2 components
• For k.e.gt10 GeV geomagnetic cutoff, a power
  law spectrum (see fit)
• Below the cutoff, a second spectrum different
  from that observed in the Van Allen belts and in
  upper atmosphere.
• Observed to be isotropic

AMS Data Physics Reports 366, 331 (2002).
3
Program Generates

• 1.010355 prot
• 2.846164 hel3
• 2.792072 prot
• 1.599854 prot
• 0.3606503 prot
• 0.7046497 prot
• 16.01863 hel3
• 5.046957 prot
• 5.199442 prot

Particles, their 4-vector Starting point, etc
4
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.
• Orbital Parameters
• Perigee 10,000 km, Apogee 100,000 km, inclination
  26.3 deg.
• I sent email to the codemaster of CREME96 asking
  him to change the upper limit of the apogee.
• I generated a table of proton fluences for
  comparison with the AMS data.

5
CREME96 vs AMS

• KEY
• CREME96 interplanetary protons
• CREME96 trapped protons
• AMS data (interplanetary protons)
• Spectra agree pretty well in the region both are
  available.

6
Summary and Promises

• The CREME96 program provides cosmic ray fluences
• We can easily use in our MC.
• Wider energy range then AMS data.
• Limitations in the orbital parameters need to be
  addressed by CREME96 people.
• The CREME96 fluences match closely with AMS data
  in range of overlapped energy.