e. mignecoerice, iscra 2-13 june 2004 future cubic kilometer arrays erice iscra school 2004 emilio...

E. Migneco Erice, ISCRA 2-13 June 2004

Future cubic kilometer arrays

Erice ISCRA School 2004

Emilio Migneco


Topics

Future cubic kilometer arrays for HE neutrino astronomy

Review of existing detectors and projectsFuture detectors:

impact of site parametersarchitecturesimulations and expected performancesexperimental challenges

Future cubic kilometer arrays for HE neutrino astronomy

Review of existing detectors and projectsFuture detectors:

impact of site parametersarchitecturesimulations and expected performancesexperimental challenges


The observation of TeV neutrino fluxes requires km2 scale detectors

neutrino

muon

Cherenkov light

~5000 PMT

Connection to the shore

neutrino

atmospheric muon

depth>3000m


Neutrino telescopes brief history

80’s: DUMAND R&D

90’s: BAIKAL, AMANDA, NESTOR

2k’s: ANTARES, NEMO R&D

2010: ICECUBE

Mediterranean KM3 ?

AMANDAICECUBE

Mediterraneankm3

BAIKAL

DUMAND

Pylos

La Seyne

Capo Passero


The present of HE neutrino detectors

Two experiments have recorded HE neutrino events and are

currently taking data:

BAIKAL in Sibiria

AMANDA in South Pole

Two experiments have recorded HE neutrino events and are

currently taking data:

BAIKAL in Sibiria

AMANDA in South Pole


The pioneer experiment: BAIKAL

Baikal-NT: 192 OM arranged in 8 strings, 72 m height

effective area >2000 m2 (E>1 TeV)

3600 m

1366

m

successfully running since 10 yearsatmospheric neutrino flux measured

Depth max 1300m

Blue light absorption length ~20 m

No 40K but high bioluminescence rate


The largest detector up to date: AMANDA

Optical Module

AMANDA-II19 strings677 OMsDepth 1500-2000m

Effective Area 104 m2 (E TeV)

Angular resolution 2° See Silvestri’s talks


The future of underice neutrino telescope: ICECUBE

The technology for underice detectors is well established.

The next step is the construction of the km3 detector ICECUBE.

The technology for underice detectors is well established.

The next step is the construction of the km3 detector ICECUBE.


80 strings (60 PMT each)

4800 10” PMT (only downward looking)

125 m inter string distance

16 m spacing along a string

Instrumented volume: 1 km3 (1 Gton)

ICECUBE

IceCube will be able to identify

tracks from for E > 1011 eV

cascades from e for E > 1013 eV

for E > 1015 eV

IceCube Funding, by Phase

$0$10$20$30$40

$50$60$70

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

$M Concept/Development Implementation Operations & Maintenance

The enhanced hot water drill

5 MW


ICECUBE vs. AMANDA

Eµ= 10 TeVEµ= 6 PeV

Measure energy by counting the number of fired PMT.

(This is a very simple but robust method)

AMANDA

Halzen

Expected energy resolution 0.3 in log(E)


Expected ICECUBE perfomances

cos

Aef

f /

km2

Effective area vs. zenith angle (downgoing muons rejected)

above 1 TeVresolution ~ 0.6 - 0.8° for most zenith angles

Halzen


Scientific motivations for two km3 detectors

There are strong scientific motivations that suggest to install two

neutrino telescopes in opposite hemispheres :

• Full sky coverage

The Universe is not isotropic at z<<1, observation of transient phenomena

• Galactic Center only observable from Northern Hemisphere

There are strong scientific motivations that suggest to install two

neutrino telescopes in opposite hemispheres :

• Full sky coverage

The Universe is not isotropic at z<<1, observation of transient phenomena

• Galactic Center only observable from Northern Hemisphere

The most convenient location for the Northern km3 detector is the

Mediterranean Sea:

vicinity to infrastructures

good water quality

good weather conditions for sea operations

The most convenient location for the Northern km3 detector is the

Mediterranean Sea:

vicinity to infrastructures

good water quality

good weather conditions for sea operations


Observation time

TeV sourcesQSO

Galactic centre

Galactic coordinatesMediterranean km3

ICECUBE

1.5 sr common view per day


The Mediterranean km3 detector potentials and payoffs

Structures can be recovered:

• The detector can be maintained

• The detector geometry can be reconfigured

The underwater telescope can be installed at depth 3500 m

Muon background reduction

Light effective scattering length (>100 m) is much longer than in ice (20 m)

