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Baikal Neutrino Telescope – an underwater laboratory for astroparticle physics and

Baikal Neutrino Telescope – an underwater laboratory for astroparticle physics and environmental studies. N. Budnev, Irkutsk State University. For the Baikal Collaboration. BAIKAL - Collaboration Institute for Nuclear Research, Moscow, Russia. Irkutsk State University, Russia.

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Baikal Neutrino Telescope – an underwater laboratory for astroparticle physics and

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  1. Baikal Neutrino Telescope – an underwater laboratory for astroparticle physics and environmental studies. N. Budnev, Irkutsk State University. For the Baikal Collaboration

  2. BAIKAL - Collaboration • Institute for Nuclear Research, Moscow, Russia. • Irkutsk State University, Russia. • Skobeltsyn Institute of Nuclear Physics MSU, Moscow, Russia. • DESY-Zeuthen, Zeuthen, Germany. • Joint Institute for Nuclear Research, Dubna, Russia. • Nizhny Novgorod State Technical University, Russia. • St.Petersburg State Marine University, Russia. • Kurchatov Institute, Moscow, Russia.

  3. W49B g n SN 0540-69.3 P+Nuclears Crab Cas A E0102-72.3 Messengers from the Universe • Photons currently provide all information on the Universe. But they are rather strongly reprocessed and absorbed in their sources and during propagation. For Eg > 500 TeV photons do not survive journey from Galactic Centre. • Protons+Nuclear directions scrambled by galactic and intergalactic magnetic fields as well for Epr >2021 eV they loss energy due to interaction with relict radiation (GZK-effect). • Neutrinos have discovery potential because they open a new window on the Universe

  4. O(km) long muon tracks Electromagnetic & hadronic cascades  5-15 m ~ 5 m CCe + Neutral Current Charged Current (CC)  1960 - M. Markov: High Energy neutrino detection in natural transparent media (ocean water, ice):

  5. pp core AGN p blazar jet log(E2 Flux) Top-Bottom GZK WIMPs Oscillations GRB (W&B) 3 6 9 log(E/GeV) TeV PeV EeV Air showers Underground Radio,Acoustic Underwater Microquasars etc.

  6. NT200+/Baikal-GVD 1993-1998 (~2015) KM3NeT (~2014) ANTARES A N N NEMO NESTOR Amanda/IceCube 1996-2000 (~2011)

  7. First underwater neutrino telescope NT200

  8. The first underwater neutrino telescope NT200 have been operated in Lake Baikal since 1998. Why Lake Baikal? Length – 720 km, width – 30-50 km, depth -1300-1640 m 20% of kind fresh water

  9. Site conditions • Sufficient depth (1370 m) is located at distance 3 km from the shore. • Absorption length typically is (20 – 25) m, scattering length typically is (50 – 70!) m. • No bioluminescence flashes, background, as a rule, in 10 -100 times less then in a sea water. • Small water currents, especially at large depths (a few millimeters per second). • Fresh water, cheaper materials can be used. • Convenient transport communication.

  10. Ice as a natural deployment platform • Ice stable for 6-8 weeks/year: • Maintenance & upgrades • Test & installation of new equipment Winches used for deployment

  11. The Ice Camp (4km offshore)

  12. Schematic view on the deep underwater complex NT200 10-Neutrino Telescope NT200 7-hydrophysical mooring 5-sedimentology mooring 12-geophysical mooring 13-18-acoustic transponders 1-4 cable lines Buoy Anchor

  13. NANP’03 • NT200running since 1998 • - 8 strings with 192 optical modules, • 72m height, • R=21.5m radius, • 1070m depth, Vgeo=0.1Mton • effective area: S >2000 m2 (E>1 TeV) • Shower Eff Volume: ~1 Mt at 1 PeV

  14. “Quasar” photoelectric detector G= 20-30

  15. The items for NT200 • Low energy phenomena (10 GeV-100 TeV) • atmospheric neutrinos and muons • -Search for dark matter • neutrino signal from WIMP annihilation • Search for exotic particles • magnetic monopoles • High energy phenomena(100TeV- 1000PeV) • diffuse neutrino flux • neutrinos from GRB • HE neutrino sources • prompt muons and neutrinos • Environmental studies

  16. “Low” energy neutrino search strategy We look for upward going muons p p Atmosphere n m m m The neutrino telescope n Earth m p At the 1km depth : m p m m - 6  10

