Baikal Neutrino Telescope –an underwater laboratory for

astroparticle physics and environmental studies.

N. Budnev, Irkutsk State University.For the Baikal Collaboration

BAIKAL - CollaborationBAIKAL - 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.

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).

• NeutrinosNeutrinos have discovery potential because they have discovery potential because they open a new window on the Universeopen a new window on the Universe

W49B

SN 0540-69.3

Crab

E0102-72.3

Cas A

P+Nuclears

1960 - M. Markov: High Energy neutrino detection in natural transparent media (ocean water, ice):

O(km) long muon tracks

5-15 m

Charged Current (CC)

Electromagnetic & hadronic cascades

~ 5 m

CC e + Neutral Current

log(

E2

Flu

x)

log(E/GeV)TeV PeV EeV

3 6 9

pp core AGN p blazar jet

Top-Bottom GZK

GRB (W&B)

WIMPsWIMPsOscillationsOscillations

UndergroundUnderground

UnderwaterUnderwaterRadio,AcousticRadio,Acoustic

Air showersAir showers

Microquasars etc.

A

NT200+/Baikal-GVD1993-1998 (~2015)

N N

KM3NeT(~2014)

Amanda/IceCube/IceCube1996-2000 (~2011)(~2011)

ANTARES

NEMO

NESTOR

First underwater neutrino telescope NT200

The first underwater neutrino telescope NT200have been operated in Lake Baikal since 1998.

Length – 720 km, width – 30-50 km, depth -1300-1640 m20% of kind fresh water

Why Lake Baikal?

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.

Ice as a natural deployment Ice as a natural deployment platformplatform

Ice stable for 6-8 weeks/year: Ice stable for 6-8 weeks/year:

– Maintenance & upgrades Maintenance & upgrades

– Test & installation of new Test & installation of new equipmentequipment

Winches used for deploymentWinches used for deployment

The Ice Camp (4km offshore)

Schematic view on the deep underwater complex NT200

136

6 m

1.5km

44

5

11

9

12

13

3600 m

100 m 100 m

1 2 3

6 7 8 10

14

18

17

16

15

600 m

10-Neutrino Telescope NT2007-hydrophysical mooring 5-sedimentology mooring

12-geophysical mooring 13-18-acoustic transponders

1-4 cable lines

Anchor

Buoy

NANP’03NANP’03

NT200 running 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

“Quasar” photoelectric detector

G= 20-30

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

“Low” energy neutrino search strategy

Atmosphere

p

p

Earth

The neutrinotelescope

10

- 6

At the 1km depth :

We look for upward going muons

Photoelectrons

Amplitude (Chan 12)

Time difference (dt = t52-t53)

t, ns

Atmospheric muons: Calibration BeamAi, ti

atm.

Reconstructed ’s :Cos(zenith) distributionvs. Corsika

cos ( )

Sky plot for upward going neutrino

April1998 - February 2003 years, 1038 days,462 events.

Threshold – 15 GeV

23

Search for WIMP Neutrinos from the Center of the Earth

+ b + b

W + + W -

C + +

Detection area of NT-200 for vertically up-going muonsdetection (after all cuts)

WIMP Neutrinos from the Center of the Earth

Limit on excess neutrino induced upward muon flux 90% c.l. limits from the Earth ( 1038 days NT200 livetime, E > 10 GeV )

1038 days livetime NT200 (1998 -2003)48 evts - experiment73.1 evts - prediction without oscillations56.6 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.

N= n2 (g/e)2 N = 8300 N g = 137/2, n = 1.33

Event selection criteria:

hit channel multiplicity - Nhi t> 35 ch,upward-going monopole -(zi-z)(ti-t)/(tz) > 0.45 & o

Background - atmospheric muons

Limit on a flux of relativistic monopoles: < 4.6 10-17 cm-2 sec-1 sr-1

90% C.L. upper limit on the flux of fast monopole (1003 livedays)

Search for fast monopoles ( > 0.8)

27

Search for High Energy neutrino (cascades)

NT200

large effective volume

(BG)

Look for events with large number hit channels and for upward moving light fronts.

Number of Cherenkov photons

Nph = 200 (E / 2 MeV) for

E=10 Pev Nph = 1012!!!

The 90% C.L. Limits Obtained WithNT-200 (1038 days)

DIFFUSE NEUTRINO FLUX

(Ф ~ E-2, 10 TeV < E < 104 TeV)

e = 1 2 0 (AGN)

e = 1 1 1 (Earth)

Diffuse flux of e, , : cascades

W-RESONANCE ( E = 6.3 PeV, 5.3 ·10-31 cm2 )

Baikal Фe < 3.3 · 10-20 (cm2 · s · sr · GeV )-1

AMANDA Фe < 5.0 · 10-20 (cm2 · s · sr · GeV )-1

Baikal E2 Ф < 8.1 ·10-7 GeV cm-2 s-1 sr-1

AMANDA E2 Ф < 8.6 ·10-7 GeV cm-2 s-1 sr-1

Vg(NT200)

AMANDA II

Flux of e, , : cascades

Astropart. Phys. 25 (2006) 140

Toward Gigaton Water Detector(KM3 detector on lake Baikal)

2005 year. Upgrade to NT200+ finished

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

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

New ShoreCable

100 m

Foto from Mar, 2005, 4km off-shore:NT200+ deployment from 1m thick ice.