Cherenkov photons directionality preserved

40K decay in water + bioluminescence

Optical background and dead time increased

Light absorption length in water (70 m) is smaller than in ice (100 m)

Less Cherenkov photons detected

Sediments and fouling

Optical modules obscuration maintenance


The Mediterranean km3

There are three collaborations active in the Mediterranean Sea:

ANTARES, NEMO and NESTOR

There are three collaborations active in the Mediterranean Sea:

ANTARES, NEMO and NESTOR

Capo Passero 3400 m

Toulon 2400 m

Pylos 3800:4000 m

ANTARES

NEMO NESTOR


NESTOR

1 floor equipped with 12

PMTs deployed at 3800 m

depth in March 2003

NESTOR aims at installing a “tower” equipped with optical modules of

20.000 m2 detection area.Resvanis

745 atmospheric muon events reconstructed


ANTARES

ANTARES is installing a 0.1 km2 demonstator detector close to Toulon

• 12 lines• 25 storeys / line• 3 PMTs / storey• 900 PMTs

~70 m

350 m

100 m

14.5 m

Submarine links

JunctionBox

40 km toshore

Anchor/line socket

to be deployed by 2005-2007 See

Sulak’stalk


NEMO

The NEMO Collaboration is dedicating a special effort in:

• development of technologies for the km3 (technical solutions

chosen by small scale demostrators are not directly scalable

to a km3)

• search, characterization and monitoring of a deep sea site

adequate for the installation of the Mediterranean km3.

The NEMO Collaboration is dedicating a special effort in:

• development of technologies for the km3 (technical solutions

chosen by small scale demostrators are not directly scalable

to a km3)

• search, characterization and monitoring of a deep sea site

adequate for the installation of the Mediterranean km3.


The NEMO test site in Catania

A fully equipped facility to test and develop

technologies for the Mediterranean km3

cable:10 OF; 6 conductors

Shore laboratoryport of Catania

Underwater test site:21 km E offshore Catania2000 m depth

2004-2006


The NEMO experiment at LNS

A 5 km fiber optic link connects the

NEMO test site in the port of Catania

with the Laboratori Nazionali del Sud

INFN

Bidirectional optical link


The Catania test site and Geostar ESONET

The NEMO test site in Catania will also host GEOSTAR a deep sea

station for on-line seismic and environmental monitoring by INGV.

The NEMO test site will be the Italian site for ESONET (European

Seafloor Observatory NETwork).


EU FP6 Design Study: KM3NET

Astroparticle Physics Physics AnalysisSystem and Product

Engineering

Information TechnologyShore and deep-sea

structureSea surface

infrastructure

Risk AssessmentQuality Assurance

Resource Exploration Associated Science

A Technical Design Report (including site selection) for a Cubic kilometre Detector in the Mediterranean

WO

RK

PA

CK

AG

ES

• Collaboration of 8 Countries, 34 Institutions

• Aim to design a deep-sea km3-scale observatory for high energy neutrino

astronomy and an associated platform for deep-sea science

• Request for funding for 3 years

Thompson

The experience and know how of the three collaborations

is merging in the KM3-NET activity


Towards the Mediterranean km3

• Select an optimal site for the km3 installation

• Submarine technology R&D

• Construction: improve reliability, reduce costs

• Deployment: define strategies taking profit of the

newest technological break-through

• Connections: improve reliability, reduce costs

• Electronics technology R&D

• Readout: reduce power consuption

• Transmission: increase bandwidth, reduce power

consumption

• Select an optimal site for the km3 installation

• Submarine technology R&D

• Construction: improve reliability, reduce costs

• Deployment: define strategies taking profit of the

newest technological break-through

• Connections: improve reliability, reduce costs

• Electronics technology R&D

• Readout: reduce power consuption

• Transmission: increase bandwidth, reduce power

consumption

NEMO activities


Towards the Mediterranean km3: Site selection

Depth

Lower atmospheric muon background

Water optical transparency

Large Cherenkov photons mean free path (absorption)

No change of photon direction (scattering)

Low biological activity

Low optical background (bioluminescence)

Low biofouling and sedimentation on Optical Modules

Low particulate density (light scattering)

Weak and stable deep sea currents

Reduced stresses on mechanical structures

Reduced stimulation of bioluminescent organisms

Distance from the shelf break and from canyons

Installation safety (turbidity avalanches)