  17. Atmospheric muons: Calibration Beam Ai, ti atm. m Time difference (dt = t52-t53) Amplitude (Chan 12) Reconstructed m’s : Cos(zenith) distribution vs. Corsika dt, ns cos (  ) Photoelectrons

  18. Sky plot for upward going neutrino April1998 - February 2003 years, 1038 days,462 events. Threshold – 15 GeV

  19.  +  b + b C +  +   W + + W - Detection area of NT-200 for vertically up-going muons detection (after all cuts) Search for WIMP Neutrinos from the Center of the Earth 23

  20. Limit on excess neutrino induced upwardmuon flux 90% c.l. limits from the Earth ( 1038 days NT200 livetime, E> 10 GeV ) WIMP Neutrinos from the Center of the Earth 1038 days livetime NT200 (1998 -2003) 48 evts - experiment 73.1evts- prediction without oscillations 56.6 evts - prediction with oscillations 3.6 evts - atm. Muons (backgraund) Systematic uncertainties: 24% Within statistical and systematic uncertainties 48 detected events are compatible with the expected background induced by atmospheric neutrinos with oscillations.

  21. N= n2 (g/e)2 N= 8300 N g = 137/2, n = 1.33 90% C.L. upper limit on the flux of fast monopole (1003 livedays) Search for fast monopoles (b > 0.8) Event selection criteria: hit channel multiplicity - Nhi t> 35 ch, upward-going monopole - (zi-z)(ti-t)/(tz) > 0.45 & o Background - atmospheric muons Limit on a flux of relativistic monopoles:F < 4.6 10-17 cm-2 sec-1 sr-1

  22. NT200  large effective volume Search for High Energy neutrino (cascades) Look for events with large number hit channels and for upward moving light fronts. (BG) Number of Cherenkov photons Nph = 200 (E / 2 MeV) for E=10 Pev Nph = 1012!!! 27

  23. Diffuse flux ofne, nt, n: cascades The 90% C.L. Limits Obtained With NT-200 (1038 days) DIFFUSE NEUTRINO FLUX (Ф~ E-2, 10 TeV < E < 104 TeV) ne n nt= 1  2  0 (AGN) ne  n nt= 1  1  1 (Earth) NT-200 AMANDA II BaikalE2 Фn< 8.1 ·10-7GeV cm-2 s-1 sr-1 AMANDA E2 Фn< 8.6 ·10-7GeV cm-2 s-1 sr-1 W-RESONANCE ( E = 6.3 PeV, s = 5.3 ·10-31 cm2 ) BaikalФne < 3.3 · 10-20 (cm2 · s · sr ·GeV )-1 AMANDAФne < 5.0 · 10-20 (cm2 · s · sr ·GeV )-1 Vg(NT200)

  24. Flux ofne, nt, n: cascades Experimentalimits and theoretical predictions Astropart. Phys. 25 (2006) 140

  25. Toward Gigaton Water Detector(KM3 detector on lake Baikal)

  26. 2005 year. Upgrade to NT200+ finished Laser intensity - cascade energy: (1012 – 5 1013 ) g/puls- (10 – 500) PeV

  27. Ice – A perfect natural deployment platform Foto from Mar, 2005, 4km off-shore: NT200+ deployment from 1m thick ice. 100 m New ShoreCable ExtString 1 ExtString 3 ExtString 2 NT200 Central+Outer Str.

  28. 110100 1000PeV 41523 40Mton 2005: NT200+ - intermediate stage to Gigaton Volume Detector (km3 scale)iscommissioned in Lake Baikal Main physics goal: Energy spectrum of all flavor extraterrestrial HE-neutrinos (E > 100 TeV) • Total number of OMs – 228 / 11 strings • Instrumented volume – 5 Mt • (AMANDA II, ANTARES – 10 Mt) • Detection volume >10 Mt for En>10Pev • high resolution of cascade vertex and • energy neutrino energy

  29. Sparse instrumentation: 91 – 100 strings with 12 – 16 OMs (1300 – 1700 OMs)  effective volume for >100 TeV cascades ~ 0.5 -1.0 km³ dlg(E)~ 0.1, dqmed< 4o  detects muons with energy > 10 - 30TeV Ultimate goal of Baikal Neutrino Project: Gigaton (km3) Volume Detector in Lake Baikal 208m 624m 70m 70m 120m 280m

  30. A Gigaton (km3) Detector in Lake Baikal - Status - • - Basic detector element is NT200+. Under “Real Physics Test“ since 4/2005. • Dedicated R&D for Baikal/km3 – technology starts in 2006. • Redesign of some key elements is under consideration. • Issues: • Optical Module: Quasar vs other? Grouping 2 vs 3? FADC readout? ... • Time synchronization: electrical vs. optical, .... • System architecture: subarray trigger, string controller, data transfer, ... • Auxiliary systems: acoustic positioning, bright laser sources, … • MC design optimization • ... • Interaction Baikal/km3  KM3NeT : • Common activities for a few selected technical issues - could this be useful ? • e.g. OMs (design/in-situ tests@NT200+); MC (design; verification); TimeSync.; Auxil.Dev.; …,...

