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Antonis LeisosAntonis Leisos

A sea top infrastructure for A sea top infrastructure for calibrating an underwater calibrating an underwater

neutrino telescopeneutrino telescope

• the calibration principle using atmospheric showersthe calibration principle using atmospheric showers

• construction and performance of the prototype detector stationconstruction and performance of the prototype detector station

• Monte Carlo Studies Monte Carlo Studies

TeV Particle Astrophysics 2007

27-31 August 2007 Venice, Italy

G. Bourlis, P. Christopoulou, N. A. B. Gizani, A. Leisos, P. Razis ,A. G. Tsirigotis and S.E. Tzamarias

1 km

2 km

SPASE air shower arrays

calibration of AMANDA angular resolution and pointing !

resolution Amanda-B10 ~ 3.5°

spase-amanda

IceCube IceTop

The General Idea…

•Angular offset

•Efficiency

•Resolution

•Position

Physics ?

C.R. composition

UHE ν - Horizontal Showers

Veto atmospheric background – Study background

~4km

~20km

Isotropic on the top of the atmosphere

BUT …

~ coscos

dN

d

Pierre Auger: M. Are et al. Ast.Part. 14: 109-120 2000

0 23 4km instrumented area

17

0 2

for detection Ε 6×10 eV

θ 80 0.35/km /year 1.4showers/year

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 0θ 80

reweightingBlind fit

Okada model NESTOR: muon flux @ 4000m

http://www.ast.leeds.ac.uk/haverah/havpark.html

Floating stations

The Concept

3 stations with at 16 m2 scintillator detectors each

•Angular offset

•Efficiency

•Resolution

•Position

reweightingBlind fit

Okada model

~ coscos

dN

d

NESTOR: muon flux @ 4000m

HELYCON Station

GPSScintillator-PMT

Scintillator-PMT

Scintillator-PMT

DAQ

~20 m

1 m2

Single Station Set-Up

Triangulation

Shower Direction

Scintillator-PMT

4·(1W/counter)+30W(PC+electronics)

Simulation Tools

CORSIKA(Extensive Air Shower

Simulation)

GEANT4(Scintillation, WLS & PMT response)

Fast Simulation also available

Simulation Tools

DAQSIM(DAQ Simulation)

HOUANA(Analysis &

Track Reconstruction)

Time (ns)

Height (mV)

Zentih (degrees)

Simulation Tools

GEANT4Muon Propagation to KM3

HOU-KM3Muon track (s) reconstruction

dm

L-dm

(Vx,Vy,Vz) pseudo-vertex

dγ

d

Track Parameters

θ : zenith angle φ: azimuth angle (Vx,Vy,Vz): pseudo-vertex coordinates

θc

(x,y,z)

Monte Carlo Studies- Outlook 1014 - 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…Specifically…

Monte Carlo Studies

Depends on:

Detector separation

Selection criteria

Shower direction

Typical Values

1) No cut: σ= 4.5ο

2) Total Collected Charge > 10 mips: σ=2.22ο



Atmospheric shower simulation by CORSIKA - muon transportation to the detector DEPTH by GEANT4 - Sea-Top Detector detailed simulation GEANT4_HOU

PRELIMINARY

Θrec-Θtrue

Angular Resolution inSingle Shower Reconstruction

Multi Station Set upimprove resolution – higher energies

GPS Synchronisation

Δt <±6ns using sawtooth correction

curvature

thickness

Total collected charge [pe]

Tim

e D

ela

y (

ns

)T

ime

Sp

rea

d (

ns

)

Multi-Station Operation Monte Carlo Studies in Progress

Total collected charge [pe]

The HELYCON Detector Module

Scintillator 2

Scintillator 3

GPS timestamp

Station Server

Scintillator 3

HELYCON ReadOut Electronics

GPS Input

USB PortTrigger Ouput4 PMT Signal Inputs

25ps accuracy TDC

HPTDC

• 32 channels (LR) – 8 Channels (HR)

•25ps (HR) to 800 ps (LR) accuracy

•Self Calibrating

D. Loucas INP DEMOKRITOS

Response to Showers

Discriminator

(1.5 MIP)

Trigger

Input A

Input B

~10m

trigger arrival time

~60 mip’s

~50 mip’s

14.2ns

5.4ns

θ=31ο ± 8ο

Response to Minimum Ionizing Particles

Scintillator A

Scintillator B

Lead

DAQ based on TDS5052 Tektronix (5 Gsamples/s)

discriminators

Inputs

Trigger

Response to a MIP

DAQ S/W based on LabView

On-Line analysis - distributions

Charge (in units of mean p.e. charge)

