Moscow, 18.10.2005Moscow, 18.10.2005

V. Aynutdinov, INR RASV. Aynutdinov, INR RASfor Baikal collaborationfor Baikal collaboration

The Baikal neutrino telescope:The Baikal neutrino telescope: Physics results and future plansPhysics results and future plans

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.

CollaborationCollaboration

BAIKAL in BAIKAL in CernCourier 7/8-CernCourier 7/8-20052005

A

Amanda/IceCube

Baikal

N NNeutrino telescope NT200 (1998) Design Physics Results (selected) : NT200 upgrade -> NT200+ (2005) New Design Calibration (new laser)Perspectives: Gton scale detector (GVD) at Baikal NT200+ as a basic cell of future Gton detectorSummary Motivation Present telescope configuration is perfect test facility for future Gton detector

Outline:

Shore station

4000 m

1366 m

The SiteThe Site

1070 m depthAbsorption length: 20-30 mScattering length: 30-70 mIce as a natural deployment platform

51 d 45’’ 59’ N51 d 45’’ 59’ N104 d 25’ 09’’ E104 d 25’ 09’’ E

Ice as a natural deployment platform

• Ice stable for 6-8 weeks/year: – Maintenance & upgrades – Test & installation of new equipment

BaikalBaikal

Abs. Length: 22 ± 2 m Scatt. Length (geom) ~ 30-50 m cos ~ 0.85-0.9

Baikal - Optical Properties

Open configuration of the Telescope and good water parameters of Baikal waterOpen configuration of the Telescope and good water parameters of Baikal water allow to observe big water volume much more than geometrical boundariesallow to observe big water volume much more than geometrical boundaries

Example of interaction between ANTARES,NEMO Baikal

Verification of Lake Baikal Attenuation / Absorb. / Scatt. results

Cross-Calibration: AC9 (Antares/Nemo) vs. Burhan ASP15

Baikal-NEMO Campaign March, 2001

see: NIM A498 (2003)

1998: NT200192 OM at 8 strings 1 Mton at 1 PeV

1996 NT96 96 OM at 4strings

2005: NT200+228 OM at 8 + 3 strings 10 Mton at 10 PeV

Project Milestones1991 Project NT200 approved 1993 NT36

36 OM at 3 strings The first underwater array operatesFirst ’s and ’s in Neutrino Telescope

-8 strings: 72m height - 192 optical modules 96 measuring channels T, Q measure *Timing ~ 1 nsec *Dyn. Range ~ 1000 pe

Effective area: 1 TeV ~2000 m² Eff. shower volume: 10TeV ~0.2Mt

Quasar PMT: d = 37cmHeight x = 70m x 40m, Vgeo=105m3=

0.1Mton

Selected ResultsNT200

Low energy phenomena (muons) - Atmospheric neutrinos - WIMP neutrinos High energy phenomena (cascades) - DDiffuse neutrino fluxiffuse neutrino flux - Neutrinos from GRB - Prompt muons and neutrinos - Exotic HE muons Search for exotic particles - Magnetic monopoles

Atmospheric Neutrinos

372 Neutrinos in 1038 Days (1998-2003)

Skyplot (equatorial coordinates) Skyplot (equatorial coordinates) of neutrino eventsof neutrino events

EETHRTHR 15-20 GeV 15-20 GeV Important calibration tool

WIMP Search

+ b + b

C + +

Search of nearly vertically upwardSearch of nearly vertically upwardgoing muons , exceeding the flux of going muons , exceeding the flux of

atmospheric neutrinosatmospheric neutrinos

Limits on the excess muon flux from theLimits on the excess muon flux from the centre of the Earth as a function of WIMP masscentre of the Earth as a function of WIMP mass

Angular distribution of selected neutrinoAngular distribution of selected neutrinocandidates as well as background expectation candidates as well as background expectation

Physics topics:- HE cascades from e - NC/CC

* Diffuse astroph.flux * GRB correlated flux

- HE atmospheric muons * Prompt * Exotic

NT-200 is used to watch the volume below for cascades.

