Status of the Baikal Neutrino Telescope Status of the Baikal Neutrino Telescope

NT200+ NT200+

VLVNT2 Workshop, Catania, 9.11.2005VLVNT2 Workshop, Catania, 9.11.2005

Ralf Wischnewski

DESY, Zeuthen

Outline:- Motivation / Methods

- The new Detector NT200+ : Design + First Light

- Why NT200+ ? - Diffuse cosmic neutrino searches with NT200

- Sensitivity of NT200+ : diffuse cosmic

neutrinos.

Other physics results from NT200 See talk by Z.Djilkibaev on Friday (Monopoles, WIMPs, HE muons, prompt

leptons,..)

- Future: A km3 “Gigaton Volume Detector” at Baikal.

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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 ( + µ ; cross sections, …)

Exotic particles:

Magnetic Monopoles (relativistic or ultra-slow) … CR: HE atmospheric muons (exotic component ?), composition…

Neutrino Telescopes: Physics Motivation

Astro -

Astro -

- Particle P

hysics

- Particle P

hysics

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HE Neutrino Detection: “Muons” and “Cascades”

O(km) long muon tracks

direction determination by Cherenkov light timing

5-15 m

- Good directionality by Cherenkov timing

- Poor energy resolution

Charged Current (CC)

Electromagnetic & hadronic cascades

~ 5 m

- Good energy resolution

- Bad pointing

CC e + Neutral Current

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Baikal

Baikal Collaboration: Russia – Germany - Institute of Nuclear Research, Moscow - Moscow State University - DESY Zeuthen - Irkutsk State University - Nishni Novgorod State Techn. Univ. - State Marine Techn. Univ. St.Petersburg - Kurchatov Institute, Moscow - JINR, Dubna

~45 authors

Project Milestones:

>1983: site / water studies; R&D: large area PMT, underwater

techno., physics small setups (exotics search)

1991: Project NT200 approved

1993: NT36 – Telescope the first underwater array operates ...first ’s and ’s in NeutrinoTelescope

1998: NT200 commissioned

2005: NT200+ commissioned

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4km OffShoreDepth: 1366 m

Shore Station

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ExtString 1 ExtString 3 ExtString 2 NT200 Central+Outer Str.

New ShoreCable

100 m

Foto from March, 2005, 4km off-shore:

NT200+ deployment from 1m thick 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 (all connections done dry)

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NT200 running since 1998

- - 8 strings with 192 optical modules

- - 72m height, R=20m, 1070m depth, Vgeo=0.1Mton

- effective area: >2000 m2 (E>1 TeV)

- Shower Eff Volume: ~1 Mton at 1 PeV

NT200+ commissioned April 9, 2005

- 3 new strings, 200 m height, 36 OMs- 1 new bright Laser for time calibration imitation of 10 PeV-500 PeV cascades, >10^13 photons/pulse w/ diffusor, SNO-Calib- 2 new 4km cables to shore- DAQ – New Underwater & Shore Station: Underwater Linux embedded PCs, Industrial Ethernet Systems

4 Km to shore

NT200+ is tailored to UHE -induced cascades- 5 Mton equipped volume- V_eff >10 Mton at 10 PeV

4fold sensitivity gain with only 20% additional PMTS.

The Baikal Detector NT200+

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84 Km to shore

DAQ and Slow Control of NT200+

DAQ Modernization (2004/05): - First PCs/PC104 used underwater;- DSL Mbps to shore (w/ spare);- UW-ethernet (hot spares); - Full multiplexing of all data/control streams; - Industrial auxiliary components (EthRelais, ...)- Linux (uw + shore)

UW-PCs and other Central DAQ-Spheres

UW-PCs design

NT200+ DAQ/SlowControl schematcis

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Laser intensity ~ 1012 – 5 1013 /pulse E_Shower ~ 10 – 500 PeV

- Ch.13 – 187 m away from Laser- Time Jitter = Light Scattering + Electronics

First light on NT200+: Laser pulses as high-energy cascades

FWHM ~10ns @2pe,190m !

