Neutrino Telescopes in
the Mediterranean Sea
TeV Particle Astrophysics, SLAC,
July 2009
Juan de Dios Zornoza (IFIC - Valencia)
Neutrino Astronomy
Photon and proton mean free range path
• Advantages w.r.t. other
messengers:
– Photons: interact with CMB and matter
– Protons: interact with CMB and are
deflected by magnetic fields
– Neutrons: are not stable
• Drawback: large detectors (~GTon)
are needed.

n
p

Production Mechanism
• Neutrinos are expected to be
produced in the interaction of high
energy nucleons with matter or
radiation:
N  X    ( K  ...)  Y      (  )  Y
Cosmic rays

e  e ( e )   (  )
• Moreover, gammas are also produced
in this scenario:
N  X  0 Y    Y
Gamma ray astronomy
Scientific scopes


Detector size
Origin of cosmic rays
Hadronic vs. leptonic signatures
Supernovae
Limitation at high
energies:
Fast decreasing
fluxes E-2, E-3
Oscillations
Limitation at low
energies:
-Short muon range
-Low light yield
-40K (in water)
MeV
Dark matter (neutralinos)
Astrophysical neutrinos
GZK, Topological Defects
GeV
TeV
PeV
Detector density
Other physics: monopoles, etc...
EeV
Galactic sources
• Supernova remnants
– Different scenarios: plerions (center filled SNRs), shell-type SNRs, SNRs
with energetic pulsars…
– ~10 ev/km2 for Vela Junior or RXJ1713.7-3946
• Micro-quasars
– a compact object (BH or NS) accreting matter from a companion star.
Neutrino beams could be produced in the MQ jets
– ~1 neutrino per year could be detected by cubic kilometer detectors
• Magnetars
– Isolated neutron stars with surface dipole magnetic fields ~1015 G, much
larger than ordinary pulsars
– Seismic activity in the surface could induce particle acceleration in the
magnetosphere
• Galactic plane
– MILAGRO reported extended multi-TeV gamma emission in a extended
region, correlated with gas density  spectrum of CR harder than local
– Diffuse flux from the Galactic plane: 4-9 events/km3/year
Extra-galactic sources
• Active galactic nuclei
•
•
•
•
It includes Seyferts, quasars, radio galaxies and blazars
Standard model: a super-massive (106-108 Mo) black hole towards which
large amounts of matter are accreted
Detectable neutrino rates (~1 ev/year/km2) could be produced
Time-variable emission would enhance chances of detection
• Gamma-ray bursters
•
•
GRBs are brief explosions of  rays (often + X-ray, optical and radio) In the
fireball model, matter moving at relativistic velocities collides with the
surrounding material. The progenitor could be a collapsing super-massive
star.
Neutrinos could be produced in several stages: precursor (TeV), mainburst (100 TeV-10 PeV), after-glow (EeV). The time information makes
detection almost background free.
• Starbust galaxies
•
•
•
Starbust galaxies: regions with abnormaly high rate of star formation
Supernova explosions could inject relativistic protons and electrons
Expected rate: ~10 ev/km3/year
Neutrino Telescopes

Several projects are working/planned, both in ice and ocean and
lakes.
ANTARES
NESTOR
NEMO
KM3NeT
Baikal
AMANDA
IceCube
Juande Zornoza (UW-Madison - IFIC)
Detection principle

The neutrino is detected by
the Cherenkov light emitted
by the muon produced in the
CC interaction.


