Hellenic Open University Physics Laboratory School of Science and Technology Hellenic Open University Calibration and Optimization of a Very Large Volume Deep-Sea Neutrino Telescope using Extensive Air Showers Antonios Leisos International Workshop On Very large Volume Neutrino Telescopes 13-15 October 2009, Athens, Greece

Outline ν-Telescope Calibration (updated analysis) Air Shower detection for Deep Sea ν-Telescope Calibration (updated analysis) Calibration using single muons or extensive (air) showers? New Crude Analysis for Optimum angular offset determination (motivated from IceTop Analysis)

(propagation & Energy Loss) A Calibration Study At least one muon with E>2TeV passing through the neutrino telescope dt=0 dt1 μ track dt2 Coming back to the calibration, only a portion of the reconstructed showers are usefull. Specifically we accept showers wich contain a muon with energy grater than 2 TeV with a direction towards the km3 detector. The most efficient position of the platform is found to be just above the v-telescope restricting us to showers with zenith angle less than 13 degrees. Detailed Simulation (propagation & Energy Loss) dt3 d: distance from the shower axis km3

A Calibration Study 3 stations for 10 days 5m 19m Coming back to the calibration, only a portion of the reconstructed showers are usefull. Specifically we accept showers wich contain a muon with energy grater than 2 TeV with a direction towards the km3 detector. The most efficient position of the platform is found to be just above the v-telescope restricting us to showers with zenith angle less than 13 degrees.

Comparison of Estimations Θ array φ array φ telescope Detector: SeaWiet Depth: 2500 m Quality cuts: mean deposited charge in active counters >1.7 number of PMT hits > 10. Θ telescope σ=47m σ=6.70 σ=420 θTelescope-θarray φTelescope-φarray ΧTelescope-Χarray

Can we make it better? Monte carlo Results 3X16 counters 10 days of operation SeaWiet νOne Depth Offset Sensitivity θ φ 2500 0.040±0.005 0.26±0.03 3500 0.045±0.01 0.34±0.07 Depth Offset Sensitivity θ φ 2500 0.040±0.006 0.20±0.02 3500 0.09±0.02 0.46±0.05 1000m SeaWiet νOne Depth Offset Sensitivity θ φ 2500 0.05±0.005 0.24±0.04 3500 0.1±0.02 0.28±0.08 Depth Offset Sensitivity θ φ 2500 0.06±0.007 0.23±0.02 3500 0.15±0.07 0.42±0.07 Can we make it better?

Total number of muons through S Shower vs Single muon Total number of muons through S for 10 days operation S Depth (m) S (m2) 3800 3115 2115 104 (30% eff)* 4538 14495 108095 2.5 103 (30% eff) * 1134 3624 27024 9 102 (30% eff) * 409 1304 9728 50 (30% eff) * 23 72 540 50 (10% eff- FR**) - 3500 15000 D *Numbers calculated assuming R0=1km, 30% reconstruction efficiency of ν-Telescope ** Results of MC simulation with full reconstruction (10 % efficiency) R0 Offset resolution in 10 days (3X16 m2) θ φ 0.005 0.02

Detector Module GPS timestamp DAQ S/W based on LabView On-Line analysis - distributions Scintillation Tiles WLS fibers

Typical Mean Numb. of p.e. per m.i.p. : 21 Module Calibration Charge (pCb) Single p.e Response to a MIP Detector Uniformity @ “nominal” H.V. gain: ~ 4 105 <charge>/p.e. ~ 0.07pCb <pulse height>/p.e. ~ 1.05mV Typical Mean Numb. of p.e. per m.i.p. : 21 ± 10% variation

Monte Carlo & Data Comparison Detailed Monte Carlo description A1 B2 A3 Input C Trigger B3 A2 B1 At the Detector Center  Data ___ M.C. Prediction Data - Monte Carlo Prediction μ=-0.1±0.3 σ=7.6 ± 0.2 Charge (in units of mean p.e. charge) θΑ-θΒ

