Antonis LeisosAntonis Leisos

KM3NeT Design StudyKM3NeT Design Study

• 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

XXV Workshop on Recent Developments in High Energy Physics & Cosmology

NTUA Greece 28 - 31 March 2007

Calibration systems and methods for underwater neutrino telescopeCalibration 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 …

~ 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

Floating stations

The Concept

We propose a minimum of 3 stations with at least 16 m2 scintillator

detectors each

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)

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: 105 GeV – 5 105 GeV

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

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

3) Total Collected Charge > 25 mips: σ=1.33ο

4) Total Collected Charge > 30 mips: σ=1.2ο

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

Monte Carlo Studies

Reconstruction efficiency Resolution (degrees)

Three Stations Working Independently for 10 days

Single Station: 4 detectors (1m2 plastic scintillator), 20 m distance between the detectors, three out of four selection trigger

PRELIMINARY

Minimum of total collected charge [mip equivalent]zen

ith

an

gle

re

so

luti

on

[d

eg

ree

s]

dt=0

Proposed Detector

19m

19m

5m

1 m2 Scintillation Counter

dt1

dt2

dt3

2

exp2 i

hits dt

dt dt

curvature

thickness

Tim

e S

pre

ad

(n

s)

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

deposited charge (mip)

delay (ns)

delay spread (ns)

deposited charge (mip)

Time residual

Time Residual meas true

dt

dt dt

Consistent Estimations

g g ˆ ˆ( , ) ( , )R 2 2χ χ

Tg g

1

g g

ˆ ˆ-Λ = D

ˆ ˆ- -

2 (P R,2) 2 (P ,2)

Minuit Minimization

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 Propagation

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)

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)

Effective Area

log(E) (GeV)

2Effective Area (m )

~ 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…