Lake Baikal Neutrino Experiment Present and Future G.V.Domogatsky (INR, Moscow) for the Baikal collaboration

1.Institute for Nuclear Research, Moscow, Russia. 2.Irkutsk State University, Irkutsk, Russia. 3.Skobeltsyn Institute of Nuclear Physics MSU, Moscow, Russia. 4.DESY-Zeuthen, Zeuthen, Germany. 5.Joint Institute for Nuclear Research, Dubna, Russia. 6.Nizhny Novgorod State Technical University, Nizhny Novgorod, Russia. 7. St.Petersburg State Marine University, St.Petersburg, Russia. 8. Kurchatov Institute, Moscow, Russia. The Baikal Collaboration

4km OffShore Depth: 1366 m Shore Station 1366m Depth

Neutrino Telescope NT200+ (April, 2005)

6 The NT-200 Telescope -8 strings: 72m height optical modules - pairwise coincidence  96 space points - calibration with N-lasers - timing ~ 1 nsec - Dyn. Range ~ 1000 pe Effective area: 1 TeV ~2000 m² Eff. shower volume: 10TeV ~0.2Mt Quasar PMT: d = 37cm Height x  = 70m x 40m, V=10 5 m 3 Installation

Camp Ice as a natural deployment platform ~ 2 months

GOALS Natural flux of neutrinos with energy E>15GeV (search for point sources of neutrinos) Natural flux of neutrinos with energy E>15GeV (search for point sources of neutrinos) WIMP WIMP Magnetic Monopoles Magnetic Monopoles Diffuse flux of very high energy (E>10 TeV) neutrinos Diffuse flux of very high energy (E>10 TeV) neutrinos

Neutrino events from low hemisphere April February 2003, 1038 d, 372 events.

Atmospheric Muon-Neutrinos - With looser cuts, : 372 events. N  (>15GeV)/N  (>1GeV)~1/7  A higher statistics neutrino sample for Point-Source Search. - MC: 385 ev. Expected (15%BG). Skyplot (galactic coordinates) E_thr ~ 15GeV

Search for fast monopoles (  N   = n 2 (g/e) 2 N   = = 8300 N   g = 137/2, n = 1.33 ~E  =10 7 GeV Event selection criteria: hit channel multiplicity - N hi t > 35 ch, upward-going monopole -  (z i -z)(t i -t)/(  t  z ) > 0.45 &  o Background - atmospheric muons 90% C.L. upper limit on the flux of fast monopole (994 livedays)

19 Search for High Energy - Cascades NT-200 large effective volume 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 channel )  (BG)

Baikal Absorbtion Length: 22 ± 2 m Scattering Length ~ m  cos  ~ Optical properties

Fiducial volume V g (NT-200) AMANDA II Position of cascade vertex Neutrino Energy, lg(E/ТeV)

UPPER LIMITS ON THE DIFFUSE NEUTRINO FLUX (theoretical and experimental) НТ-200+ км 3

NT200+ commissioned April outer strings were installed 2. New DAQ – final modernization - 2 Underwater PC with Flex DSL modem (1 Mbod), - 2 Underwater PC with Flex DSL modem (1 Mbod), Underwater Ethernet Underwater Ethernet - Synchronization unit - Synchronization unit * time synchronization * time synchronization NT200 outer strings NT200 outer strings * event clusterization * event clusterization 3. New Software DOS -> Linux, Remote control DOS -> Linux, Remote control 4. New 2 cables to shore (2x4 km) 5. Calibration - New bright Laser

PeV Mton NT200+

Cascade coordinates (energy) reconstruction efficiency NT

NT200+ time synchronization (new laser) mm Time differences NT200 – outer string: 2-4nsec fwhm interstring/NT200 jitter >10 12 photons/pulse

NT200+ Start of operation April 2005 Examples of events

NT200+ as a module of Gigaton (km3) Detector in Lake Baikal

A Gigaton (km3) Detector in Lake Baikal. Sparse instrumentation: 91 strings with 12 OM = 1308 OMs  effective volume for 100 TeV cascades ~ km³  muon threshold between 10 and 100 TeV 624 m 280m 70m 120m 208m

Baikal – GVD Schedule Milestones R&D, Testing NT R&D, Testing NT Technical Design 08 Technical Design Fabrication (OMs, cables, Fabrication (OMs, cables, connectors, electronics) connectors, electronics) Deployment (0.1 – 0.3) km Deployment (0.1 – 0.3) km Deployment (0.3 – 0.6) km Deployment (0.3 – 0.6) km Deployment (0.6 – 0.9) km Deployment (0.6 – 0.9) km3 Overall cost with logistics ~ 20 MEuro Detector ~ 16 MEuro Logistics, including infrastructure ~ 4 MEuro