Ice – A perfect natural deployment platform

1 10 100 1000 PeV

4 15 23 40 Mton

Total number of OMs – 228 / 11 strings

Instrumented volume – 5 Mt(AMANDA II, ANTARES – 10 Mt)

Detection volume >10 Mt for E>10Pev

- high resolution of cascade vertex and energy neutrino energy

2005: NT200+ - intermediate stage to Gigaton Volume Detector (km3 scale) is commissioned in Lake Baikal

Main physics goal: Energy spectrum of all flavor extraterrestrial HE-neutrinos (E > 100 TeV)

Ultimate goal of Baikal Neutrino Project:

Gigaton (km3) Volume Detector in Lake Baikal Sparse instrumentation:

91 – 100 strings with 12 – 16 OMs (1300 – 1700 OMs) effective volume for >100 TeV cascades ~ 0.5 -1.0 km³

lgE) ~ 0.1, med< 4o

detects muons withenergy > 10 - 30TeV

624m

280m

70m

70m120m

208m

- 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 -

PM selection for the km3 prototype stringPM selection for the km3 prototype stringBasic criteria of PM selection is its effective sensitivity to Cherenkov Basic criteria of PM selection is its effective sensitivity to Cherenkov

light which depends onlight which depends onPhotocathode areaPhotocathode area Quantum efficiency Quantum efficiency Collection 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

4 PM R8055 4 PM R8055 (Hamamatsu) (Hamamatsu) и 2 и 2 XP1807 (Photonis)XP1807 (Photonis)were installed to were installed to NT200+ detector (April NT200+ detector (April 2007).2007).

4 PM: central telescope 4 PM: central telescope NT 200;NT 200;2 PM R8055: outer 2 PM R8055: outer string, FADC prototype.string, FADC prototype.

Quasar-370Quasar-370

Quasar-370Quasar-370

Quasar-370Quasar-370

Quasar-370Quasar-370

R8055R8055

XP1807XP1807

PM selection: Underwater tests PM selection: Underwater tests (2007)(2007)

LaserLaser

160…

180 m

Relative effective sensitivities of large area PMsRelative effective sensitivities of large area PMs(preliminary results)(preliminary results)

0 1 2 3 4 5 60,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

XP1807 #1026

XP1807 #1006 R8055

#186 R8055 #314

R8055 #228

Quasar-370

Rel

ativ

e P

M s

ensi

tiviti

es

PMT number

Relative effective sensitivities of large area PMs R8055/13” , XP1807/12” and Quasar-370/14.6”. Laboratory measurements (squares), in-situ tests (dots).

Smaller size (R8055, XP1807) tends to be compensated by higher photocathode sensitivities.

Design of Prototype string Design of Prototype string

PMT pulses & Power 12 VControl line

Data (Ethernet), Trigger

FA DC

P Csphere

OM4

OM6

OM5

FA DC

OM3

OM1

OM2

OM6

OM4

OM5

OM1

OM3

OM2

PC-104

RS485c onv er

ter

DSL

modem

RS485c onv er

terEth

Sw itc h

Tr iggerc ontro l

VME

Contr

FADC9

101112

FADC5678

FADC1234

Power

Trigger

Multic hannel A mplif ier&Pow er output

PMT

D iv id e r /A m p lif ie r

C O N T R O L L E R O M-M C C 8 0 5 1 F 1 2 4-R S 4 8 5 in te r fa c e-P M T p u ls e c o u n te r-P o w e r (H V , L V ) m o n ito r

H V U N ITP H V 1 2 -2 .0 K

LEDs

L E Dc o n tr o l- A m p l- D e la y

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

30

0 m

FADC unit is operating nowin Tunka EAS 1 km2 detector(astro-ph/0511229)

Baikal – GVDBaikal – GVD Schedule Milestones 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

Overall cost ~ 20 MEuro Detector ~ 16 MEuro

Logistics, including infrastructure ~ 4 MEuro

Acoustic detection of high energy neutrino

Acoustic Detection of High Energy Neutrino

Absorption of sound in water

10mPa

1mPa

Acoustic noise within 22-44 kHz frequency band at different depths Example of bipolar pulse

Listening from top to down

Absorption length of acoustic signal in water

Angular distribution of detected bipolar events

Energy dependence of expected acoustic signal amplitudes from cascades

I.Belolaptikov 54

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

The interdisciplinary environmental studies

Length – 720 km,

width – 30-50 km,

depth –1.3-1.64km

20% of fresh water

The water bodyof the lake is

fully oxygenated

Several hundred endemic speciesInhabit all depths

of the lake

B.Koty

Why water is so kind?

