1. TIERRAS: an AIRES package to simulate high energy cosmic ray showers underground and underwater Matías Tueros Instituto de Física La Plata – Universidad Nacional de La Plata XLIVth Rencontres du Moriond La Thuile, Italy – February 1-8, 2009

2. AIRES: Extended Air Shower Simulator  Used by several collaborations on the Cosmic Ray community for the last 10 years.  Fast, stable, portable and with a small output, it is ideal for applications that require a huge amount of simulations to improve statistics.  Sybill, QGSJET and QGSJET-II models for high energy hadronic interactions. EPOS is to be added on the next release. MOCCA extended low energy interactions model. Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar

3. TIERRAS: Original Aim & Scope  Continue cosmic ray shower simulations 3m underground (540 g/cm -2 ) to calculate muon lateral distributions (for AMIGA muon counters)  Use the several thousands AIRES showers already simulated up to ground level.  Use only one simulation software: same physics, same output, same interface with the detector simulation at gound level. Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar

4. Module Description  TIERRAS is currently implemeted as several AIRES Special Primary modules  Modified “Atmospheres” for propagation: Soil, Standard Rock, Standard Sea Water and Ice  Use the AIRES propagation routines/physics but Modified LPM Effect Routines Modified Dielectric Suppression Routines Caveat: AIRES Misses Muon induced spallation! TIERRAS underestimates Muon Energy deposit above 2 TeV (Not a problem for AMIGA as on a 10EeV shower, all muons outside of the core are below 500 GeV at ground level) Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar

5. Muon Energy Loss TIERRAS simulation Usual parametrizations

6. Muon Flux Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar MACRO experiment TIERRAS (of muon at ground)

7. Sample Results: AMIGA Depth Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar AMIGA (Auger Muons and Infill for the Ground at Array) Is an upgrade to the Auger Observatory consisting of  A 27.5 km 2 infill of the array, to take the detection threshold of the observatory down to 1x10 17 eV.  30 m 2 muon counters burried 3m underground to determine the muon content of the showers for mass composition studies. AIRES + UndergroundShower + AbovegroundShower 1 EeV Vertical Shower, 10 -6 thinning, 3m of soil

8. Muon Lateral Distribution Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar

9. Muon/Electron ratio Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar

10. Number of Gammas Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar AIRES TIERRAS UndergroundShower TIERRAS AbovegroundShower Regain continuity Ground level Simulation End (upgoing particles that would have been produced are missing)

11. Energy of Gammas Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar Total Energy Mean Energy

12. Number of Gammas Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar 1 EeV Proton 1 EeV Iron

13. Number of Muons Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar 1 EeV Iron 1 EeV Proton

14. Mean Muon Energy Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar 1 EeV Proton 1 EeV Iron

15. Start an upgoing shower Continue an Airshower Underground Continue an Underground Shower on air TIERRAS code Start an upgoing or downgoing neutrino or exotic shower AIRES 2.8.4 code

16. TIERRAS: Evolving Aim & Scope  Fast particle propagation through dense homogeneous medium.  Applications for shallow (< 3 k.w.e) underground, underwater and underice sites for detector design, detector simulation input, detector calibration and results analysis.  Upgoing and skimming neutrino or exotic particles induced hadronic and electromagnetic showers.  Earth and moon albedo simulations. Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar

17. Sample Result: Antares Depth Energy spectrum of 2TeV muons and all its secondaries propagated through 3 km of sea water, without thinning. Only 2 seconds per muon on my 2Ghz celeron, 7 years old Laptop! Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar Comparison data from V. A. Kudryavtsev, arXiv:0810.4635v1 25 Oct 2008

18. Sample Result: LPM on e - from  e LPM effect and Dielectric suppression are very important on standard rock above 77 TeV! Idea from S. Klein, arXiv:0412546v1 21 Dec 2004 Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar 100s m!

19. Outlook: a new simulation tool  A beta release version is available upon request for evaluation and testing  Include hard muonic processes and neutrino propagation for very deep simulations is possible, and might be done if sufficient interest from users arises.  Still necessary to validate physics results for Neutrons, Pions and other particles, but looking good.  Independent tests and comparisons with other codes are most welcome! Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar

20. This is not the end, my friend

21. Electrons to Muons ratio Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar 1 EeV Iron 1 EeV Proton

22. Total Number of Particles Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar 1 EeV Proton 1 EeV Iron

23. Number of Electrons Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar 1 EeV Proton 1 EeV Iron

24. Number of Neutrons Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar 1 EeV Proton 1 EeV Iron

25. Number of Pions Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar 1 EeV Proton 1 EeV Iron

26. Electron Lateral Distribution Underground Shower Simulations – MJ Tueros tueros@fisica.unlp.edu.ar