W
N

1.2 TeV muon traversing ANTARES
X

Physical Background
•There are two kinds of background:
-Muons produced by cosmic rays in the
atmosphere (→ detector deep in the sea
and selection of up-going events).
-Atmospheric neutrinos (cut in the energy).
p

p
 e     e
n    ( K  ...)     
 e     e


p    ( K  ...)     
Ice vs. Sea
• Very large volumes of medium transparent to Cherenkov light are
needed:
– Ocean, lakes…
– Antarctic ice
• Advantages of oceans:
–
–
–
–
Larger scattering length  better angular resolution
Weaker depth-dependence of optical parameters
Possibility of recovery
Changeable detector geometry
• Advantages of ice:
–
–
–
–
Larger absorption length
No bioluminescence, no 40K background, no biofouling
Easier deployment
Lower risk of point-failure
• Anyway, a detector in the Northern Hemisphere in necessary for
complete sky coverage (Galactic Center!), and it is only feasible in the
ocean.
Region of sky observable by
Neutrino Telescopes
AMANDA/IceCube (South Pole)
ANTARES (43° North)
Mkn 421
Mkn 501
Mkn 501
CRAB
SS433
RX J1713.7-39
SS433
V. Bertin - CPPM ARENA'08 @ Roma
GX339-4
Galactic
Centre
CRAB
VELA
ANTARES
The ANTARES Collaboration
NIKHEF, Amsterdam
 KVI Groningen
 NIOZ Texel



ITEP,Moscow
University of Erlangen

IFIC, Valencia
 UPV, Valencia

CPPM, Marseille
 DSM/IRFU/CEA, Saclay
 APC Paris
 IPHC (IReS), Strasbourg
 Univ. de H.-A., Mulhouse
 IFREMER, Toulon/Brest
 C.O.M. Marseille
 LAM, Marseille
 GeoAzur Villefranche

University/INFN of Bari
 University/INFN of Bologna
 University/INFN of Catania
 LNS – Catania
 University/INFN of Pisa
 University/INFN of Rome
 University/INFN of Genova

