The BAIKAL Neutrino Telescope: from NT200 to NT th ICRC Pune, India, Ralf Wischnewski DESY-Zeuthen R.Wischnewski 29thICRC, Pune, India, Outline: -Motivation + Detection Principle -Design: NT200 and NT Physics Results (selected) : NT Perspective + Summary R.Wischnewski 29thICRC, Pune, India, High Energy -Astronomy --> Catch first astrophyical HE s Cosmic ray acceleration sites New observational window to Universe (new objects ?) Dark Matter (neutralino annihilation in Earth/Sun/Gal.C.) Prompt lepton production in atmosphere ( + ; cross sections, ) Exotic particles: Magnetic Monopoles (relativistic or slow [ ]) HE atmospheric muons (exotic component ?), Neutrino Telescopes: Physics Motivation Astro - Astro - - Particle Physics R.Wischnewski 29thICRC, Pune, India, Physics Background: atmospheric neutrinos A. Point sources Find the sources on the sky + clean signal - needs strong enough single sources B. Anomalies in atmospheric -energy spectrum + all weak point sources should add up + model predictions ~ exp.sensitivities - systematics Astrophysical s: Two detection methods Skyplot with Hot spot(s) (galactic coordinates) Charged Current (CC) N X Electron / hadron cascades from CC + NC e / / ( ) log [ E 2 Flux(E ) 3 96 AGN atmospheric log (E /GeV) Point source search Search for a diffuse flux R.Wischnewski 29thICRC, Pune, India, A Amanda/IceCube Baikal N N Baikal Telescope: Russia Germany - Institute of Nuclear Research, Moscow - Moscow State University - DESY Zeuthen - Irkutsk State University - Nishni Novgorod State Technical University - State Marine Technical University, St.Petersburg - Kurchatov Institute, Moscow - JINR, Dubna ~45 authors The Site 4 cables x 4km to shore. 1100m depth 3600 m 1366 m NT200+ R.Wischnewski 29thICRC, Pune, India, NT200+ = NT long outer strings - Height = 210m - = 200m - = 200m - Volume ~ 5 Mton R.Wischnewski 29thICRC, Pune, India, The NT-200 Telescope -8 strings: 72m height optical modules = 96 pairs (coincidence) - measure T, Charge - T ~ 1 ns - dyn. range ~ 1000 p.e. Effective area: 1 TeV ~2000 m Eff. shower volume: 10TeV ~0.2Mt Quasar PMT: d = 37cm Height x = 70m x 40m, V geo =10 5 m 3 = 0.1Mton R.Wischnewski 29thICRC, Pune, India, NT200+ commissioned April 9, 2005 Upgrade : - 3 outer strings were installed - DAQ modernization - 2 Underwater PC with Flex DSL modem (1 Mbps), full multiplexing, Underwater Ethernet - Synchronization unit * time synchronization (~ ns) NT200 outer strings * event building - Transition to Linux, RemoteCntrl. - Calibration - New bright Laser - 2 new cables to shore (2x4 km) R.Wischnewski 29thICRC, Pune, India, ExtStr 1 ExtStr 3 ExtStr 2 NT200 Center+Outer New ShoreCable 100 m March, 2005, 4km off-shore: NT200+ deployment from ice. Ice A perfect natural deployment platform Ice is stable for 6-8 winter-weeks/year: Upgrades & maintenance Test & installation of new equipment Operation of surface detectors (EAS, acoustics, ) Electrical winches used for deployment operations R.Wischnewski 29thICRC, Pune, India, NT200+ Time Synchronization (new laser) >10 12 photons/pulse Laser: (400kW / 1 ns) Time calibration + Imitation of 20TeV-10PeV cascades, >10^12 photons/pulse w/ diffusor, >10^12 photons/pulse w/ diffusor, up to ~200m for full NT200+ up to ~200m for full NT200+ Time differences NT200 - outer string: Jitter is < 3ns rms for NT+/NT200. R.Wischnewski 29thICRC, Pune, India, NT200 - Selected Results - - Low energy phenomena - Atmospheric neutrinos - WIMP Neutrinos - -High energy phenomena Diffuse neutrino flux - Diffuse neutrino flux - Neutrinos from GRB - Prompt muons and neutrinos - Exotic HE muons - - Search for exotic particles - Relativistic Magnetic monopoles Data sample : 1038 days (Apr.98-Feb.03) : 502 livetime days earlier results Poster HE2.3 R.Wischnewski 29thICRC, Pune, India, Relativistic Monople Flux limit Fig 4.9()% C.L. upper limit on the flux of fast