At the Detector Center

Data

- Monte Carlo Prediction

Detailed Monte Carlo description

PRELIMINARY

Digitized Waveforms saved on hard disk

Response to a MIP

Detector Uniformity (the worst case)

Charge (in units of mean p.e. charge)

X Y

Typical Mean Numb. of p.e. per m.i.p. : 23 (± 16% variation)

PRELIMINARY

Response to a MIP

Detector Uniformity - Timing

Scintillator A

Scintillator B

Lead

discriminators

Inputs

Trigger

ΔΤ consistent with the difference of optical path (fiber refractive index n=1.6)

PRELIMINARY

Timing vs Pulse Hight

thickness

Input A

Input B

Discriminator

(1.5 MIP)

Trigger

Slewing

Resolution

Response to Showers

Trigger Detectors >1 mip

Detectors A.and.B > 0.5 mip’s

~ coscos

8.5 0.4

dN

d

zenith angle [degrees] zenith angle [degrees]

~ coscos

9.4 0.6

dN

d

Trigger Detectors > 1 mip

Detectors A.and.B > 1.5 mip’s

α=9.4±0.2

PRELIMINARY PRELIMINARY

Lab Measurements (a)

Discriminator

(1.5 MIP)Input C Trigger

A1

A2

A3

B1

B2

B3θΑ-θΒ

μ=-0.1±0.3

σ=7.6 ± 0.2

Pull

• Deposited Charge per counter > 4 mips 6 Active counters

μ=-0.06±0.05

σ=1.02 ± 0.03

MC -Data Data

___ M.C. Prediction

Lab Measurements (b)

Discriminator

(1.5 MIP)Input C Trigger

A1

A2

A3

B1

B2

B3

• Deposited Charge per counter > 4 mips 6 Active counters

μ=0.1±0.6

σ=4.5 ± 0.5

θm-θtr

Pull

μ=0.01±0.1

σ=0.9 ± 0.1

MC PredictionGROUP A

GROUP Bμ=0.3±0.8

σ=5.2 ± 0.8

θm-θtr

Pull

μ=0.02±0.1

σ=0.9 ± 0.1

DATA

δθ=4.6

DATA

δθ=5.6

dt=0

16m2 Scintillator Station

19m

19m

5m

1 m2 Scintillation Counter

dt1

dt2

dt3

2

exp2 i

hits dt

dt dt

Time corrections

deposited charge (mip)

delay (ns)

delay spread (ns)

deposited charge (mip)

Time residual

Time Residual meas true

dt

dt dt

Detection Efficiency

Distance from Shower Impact (meters)

Distance from Shower Impact (meters)

Efficiency

Events

Number of Active Counters (trigger)

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 vs Shower Axis

muon primaryθ - θ (deg) μ-shower Space angle (deg)

Primary Zenith Angle Resolution

reconstructed true

Θ

θ - θ

σreconstructed trueθ - θ (deg)

• Deposited Charge per counter > 4 mips

• Number of Hits > 10

Primary Azimuth and Space angle Resolution

reconstructed trueφ - φ (deg) Space angle (deg)

• Deposited Charge per counter > 4 mips Number of Hits > 10

Performance Plots

Minimum number of Active counters

Minimum number of Active countersMinimum number of Active counters

2Effective Area (m )

θ resolution (deg)

Telescope Offset Resoltuion (deg)

Charge

Time (ns)Charge (in units of mean p.e. charge)

At the Detector Center

Data

- Monte Carlo Prediction

Scintillator A

Scintillator B

Lead

discriminators

Inputs

Trigger

Data

___ M.C. Prediction

Charge parameterization

Distance from shower core (m) Distance from shower core (m)

2Mean density (mip/m )2RMS density (mips/m )

2

( ) 1 11000

a h a

M M

r r rr C

R R

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

total charge collected (mip)

Impact Resolution (m)

Impact x (m)

Absolute Position resolution ~ 0.5 m

Performance Plots

Minimum number of Active counters

Minimum number of Active countersMinimum number of Active counters

2Effective Area (m )

Spatial Resolution (m)

Telescope Offset Resoltuion (deg)

Telescope Resolution

Telescope resolution ~ 0.1 deg

Surface Area resolution ~ 1 deg

Telescope’s resolution measurement Impossible

Inter calibration

σ=0.014

σ=0.094

σ=0.062

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!

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