ISS, Bucarest
Location
•The detector will be located in the
Mediterranean Sea (42º50’N,
6º10’E) at 2500 m depth, off the
coast of Toulon (France).
•This location benefits from
IFREMER infrastructures.
Shore station (La Seyne sur Mer)
Submarine Cable
2500 m
• The ANTARES detector will observe 3.5 sr
(0.6 sr overlap with AMANDA/IceCube).
• The Galactic Centre is observable 67% of the
day.
The ANTARES detector
• 12 lines (900 PMTs)
• 25 storeys / line
• 3 PMT / storey
Buoy
Storey
14.5 m
Horizontal layout
350 m
Detector completed in May 2008
100 m
Junction
box
Electrooptical
cable
~60-75 m
Readout cables
Detector elements
The Optical Module contains
a 10” PMT and its electronics
The Optical
Beacons allows
timing calibration
and water
properties
measurements
The Local Control
Module contains
electronics for
signal processing
It receives power from shore
station and distributes it to the
lines. Data and control signals
are also transmitted via the JB.
It provides power
and data link
between the
shore station and
the detector
(40 km long)
Milestones
2001 – 2003:
 Main Electro-optical cable in 2001
 Junction Box in 2002
 Prototype Sector Line (PSL) &
Mini Instrumentation Line (MIL) in 2003
2005 – 2006:
 Mini Instrumentation Line with OMs (MILOM) running since April 2005
 Line 1 running since March 2006,
first complete detector line
 Line 2 running since September 2006
First Physics
analysis started with
first line
2007 – 2008:
 Line 3-5 running since Jan 2007
 Line 6-10+IL07 since Dec 2007
 Line 11-12 since May 2008
2008+: Physics with full detector !
Deployment
Connection
Nautile
(manned)
Victor
(ROV)
Pictures from
the seabed
Detector layout
Days in the sea (22/6/09)
12
11
10
9
8
7
6
5
4
3
2
1
256
270
Days connected
Days deployed
358
390
532
550
531
665
• A problem with the electro532
684
optical-cable
prevented
532
778
operation during
July and
532August 2008.
798
•The cable has
843been repaired
857
and the detector
data taking
843
had continued 864
smoothly
845
904
973
1029
1176
1192
Time calibration with LED
beacons
•Four LED beacons/line
(with 36 blue LEDs
each) allow to illuminate
the neighbouring OMs
•Good technical
performance (45/47 are
working)
•Additional output: water
optical parameter
measurement
•Residual time offset grows
with distance (early photon
+ walk effect) according to a
straight  offsets measured
in the dark room before
deployment can be
corrected
•Checked with independent
K40 tests
σ = 0.4 ns
Electronics
contribution
less than 0.5 ns
Lines 1-10
DR - OB offset difference
RMS 0.7 ns
Only 15%
are larger
than 1 ns
Positioning
 Acoustic system:
 One emitter-receiver at
the bottom of each line
 Five receivers along
each line
 Four autonomous
transponders on
pyramidal basis
 Additional devices
provide independent
sound velocity
measurements
Measure every 2 min
-Distance line bases
to 5 storeys/line and
transpoders
-Headings and tilts
Optical background
Optical background has two components:
• base line: potassium-40 and bioluminescence
• bursts: living organisms.
MILOM
& L1
L1 & L2
MILOM
out
MILOM
Only
2005
2006
Ant. 5L
Ant. 10L
& IL07
Full Antares
Cable Fault
2007
2008
2009
• Some years (2006, 2009), high rates of bioluminescence in spring, maybe
correlated to particularly cold winters.
Neutrino sky-map (pointsource search with 5 lines)
Point-like searches with 5 lines
• No excess found, neither in the
search within the list of candidates
nor in the all-sky search:
– Significance of fluctuations:
• 1.6 (list of sources)
• 1.0  (all sky)
• First limits have been set and are
competitive with previous multi-year
experiments (with only less than half
of the detector and 140 of live time!)
• Blindinig policy has been followed.
• Paper with these results almost
ready for submission.
Flux upper limits
(as E-2 d/dE  90 x 10-10 TeV cm-2 s-1)
NESTOR
NESTOR: Site
• Large depths (4100 m)
relatively close to shore (15
km).
• Good attenuation length: 55 m
• Extremely low rate of
sedimentation and bio-fouling
which allows up-going OMs.
• Low 40K background: 50 Hz
• Low bio-luminescence: 1% of
dead time)
broad plateau: 8x9 km2
NESTOR: layout
• Array of towers (360 m high)
• 144 PMT/tower
• 12 floors/tower in the form of 6pointed stars.
• Two PMTs in each arm: one
looking up and the other down.
• Electronics container in the center
of each floor
• Effective area (one tower): 20,000
m2
• Test floor deployed in 2003.
• Deployment of 4 floors planned in
