1. CORSIKA bug and other updates
Dmitry Chirkin
UC Berkeley

2. CORSIKA updates
Track times are given relative to the shower core arrival to the surface
F2k and related fixes: track numbers and parent ids (treated by ucr), p->Z1
All coordinates are given at the observation level (ice surface), track length now exact
Shower times can now be assigned and coincident showers can be treated (by combining them within a predefined time window)

3. CORSIKA bug
CORSIKA version and earlier had muon radiative energy losses underestimated by 103. As of version this is corrected. Effect on the background calculation is minor.

4. Nch distributions
To estimate the differences between different CORSIKA versions and CR spectrum models, and effect of the coincident showers on the background simulation, Nch distributions are compared.

5. Spectrum index corrections
1st method
2nd method
results

6. CORSIKA updates (continued)
Possible to choose between Wiebel-Sooth and Jorg Horandel published primary spectra. The latter is implemented within the poli-gonato model of the CR energy spectrum. This implementation is now valid up to 50 PeV

7. Poli-gonato CR spectrum fits
From J-H

8. Conclusions Many updates to CORSIKA were implemented
CORSIKA bug is corrected in current version (6.030) and has no effect on the background muon simulation
Coincident shower events do not significantly affect the background simulation
Change from Wiebel-Sooth CR spectra to the Jorg Horandel poli-gonato model does affect the background simulation, the change in spectral index is of the order 0.02

9. Auxiliary slides
Spectrum correction depth profiles

10. Spectrum corrections method
1st method
2nd method
Also my spectrum corrections method was applied