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tt11

tt22

tt1212

5 series of Laser pulses5 series of Laser pulses

NT200+ time resolutionNT200+ time resolution

t = tt = t11+ t+ t12 12 – t– t22

tt11, , tt22 - PMT jitter and light scattering - PMT jitter and light scattering

tt1212) ) 2 ns - electronics jitter 2 ns - electronics jitter

1 10 1000

2

4

6

8

10

, n

s

Np.e.

Light scatteringLight scattering- scattering length 30 m- scattering length 30 m- distance to Laser ~200 m- distance to Laser ~200 m

Jitter of electonics ~2 nsJitter of electonics ~2 ns- synchro cable length 1.2 km - synchro cable length 1.2 km - TDC bin 2 ns- TDC bin 2 ns

The amplitude dependence of relative time jitter measured for several pairs of channels of NT200 andexternal strings. Red line is result of Scat_MC calculation.

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Laser intensity reconstruction

r < 1 m

I/I ~ 6%

lowest intensity

five laser intensities

NT200+: “Laser-cascade” reconstruction

NT200

NT200+

3 outer str.

Reconstruct z-r

Laser vertex reconstruction

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Why NT200+ ?

Diffuse Cosmic Neutrino Search with

NT200.

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NT200: Search for High Energy Diffuse Cascades

Watch the non-instrumented volume below

detector for cascades = Upward moving light fronts.

(„BG“)

large effective volume

NT200

Vgeo (NT-200)

10 Mton

Effective Volume vs. Energy

NT200+ : Instrument the volume below detector better BG suppression and improved physics.

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Limits for diffuse cosmic neutrino fluxes

1:1:1 flavor flux ratio @earth

limits given for all-flavors ( e + e + + + + )

Baikal + Amanda

1: B10, 97, ↑μ2: A-II, 2000, unfold.3: A-II, 2000, cascade4: B10, 97, UHE5: NT200, 98-02, cascade6: A-II, 2000, UHE sens.7: A-II, 2000-03 ↑μ sens.8: IceCube 3 years9: NT200+, 3yr, casc sens.

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Baikal Cascades (98-02) subm. APP

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Expectation for NT200+

Predicted all-flavor-sensitivity for astrophysical ‘s ‘s : E2 Ф < 2.7 · 10-7 GeV cm-2 s-1 sr-1 (3 years) ~ A-II / 4yr mu

3-4 fold improvement over NT200.

Much improved reconstruction of cascade coordinates + energy

• NT200NT200

• NT200+NT200+

Is a conservative predicition: vertex + energy reconstruction will improve sensitivity !

e

15Mton 30Mton

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Future:

A Gigaton Volume (km3) Detector at

Baikal

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NT200+ - important step towards a km3 @ Baikal

NT200+ as a subunit of a km3 scale detector.

For High Energy Cascades:A single small string replacing the NT200 central core reduces Veff less than x3 for E>100TeV. A short string instead of NT200 as a subunit for a Gton scale detector is ok !

140 m

Effective volume for simplified Effective volume for simplified NT200’s.NT200’s.

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Sparse instrumentation:

91 strings with 12/16 OM = 1308 OMs

Casacde effective volume for 100 TeV: ~ 0.5 -1.0 km³

Muon threshold between 10 and 100 TeV

Baseline schedule:

- R&D +TechDesRep 2006-08.

Funded.- Construction ≥2009.

A Gigaton (km3) Detector in Lake Baikal

Mini NT200+Mini NT200+

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- 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.; …,...

A Gigaton (km3) Detector in Lake Baikal

- Status -

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The Baikal Telescope is successfully running since >10 years.

NT200NT200 - High Sensitivity in HE-diffuse search (cascades): “Mton-detector” - Number of relevant other results: Magnetic Monopoles, WIMPs, GRB, atm.

NT200+ - Natural upgrade after diffuse NT200–success story: New 5 Mton instrumented detector commissioned in April, 2005. - Tailored to diffuse cosmic nu’s: >10Mton at 10PeV.

Diffuse sensitivity: E2 Ф < 0.9 ·10-7 GeV cm-2 s-1 sr-1 (3yr NT200+)

- Shower analysis improvement: vertex, energy + direction.

- UHE cosmic and transient sources: sensitivities under study.

Future: Gigaton Volume Detector (km3) in Baikal.

- NT200+ serves as realistic test object. Technical Proposal within 3 yrs.

Summary

see talk on physics by

Z.Djilkibaev