KM3Net

10.03.2005 U. Katz: Neutrino Telescopy ... 1

KM3NetKM3Net

A Deep-Sea Research Infrastructure in the Mediterranean Sea Incorporating a

Neutrino Telescope

Why particle physics community wants a neutrino telescope

Principles behind a neutrino telescope

Current telescope

KM3NeT

Science

Data Access and distribution

Current status


Why Neutrino Telescopes?• Neutrinos traverse space without deflection or attenuation

– they point back to their sources;

– they allow for a view into dense environments;

– they allow us to investigate the universe over cosmological distances.

• Neutrinos are produced in high-energy hadronic processes→ distinction between electron and proton acceleration.

• Neutrinos could be produced in Dark Matter annihilation.

• Neutrino detection requires huge target masses→ use naturally abundant materials (water, ice).


Aiming at a km3-Detector in the Mediterranean

HENAP Report to PaNAGIC, July 2002:

• “The observation of cosmic neutrinos above 100 GeV is of great scientific importance. ...“

• “... a km3-scale detector in the Northern hemisphere should be built to complement the IceCube detector being constructed at the South Pole.”

• “The detector should be of km3-scale, the construction of which is considered technically feasible.”


Particle propagation in the Universe

Photons: absorbed on dust and radiation;Protons/nuclei: deviated by magnetic fields, reactions with radiation (CMB)

1 parsec (pc) = 3.26 light years (ly)

gammas (0.01 - 1 Mpc)

protons E>1019 eV (10 Mpc)

protons E<1019 eV

neutrinos

Cosmic accelerator


The Principle of Neutrino Telescopes

Role of the Earth: Screening against all particles

except neutrinos. Atmosphere = target for production

of secondary neutrinos.

Čerenkov light: In water: θC ≈ 43° Spectral range used: ~ 350-500nm.

Neutrino reactions (key reaction is N→ X): Cross sections and reaction mechanisms known from

acceleratorexperiments (in particular HERA).

Extrapolation to highest energies (> 100 TeV) uncertain.


The Neutrino Telescope World Map


IceCube: a km3 Detector in Antarctic Ice

South PoleDark sector

AMANDA Dome

Skiway

IceCube


AMANDAThe IceCube Project

1400 m

2400 m

IceTop

Skiway• 80 Strings;

• 4800 PMTs;

• Instrumented volume: 1 km3 (1 Gigaton)

• IceCube is designed to detect neutrinos of all flavors at energies from 107 eV (SN) to 1020 eV

10.03.2005 U. Katz: Neutrino Telescopy ... 10Locations of the sites of the three Mediterranean Neutrino Telescope projects


•String-based detector;•Underwater connectionsby deep-sea submersible;

•Downward-looking PMs,axis at 45O to vertical;

•2500 m deep.

ANTARES: Detector Design

14.5m

100 m

25 storeys,348 m

Junction Box


ANTARES: First Deep-Sea Data• Rate measurements: Strong fluctuation of bioluminescence

background observed

10min 10min

PM Rate (kHz)

time (s)

Constant baseline ratefrom 40K decays


Schematic view of the major components of the KM3NeT neutrino telescope. Note that the drawing is not to scale and that the number of components indicated is much smaller than in reality. A marine science node is also shown

Schematic concept of complementing the KM3NeT neutrino telescope with marine science instrumentation


Seafloor layouts (top) and 3-dimensionl visualisations (bottom) of example neutrino telescope configurations of the type “homogeneous”, “cluster” and “ring” (left to right). In the top panel, each red point indicates a vertical arrangement of OMs or storeys, in the bottom panel each red point represents a storey.


Suggested Sea Floor Geometry of KM3NeT at CDR

91 Towers Regular Hexagon


Earth-Sea Science

• Junction Boxes around the neutrino telescope.• Science instruments within the Neutrino telescope for

monitoring the array behaviour and calculating the accurate position of the detection units

• Initial instrumentation around the array consisting of mission proved and comercially available sensors and components.


1000m

Safety Radius

Max 10 km

Each ESSJB can be located independentlywithin 10km of the centre.Each requires a 500 m radius (minImum)“flat” area around it.

Telescope site 2km diameter

SUGGESTED SEA FLOOR GEOMETRYDISTRIBUTED CIRCLES CASE


Criteria for selecting Earth-Sea Science node placement

Outside the anticipated area of the Neutrino telescope expansion

Monitoring a transect perpendicular to the continental margin line

Monitoring of residual particle fluxes from canyons

Current monitoring near the sea floor or within the water column

Artificial reef effect of the telescope infrastructure on the benthic life

Activities of marine mammals with respect to the infrastructure

Position of backbone cables (interference between cables and instrumentation)

Interference between experiments and their respective instrumentation set

Maintenance activity (ROV manoeuvrability and support vessel drift due to currents)

Future expansion over a twenty year span of the Earth-Sea science activities


Earth-Sea Science

Instruments within the telescope

1.Use Data from PMTs for Bioluminescence

2. Use data from acoustics

3. Study positions of the PMTs to interpret flow.

4. Utilise “house keeping” environmental instrumentation. E.g current meters

Add additional earth sea science sensors within the array

e.g. high speed, high precision thermistors


NIOZ3: Custom-made sensitive temperature sensor to study internal waves and large

turbulence scales

Specifications:• Accuracy <0.001 °C• Response time 0.25 s• Autonomy 1.5 years at 1 Hz sampling

• Sensors are independent :-> any number (100 or more)-> at any position on moorings-> no connecting cables

• Every clock is synchronized inductively-> sensors stay synchronized at < 1 s

• Broadcast programming with LED-code indicators -> no need to open the sensors


1. Eth 1000LX (fiber) – 400VDC – NTP/PTPApplications: •Daisy chain for another JB, •high power equipment: •robotics, vertical profiler… •network extension up to 20km

Daisy chain

Extension to 20 km

2. Eth 100BT (copper) – 48VDC –NTP/PTP + PPS/NMEAEthernet scientific instruments, •Seismometer (OBS), •still camera , •video, •hydrophone, •crawler…

<1km

<1km

3. RS232/422/485 – 48VDC – PPS/NMEASerial scientific instruments •ADCP, •piezometer (pore pressure sensor) , •seismometer, •CTD, •chemical analyzer,…

4. VDSL2 Modem – 400VDC – NTP/PTPNetwork extension, •measurements in water column, •instrument or instrument cluster up to 5-6km •(low cost extension (vs. fiber), •seismic network, •acoustic network

Up to 5-6km


Earth-Sea Science dataflow

Neutrino Telescope Science & calibration data

Particle Physics data centre

?


Users and stakeholders of the KM3NeT marine science node(s)


ANTARES: Detector Design

14.5m

100 m

25 storeys,348 m

Junction Box

• String-based detector;

• Underwater connectionsby deep-sea submersible;

• Downward-looking PMs,axis at 45O to vertical;

• 2500 m deep.

KM3Net

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