Proximity to the coast and to existing infrastructures

Easy access for sea operations

Reduction of costs for installation and maintenance

Depth

Lower atmospheric muon background

Water optical transparency

Large Cherenkov photons mean free path (absorption)

No change of photon direction (scattering)

Low biological activity

Low optical background (bioluminescence)

Low biofouling and sedimentation on Optical Modules

Low particulate density (light scattering)

Weak and stable deep sea currents

Reduced stresses on mechanical structures

Reduced stimulation of bioluminescent organisms

Distance from the shelf break and from canyons

Installation safety (turbidity avalanches)

Proximity to the coast and to existing infrastructures

Easy access for sea operations

Reduction of costs for installation and maintenance


Candidate sites for the km3

ANTARES

APpEC Meeting, January 2003

3800:4000 m

2400 m

3400 m

NEMONESTOR


Site selection: Expected atmospheric muon fluxes

Downgoing muon background is

strongly reduced as a function of

detector installation depth.

Depth 3500 m (equivalent to

Gran Sasso, Kamioka,..) is

suggested for detector installation

NEMO (Capo Passero)

NESTOR (Pylos)

ANTARES (Toulon)AMANDA (Antarctica)

Bugaev

BAIKAL


Water optical properties

• absorption a()

• scattering b()

• attenuation c() = a() + b()

• effective scattering b() (1-<cos >)

Blue light (~440nm): • maximum transmission in water

• peak of PMT Q.E. (bialkali)

• Cherenkov emission region

La =1/a

glass cutoff Blue light

La ~70 m

large area PMT (8”:13”)

mu-metal shield

Pressure resistant glass housing (17”)

Smith & Backer


km3 depths interval

temperature salinity c(440) a(440)

Capo Passero: Seasonal dependence of water optical properties

Profiles as a function of depth of oceanographic and optical properties in Capo Passero

• Seasonal dependence of

oceanographical (Temperature and

Salinity) and optical (absorption and

attenuation) properties has been

studied in Capo Passero

• Variations are only observed in

shallow water layers

August (3 profiles superimposed)

March (4 profiles superimposed)

May (2 profiles superimposed)

December (2 profiles superimposed)

Data taken in

Indirect estimation of Lb 70 m

eff bb

LL 100m

1 cos

La= 66 5 m

pure seawater


• Absorption lengths measured in

Capo Passero are close to the

optically pure sea water data

• Differences between Toulon and

Capo Passero are observed for the

blue light absorption

Seawater optical properties in Toulon and Capo Passero

NEMO data

ANTARES data

Optical properties have been measured in joint ANTARES-NEMO campaigns in Toulon and in Capo Passero (July-August 2002)


Capo Passero: Optical background

Optical background was measured in Capo Passero with different devices. Data

are consistent with 30 kHz background on 10” PMT at 0.3 spe (mainly 40K decay,

very few bioluminescence).

Optical data are consistent with biological measurements:

No luminescent bacteria have been observed in Capo Passero below 2500 m

Bioluminescent bacteria concentration 100 ml-1

Co

un

tin

g r

ate

(kH

z)

1

10

100

1000

10000

0 5 10 15 20 25 30

Time (mn)

30 kHz

2002 data

Schuller


Capo Passero: Optical background long term measuremts

Measurements were carried out in different seasons showing the same

optical background values.

15

20

25

30

35

0 7 14 21 28 35 42 49

Co

un

tin

g r

ates

(kH

z)

0.0%

0.5%

1.0%

1.5%

2.0% Tim

e abo

ve 200 kHz

Days

Spring 2003 data 30 kHz

Schuller

Schuller


Baserate:median of rate in 15 min for 65 days

BurstFraction: fraction of time in 15 min in which rate is>1.2 x baserate

Toulon: Optical background measured by prototype line

Quiet phases:60 kHz


Capo Passero site characteristics

• Light absorption lengths (~70 m @ 440 nm) are compatible with

optically pure sea water values. Measured values of optical

properties are constant through the years (important: variations on

La and Lc will directly change the detector effective area)

• Optical background is low (consistent with 40K background with only

rare occurrences of bioluminescence bursts)

• The site location is good (close to the coast, flat seabed for

hundreds km2, far from the shelf break and from canyons, far from

important rivers)

• Measured currents are low and regular (2-3 cm/s average; peak value

<12 cm/s)

• The Sedimentation rate is low (about 60 mg m-2 day-1)

• No evidence of recent violent events from core analysis (last 60000

years ago)


Towards the Mediterranean km3: architecture

The design of the Mediterranean km3 detector is addressed

to fit physics requirements:

• Effective area 1 km2

• Angular resolution close to intrinsic resolution

( 0.1° for muons produced by E10 TeV )

• Energy threshold of a few 100 GeV

The design of the Mediterranean km3 detector is addressed

to fit physics requirements:

• Effective area 1 km2

• Angular resolution close to intrinsic resolution

( 0.1° for muons produced by E10 TeV )

• Energy threshold of a few 100 GeV

Design detector layout and study detector performances as a

function of site parameters (depth, water properties,...)