(„BG“)

NT-200

large effective volume

Search for High Energy CascadesLook for upward moving light fronts.

Signal: isolated cascades from neutrino interactions

Background :Bremsshowers fromh.e. downward muons

Final rejection of backgroundby „energy cut“ (Nhit)

tmin > -10nsNhit > 15 ch.

Hit channel multiplicity(experiment and background

expectation)

Diffuse Neutrino Flux

atm

2.5

1.5

2

Shape of signal in Nhit distribution for = A E- (=1.5, 2.0, 2.5).

NT200 (1038 days)

DIFFUSE NEUTRINO FLUX(Ф ~ E-2, 10 TeV < E < 104 TeV)e(AGN)e(Earth)Ф(e))

<8.1 ·10-7 GeV cm-2 s-1 sr-1

W-RESONANCE ( e )( E = 6.3 PeV, 5.3 ·10-31 cm2 )Фe < 3.3 · 10-20 (cm2 · s · sr · GeV )-1

~

Experimental limits + bounds/ predictions

Models already ruled out by the experimentsSS - Stecker, Salamon96 (Quasar)SeSi - Semikoz, Sigl (Models/Expts. are rescaled for 3 flavours)

Diffuse Flux Limits + Models

New configuration NT200+

140 m

100m

36 additional PMTs on 3 far ‘strings‘ 4 times better sensitivity Improve cascade reconstruction

Vgeom ~ 4 ·106 m3

Eff. shower volume: 104TeV ~ 10 MtonExpected -sensitivity (3 yrs NT200+) : E2 ФV < 0.9 · 10-7 GeV cm-2 s-1 sr-1

NT200+ as test facility for Gton scale detector1. Optical module 2. Calibration system3. New electronics 4. Data acquisition system5. Time synchronization 6. Cable communications

NT200+ commisioned April 2005 1. 3 outer strings were instaled1. 3 outer strings were instaled

2. New DAQ – final 2. New DAQ – final modernization modernization

-- 2 Underwater PC with Flex 2 Underwater PC with Flex DSL modem (1 Mbod),DSL modem (1 Mbod),

Underwater Ethernet Underwater Ethernet -- Synchronization system Synchronization system ** time synchronization time synchronization NT200 <-> outer NT200 <-> outer

stringsstrings ** event clusterisation event clusterisation

3. New Software 3. New Software DOS DOS --> Linux, Remote > Linux, Remote

controlcontrol

4. New 2 cables to shore (2x4 4. New 2 cables to shore (2x4 km)km)

5. Calibration - New bright 5. Calibration - New bright LaserLaser

Shore Center

M odem line

D E M D E MC E M

S C M CON TROL

Trig NT200

String trigger

Un derw ater PC

S tr# 7S tr# 2 S tr# 8

S tr# 3 S tr# 4

N T -200

S tr# 1

S tr# 2

N T +

ControlNT+

ControlNT200

TDC

Sto

p

Tri g

Re q

, Da t

a

S tr# 6S tr# 1

S tr# 5

S C M

S tr# 3

Ethernet

CONTROL

TrigReqString time

Data NT200Data NT+

Trig

NT+

Dat

a

TDC Stop

DAQ and control system of NT200+

Two subsystems: NT200 and NT+

Two-level time measurement and dataacquisition systems:

Low level: - Strings: PMT time and amplitude measurements; - DEM: trigger and event clusterisation systems - SEM: slow control

DAQ Center

- 2 underwater PC connected to shore; - CEM: trigger time measurement

PC104: Advantech-PCM9340

DSL-M: DSL-modem FlexDSL-PAM-SAN with hub and router, 2 Mbit/s.