monopole and experimental limits from [4,6,7] Baikal Search: See Poster Session2 HE 2.3 R.Wischnewski 29thICRC, Pune, India, Atmospheric Muon-Neutrinos - With looser cuts, : 372 events. A higher statistics neutrino sample for Point-Source Search. - MC: 385 ev. Expected (15%BG). - No indication for Point Sources found. Skyplot (galactic coordinates) E_thr ~ 15GeV Search for High Energy Cascades NT-200 is used to watch the volume below for cascades. Look for upward moving light fronts. Signal: isolated cascades from neutrino interactions Background : Bremsshowers from h.e. downward muons Final rejection of background by energy cut (N hit ) (BG) NT-200 large effective volume e cascades Allowed by excellent scatt scatt =30-50m Radius, m Physics topics: - - HE cascades from e - NC/CC Diffuse astroph.flux GRB correlated flux - - HE atmospheric muons ( the BG to s ) Prompt Exotic -... Search for High Energy Cascades NT-200 is used to watch the volume below for cascades. (BG) NT-200 large effective volume Hard signal spectra would pile up in the energy parameter N hit = Number of Channels hit Shape of signal in Nhit distribution for A E - ( Selecting HE Cascades atm 2.5 cut Data + MC Showers along Diffuse Flux e, , Limit 90% C.L. Limit via W-RESONANCE production ( E = 6.3 PeV, 5.3 cm 2 ) e < 3.3 (cm 2 s sr GeV ) -1 (Baikal 2005) e < 5.0 (cm 2 s sr GeV ) -1 (AMANDA 2004) No events observed (+ 24% system. err.) 2.5 evt exp. The 90% C.L. all flavour limit (1038 days) for a =2 spectrum ~ E -2 (20 TeV < E < 50 PeV), and assuming e : : = 1 1 1 at Earth ( 1 2 0 at source ) E 2 < 8.1 10 -7 GeV cm -2 s -1 sr -1 (Baikal 2005) E 2 < 8.6 10 -7 GeV cm -2 s -1 sr -1 (Cascades AMANDA-II, 2004) V geo (NT-200) AMANDA II V eff > 1 Mton at 1 PeV Effective Volume vs. Energy R.Wischnewski 29thICRC, Pune, India, Experimental limits + bounds/ predictions Diffuse Flux Limits + Models Models already ruled out by the experiments: SDSS - Stecker et al.92 SS - Stecker, Salamon96 (Quasar) SP - Szabo, Protheroe92 (Models/Expts. are rescaled for 3 flavours) NT200 + NT200+ as a subunit of a Gton scale detector ? For High Energy Cascades: A single small string replacing the NT-200 central core reduces V eff less than x3 for E>100TeV. Short strings as a subunit for a Gton scale detector = ok. 140 m Effective volume with R.Wischnewski 29thICRC, Pune, India, NT200 + Much improved cascade coordinates (+ energy ) reconstruction. Expected e - sensitivity (3 yrs NT200+) : E 2 < 0.9 GeV cm -2 s -1 sr -1 3-4 fold rise in sensitivity for classical HE cuts (vertex + energy reco will improve !) A future Gigaton (km3) Detector in Lake Baikal. Sparse instrumentation: 91 strings with 12/16 OM = 1308 OMs effective volume for 100 TeV cascades ~ km! muon threshold between 10 and 100 TeV R.Wischnewski 29thICRC, Pune, India, The Baikal Telescope NT200 is in operation since NT200 is focusing on search for HE-diffuse neutrinos: A Mton-detector with only 100kt enclosed volume. - Diffuse flux limits for 4 years (98-03) are attacking AGN-models. At same level as Amanda (1yr) & complementary (method, North,) - Other new results from NT200 (not presented here): Fast Magnetic Monopoles, HE atm. (prompt; exotic), WIMPs, GRBs 3. Upgrade to NT200+ in April, 2005: - NT200+ is tailored to diffuse cosmic neutrinos - 5 Mton equipped volume; V_eff > 10 Mton at 10 PeV sensitivity improvement by 34 x 4. Ideas for future: Gigaton Volume Detector (km3-size array) 5. Baikal is complementary to Amanda: location, water (low scatt), reconstruction Summary R.Wischnewski 29thICRC, Pune, India, BAIKAL NT200+ will for a while be the largest Northern hemisphere HE-nu Cherenkov Telescope. BAIKAL NT200+ will for a while be the largest Northern hemisphere HE-nu Cherenkov Telescope. R.Wischnewski 29thICRC, Pune, India, Reserve Fig 4.9()% C.L. upper limit on the flux of fast monopole and experimental limits from [4,6,7]