The Baikal Neutrino Telescope - - Status and Plans Status and - PowerPoint PPT Presentation

The Baikal Neutrino Telescope - - Status and Plans Status and Plans The Baikal Neutrino Telescope Outline: - Detection Methods - The Detectors: NT200 and NT200+ - Physics Results from NT200 � Diffuse cosmic neutrino search - The Km3 Baikal Detector Project ( “Gigaton Volume Detector” ) Ralf Wischnewski DESY, Zeuthen Poster: - for the Baikal Collaboration - - A prototype acoustic neutrino detector / 0639 - NT200 Physics Results / 1088 th ICRC, 30 th ICRC, Merida Merida, Mexico, July 2007 , Mexico, July 2007 30

The Baikal Collaboration - Institute of Nuclear Research, Moscow - Moscow State University - DESY Zeuthen - Irkutsk State University ICRC, Merida, 2007 - Nishni Novgorod State Techn. Univ. - State Marine Techn. Univ. St.Petersburg - Kurchatov Institute, Moscow - JINR, Dubna R.Wischnewski ~45 authors 2

Project Milestones >1983: Site / Water studies; R&D: large area PMT, underwater technology, Physics small setups (exotics search) ICRC, Merida, 2007 1991: Project NT200 submitted 1993: NT36 – the first underwater array operates 1998: NT200 commissioned R.Wischnewski 2005 - 2006: Upgrade to NT200+ completed; operating >2006: R&D activity for a Km3 detector in Lake Baikal („Gigaton Volume Detector“) ~2010: expected start of Km3 deployment 3

Baikal 4 R.Wischnewski ICRC, Merida, 2007

ICRC, Merida, 2007 Shore Station R.Wischnewski 4km OffShore Depth: 1366m 5 Lake Baikal

NT200+ = NT200 ICRC, Merida, 2007 + 3 long outer R.Wischnewski strings - Height = 210m Height = 210m - - ∅ = 200m = 200m - - Geom.Volume Geom.Volume ~ 5 ~ 5 Mton Mton - 6

- 8 strings - 192 optical modules = 96 pairs (coincidence) The NT-200 Telescope - measure Time, Charge - σ T ~ 1 ns - dyn. range ~ 1000 p.e. Effective area: 1 TeV ~ 2000 m² Eff. Shower volume: 10 TeV ~ 0.2Mt 1 PeV ~ 1Mton ! Height = 70m, ∅ = 42m � V inst = 10 5 m 3 Quasar PMT: d=37cm (14.6”)

Advantages (1): Ice – Perfect Deployment Platform ICRC, Merida, 2007 100 m R.Wischnewski ExtString 1 New ShoreCable ExtString 3 ExtString 2 NT200 Central+Outer Str. Foto from March, 2005, 4km off-s NT200+ deployment from 1m thick • Ice is available 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 (all connections done dry) 8

Advantages (2): Water – Good Optical Properties Baikal: Baikal: Fresh water Fresh water m -1 � No K40 BG No K40 BG � m -1 , n o , i n t c o e i t s c ICRC, Merida, 2007 e s s s Short periods of Short periods of o s ~15m possible. ~15m possible. r s c Baikal o n r c o i g t p Baikal n r i o r e s R.Wischnewski t b t a A c S λ , nm λ , nm Abs. Length: 22 ± 2 m Scatt. Length ~ 30-50 m (geom.scat.L.) 〈 cos Θ〉 ~ 0.85-0.9 In-situ measurements Note: IceCube‘s „effective“ (diffusion) scattering is ~30m over many years � for Baikal: ~300 - 500m ! 9

In-situ: Verification of Scattering @ large distances Calibration Laser ~ 10 12 – 5 10 13 γ /pulse (1 ns) → E_Shower ~ 10 – 500 PeV - Measure: Photon arrival times on Chan13 @187m distance FWHM ~12ns @2pe,190m ! - Time Jitter = Scattering + Electronics ICRC, Merida, 2007 R.Wischnewski 10 Light scattering Light scattering - scattering length 30 m - scattering length 30 m t 13 t 8 13 - distance to Laser ~200 m distance to Laser ~200 m - 6 σ T vs. number of p.e. σ , ns t 106 t Laser 4 106 2 0 10 1 10 100 Np.e.

NT200 - Selected Results Data sample: 1998-2002 (Apr/98-Feb/03) - Low energy phenomena 1038 days - Atmospheric neutrinos ICRC, Merida, 2007 - WIMP Neutrinos - Search for exotic particles - Relativistic Magnetic monopoles R.Wischnewski - High energy phenomena - D Diffuse neutrino flux iffuse neutrino flux - Neutrinos from GRB - Prompt muons and neutrinos - Exotic HE muons 11

Atmospheric Muon-Neutrinos E_thr ~ 15GeV ~ 15GeV E_thr ICRC, Merida, 2007 R.Wischnewski Skyplot of NT200 neutrino events / 5 years Galactic center (galactic coordinates) visible 18 hours per day - Data: 372 upward ν events (1998-2002). ( N μ (>15GeV)/N μ (>1GeV)~1/7 ) - MC: 385 ev. expected (15%BG). � A high statistics neutrino sample for Point-Source Search, incl. GalCenter. No evidence for non-atmosph. ν ‘s. 12

