ANTARES performances
with the 5 line data
K. Fratinion behalf of the
ANTARES collaboration
XXth Rencontres de Blois
Outline
• 5 line data– description– calibration
• systematic studies on MC• searching for neutrinos
XXth Rencontres de Blois K.Fratini
The ANTARES detectorThe ANTARES detector
60 m60 m
1122 lines lines 2525 storeys / line storeys / line 3 PMT / storey3 PMT / storey
4450 m50 m
JunctionJunctionboxbox
Readout cablesReadout cables
40 km to40 km toshoreshore
2400m2400m
200729 jan - 4 dec
XXth Rencontres de Blois K.Fratini
x,t,Q
Single PMT rate
The detector is a grid of PMTs observing:• Cherenkov light emitted by
– – e- from decay of 40K
• Bioluminescense
“baseline” rate40K and bioluminescence
track reconstruction
“burst”
Data
Trigger rate: ~1 Hz (5 lines)
19106 detected
Date (2007)
All data active time: ~ 80%
XXth Rencontres de Blois K.Fratini
Time calibration
Relative time resolution (among OMs) depends on:
• Time transit spread (TTS) in PMTs ~ 1.3 ns
• Sea water properties (light scattering, chromatic dispersion) ~ 2 ns
• Electronics + calibration < 0.5 ns
σ = 0.4 ns
Time difference between
the LED OB and an OMElectronics contribution less
than 0.5 nsXXth Rencontres de Blois K.Fratini
XXth Rencontres de Blois K.Fratini
25 gradients (tiltmeter&compass data from each storey)
5 position sampling points(hydrophones)
Position calibration
Measured position resolution < 10 cm
=35o
First 5 line neutrino candidate
XXth Rencontres de Blois K.Fratini
NO quality cuts
Agreement within 10%
Atmospheric muons: MC vs data
Preliminary
XXth Rencontres de Blois K.Fratini
Estimate of some systematic effects
• simulation uses in-situ measurements
• simulation was repeated with:
– abs - 10 %
abs +10 %
- 20 % reco track rate
+ 25 % reco track rate
• Physics effect: ~30-50%– hadronic model– indetermination on the primary
flux
• Other effects:?????– environmental parameters
(absorption length)– PMT properties (efficiency,
angular acceptance)
absorption length
XXth Rencontres de Blois K.Fratini
PMT efficiency
PMT total efficiency:
photocatode area
quantum efficiency
collection efficiency
mu-metal cage shadow
effect on flux - 7 %
Decrease in efficiency of 10%-15% atmospheric muon reconstructed track rate
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PMT angular acceptance
cut-off on the angle between PMT axis and Cherenkov photon direction
uncertainty ~20-25 % on reconstructed track rate
mainly downward tracks
XXth Rencontres de Blois K.Fratini
Atmospheric neutrinos
• 5 line data• 100 active days • reconstruction
quality cut applied
Preliminary
5 line data MC true MC reco MC true MC reco
• neutrino candidate: 78
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Conclusion
• Data with 5 lines were taken for almost one year. People are analysing them:
– atmospheric muons: total systematic uncertainties on the reconstructed track rate in MC simulation due to environmental and PMT parameters ~ ±35%
– atmospheric neutrinos: first signal!
• 10 lines in acquisition, detector completed, soon 12 line connection!
XXth Rencontres de Blois K.Fratini
Primary all particle CR. Comparison between models
100
1000
10000
1,E+04 1,E+05 1,E+06 1,E+07 1,E+08
E, GeV
Flux*E^(2.5) [m-2s-1sr-1GeV+1.5]
HORANDEL -APP23(03),193
MUPAGE- APP25(06),1
Bugaev-Ph.Rev.D58(98)054001
KASCADE- APP24(05),1
Region of the primary CR spectrum producing 90% of the muons triggering ANTARES