2009
diameter: 32 m
Delta-Berenike platform
 A dedicated deployment platform
 In the final stage of construction
 Can be important asset for
KM3NeT deployment
NESTOR: data from test line
• Data from the first floor have been used to reconstruct atmospheric
muons
• Results agree with the MC prediction
• Trigger rates also agree with simulation
1/N dN/d(cos)
45800 4-fold events
zenith angle (deg)
Trigger rate: data (red point), MC atm. muons+ 40K
(solid line) and MC atm. muons (dashed line)
NEMO
NEMO: Deployment
schedule
test line
5184 PMTs
81 towers
16 floors/tower
Mini-Tower
Tower
TS S
Frame
Electro-optical cable
Junction Box
Junction box
Deployed
in Jan 05
Installed
in Dec 06
Installed
in Dec 06
Juande Zornoza (UW-Madison - IFIC)
4 floors
16 OMs
NEMO Phase-1
NEMO Phase-1 has been a technological demonstrator installed at 2000 m depth.
Data taking from December 2006 to May 2007 (Stop due to buoyancy failure).
NEMO mini-tower
(4 floors, 16 OM)
25 km E offshore
Catania
2000 m depth
e.o. connection
e.o. cable
from shore
TSS Frame
Buoy
Vertical muon flux measured
31000 muon tracks reconstructed
Live time 185 h
NEMO Phase-1 data
Bugaev et al (1998)
Junction Box
The Capo Passero Site
Results from about 10 years of site seeking and monitoring activities
demonstrate that Capo Passero Site is very well suited for the installation of
the telescope.
• Depths of more than 3500 m are reached at about 100 km distance from the shore
• Very good water optical properties (La ≈ 70 m @  = 440 nm)
• Optical background from bioluminescence is extremely low (40 kHz on 10’’ PMT, 0.3 s.p.e.)
• Deep sea water currents are low and stable (3 cm/s avg., 10 cm/s peak)
• Wide abyssal plain, far from the shelf break, allows for possible reconfigurations of the
detector layout
The site selected for the
km3 detector lies on a flat
and wide plateau
CP Site
Infrastructure for the km3 in Capo Passero
-
100 km electro-optical cable (60kW, 20 fibres) deployed
DC/DC power converter built by Alcatel tested and working; installation in July 2009
On-shore laboratory (1000 m2) completed
ROV and Deep Sea Shuttle (PEGASO) for 4000m depth acquired and under test
Optical fibre link from Capo Passero harbour to LNS-INFN foreseen by INFN
Full tower mechanical demonstrator ready: deployment in July 2009
Full tower mechanical demonstrator
Alcatel shore power supply
Alcatel DC/DC converter
Shore Laboratory in Capo Passero Harbour
Cougar ROV (PEGASO)
KM3NeT
KM3NeT
• KM3NeT us the project of joint effort for the construction
of a cubic kilometer neutrino detector in the
Mediterranean Sea.
• The first step is R&D phase, in which the experience of
present projects will be an important input.
• The expansion from 0.1 km2 to 1 km3 is not straightforward.
• Parallel contributions to marine biology, geophysics,
oceanography, etc. will be important.
• 30+ Particle/Astroparticle institutes + 7 Sea
science/technology institutes (10 European countries)
KM3 R&D
Self-unfolding
structures
for massive
deployment
… + studies on data
transmission, power distribution,
time calibration and positioning,
marine operations,
KM3 R&D
Several photo-sensors and optical
module arrangements studied.
Performance in terms of effective
area and resolution for different
configurations have been studied
 triangle-like
 beam-like
KM3NeT project timeline
NOW
funded by the 6th Framework
Programme
funded by the 7th Framework
Programme
Conclusions
• Neutrino astronomy will be a powerful tool for Astrophysics and
Particle Physics
• ANTARES has already been completed and is taking data for more
than one year. The collaboration has shown good response capability
for solving the different technical difficulties arisen during the process.
• First analysis have already started (search for point-like sources,
muon flux intensity …)
• The expected sensitivity for point-like sources of ANTARES for 365
days is comparable to the limits set by AMANDA in 1001 days (20002004)
• The technical success of ANTARES paves the way for the cubic
kilometer detector in the Mediterranean Sea: KM3NeT.
• The project for construction of KM3NeT is quite mature after years of
R&D (CDR in 2008, TDR in Oct. 2009) and the support of several
panels (ESFRI List, ESFRI Roadmap, Design Study in the FP6,
ASPERA list, Preparatory Phase in FP7, ASTRONET Roadmap…)
Neutrino candidate with the ANTARES detector
Flux (m2 sr s GeV)-1
Cosmic Rays