Design detector layout and study detector performances as a

function of site parameters (depth, water properties,...)


km3 architecture: homogeneous lattice or high local density ?

“Tower” detector (5832 PMTs):

81 towers arranged in 9x9 lattice

140 m between towers

20 m beam length

40 m vertical distance between beams

Homogeneous detector (5600 PMTs):

400 strings arranged in 20x20 lattice

60 m between strings

60 m vertical distance between PMTs

750

m h

eig

ht

780

m h

eig

ht


The NEMO tower

Height:compacted 15:20 mtotal 750 minstrumented 600 mn. beams 16 to 20n. PMT 64 to 80Beams:length 20mspacing 40 m

The NEMO tower is a semi-rigid 3D structure designed to allow easy

deployment and recovery.

High local PMT density is designed to perform local trigger.


km3 architecture: homogeneous lattice or high local density ?

“Tower” detector (5832 PMTs):

81 towers arranged in 9x9 lattice

140 m between towers

20 m beam length

40 m vertical distance between beams

Homogeneous detector (5600 PMTs):

400 strings arranged in 20x20 lattice

60 m between strings

60 m vertical distance between PMTs

750

m h

eig

ht

780

m h

eig

ht


km3 architecture: effect of water properties

Effective areas and median angles for the two different detector architectures

and different optical background rates

Simulations performed with the

ANTARES simulation package

NEMO Tower detector 5832 PMTs 20 kHz



Homogeneous lattice detector 5600 PMTs 20 kHz

10

2 3 4 5 6

0.2

0.4

0.6

0.8

Log E (GeV)

Med

ian

(d

egre

es)

10 -2

10 -1

10 0

Eff

ect

ive

Are

a (k

m2)

Optical noise


km3 architecture: angular resolution of the “tower detector”

cos A

eff /

km2

Icecube

2

signal AT ATPoint Sources

background AT

Icecube

1 10 TeV10 100 TeV100 1000 TeV

NEMO simulations: optical background 30 kHz, optical properties of Capo Passero


Towards the Mediterranean km3: technological challenges

electro optical cable: construction anddeployment

Data transmission system

Underwaterconnections

Detector:design and constructiondeployment and recovery

Power transmission system

Electronics

Power Distribution

Acoustic positioning


Towards the Mediterranean km3: technological challenges

Recent break-through in submarine technology

Large bandwidth optical fibre telecommunications (DWDM):

”all data to shore”

under test in NEMO and ANTARES

Low power consumption electronics

under test in NEMO


under test in ANTARES

High reliability wet mateable connectors

under test in ANTARES and in NEMO

Deep sea ROV and AUV technology


Recent break-through in submarine technology

Large bandwidth optical fibre telecommunications (DWDM):

”all data to shore”


Low power consumption electronics

under test in NEMO


under test in ANTARES

High reliability wet mateable connectors

under test in ANTARES and in NEMO

Deep sea ROV and AUV technology



km3 technological challenges: data transmission system

Data transmission goals• Transmit the full data rate with minimum threshold• Only signal digitization should be performed underwater• All triggering should be performed on shore• Reduce active components underwater

Assuming• An average rate of 50 kHz (40K background) on each OM• Signal sampling (8 bits) at 200 MHz• Signal length of 50 ns (true for 40K signals) 10 samples/signal

5 Mbits/s rate from each OM 25 Gbits/s for the

whole telescope (5000 OM)

Rate affordable with development and integration of available

devices for telecommunication systems



A1

B1

C1

D1

E1

F1

G1

H1

A2

B2

C2

D2

E2

F2

G2

H2

A3

B3

C3

D3

E3

F3

G3

H3

A4

B4

C4

D4

E4

F4

G4

H4

A6

B6

C6

D6

E6

F6

G6

H6

A7

B7

C7

D7

E7

F7

G7

7H

A8

B8

C8

D8

E8

F8

G8

H8

A5

B5

C5

D5

E5

F5

G5

H5

1 2 3 4

8765

TowerSecondary JBPrimary JB

Possible architecture for the km3 detector

Mostly passive components Very low power consumption

Based on DWDM and Interleaver techniques

First Multiplation Stage (Tower base):

– 16 Channels coming from the 16 tower

floors. The channels are multiplexed in

one fibre at the base of each tower.

