There are 4 major steps in determining fluxes in the atmosphere

1. There are 4 major steps in determining fluxes in the atmosphere • Determine the composition and spectrum of cosmic rays at local interstellar space • Solar Modulation • Geomagnetic Cutoff • Transport of particles through the atmosphere In this analysis 1 & 2 are combined and 3 can be ignored at the pole.

2. Input spectrum was determine through a global fit to simultaneous primary observations of Protons and Alphas. LISM: The form of the local interstellar spectrum in Rigidity Space Kappa is the Solar Modulation Diffusion Coef in the spherically symmetric Folker-Planck equation Two sets of K1, K2, K3 values: one for Protons and one for Alphas One set of values for K5 and K6 K4 determines the modulation level for each observation

3. The propagation of primary particles through the Earth's atmosphere was calculated with FLUKA. Primary protons and alphas are generated within the rigidity range of 0.5GV-20TV uniform in cos2. Since FLUKA does not transport nuclei, helium ions are initially transported with a separate package called HEAVY to simulate fragmentation. This package interfaces with FLUKA to provide interaction starting points for each nucleon originating from a helium nucleus

4. The atmosphere is divided into 180 (bottom boundary radius = 6378.14km) concentric spherical shells with differing radii and density to simulate the actual density profile with a vertical total 1035g/cm2 column density for sea level and 695g/cm2 for 10,000ft. Atmospheric composition is constant with a 23.3% O2, 75.4% N2 and 1.3% Argon distribution by mass

5. The outer air-space boundary is radially separated by 65 kilometers from the inner ground-air boundary. A single 1cm2 element on the air-space boundary is illuminated with primaries. This area element defines a solid angle element with respect to the center of the Earth which subtends a slightly smaller area element at different depths. Particle intensity at various depths is determined by superimposing all elements on the spherical boundary defining the depth. Due to rotational invariance this process is equivalent to illuminating the entire sky and recording the flux in a single element at ground level, but requires far less computer time [Clem et al., 1997]

6. South Pole Calculation Particle Fluxes were calculated for the South Pole assuming 690g/cm^2 atmospheric overburden. A primary flux expected for June-20-1999 was assumed. This spectra lie between the AMS and IMAX observations shown in Slide 2. Current exposure is 5days-cm^2 (probably need more stats) Zero geomagnetic cutoff for all arriving directions of primary particles.. Below the south pole surface 2m of ½ density water was assume, and then 10m of 0.92g/cm^3 water and then zero-gravity black hole material was used below the water. Shown in the next 4 figures 5 particle-type spectra were collected (electrons ( with positrons), muons, photons, protons and neutrons) at the surface and 50cm below surface For both levels both the vertical direction on a flat detector and downward omni-direction on a unit sphere detector were considered.

8. Plan: To acquire more statistics and compare with observations