Antonis Leisos KM3NeT Design Study the calibration principle using atmospheric showers the calibration principle using atmospheric showers construction and performance of the prototype detector station construction and performance of the prototype detector station Monte Carlo Studies Monte Carlo Studies XXV Workshop on Recent Developments in High Energy Physics & Cosmology NTUA Greece March 2007 Calibration systems and methods for underwater neutrino telescope G. Bourlis, E. P. Christopoulou, N. Fragoulis, N. Gizani, A. Leisos, S. E. Tzamarias, A. Tsirigotis, B. Verganelakis

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

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

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

Pierre Auger: M. Are et al. Ast.Part. 14: Haverah Park ( 12km 2 effective area and 2π coverage in φ for 10 years operation less than 100 detected showers with reweighting Blind fit Okada model NESTOR: muon 4000m

Floating stations The Concept We propose a minimum of 3 stations with at least 16 m 2 scintillator detectors each

HELYCON Station GPS Scintillator-PMT DAQ ~20 m 1 m 2 Single Station Set-Up Triangulation  Shower Direction Scintillator-PMT 4·(1W/counter)+30W(PC+electronics)

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

Simulation Tools CORSIKA (Extensive Air Shower Simulation) GEANT4 (Scintillation, WLS & PMT response) Fast Simulation also available Number of particles to the ground Energy: 10 5 GeV – GeV

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

Simulation Tools GEANT4 Muon Propagation to KM3 HOU-KM3 Muon track (s) reconstruction dmdm L-d m (V x,V y,V z ) pseudo-vertex dγdγ d Track Parameters θ : zenith angle φ: azimuth angle (Vx,Vy,Vz): pseudo-vertex coordinates θcθc (x,y,z)

Monte Carlo Studies- Outlook ·10 15 eV E~ ·10 15 eV: 2500 showers/m 2 /year Single station detection: 351m 2 effective area (depends on geometry and selection cuts) Multi-Station: separation <100m, better resolution E> eV: 1 shower/m 2 /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 0.15 o

Monte Carlo Studies Depends on: Detector separation Selection criteria Shower direction Typical Values 1)No cut: σ= 4.5 ο 2)Total Collected Charge > 10 mips: σ=2.22 ο 3)Total Collected Charge > 25 mips: σ=1.33 ο 4)Total Collected Charge > 30 mips: σ=1.2 ο Atmospheric shower simulation by CORSIKA - muon transportation to the detector DEPTH by GEANT4 - Sea-Top Detector detailed simulation GEANT4_HOU PRELIMINARY Θ rec -Θ true Angular Resolution in Single Shower Reconstruction

Monte Carlo Studies Reconstruction efficiencyResolution (degrees) Three Stations Working Independently for 10 days Single Station: 4 detectors (1m 2 plastic scintillator), 20 m distance between the detectors, three out of four selection trigger PRELIMINARY Minimum of total collected charge [mip equivalent] zenith angle resolution [degrees]

dt=0 Proposed Detector 19m 5m 1 m 2 Scintillation Counter dt 1 dt 2 dt 3

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

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

Time corrections

Consistent Estimations Minuit Minimization

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

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

Muon Propagation

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

Primary Azimuth and Space angle Resolution

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”

Primary Impact determination

Effective Area ~ 30 showers per day reconstructed at the surface and in the deep sea

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…