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
N. Budnev, Irkutsk State University.
For the Baikal Collaboration
O(km) long muon tracks
Electromagnetic & hadronic cascades
~ 5 m
CCe + Neutral Current
Charged Current (CC)
pp core AGN
p blazar jet
3 6 9
TeV PeV EeV
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
Ice as a natural deployment platform
Winches used for deployment
10-Neutrino Telescope NT200
1-4 cable lines
We look for upward going muons
At the 1km depth :
(dt = t52-t53)
Amplitude (Chan 12)
Reconstructed m’s :
cos ( )
Sky plot for upward going neutrino
April1998 - February 2003 years, 1038 days,462 events.
Threshold – 15 GeV
+ b + b
C + +
W + + W -
Detection area of NT-200 for vertically up-going muons
detection (after all cuts)
Limit on excess neutrino induced upwardmuon flux 90% c.l. limits from the Earth ( 1038 days NT200 livetime, E> 10 GeV )
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.
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)/(tz) > 0.45 & o
Background - atmospheric muons
Limit on a flux of relativistic monopoles:F < 4.6 10-17 cm-2 sec-1 sr-1
large effective volume
Look for events with
large number hit
and for upward moving
Number of Cherenkov photons
Nph = 200 (E / 2 MeV) for
E=10 Pev Nph = 1012!!!
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)
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
( 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
Flux ofne, nt, n: cascades
Experimentalimits and theoretical predictions
Astropart. Phys. 25 (2006) 140
2005 year. Upgrade to NT200+ finished
Laser intensity - cascade energy:
(1012 – 5 1013 ) g/puls- (10 – 500) PeV
Foto from Mar, 2005, 4km off-shore:
NT200+ deployment from 1m thick ice.
2005: NT200+ - intermediate stage to Gigaton Volume Detector (km3 scale)iscommissioned in Lake Baikal
Main physics goal:
Energy spectrum of all flavor
(E > 100 TeV)
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
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
Quantum efficiency 0.15
Quantum efficiency 0.20
Quantum efficiency 0.24
PM selection: Underwater tests (2007)
4 PM R8055 (Hamamatsu) и 2 XP1807 (Photonis)
were installed to NT200+ detector (April 2007).
4 PM: central telescope
2 PM R8055: outer string, FADC prototype.
Relative effective sensitivities of large area PMs
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).
Design of Prototype string
FADC unit is operating now
in Tunka EAS 1 km2detector
& Power 12 V
Acoustic noise within 22-44 kHz
frequency band at different depths
Example of bipolar pulse
Angular distribution of detected bipolar events
Energy dependence of expected acoustic
signal amplitudes from cascades
Absorption length of acoustic signal in water
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!!!!!!
The interdisciplinary environmental studies
is so kind?
Why conditions for
life are so good?
Length – 720 km,
20% of fresh water
The water body
of the lake is
Several hundred endemic species
Inhabit all depths of the lake
These is only
the high rate
Temperature depth dependence in Lake Baikal
of temperature of
Epilimnion (0-40 m)
Thermocline (2-150 m)
Hypolimnion (30m –
TMD = 3.9839 - 1.9911∙10-2 ∙ P - 5.822 ∙ 10-6 ∙ P2 - (0.2219 + 1.106 ∙ 10-4 ∙ P) ∙S
on 0.1 degree
La –absorption length
Far away from a point like light source
E(r) ~ exp(-r/Las)/r
The photon flux density I(photon cm-2 s-1) = (3.5+/- 1) N
The luminescence is a natural indicator of development of
hydrobiological and hydrophysical phenomena in the Lake Baikal.
Counting rate of the 3 optical modules of NT-200 situated
Мелозира байкальская - Aulacoseira baicalensis
y = cos(23t/11)
Welcome to Lake Baikal