MUPAGE MU on PA rametric GE nerator A fast generator of atmospheric muon events

1. MUPAGEMUon PArametric GEneratorA fast generator of atmospheric muon events Giada Carminati Physics Department and INFN Bologna G. Carminati – KM3Net Meeting WP2

2. Standalone C++ code based on the parameterization of the flux of single and multiple atmospheric muonsAPP 25 (2006) 1-13 G. Carminati – KM3Net Meeting WP2

3. Features of the parameterization • Based on a full Monte Carlo simulation • Takes into account muon multiplicity • Restrictions: • water vertical depth range from 1.5 to 5 km.w.e.; • zenith angle range from 0 to 85 degrees; G. Carminati – KM3Net Meeting WP2

4. C++ code Parametric formulas MUPAGE Submitted to G. Carminati – KM3Net Meeting WP2

5. CAN: cylinder surface surrounding active volume Input parameters(set by users) • Geometrical and physical information: • vertical depth with respect to the sea level • detector geometry • min and max zenith angle range • max distance of muons from the shower axis in a bundle • min and max muon energy • min and max multiplicity • medium properties Can affect significantly CPU time G. Carminati – KM3Net Meeting WP2

6. Output files • ASCII file in table format or ANTARES format (I/O ANTARES library required) • Run number • Equivalent livetime • Track event information • Equivalent livetime for the simulated run G. Carminati – KM3Net Meeting WP2

7. Table format Event number & bundle multiplicity For each muon in bundle: • - Track id • - Coordinates of the muon impact point on the can surface (x, y, z)in meters • - Direction cosines (vx, vy, vz) • - Energy in GeV • - Arrival time in ns of the ith muon (0 is the arrival time of the first one) • - GEANT particle identification number: m G. Carminati – KM3Net Meeting WP2

8. ANTARES format GEANT particle Event number & bundle multiplicity Direction cosines (vx, vy, vz) Arrival time Energy Track id Coordinates (x, y, z) G. Carminati – KM3Net Meeting WP2

9. Zenith angle range Livetime output file Generated rate of muon event + Statistical error Generated rate of muon event Livetime (T = N*/N*_MC) + Statistical error Each event has the same weight G. Carminati – KM3Net Meeting WP2 Weighted average livetime

10. Main steps • (uniform) random generation of axis bundle features: • bundle direction (q, f) • impact point on a can surrounding the active volume (x, y, z) • bundle multiplicity • Hit-or-Miss method to reproduce the dependence of the flux on depth, zenith and multiplicity • Two different strategies for: • Single muon event • Multiple muon event G. Carminati – KM3Net Meeting WP2

11. G. Carminati – KM3Net Meeting WP2

12. Example for ANTARES detector ANTARES CAN: Radius ~ 300 m Height ~ 600 m max depth ~ 2.5 km.w.e. Computing test on 2xIntel Xeon Quad Core, 2.33 GHz G. Carminati – KM3Net Meeting WP2

13. Conclusions • Fast generator of atmospheric muons • CPU time 10 times smaller than for KM3 (code to generate Čerenkov light) • Code validated by studies in ANTARES and NEMO collaborations G. Carminati – KM3Net Meeting WP2