Search for Fast Monopoles (β > 0.8) N γ (λ) = n 2 (g/e) 2 N γμ (λ) = 8300 N γμ (λ) (!!) g = 137/2, n = 1.33 � Bright light source, like muons ~E μ =10 7 GeV -15 10 ICRC, Merida, 2007 Monopole selection criteria: • large hit channel multiplicity: N hit > 35 ch • clearly upward going track -16 Background : atmospheric muons (downward) R.Wischnewski 10 Amanda-II/ICRC2007 NT200 (1998-2002) -17 10 0.6 0.8 1 Baikal, 2006 Baikal, 2006 90% C.L. upper limit on the flux of fast monopoles (1003 livedays). N hit vs distance 13

Search for High Energy Diffuse Cascades Search within non-instrumented volume NT200 below NT200 detector for cascades = Upward moving light fronts. ICRC, Merida, 2007 Effective Volume vs. Energy 10 Mton R.Wischnewski ν μ („BG“) e m u l o v e v i t c e f f e V geo (NT200) e g r a l NT200+ : Instrument the volume below detector � better BG suppression and improved physics. V det > 1 Mton at 1 PeV 14

Diffuse Flux Limits Exp. Limits, model predictions, For a γ =2 spectrum Ф ν ~ E -2 the and atmospheric ν -BG. Baikal NT200 limit is (20 TeV < E < 50 PeV): -2 s -1 sr -1 E 2 Ф ν < 8.1 ·10 -7 GeV cm -2 s -1 sr -1 ν e : ν µ : ν τ =1:1:1 atm. MACRO ν -5 10 - - Astropart.Phys. 25 (2006) 140 AMANDA( e , res) BAIKAL( e , res) ICRC, Merida, 2007 ν ν E 2 Φ (E), GeV cm B Υ MPR NMB Υ AMANDA -6 10 BAIKAL R.Wischnewski B(E -2 ) NT200+ sensitivity (~ Amanda-II) ν *3 AMANDA II NT200+ (3 years) µ MPR -7 10 Amanda-II, this conf. WB ν pr TD -8 10 3 4 5 6 7 8 9 10 11 lg(E/GeV) limits given for all-flavors Exp . ν µ limits are 1:1:1 flavor flux ratio @earth assumed (source1:2:0) multiplied x3 15

Limits on Neutrino Source Models E 2 Φ ,[GeV s -1 sr -1 cm -2 ] BAIKAL ν e : ν µ : ν τ =1:1:1 -5 SS91=10 SS05 10 SeSi ICRC, Merida, 2007 -6 SS91 10 SeSi SS SS05 -7 10 R.Wischnewski 3 4 5 6 7 8 9 10 lg(E/GeV) Model BAIKAL AMANDA Neutrinos from Quasar Cores SS05 Quasar 2.5 1.6 SS – Stecker, Salamon (91,05) SP u 0.062 0.054 SP – Szabo, Protheroe (92) SP l 0.37 0.28 M pp+p γ 2.86 - Neutrinos from Blazars M pp+p γ - Mannheim (95) P P γ 1.14 1.99 P p γ - Protheroe (96) MPR 4.0 2.0 MPR - Mannheim, Protheroe, Rachen (01) SeSi 2.12 - SeSi - Semikoz, Sigl, (03) 16 Model survival factor n 90% /N model

The New Project: ICRC, Merida, 2007 A Km3 – size Detector in Lake Baikal (“Gigaton Volume Detector”) R.Wischnewski 17

A Km3 - Scale Baikal Neutrino Detector A sparsely instrumented array: - 1300-1700 OMs ICRC, Merida, 2007 - 90-100 strings, 350m length - 12-16 OM/string - string radial distance ~120m * 208m 624 m R.Wischnewski � Casacde effective volume for ≥ 100 TeV: ~ 0.5-1. km³ δ lg ( E) ~ 0.1, δθ med < 4 o � Muon detection from 10-30TeV 70m 70m 120m 280m * Toy model (MC optimization in progress) Basic cell: a minimized NT200+ Basic cell: a minimized NT200+ 18

Km3 Design Studies (in progress) contained events I(E)/I(1 PeV) cascades Cascades 1 0.8 16 Channel / String instrumented volume V=3.5 10 8 m 3 ICRC, Merida, 2007 (Channel = 1 OM) 0.6 0.4 0.2 R.Wischnewski 0 lg(E_sh/TeV) 1 1.5 2 2.5 3 3.5 4 4.5 lg(E sh /TeV) I(E)/I(100 PeV) Muons muons 1 <S>= 0.8 10 6 m 2 0.8 0.6 8 Channel / String (Channel = 2 OM) 0.4 0.2 0 1 1.5 2 2.5 3 3.5 4 4.5 lg(E_mu/TeV) 19 lg(E µ /TeV)

PMT Selection for Km3 Basic criteria of PM selection is effective sensitivity to Cherenkov Basic criteria of PM selection is effective sensitivity to Cherenkov light light which depends on which depends on Photocathode area × × Quantum efficiency Quantum efficiency × × Collection efficiency Collection efficiency Photocathode area and Optical Module design (FOV). and Optical Module design (FOV). ICRC, Merida, 2007 R.Wischnewski IceCube IceCube Baikal Baikal Antares Antares NEMO? NEMO? NT200+ NT200+ Quasar-370 Hamamatsu R8055 Photonis XP1807 ? ? ? ? D ≈ 14.6” D ≈ 13” D ≈ 12” ≈ ≈ ≈ ≈ Quantum efficiency ≈ 0.15 Quantum efficiency ≈ 0.20 Quantum efficiency ≈ 0.24 PMT development now is an active field with KM3NET/ BAIKAL- -km3/ km3/… … : : PMT development now is an active field with KM3NET/ BAIKAL QE >30% , new Smart QE >30% , new Smart- -PMT designs (QUASAR PMT designs (QUASAR- -like by like by Photonis Photonis/ /… …?), ?), … … 20