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!
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