CORSIKA/MMC for the IceCube simulation production Dmitry Chirkin chirkin@physics.berkeley.edu University of California at Berkeley, Berkeley, CA 94720, USA IceCube Detector Simulation workshop, Belgium, October 2003

Talk outline generators/propagators – what are they good for? description of optimizations done for AMANDA-II: CORSIKA MMC conclusions

Simulation chain as used in AMANDA known muon propagators: MMC MUM mudedx Lip Loh generator step known air shower generators: CORSIKA based dCORSIKA pCORSIKA basiev propagator step Also new possible applications: CORSIKA => atm. ν generation Kosta Schinarakis, Wuppertal MMC => monopole propagation Peter Niessen, Arvid Pohl

CORSIKA settings 6 interaction models, QGSJET, VENUS and NEXUS describe AMANDA-II data best, QGSJET is by far the fastest Atmosphere and Earth’s surface are curved Detector is assumed cylindrical

Running CORSIKA consists of 2 steps: CORSIKA (shower generation) UCR (Utility for CORSIKA output Randomization – shower location randomizer)

USER_DEF mmc_en NR E_INI E_CPD E_IN E_OUT CDP_X CDP_Y CDP_Z Z_IN Z_OUT Running MMC Basic features: can propagate muons with fixed vcut or ecut in regions 1 and 2 (use negative values to change default behavior) propagates muons with up to 1020 eV, can be used up to 1030 eV (enable with “–ebig=1.e21” flag) can propagate muons and/or taus. To propagate both, run MMC for taus first, then pipe into MMC for muons Can propagate muons though multiple media with spherical or flat interfaces. For concentric media uses external file with media location definitions User line can be enabled for each muon. To ensure compatibility with other AMANDA software, use “-rdmc” (for f2k) and/or “-amasim” (for AMASIM) provides multiple output formats (3 at the moment) Vcut=0.05, 0.01, 10-3 and 10-4 Usual (no cont) vs. cont option Defalt values used for AMANDA: vcut=0.05, cont ecut=500 MeV no cont vcut=1.0 no cont User line definition: USER_DEF mmc_en NR E_INI E_CPD E_IN E_OUT CDP_X CDP_Y CDP_Z Z_IN Z_OUT

MMC optimizations cont. Interpolation routines and strategy of their use have been heavily optimized Parameterization and interpolation settings can be easily reconfigured (e.g. with “-g=[romberg]” option at run time or with “-hifi” option during compilation) Algorithm works to the extreme: tested up to the muon energy of 1030 eV and vcut as low as 10-15.

Conclusions and dicussion CORSIKA and MMC have been heavily optimized Please note that some optimization settings are AMANDA-II specific and need to be recalculated for desired IceCube geometry