Physics Laboratory

1. Antonis Leisos Physics Laboratory School of Science and Technology Hellenic Open University KM3NeT Collaboration Meeting Calibration of km3 with EAS G. Bourlis, E. P. Christopoulou, N. Fragoulis, N. Gizani, A. Leisos, S. E. Tzamarias, A. Tsirigotis, B. Verganelakis • the calibration principle using atmospheric showers • Monte Carlo Studies • Lab Measurements Pylos Greece 16 - 19April 2007

2. reweighting Blind fit Okada model The Concept Floating stations 3 stations with at 16 m2 scintillator detectors each NESTOR: muon flux @ 4000m • Angular offset • Efficiency • Resolution • Position

3. Shower Detection Principle Minimum Station Set-Up GPS Scintillator-PMT Scintillator-PMT 1 m2 Scintillator-PMT ~20 m Scintillator-PMT Triangulation Shower Direction Station Server DAQ 4·(1W/counter)+30W(PC+electronics)

4. The Scintillator Module trigger arrival time Scintillator 2 Scintillator 3 Scintillator 3

5. Simulation Tools CORSIKA (Extensive Air Shower Simulation) GEANT4 (Scintillation, WLS & PMT response) Fast Simulation also available Energy: 105 GeV – 5 105 GeV Number of particles to the ground

6. Simulation Tools DAQSIM (DAQ Simulation) HOUANA (Analysis & Track Reconstruction) Height (mV) Time (ns) Zentih (degrees)

7. d L-dm (x,y,z) θc dγ Track Parameters θ : zenith angle φ: azimuth angle (Vx,Vy,Vz): pseudo-vertex coordinates dm (Vx,Vy,Vz) pseudo-vertex Simulation Tools GEANT4 Muon Propagation to KM3 HOU-KM3 Muon track (s) reconstruction

8. 4m2 Scintillator Detector Atmospheric shower simulation by CORSIKA - muon transportation to the detector DEPTH by GEANT4 - Sea-Top Detector detailed simulation GEANT4_HOU Angular Resolution in Single Shower Reconstruction • Typical Values • No cut: σ= 4.5ο • Total Collected Charge > 10 mips: σ=2.22ο • Total Collected Charge > 25 mips: σ=1.33ο • Total Collected Charge > 30 mips: σ=1.2ο PRELIMINARY zenith angle resolution [degs] Θrec-Θtrue Minimum of total collected charge [mip equivalent] Single Station: 4 detectors (1m2 plastic scintillator), 20 m distance between the detectors, three out of four selection trigger

9. 16m2 Scintillator Station 5m 1 m2 Scintillation Counter 19m dt=0 dt1 dt2 dt3 19m

10. curvature thickness Multi-Station Operation Monte Carlo Studies in Progress First coming particles Time Spread (ns) Total collected charge [pe]

11. Timing vs Pulse Hight Input A Input B Discriminator (1.5 MIP) Trigger Slewing Resolution

12. Time corrections

13. Consistent Estimations Minuit Minimization

14. Detection Efficiency Efficiency Events A hit is considered when there is more than 4 mips deposited charge

15. Muon Propagation Accepted if muon with E>2TeV goes through km3 Geant Simulation (propagation & Energy Loss) μ track Zenith angle < 13 deg Muon Track Reconstruction (A. Tsirigotis talk) km3

16. Muon Propagation

17. Primary Zenith Angle Resolution • Deposited Charge per counter > 4 mips • Number of Hits > 10

18. Primary Azimuth and Space angle Resolution • Deposited Charge per counter > 4 mips Number of Hits > 10

19. Effective Area ~ 30 showers per day reconstructed at the surface and in the deep sea • Deposited Charge per counter > 4 mips Number of Hits > 10

20. Performance Plots

21. B2 A1 A3 A2 B1 B3 Discriminator (1.5 MIP) Input C Trigger Lab Measurements (a) MC -Data μ=-0.1±0.3 σ=7.6 ± 0.2  Data ___ M.C. Prediction θΑ-θΒ μ=-0.06±0.05 σ=1.02± 0.03 • Deposited Charge per counter > 4 mips 6 Active counters Pull

22. B2 A1 A3 A2 B1 B3 Discriminator (1.5 MIP) Input C Trigger Lab Measurements (b) MC Prediction GROUP A μ=0.1±0.6 σ=4.5± 0.5 DATA δθ=4.6 θm-θtr μ=0.01±0.1 σ=0.9± 0.1 Pull GROUP B μ=0.3±0.8 σ=5.2± 0.8 DATA δθ=5.6 θm-θtr μ=0.02±0.1 σ=0.9± 0.1 • Deposited Charge per counter > 4 mips 6 Active counters Pull

23. discriminators Scintillator A Lead Scintillator B At the Detector Center • Data - Monte Carlo Prediction Inputs Trigger Time (ns) Charge (in units of mean p.e. charge) Charge  Data ___ M.C. Prediction

24. Charge parameterization AGASA parameterization (S. Yoshida et al., J Phys. G: Nucl. Part. Phys. 20,651 (1994) Parameters depend on (θ,Ε, primary) “Mean particle density registered by an active counter”

25. Primary Impact determination Muons are distributed around the impact with rms Absolute Position resolution ~ 0.5 m

26. Telescope Resolution Telescope resolution ~ 0.1 deg Surface Area resolution ~ 1 deg Telescope’s resolution measurement Impossible Inter calibration

27. Conclusions The operation of 3 stations (16 counters) for 10 days will provide: • The determination of a possible offset with an accuracy ~ 0.05 deg • The determination of the absolute position with an accuracy ~ 0.6 m • Efficiency vs Energy and Zenith angle… • Resolution No!