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Rezo Shanidze ECAP, University of Erlangen

This study explores the correlation between the direction of KM3NeT events and multi-PMT.DOM hits, using MC simulations. The results show a clear correlation, with a zenith angle resolution of about 17°. The multi-PMT.DOM directionality can be useful for the detection and reconstruction of KM3NeT events.

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Rezo Shanidze ECAP, University of Erlangen

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  1. Multi-PMT directionality and the KM3NeT events Rezo Shanidze ECAP, University of Erlangen KM3NeT General Meeting 21 Feb. 2012 Catania, Italy

  2. Introduction Distinctive feature of KM3NeT: multi-PMT DOM : • Larger photocathode area in • comparison to the ANTARES/IceCube OMs • Homogeneous coverage of the OM surface, • more isotropic detection of Cherenkov photons • Better photon counting and larger dynamical range • Local time/spatial coincidences between PMTs • Directional sensitivity Multi-PMT Digital OM 31 x 3 PMTs PMTi ( Qi, fi) R. Shanidze KM3NeT General Meeting, 21/02/2012, Catania

  3. Multi-PMT directionality • Multi-PMT DOM: 31 PMT (Qi, fi) • PMT – unit vector (normal to surface): (ux, uy, uz) = (sinQcosf, sinQsinf, cosQ) • “Hit direction” ( in the time interval of Dt) • h = Σ wiui wi – hit amplitude Is there correlation between the direction KM3NeT events and directions and multi-PMT DOM hits ? - atmospheric muons (down going m) - nm-neutrino event (up going m) - showers from contained n-events R. Shanidze KM3NeT General Meeting, 21/02/2012, Catania

  4. m-bundles at different KM3NeT sites Atmospheric–m events (mupage) at KM3NeT: 108 events at each site. a) Energy of m-bundle at different KM3NeT sites. b) Rate of atmospheric-m as a function of zenith angle(Qm) at different KM3NeT sites. 4 R. Shanidze KM3NeT General Meeting, 21/02/2012, Catania

  5. Atmospheric-m events in KM3NeT Atmospheric m-bundle direction: m (Qm, fm) Atmosphreric muon production for the KM3NeT Reference detector was used in this study QC Signal hits: L1i(Qi, fi) (OMi with at list 2 PMT hits, in Dt < 10 nsec) L1i(Qi, fi) L1i(Qi, fi) Reconstructed direction in KM3NeT: LR(QR, fR) LR (QR, fR) = S L1i(Qi, fi) m (Qm, fm ) L1i(Qi, fi) (Current study: without background L1 hits) R. Shanidze KM3NeT General Meeting, 21/02/2012, Catania

  6. Zenith angles: Qm, QC and QR z z Qm: atmospheric muon zenith angle Qm QC: Cherenkov angle: cosQc =1/nref nref = 1.3499, Qc = 42.2o A QR QC C QR: angle reconstructed in milti-PMT DOM From ABC: Qm = p + (Qc-QR ) B - cosQm = cosQccosQR + sinQcsinQR Qm m R. Shanidze KM3NeT General Meeting, 21/02/2012, Catania

  7. Qm vs QR MC data sample: atmospheric m : mupage production for the “reference detector” (@Lyon) Atmospheric m- bundle direction: ( 90o < Qm < 180o) Correlation between direction of m-bundles and reconstructed direction from L1 hits QR = p - (Qm - Qc ) Qm = p + (Qc-QR ) R. Shanidze KM3NeT General Meeting, 21/02/2012, Catania

  8. Zenith angle reconstructed from L1 hits All m-bundles m-bundles with 5L1 signal hits Atmospheric-m direction reconstructed from the L1 signal hits R. Shanidze KM3NeT General Meeting, 21/02/2012, Catania

  9. Atmospheric-m rates vs Qm and QR Diff. rates vs cosQm for Capo-Passero (red) 3500 m depth and Pylos (blue) 4500 m depth Points: events selected with at least 5L1 hits Histogram: direction reconstructed from signal L1 hits R. Shanidze KM3NeT General Meeting, 21/02/2012, Catania

  10. Atmospheric-m rates vs Qm and QR Cumulative rates vs cosQm for Capo-Passero (red) 3500 m depth and Pylos (blue) 4500 m depth Points: events selected with at least 5L1 hits Histogram: direction reconstructed from signal L1 hits R. Shanidze KM3NeT General Meeting, 21/02/2012, Catania

  11. Angular resolution Angle between m-bundle z-direction and direction reconstructed from L1 hits. s(DQ) ~17o R. Shanidze KM3NeT General Meeting, 21/02/2012, Catania

  12. Background and triggering • L1 hits: • large background sample; • ~1 kHz/DOM), L1 hits/msec: ~ 6.2 • trigger snapshot time: ~10-20 msec • T1 hits: 2 L1/bar in 50 nsec. • ( ~ 0.1 Hz/storey) • background T1 /msec: ~ 3.1 × 10-4 • T1 hits are almost background free ! Atmospheric-m events triggered with 5L1 and 2T1 for Toulon site R. Shanidze KM3NeT General Meeting, 21/02/2012, Catania

  13. Trigger efficiency for 5L1 and 2T1 Trigger efficiency for atmospheric-m for 5L1 and 2T1 hits at the different KM3NeT sites. R. Shanidze KM3NeT General Meeting, 21/02/2012, Catania

  14. Summary and Outlook • A clear correlation is observed between the direction of simulated • m-bundles and the event direction reconstructed from L1(T1) hits. • The zenith angle resolution of the KM3NeT events reconstructed from • the L1 hits is about 17o. The rate of events reconstructed as up going • (mis-reconstructed) is below 1%. • The multi-PMT DOM directionality can be applied for the study • of detection (triggering) an reconstruction of KM3NeT events. • Data with multi-PMTs DOMs from ANTARES instrumented line and • PPM DU are necessary to confirm results obtained from MC simulations. R. Shanidze KM3NeT General Meeting, 21/02/2012, Catania

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