Antonis LeisosAntonis Leisos

KM3NeT Collaboration MeetingKM3NeT Collaboration Meeting

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

• Monte Carlo Studies Monte Carlo Studies

• Lab MeasurementsLab Measurements

Pylos Greece 16 - 19 April 2007

Calibration of km3 with EASCalibration of km3 with EAS

G. Bourlis, E. P. Christopoulou, N. Fragoulis, N. Gizani, A. Leisos, S. E. Tzamarias, A. Tsirigotis, B. Verganelakis

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

Shower Detection Principle

GPSScintillator-PMT

Scintillator-PMT

Scintillator-PMT

DAQ

~20 m

1 m2

Minimum Station Set-Up

Triangulation

Shower Direction

Scintillator-PMT

4·(1W/counter)+30W(PC+electronics)

Station Server

The Scintillator Module

Scintillator 2

Scintillator 3

Scintillator 3

trigger arrival time

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)

4m2 Scintillator Detector

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

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

Minimum of total collected charge [mip equivalent]

zen

ith

an

gle

res

olu

tio

n

[deg

s]

dt=0

16m2 Scintillator Station

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)

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

Effective Area

log(E) (GeV)

2Effective Area (m )

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

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

Performance Plots

Minimum number of Active counters

Minimum number of Active counters

Minimum number of Active countersMinimum number of Active counters

2Effective Area (m )

θ resolution (deg)

Telescope Offset Resoltuion (deg)

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

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)

Muons are distributed around the impact with rms

Absolute Position resolution ~ 0.5 m

Telescope Resolution

Telescope resolution ~ 0.1 deg

Surface Area resolution ~ 1 deg

Telescope’s resolution measurement Impossible

Inter calibration

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!