physics laboratory

Calibration and Optimization of a Very Large Volume Deep-Sea Neutrino

Telescope using Extensive Air Showers

International Workshop On Very large Volume Neutrino TelescopesInternational Workshop On Very large Volume Neutrino Telescopes13-15 October 2009, Athens, Greece13-15 October 2009, Athens, Greece

Antonios LeisosAntonios Leisos

Outline

• 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)

A Calibration Study

μ track

km3

Detailed Simulation

(propagation & Energy Loss)

At least one muon with E>2TeV passing

through the neutrino telescope

dt=0 dt1

dt2

dt3

)),(;(

dtPL i

d: distance from the shower axis

A Calibration Study3 stations for 10 days

Minimum number of Active counters

Resolution in Estimating

a Possible Angular Offset [deg]

19m

5m

θTelescope-θarray

σ=6.70

φTelescope-φarray

σ=420 σ=47m

ΧTelescope-Χarray

Detector: SeaWiet Depth: 2500 mQuality cuts: • mean deposited charge in active counters >1.7• number of PMT hits > 10.

Comparison of Estimations

Θ telescope

Θ

array

φ

array

φ telescope

Depth Offset Sensitivity

θ φ

2500 0.040±0.005 0.26±0.03

3500 0.045±0.01 0.34±0.07


θ φ

2500 0.040±0.006 0.20±0.02

3500 0.09±0.02 0.46±0.05

SeaWiet νOne

Monte carlo Results

Can we make it better?


θ φ

2500 0.05±0.005 0.24±0.04

3500 0.1±0.02 0.28±0.08


θ φ

2500 0.06±0.007 0.23±0.02

3500 0.15±0.07 0.42±0.07

SeaWiet νOne

1000m

3X16 counters10 days of operation

Shower vs Single muon

R0

D

a

Dr

D

DrrdrdI

dt

dN

22220

cos0Idtdsd

dN

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

S

*Numbers calculated assuming R0=1km, 30% reconstruction efficiency of ν-Telescope** Results of MC simulation with full reconstruction (10 % efficiency)

θ φ

0.005 0.02

Offset resolution in 10 days (3X16 m2)

Total number of muons through S

for 10 days operation

Detector Module

Scintillation Tiles

WLS fibers

GPS timestampDAQ S/W based on LabView

On-Line analysis - distributions

Module Calibration

Charge (pCb)

Single p.e

@ “nominal” H.V.

gain: ~ 4 105

<charge>/p.e. ~ 0.07pCb

<pulse height>/p.e. ~ 1.05mV

Response to a MIP

Detector Uniformity

Typical Mean Numb. of p.e. per m.i.p. : 21

± 10% variation

Monte Carlo & Data Comparison

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

At the Detector Center

Data

- Monte Carlo Prediction

Detailed Monte Carlo description

Input C Trigger

θΑ-θΒ

μ=-0.1±0.3

σ=7.6 ± 0.2

Data

___ M.C. Prediction

A1

A2

A3

B1

B2

B3

Χμ-Χshower

Eμ>2 ΤeV

(X0,Y0.Z0)

Thomas Geisser(Performance of IceTop Array-ICRC’07

Use IceTop’s Analysis

d

(XN,YN)

(X0,Y0)

Θ 0

02

2

00

20

20

1ˆtancosˆcos

ˆˆtan

10

60

ˆtan

mYX

mYXd

YYXX

NN

NN

θ0-θshower

Crude & Accurate Estimation

Detector: SeaWiet Depth: 2500 mQuality cuts: • number of PMT hits > 10.

ΔΤ~14 hours16 m2 array

0.050

ΔΤ~1 day3X16 m2 array

0.020

ΔΤ~10 days3X16 m2 array

<0.010

θest-θ0

Angular Offset Resolution

θest-θ0θest-θ0

Only 2 counters 2 or more counters

Low & Higher multiplicity triggers

Detector: SeaWiet Depth: 2500 mQuality cuts: •number of PMT hits > 10.

Crude vs Weighted Mean

θest-θ0

θest-θw

d

(XN,YN)

(Xw,Yw)

Θ w

Detector: SeaWiet Depth: 2500 mQuality cuts: •number of PMT hits > 10

Azimuth Offset Resolution

φ0-φshower φest-φo

Detector: SeaWiet Depth: 2500 mQuality cuts: •number of PMT hits > 10.

Position Correlation

θest-θ0

θest-θ0

Xdet+10m

Xdet+50mXdet+50m

φest-φoDetector: SeaWiet Depth: 2500 m Quality cuts: number of PMT hits > 10.

Summary Of Results

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 0.02 0.06

SeaWiet νOne

Consistent Estimations when the array

Is shifted in X or Y axis

KM3NeT resolution ~ 0.1 deg

EAS Detector resolution ~ 2 deg

KM3NeT’s resolution measurement Impossible

using EAS array

Estimation of the angular resolution of the KM3NeT – (Inter-Calibration)

(Inter-Calibration)

1. Divide the detector in 2 identical sub detectors2. Reconstruct the muon separately for each sub detector3. Compare the 2 reconstructed track directions

Working Example

IceCube Geometry9600 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)

•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.

Number of active OMs in one subdetector

Number of active OMs in whole detector

Mean 24 hits

Mean 12 hits


Zenith angle resolution of subdetectors (degrees) Zenith angle resolution of whole detector (degrees)

σ=0.095o ±0.005o σ=0.07o±0.003o


Zenith angle difference between the 2 reconstructed directions (degrees)

Space angle difference between the 2 reconstructed directions (degrees)

σ=0.14o±0.01o

≈ 0.095o ±0.005o

SeaWiet

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