  31. PM selection for the km3 prototype string Basic criteria of PM selection is its effective sensitivity to Cherenkov light which depends on Photocathode area Quantum efficiency  Collection efficiency Quasar-370 D  14.6” Quantum efficiency 0.15 Hamamatsu R8055 D  13” Quantum efficiency 0.20 Photonis XP1807 D  12” Quantum efficiency 0.24 ?  ? 

  32. Laser PM selection: Underwater tests (2007) 4 PM R8055 (Hamamatsu) и 2 XP1807 (Photonis) were installed to NT200+ detector (April 2007). 4 PM: central telescope NT 200; 2 PM R8055: outer string, FADC prototype. Quasar-370 Quasar-370 R8055 XP1807 160…180 m Quasar-370 Quasar-370

  33. Relative effective sensitivities of large area PMs (preliminary results) Smaller size (R8055, XP1807) tends to be compensated by higher photocathode sensitivities. Relative effective sensitivities of large area PMs R8055/13” , XP1807/12” and Quasar-370/14.6”. Laboratory measurements (squares), in-situ tests (dots).

  34. Design of Prototype string FADC unit is operating now in Tunka EAS 1 km2detector (astro-ph/0511229) • Basic features • String lengths ~300 m • String contains 12…16 OM • Optical modules contains only PM and control electronics • 12 bit 200 MHz FADC readout is designed as multi channel separate unit. • Half-string FADC controllers with ethernet-interface connected to string PC unit • String PC connected by string DSL-modem to central PC unit 300 m PMT pulses & Power 12 V Control line Data (Ethernet), Trigger

  35. Baikal – GVD Schedule Milestones • 06-07 R&D, Testing NT200+ • 08 Technical Design • 08-14 Fabrication (OMs, cables, connectors, electronics) • 10-12 Deployment (0.1 – 0.3) km3 • 13-14 Deployment (0.3 – 0.6) km3 • 15-16 Deployment (0.6 – 0.9) km3

  36. Acoustic detection of high energy neutrino

  37. Acoustic Detection of High Energy Neutrino

  38. Absorption of sound in water

  39. Acoustic noise within 22-44 kHz frequency band at different depths Example of bipolar pulse 10mPa 1mPa

  40. Listening from top to down

  41. Angular distribution of detected bipolar events Energy dependence of expected acoustic signal amplitudes from cascades Absorption length of acoustic signal in water

  42. 1. Underwater and underice Cherenkov neutrino detectors is real way to open new window in Universe. 2. In addition to existing intermediate scale underwater/underice neutrino detectors in near future should be constructed a few KM3 Cherenkov arrays. 3. Baikal is complementary to Amanda/IcaCube: location, water (low scattering), reconstruction 4. The Baikal Telescope NT200 is in operation since 1998 and Lake Baikal is one of the most suitable place in the world for deployment of huge KM3 neutrino telescope 5. R&D on Gigaton Volume Detector (km3-size array on Lake Baikal) on the base of experience of NT200+ operation is in progress. 6. New participants and collaborators are highly appreciated, welcome!!!!!! Summary 54 I.Belolaptikov

  43. The interdisciplinary environmental studies

  44. Why water is so kind? Why conditions for life are so good? Length – 720 km, width – 30-50 km, depth – 1.3-1.64km 20% of fresh water The water body of the lake is fully oxygenated Several hundred endemic species Inhabit all depths of the lake These is only thanks to the high rate of deep-water renewal !!!!! B.Koty

  45. Temperature depth dependence in Lake Baikal Summer profile Winter profile Homothermy Depth dependence of temperature of maximum density Epilimnion (0-40 m) Thermocline (2-150 m) Hypolimnion (30m – bottom) Meter TMD = 3.9839 - 1.9911∙10-2 ∙ P - 5.822 ∙ 10-6 ∙ P2 - (0.2219 + 1.106 ∙ 10-4 ∙ P) ∙S

  46. Instrumental moorings

  47. The temperature at the near-surface zone Much January July September November May

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