Why conditions for life are so good?

These is only thanks to

the high rate of deep-water renewal !!!!!

TMD = 3.9839 - 1.9911∙10-2 ∙ P - 5.822 ∙ 10-6 ∙ P2 - (0.2219 + 1.106 ∙ 10-4 ∙ P) ∙ S

Depth dependence of temperature of

maximum density

Summer profile

Temperature depth dependence in Lake Baikal

Winter profileHomothermy

Epilimnion (0-40 m)Thermocline (2-150 m)Hypolimnion (30m – bottom)

Meter

Instrumental moorings

0 30 60 90 120 150 180 210 240 270 300 330 360Days (2000-2001 from 01 M arch)

0

2

4

6

8

10

12

Tem

per

atu

re19m

25m

77m

90m

127m

182m288m

.

MuchMay

July

The temperature at the near-surface zone

September November January

30 60 90 120 150 180 210 240 270 300 330 360 390Tim e (days from 01.03.2001)

3.3

3.4

3.5

794

3.3

3.4

3.5

996

3.3

3.4

3.5

1198

3.3

3.4

3.5

1259

3.3

3.4

3.5

1309

3.3

3.4

1362

Tem

per

atu

re

June November

Cold intrusionTemperature

decreasedon 0.1 degree

The interdisciplinary environmental studies

• Water dynamic (vertical and horizontal water exchange)

• Biological productivity

• Global climate changes

• Geophysical phenomena

The instruments and methods

• Long-term optical monitoring• 3 - dimensional monitoring of the water

luminescence• 3 - dimensional temperature monitoring• long-term monitoring of geoelectric field• Acoustic tomography • Sedimentology study (in co-operation with

EAWAG, Switzerland)

The ASP-15 instrument.

• а – absorption coefficient,

• b –scattering coefficient,

• Е – photons flux ])(exp[)( 0 xbaExE

])(exp[)( 0 xbaExE

Baikal

Baikal

Optical Properties

Far away from a point like light source E(r) ~ exp(-r/Las)/r

La, m Ls, m Lef, ,m Las,m

Baikal 22 50 0.88 416 18

Antarctic ice 100 3 0.88 25 29

Mediterranean sea 55 55 0.88 458 41

La –absorption lengthLs-scattering length

The luminescence as the instrument to study the dynamic phenomena in Baikal water

• The luminescence which appear as a result of oxidization of organic material in Baikal water was discovered in 1982 year.

• The luminescence matter is produced by biology at shallow depth and then transported to deep layers by water currents, turbulence and due to sedimentation, at the same time matter loss its ability to luminescence .

• The luminescence is a natural tracer for the development of hydrophysical phenomena and an indicator of hydrobiological activity in the Lake Baikal.

Counting rate of FEU-130 versus depth at Neutrino Telescope site in ice cover period.

The photon flux density I(photon cm-2 s-1) = (3.5+/- 1) N

N

Counting rate of an optical module of NT-200 at 1993 -1994 years.

The luminescence is a natural indicator of development of hydrobiological and hydrophysical phenomena in the Lake Baikal.

Counting rate of the 19 optical modules of NT-200 in September1993 year.

10 20 30 40 50 60 70Tim e , h from 00.00 23.09.93

12000

16000

20000

Counting R

ate/

10 ,

Hz

14:36 23.09.93 - 12:51 25.09.93 RUN 1000-1011

2

2

3

1

1

Vertical water motion.• Counting rate of the 3 optical

modules of NT-200 situated• on the same vertical string

• V vert = 2 cm/s !!!!!!!!!

Counting rate of the 3 optical modules of NT-200 situated

• on the same depth on the different strings

7.5 m

Geophysical Mooring

Synthetic rope

Synthetic rope

Electronic box

1000 mCable

Electrode 2

Electrode 1

Anchor

Twisted cable

Twisted cable

Buoy

Buoy

Vertical component of electric field

days

High frequency Ez variations.

Inertial waves15 hours

Low frequency Ez variations.

27 days

Мелозира байкальская - Aulacoseira baicalensis

1950 1960 1970 1980 1990 2000 2010 2020 2030Y e a rs

0

100

200

300

A. b

aica

lens

is n

umbe

rs in

"m

elos

ira

year

s",

thou

sand

cel

ls p

er li

tre

in th

e up

per

0-25

m la

yer

0

100

20019th

20th

21st 22nd

23rd

Sol

ar a

ctiv

ityin

Wol

f's n

umbe

rsSolar activity

Productivity of Aulacoseira baicalensis y = cos(23t/11)

Welcome to Lake Baikal

Thank you!