SwRSTP: a managed Ethernet switch RS2-4R

CSrv: WUT-58211, for PC-terminal emulation

Mc: two media-converters for coaxial connection

D-Mod, C-Mod: experiment data and control modems

Underwater PCs

New Laser 100m

100m

X2X1

X3

100m

Laser is visible >200m with high Ampl. (NT and ext.strings)

Laser intensity : cascade energy:(1012 – 5 1013 ) : (10 – 500) PeV

RMS of arrival time distribution: ~ 2 ns

tt11

tt22

tt1212

5 series of Laser pulses5 series of Laser pulses

NT200+ time resolutionNT200+ time resolutiont = 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 string. Red line is result of calculations

Reconstructed vs. simulated Reconstructed vs. simulated coordinatescoordinates

of cascades in NT200+ (blue) andof cascades in NT200+ (blue) and NT200 (red)NT200 (red)

NT200+ efficiency of cascade reconstructionLaser coordinates reconstruction

NT200

NT200+

3 extern. str.

r < 1 m

NT200+ as a subunit of a Gton scale detector

For High Energy Cascades:A single string replacing theNT200 central core reduces Veff less than x3 for E>100TeV.

12 OMs strings as a subunit for a Gton scale detector = ok.

Effective volume withEffective volume with

A future Gigaton (km3) Detector in Lake Baikal.

Sparse instrumentation:

91 strings with 12/16 OM = 1308 OMs (NT200 = 192 OMs)

effective volume for 100 TeV cascades ~ 0.5 -1.0 km³

muon threshold between 10 and 100 TeV

Gton detector at Baikal lakeGton detector at Baikal lake

1. Optical module: PMT selection 2. Detector configuration: PMT location, string

configuration, distances, …

3. Electronics: flash ADC, trigger conditions, …

4. Communications: optical cables, connectors, …

5. Data acquisition system, time synchronization

R&D on the basis of NT-200+ configurationR&D on the basis of NT-200+ configuration

CONCLUSIONCONCLUSION1. BAIKAL1. BAIKAL lake experiment lake experiment running since 12 years - Diffuse Neutrino flux limit - Limit on an excess flux due to WIMP annihilation in the Earth - Limit on the flux of fast magnetic monopoles

2. NEW configuration NT200+ start of operation April 2005 - NT200+ is tailored for diffuse cosmic neutrinos Veff ~ 10 Mton at 10PeV Expected -sensitivity (3 yrs NT200+) : E2 Фv < 10-7 GeV cm-2 s-1 sr-1

- NT200+ gives good possibilities to optimise the structure and to investigate the basic elements of future Gton scale detector

3. 3. R&D Gigaton Volume Detector (km3) at Baikal lake was started

Relativistic magnetic Monopole

Cherenkov-Light n2·(g/e)2

n = 1.33

(g/e) = 137/ 2

8300

Flu

x up

per l

imit

(cm

-2 s

-1 s

r-1)

8

1

2 4

7

3

3 +

2 +1 +

Ru n #42 (com _ev #1270)NT-200 22 сhanNT+ 7 chan

6

5

8

15

2 4

6 7

3

3 +

2 +1 +

Run #3(com _ev #1395)NT-200 9 сhanNT+ 6 chan

NT200+ Start of operation April 2005 13 Apr - 23 May 2005 - Exposition time: 640 hours - Events number : 7.6 104

- More than 1 outer string: 20 events

Examples of events

8

1

2 4

7

3

3 +

2 +1 +

Ru n #42 (com _ev #1270)NT-200 22 сhanNT+ 7 chan

6

5

8

15

2 4

6 7

3

3 +

2 +1 +

Run #3(com _ev #1395)NT-200 9 сhanNT+ 6 chan

NT200+ Start of operation April 2005 13 Apr - 23 May 2005 - Exposition time: 640 hours - Events number : 7.6 104

- More than 1 outer string: 20 events

Examples of events

New Laser: Design• Isotropizer: - Glass bulb filled with “MicroGlassSpheres” (S32 from 3M; 20-70um dia.) mixed with OpticalGel A “LaserBall” similar to the SNO calibration device. - Total loss is low: 12% - 25% only !

calibrated with “Ulbricht Sphere” (1.5m diam.)

• Absolute Laser–Calibration (with commercial Laser-PowerMeter) to optimize yield also at the lake (monitor laser vs. years)

• Expect >10^12 photons/pulse