Physics Laboratory

1. Antonis Leisos Physics Laboratory School of Science and Technology Hellenic Open University A sea top infrastructure for calibrating an underwater neutrino telescope G. Bourlis, P. Christopoulou, N. A. B. Gizani, A. Leisos, P. Razis , A. G. Tsirigotis and S.E. Tzamarias • the calibration principle using atmospheric showers • construction and performance of the prototype detector station • Monte Carlo Studies TeV Particle Astrophysics  2007 27-31 August 2007 Venice, Italy

2. spase-amanda 1 km 2 km IceCube IceTop SPASE air shower arrays  calibration of AMANDA angular resolution and pointing !  resolution Amanda-B10 ~ 3.5°

3. The General Idea… • Angular offset • Efficiency • Resolution • Position Physics ? C.R. composition UHE ν - Horizontal Showers Veto atmospheric background – Study background

4. Isotropic on the top of the atmosphere BUT … ~4km ~20km

5. reweighting Blind fit Okada model Pierre Auger: M. Are et al. Ast.Part. 14: 109-120 2000 Haverah Park (www.ast.leeds.ac.uk/haverah/havpark.html): 12km2 effective area and 2π coverage in φ for 10 years operation less than 100 detected showers with NESTOR: muon flux @ 4000m

6. 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

7. HELYCON Station Single Station Set-Up GPS Scintillator-PMT Scintillator-PMT 1 m2 Scintillator-PMT ~20 m Scintillator-PMT Triangulation Shower Direction DAQ 4·(1W/counter)+30W(PC+electronics)

8. Simulation Tools CORSIKA (Extensive Air Shower Simulation) GEANT4 (Scintillation, WLS & PMT response) Fast Simulation also available

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

10. 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

11. Monte Carlo Studies- Outlook1014 - 5·1015 eV E~ 1014 - 5·1015 eV: 2500 showers/m2/year Single station detection: 351m2 effective area (depends on geometry and selection cuts) Multi-Station: separation <100m, better resolution E> 1016 eV: 1 shower/m2/year TO BE STUDIED 35% of the detected showers include a muon which arrives at the Neutrino Telescope (depth 4000m) with an energy >300GeV General Remark: 3 stations operating for 10 days can identify an angular offset with an accuracy of 0.15o Specifically…

12. Monte Carlo Studies 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 • Depends on: • Detector separation • Selection criteria • Shower direction • 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 Θrec-Θtrue

13. Multi Station Set upimprove resolution – higher energies GPS Synchronisation Δt <±6ns using sawtooth correction

14. curvature thickness Multi-Station Operation Monte Carlo Studies in Progress Time Delay (ns) Total collected charge [pe] Time Spread (ns) Total collected charge [pe]

15. The HELYCON Detector Module GPS timestamp Scintillator 2 Scintillator 3 Station Server Scintillator 3

16. HELYCON ReadOut Electronics 4 PMT Signal Inputs Trigger Ouput USB Port • HPTDC • 32 channels (LR) – 8 Channels (HR) • 25ps (HR) to 800 ps (LR) accuracy • Self Calibrating 25ps accuracy TDC GPS Input D. Loucas INP DEMOKRITOS

17. Response to Showers trigger arrival time θ=31ο ±8ο ~60 mip’s 14.2ns ~50 mip’s 5.4ns ~10m Input A Input B Discriminator (1.5 MIP) Trigger

18. discriminators Inputs Trigger DAQ based on TDS5052 Tektronix (5 Gsamples/s) Response to Minimum Ionizing Particles Scintillator A Lead Scintillator B

19. Detailed Monte Carlo description At the Detector Center • Data - Monte Carlo Prediction Charge (in units of mean p.e. charge) Response to a MIP DAQ S/W based on LabView On-Line analysis - distributions PRELIMINARY Digitized Waveforms saved on hard disk

20. Response to a MIP Detector Uniformity (the worst case) PRELIMINARY X Y Charge (in units of mean p.e. charge) Typical Mean Numb. of p.e. per m.i.p. : 23 (± 16% variation)

21. Response to a MIP Detector Uniformity - Timing discriminators Inputs Trigger PRELIMINARY Scintillator A Lead Scintillator B ΔΤ consistent with the difference of optical path (fiber refractive index n=1.6)

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

23. Response to Showers PRELIMINARY PRELIMINARY zenith angle [degrees] zenith angle [degrees] Trigger Detectors > 1 mip Detectors A.and.B > 1.5 mip’s Trigger Detectors >1 mip Detectors A.and.B > 0.5 mip’s α=9.4±0.2

24. 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

25. 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

26. 16m2 Scintillator Station 5m 1 m2 Scintillation Counter 19m dt=0 dt1 dt2 dt3 19m

27. Time corrections

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

29. 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

30. Muon vs Shower Axis

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

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

33. Performance Plots

34. 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

35. 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”

36. Primary Impact determination Absolute Position resolution ~ 0.5 m

37. Performance Plots

38. Telescope Resolution Telescope resolution ~ 0.1 deg Surface Area resolution ~ 1 deg Telescope’s resolution measurement Impossible σ=0.014 σ=0.062 σ=0.094 Inter calibration

39. 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!