Cosmic Ray Flux
Cosmic rays follow a
broken power-law:
(1 particle per m2 - second)
SNRs
dN
 E 
dE
Knee
(1 particle per m2- year)

Pulsars?
Ankle
(1 particle per km2-year)
  2.7

  3.0
  2.7

the knee
the ankle
Beyond ~5×1019 eV, the
flux should vanish due to
the interaction of protons
with the CMB (GZK limit).
AGNs?
High energy neutrinos
could give information
about the origin of cosmic
Juande
Zornoza (UW-Madison
Energy
(eV)
rays. - IFIC)

High Energy Photons

The observation of TeV photons can be explained by
-leptonic processes (inverse Compton, bremsstrahlung) or
-the decay of neutral pions produced in hadronic interactions (neutrino
production).
Juande Zornoza (UW-Madison - IFIC)
acceleration in AGNs
RXJ1713-3946
•
Data from HESS indicate that the emission of the shell-type supernova remnant
RXJ1713-3946 seem to favor hadronic origin:
– Increase of the flux in the directions of the molecular clouds
– Unnaturally low B fields have to be assumed to avoid too high synchroton radiation B ≤ 10
μG, even interestellar fields are higher and shocks are expected to amplify fields;
measurments in other SNRs indicate B ~ 100 μG)
• Spectrum up to several tens of TeV. If gammas come from π0, then protons
are accelerated at E > several hundreds of TeV.
• Two other cases (RX J0852.0-4622 and RCW86, acceleration still unclear)
HESS image of RXJ1713-3946
synchrotron
inverse Compton
bremsstrahlung
0 decay
Juande Zornoza (UW-Madison - IFIC)
Other Signatures


Cascades are an important
alternative signature: detection
of electron and tau neutrinos.
Also neutral interaction
contribute (only hadronic
cascade)
•
•
•
•
track
cascade
Clear signature of oscillations.
ANTARES & AMANDA are too
small to detect double bang
signature (they are too rare)
However, cubic-kilometer
telescopes could detect them.
Maximum sensitivity at 1-10 PeV
double bang


1 km at 300 GeV
5-10 m long
25 km at 1 PeV
diameter ~ 10 cm
Juande Zornoza (UW-Madison - IFIC)
Ultra High Energy Neutrinos
• Protons interact with cosmic microwave background, which limits its
range at high energies (GZK cut-off): + CMB  n + +
p
1
p 
 10 Mpc @ E p  5  1019 eV
nCMB   p CMB

The GZK cut-off also leads to a measurable to neutrinos
      e    e  
~1 neutrino (E > 2x1018 eV) per km3 year
Positioning results
Comparison among storeys
Larger displacements
for upper top floor
Comparison among lines
Coherent movement
for all the lines of the
detector
Expected Performance (full detector)
Neutrino effective area
Angular resolution
Ndet=Aeff × Time × Flux
•For E<10 PeV, Aeff grows with energy •For E < 10 TeV, the angular resolution is
due to the increase of the interaction dominated by the - angle.
cross section and the muon range.
•For E > 10 TeV, the resolution is limited
•For E>10 PeV the Earth becomes
by track reconstruction errors.
opaque to neutrinos.
The first 1000
neutrinos of
ANTARES
Neutrino sky-map
•
2007+2008 data (blinded): more than 1000 neutrino candidates
(multi-) Muon Event
Example of a
reconstructed downgoing muon, detected
in all 12 detector
lines:
height
time
5-line
data
5-line data
140 active days
Reconstruction strategy #1
Reconstruction strategy #2
Detector elements
The Optical Module contains
a 10” PMT and its electronics
The Optical
Beacons allows
timing calibration
and water
properties
measurements
The Local Control
Module contains
electronics for
signal processing
It receives power from shore
station and distributes it to the
lines. Data and control signals
are also transmitted via the JB.
It provides power
and data link
between the
shore station and
the detector
(40 km long)
Detector footprint
• Detector as seen by atmospheric muons: position of the first
triggering hit
Search for point-like
sources
Two
algorithms
Expectation
Maximization
(unbinned)
Cone search
(binned) as a
cross-check
Two
search
strategies
List of
candidate
sources
All sky
Neutrino detection
techniques
• Optical Cherenkov:
– In Ice: AMANDA, IceCube
– In water: Baikal, ANTARES, NEMO, Nestor, KM3NeT
• Atmospheric showers:
– On earth: Auger
– In space: EUSO, OWL
• Radio:
– On earth: RICE, GLUE, SalSA, CODALEMA, ARIANNA
– In space: ANITA, FORTE
• Acoustic:
– Saund, SADCO, ANTARES R&D, IceCube, AUTEC, AGAM
Neutrino candidate
Example of a reconstructed upgoing muon (i.e. a neutrino
candidate) detected in 6/12
detector lines:
height
time