Second multiplation stage (secondary JB):

– 32 channels coming from a couple of

tower are multiplexed with an

interleaver;

– The output is a single fibre for each of

the four couples of towers.

All the fibres coming from the secondary JB

go directly to shore (connection to the main

electro-optical cable inside the main JB)



B1

Interleaver

…1

16

17

32

33

48

49

64

65

80

81

96

97112

113

128

200 GHz

200 GHz

200 GHz

200 GHz

200 GHz

200 GHz

200 GHz

200 GHz

200 GHz

200 GHz

100 GHz

1.. 128

1.. 32

33.. 64

65.. 96

97.. 128

100 GHz

100 GHz

100 GHz

200/100A1

…

D1

…

200 GHz

200 GHz200/100

C1

…

F1

…

200 GHz

200 GHzE1

…

H1

…

200 GHz

200 GHzG1

…

Secondary JB

Tower base

STM1 flux, 155 MB per channel

200/100

200/100


km3 technological challenges: low power electronics

Sampling Freqency: 200MHz

Trigger level remote controlled

Max Power dissipation <200 mW

Input dynamic range 10 bit

Dead time < 0.1%

Time resolution < 1 ns

LIRAX2 200 MHz Write 10 MHz Read

PLL Stand Alone 200 MHz Slave Clock Generator

LIRA’s PLL Shielded T&SPC

New full custom VLSI ASIC

Presently under final laboratory testing

Will be tested in some optical modules in NEMO

Power Budget:

ANTARES 900 PMTs: 16kW over 40km

NEMO 5000 PMTs: 30kW over 100km


km3 technological challenges: underwater connections

The tower connections will be performed in air during the tower assembling.

Some connections (link of the tower with the Junction Box) must be performed

underwater

Well tested technology - Solution adopted in Antares and NEMO

Expensive: connections must be minimized

ROV operated connection ANTARES connection


Using this method of construction for the vessels it is possible to decouple the two problems of:

• resistance to pressure• resistance to corrosion

Moreover it is possible to use an electrical transformer designed to be employed under pressure. In this way the dimensions of the pressurized vessel and its cost can be reduced.

Composite (GRP) Steel

Cavity to fill with oil

An alternative method to build high pressure vessel

km3 technological challenges: the NEMO junction box


km3 technological challenges: ROV / AUV

The ROV deep sea technology (under test in ANTARES) is well established

but implies operativity limitations due to ROV-carrier ships costs and

availability. Operativity are also dependent on sea state.

ROV is bounded to the ship through umbilical cables

Difficult movimentation in a sumbarine jungle of strings/towers

A1

B1

C1

D1

E1

F1

G1

H1

A2

B2

C2

D2

E2

F2

G2

H2

A3

B3

C3

D3

E3

F3

G3

H3

A4

B4

C4

D4

E4

F4

G4

H4

A6

B6

C6

D6

E6

F6

G6

H6

A7

B7

C7

D7

E7

F7

G7

7H

A8

B8

C8

D8

E8

F8

G8

H8

A5

B5

C5

D5

E5

F5

G5

H5

1 2 3 4

8765

AUV Docking station

ROVAUV


Summary I

The forthcoming km3 neutrino telescopes are “discovery” detectors

with high potential to solve HE astrophysics basic questions:

UHECR sources

HE hadronic mechanisms

Dark matter

...

The underice km3 ICECUBE is under way, following the AMANDA

experience

The Mediterranean km3 neutrino telescope, when optimized, will be

an powerful astronomical observatory thanks to its excellent

angular resolution


Summary II

The feasiblity of km3 detectors at depth 3500 m is widely accepted

The undersea technology for the km3 is under test and development

by three collaborations:

ANTARES

NEMO

NESTOR

A proposal for a 3 years design study of the km3 has been

submitted to EU under the KM3-NET

The answer is pending but good reasons to be confident


The km3 community is eagerly waiting for the start-up !

e. mignecoerice, iscra 2-13 june 2004 future cubic kilometer arrays erice iscra school 2004 emilio...

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