(Performance of IceTop Array-ICRC’07 Use IceTop’s Analysis Thomas Geisser (Performance of IceTop Array-ICRC’07 Eμ>2 ΤeV (X0,Y0.Z0) Χμ-Χshower

Crude & Accurate Estimation (XN,YN) (X0,Y0) Θ 0 θ0-θshower

Angular Offset Resolution ΔΤ~14 hours 16 m2 array 0.050 ΔΤ~1 day 3X16 m2 array 0.020 ΔΤ~10 days 3X16 m2 array <0.010 θest-θ0 Detector: SeaWiet Depth: 2500 m Quality cuts: number of PMT hits > 10.

Low & Higher multiplicity triggers Only 2 counters 2 or more counters Detector: SeaWiet Depth: 2500 m Quality cuts: number of PMT hits > 10. θest-θ0 θest-θ0

(XN,YN) θest-θ0 d (Xw,Yw) θest-θw Crude vs Weighted Mean Θ w Detector: SeaWiet Depth: 2500 m Quality cuts: number of PMT hits > 10

Azimuth Offset Resolution φ0-φshower φest-φo Detector: SeaWiet Depth: 2500 m Quality cuts: number of PMT hits > 10.

θest-θ0 θest-θ0 φest-φo Position Correlation Xdet+10m Xdet+50m Detector: SeaWiet Depth: 2500 m Quality cuts: number of PMT hits > 10.

Consistent Estimations when the array Is shifted in X or Y axis Summary Of Results SeaWiet νOne Depth (m) Offset Sensitivity (deg) θ φ 2500 0.005 0.02 3500 0.014 0.05 Depth (m) Offset Sensitivity (deg) θ φ 2500 0.01 0.02 3500 0.06 Consistent Estimations when the array Is shifted in X or Y axis

MultiPMT Optical Module Estimation of the angular resolution of the KM3NeT – (Inter-Calibration) KM3NeT’s resolution measurement Impossible using EAS array KM3NeT resolution ~ 0.1 deg EAS Detector resolution ~ 2 deg (Inter-Calibration) Divide the detector in 2 identical sub detectors Reconstruct the muon separately for each sub detector Compare the 2 reconstructed track directions Working Example IceCube Geometry 9600 OMs looking up & down in a hexagonal grid. 80 Strings, 60 storeys each. 17m between storeys MultiPMT Optical Module 125m

Resolution Estimation (1 TeV Muons, isotropic flux, IceCube Geometry, 9600 OMs) Number of active OMs in one subdetector Number of active OMs in whole detector Mean 24 hits Mean 12 hits Simulated events with at least 14 active OMs, after filtering out the background hits. The selected sample consisted, in average, of 24 active OMs per event, whilst the remaining contamination from K40 background hits was less than 0.5 OM per event. Each muon track was reconstructed using the information from the whole set of the active OMs as well as using the data from the two sub-groups, each containing the half of the selected OMs.

Resolution Estimation (1 TeV Muons, isotropic flux, IceCube Geometry, 9600 OMs) Number of active OMs in one subdetector Number of active OMs in whole detector Mean 24 hits Mean 12 hits Simulated events with at least 14 active OMs, after filtering out the background hits. The selected sample consisted, in average, of 24 active OMs per event, whilst the remaining contamination from K40 background hits was less than 0.5 OM per event. Each muon track was reconstructed using the information from the whole set of the active OMs as well as using the data from the two sub-groups, each containing the half of the selected OMs.

Resolution Estimation (1 TeV Muons, isotropic flux, IceCube Geometry, 9600 OMs) σ=0.07o±0.003o σ=0.095o ±0.005o Zenith angle resolution of subdetectors (degrees) Zenith angle resolution of whole detector (degrees)

Resolution Estimation (1 TeV Muons, isotropic flux, IceCube Geometry, 9600 OMs) σ=0.14o±0.01o Zenith angle difference between the 2 reconstructed directions (degrees) Space angle difference between the 2 reconstructed directions (degrees) ≈ 0.095o ±0.005o

SeaWiet

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