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CHERENKOV

ALBEDO. CHERENKOV. GRENOBLE - C.Berat, J.Chauvin, D.Lebrun, P.Stassi, D.Teyssier LISBON - P.Assis, P.Brogueira, M.C.Espirito-Santo, L.Melo, M.Pimenta, J.C.Silva, B.Tome

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CHERENKOV

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  1. ALBEDO CHERENKOV GRENOBLE - C.Berat, J.Chauvin, D.Lebrun, P.Stassi, D.Teyssier LISBON - P.Assis, P.Brogueira, M.C.Espirito-Santo, L.Melo, M.Pimenta, J.C.Silva, B.Tome PALERMO - G.Agnetta, B.Biondo, O.Catalano, G.D’Ali-Staiti, M.Gabriele, S.Giarrusso, G.Gugliotta, A.Mangano, F.Russo, P.Scarsi, TORINO - A.Cappa, L.Fava, P.Galeotti, O.Saavedra, P.Vallania, C.Vigorito 3rd EUSO Meeting - Huntsville May 2003

  2. EUSO Focal Surface Čerenkov signal Fluorescence signal Atmosphere N  The Cerenkov signal gives a unique signature to discriminate between high penetrating neutrinos and quick interacting hadrons EUSO Approach 3rd EUSO Meeting - Huntsville May 2003

  3. This kind of measurements are also very interesting by themselves since very few experimental data are available Plateau Rosa (Italy) Nuovo Cimento 6C, 2(1983) 202 SPHERA(Kazakhstan) Nuclear Physics , 52B (1997) 182 Lake-p. Mussala (Bulgaria) Proc. ICRC 2001, 900 All these experiments have measured the Čerenkov light reflected by snow with no information about the associated EAS. • Other goals of the ULTRA experiment are: • Study of the atmospheric radiative transfer (LIDAR) • Measure the UV background at different Moon phases • Meteor observations 3rd EUSO Meeting - Huntsville May 2003

  4. Top view of the ETscope setup  C H B L M Sketch of a typical configuration for detecting the Cherenkov light diffused by an EAS. The ellipse represents the coincidence area shared by UVscope and ETscope. 3rd EUSO Meeting - Huntsville May 2003

  5. UV scope ET scope What do we measure with ULTRA? • Čerenkov light diffused by: • Desert land • Grass-covered land • Ocean (water) Surface • Trees-covered land • Iced (snow) Land • as a function of the shower size and axis inclination. • Associated EAS parameters for each event: • e.m. Size Ne • Arrival Direction (q,f) 3rd EUSO Meeting - Huntsville May 2003

  6. Mont Cenis Measurements Measurements have been performed @ Mont Cenis (St. Barthelemy, Haute Savoie, France) in october 2002 • 2000 m a.s.l. (Ne ~ 10 times higher then at sea level) • UVscope and ETscope units working together for the first time 3rd EUSO Meeting - Huntsville May 2003

  7. Experimental setup 3rd EUSO Meeting - Huntsville May 2003

  8. To Baby Experimental setup d=121m h=35m ST1 ST2 ST4 23m d=40m ST3 Analysis of Mt-Cenis ETscope data 3rd EUSO Meeting - Huntsville May 2003

  9. CORE LOCATION DETERMINATION • Internal events definitions • Weak: the maximum number of particles is measured in the central detector. • Strong: the number of particles measured in the central detector minus 1 σ is greater then the number of particles measured in the outer detectors plus 1 σ. We started analyzing “strong” internal events, important for UV-scope correlation. Two methods were used: centre of mass and “circle algorithm”. 3rd EUSO Meeting - Huntsville May 2003

  10. QDC channels to m.i.p. conversion • Mean energy loss ΔE = 10.3 MeV @ 36.6° • 8.3 MeV for a vertical m.i.p. 3rd EUSO Meeting - Huntsville May 2003

  11. RESULTS • During the Mont Cenis test a total of 11616 events have been recorded with an average counting rate 0.134 Hz. • For 99.4% of the events the shower arrival direction has been reconstructed, and the distribution compared with the expected one (preliminary simulation using CORSIKA). • For the subset of strong internal events, important for correlation with UV-scope, the impact point has been reconstructed for 77% of data,and the Ne size-distribution obtained. 3rd EUSO Meeting - Huntsville May 2003

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  15. Exponential fit to NKG l.d.f. 3rd EUSO Meeting - Huntsville May 2003

  16. Effective Area and Counting Rate The effective area is the detector surface sensitive to a specific primary energy. It depends not only on the primary energy but also on the primary particle type and its arrival direction. 3rd EUSO Meeting - Huntsville May 2003

  17. Triangle Triangle + centre Square + centre Hexagon + centre detector configuration (side l) The opportunity to compare different geometrical configurations allows to establish which one is the most simple to obtain satisfactory results. We used 2 configurations: ngeo=2  triangle + centre ngeo=3  square + centre 3rd EUSO Meeting - Huntsville May 2003

  18. MC Simulations Primary energy (GeV) # of simulated events 5*104 500 1*105 2400 3*105 600 5*105 600 1*106 600 3*106 600 5*106 500 1*107 600 Monte Carlo simulations with CORSIKA using the hadronic interaction model QGSJET of EAS • Observation level: 2000m above sea level = 810 g/cm2 • Zenith angle: 0° Azimuth angle: 0° • Primary particle type: proton 3rd EUSO Meeting - Huntsville May 2003

  19. MC Simulations Primary energy (GeV) # of simulated events 1*105 2400 3*105 600 5*105 600 1*106 600 3*106 600 5*106 900 1*107 600 Monte Carlo simulations with CORSIKA using the hadronic interaction model QGSJET of EAS • Observation level: 2000m above sea level = 810 g/cm2 • Zenith angle: 20° Azimuth angle: 0° • Primary particle type: proton 3rd EUSO Meeting - Huntsville May 2003

  20. ngeo=2 l=39.84 m ngeo=3 l=39.84 m ngeo=3 l=30.00 m Effective area vs. primary energy 3rd EUSO Meeting - Huntsville May 2003

  21. Effective area vs. primary energy (internal events) ngeo=2 l=39.84 m ngeo=3 l=39.84 m ngeo=3 l=30.00 m 3rd EUSO Meeting - Huntsville May 2003

  22. From simulation 10° < q < 30° Q < 10° RESULTS Mont-Cénis: 2401 events in 17848 s, with a frequency of 0.1345 Hz, 2382 events with arrival direction reconstructed, Q < 10° 261 events, with a frequency 0.0147 Hz 10° < q < 30° 1333 events, with a frequency 0.0753 Hz 3rd EUSO Meeting - Huntsville May 2003

  23. CONCLUSIONS SEE YOU NEXT MONTHIN MONT CENIS (MOONLESS PERIOD) 3rd EUSO Meeting - Huntsville May 2003

  24. Npe=3 1014 E/Es tot T R A/(2  D2) E=primary energy (estimated by the array) Es=energy scale factor (1019 eV) tot=total detector efficiency T=Atmosphere transmission R=reflection coefficiency A=detector collection area (lens) B=average background ( photons/ns/m2/sr) T= integration gate in ns = solid angle   C H B L A ULTRA measurements Bkg=<B> A  T tot D 3rd EUSO Meeting - Huntsville May 2003

  25. 3rd EUSO Meeting - Huntsville May 2003

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