Konstantia Balasi Institute of Nuclear and Particle Physics NCSR Demokritos NCSR Demokritos Gamma Ray Burst Neutrino Telescope GRBNeT GRBNeT: an autonomous underwater telescope to detect high energy neutrinos for the observation of Gamma-ray bursts Nuclear Structute and Reaction Weak, Strange and Exotic Hirschegg, Kleinwalsertal, Austria January 11-17, 2015

GRBNeTOutline  Introduction i) Motivation for neutrino astrophysics ii) Gamma Ray Bursts  Gamma Ray Burst Neutrino Telescope - GRBNeT i) Site ii) Detector layout  Results simulations for background rejection  Summary-Conclusions KONSTANTIA BALASI GRBNeT project

GRBNeT Motivation for neutrino astrophysics KONSTANTIA BALASI GRBNeT project photons=good carriers of information neutrinos=uncharged,weakly interacting

GRBNeT Distribution of GRBs in the sky BATSE (9 years) 14 December, (Photo: Reuters) Kouveliotou et. al. ('93) Briggs et. Al. (2002) GRB duration: GRB duration: - short duration ~ 0.3 s - long duration ~ 30 s Gamma Ray Bursts KONSTANTIA BALASI GRBNeT project

GRBNeT Gamma Ray Bursts Sources KONSTANTIA BALASI GRBNeT progect Soebur Razzaque, Peter Meszaros, and Eli Waxman. Neutrino tomography of gamma ray bursts and massive stellar collapses. Phys. Rev., D68:083001,2003, astro-ph/

GRBNeT KONSTANTIA BALASI GRBNeT progect Cherenkov Detectors charged particles passing through matter will polarize some atomic electrons If the particle exceeds the speed of light c/n then an electromagnetic shock wave will be formed First observed by Pavel Cherenkov in 1934

Gamma Ray Burst Neutrino Telescope GRBNeT Autonomy -for a year Cost minimization Realistic & feasible operational requirements

---Close to the coast --- depth of 3500 m ---Good optical properties in water ---Low level of bioluminescence ---Low rate of sedimentation ---Low velocity bottom current KONSTANTIA BALASI GRBNeT project Site Selection GRBNeT

GRBNeT Detector layout 1 floor 4 floor 2 floor 3 floor 30 m 300 m KONSTANTIA BALASI GRBNeT project Detector layout GRBNeT

- a flexible detector simulation program for kilometer scale neutrino telescopes with PMTs as photo-sensors - simulates light produced by muons and secondary particles traveling through water and the subsequent conversion of their photon field into a PMT hit probability - is designed as a library of C++ classes: different telescope geometries, different PMT configurations inside the optical modules a neutrino telescope simulation programme Konstantia Balasi GRBNeT project

muon photons can E loss PDF's, PDG's light production -light production light transmission -light transmission absorption scattering light detection -light detection acceptance of PMT

Konstantia Balasi GRBNeT project Simulation efforts focusing on high background rejection -- Fast simulation package In good agreement no. of OMs been hit no. of events In good agreement no. of events

Konstantia Balasi GRBNeT project Log of muon bundle energy (GeV) Muon zenith angle Contribution of atmospheric muon background for all events with at least 1 OM Strong reduction of no. background events

Konstantia Balasi GRBNeT project Threshold acceptance 3 p.e. Threshold acceptance 5 p.e. no. of background events expected during 24 hrs of operation for OMs on the same floor

Konstantia Balasi GRBNeT project no. of background events expected during 24 hrs of operation for OMs on two floors

: The Gamma-ray Coordinates Network

Compare multi to single PMT

Konstantia Balasi GRBNeT project

Standard KM3Net Test larger Geo Konstantia Balasi GRBNeT project

Konstantia Balasi GRBNeT project Increasing visibility of PMTs

Konstantia Balasi GRBNeT project

CONCLUSION autonomous at a low costWe have proposed an autonomous underwater detector at a low cost for detecting high E neutrinos from GRBs We have performed simulations in order to optimize our detector Aim to provide valuable information, insights and answers to the question of GRB origin mechanisms Well under way both in mechanical structure, electronics and testing of the detector Planning to deploy this June

Thank you for your attention KONSTANTIA BALASI GRBNeT project From my visit to Pylos