NEMO project: towards the km Cherenkov Neutrino … project: towards the km3 Cherenkov Neutrino...

NEMO project: towards the

km3 Cherenkov Neutrino Telescope in the

Mediterranean Sea

Antonio Capone

INFN and University “La Sapienza”

Roma - Italy

Antonio Capone - INFN and University "La Sapienza", Roma - Italy UHE Neutrino Workshop - Beijing - April 23rd-25th 2

Layout of the talk

Introduction

Overview of the NEMO R&D activitiesSite exploration activities

Feasibility study

…

The NEMO Phase-1 projectStatus of the activities at the Catania Test Site

The NEMO Phase-2 projectShore and deep sea infrastructures at Capo Passero

Electro-optical cable

Conclusions and perspectives

G. Riccobene talk


NEMO R&D activities towards a km3 neutrino

detector in the Mediterranean Sea

Site selectionSearch and characterization of a deep sea site with optimal characteristics:

depth, water optical properties, …

Long term monitoring of the site

Feasibility study of the km3 detectorSystem analysis of all the construction and installation issues

Optimization of the detector geometry by means of numerical simulations

Validation of the proposed technologiesAdvanced R&D and prototyping of the proposed technical solutions


The NEMO collaboration

INFNBari, Bologna, Catania, Genova, LNF, LNS,

Napoli, Pisa, Roma

UniversitiesBari, Bologna, Catania, Genova, Napoli,

Pisa, Roma “La Sapienza”

CNRIstituto di Oceanografia Fisica, La Spezia

Istituto di Biologia del Mare, Venezia

Istituto Sperimentale Talassografico, Messina

Istituto Nazionale di Geofisica e Vulcanologia (INGV)

Istituto Nazionale di Oceanografia e Geofisica Sperimentale (OGS)

Istituto Superiore delle Comunicazioni e delle Tecnologie dell’Informazione

(ISCTI)

More than 70 researchers from INFN and other Italian Institutes


Neutrino Telescopes status

AMANDA

ICECUBE

Mediterranean

km3

BAIKAL

DUMAND

Pylos

La Seyne

Capo Passero

DUMAND R&D - finished

BAIKAL, AMANDA - taking data

ANTARES, NEMO, NESTOR - under construction / first data

ICECUBE, Mediterranean km3 - next generation

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


GX339-4SS433

Crab

VELA

South Pole Mediterranean

• The whole sky coverage needs two telescopes in different Hemispheres

• The Galactic Centre is observable only from the Northern Hemisphere

GX339-4SS433

Crab

VELA

Galactic Centre

HESS data

Two km3 neutrino telescopes ??


HESS Sources

Observable from the km3 in

the Mediterranean


> 25 sea campaigns since 1998

– light transmission properties of deep sea water(AC9 transmissometer)

– optical background (custom devices)

– deep sea currents (RCM11 and RCM8 current metre) data analysis OGS

– nature and quantity of sediment material (Sediment trap) data analysis IBM

– seabed characteristics (cores and bottom profile) data analysis CEOM-ENI

Other sites explored

Lake Baikal, in collaboration with BAIKAL site evaluation group

Toulon (ANTARES site), in collaboration with ANTARES site evaluation group

Water optical propertiesAC9 (WetLabs)

Biofouling Sediments Optical background

(V. Balkanov et al. NIM 2002)

NEMO Site Selection Activity


Sites investigated, ships

Capo Passero 3350 mUstica 3500 mAlicudi 3500 mCatania 2000 m

CONISMA R/V UNIVERSITATIS 48m

CNR R/V Thetis 32 m

CNR R/V Urania 62 m

NATO R/V Alliance 110m


Absorption and attenuation lengths

Capo Passero 2850-3250 m


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

Aug 02 (3 profiles superimposed)

Mar 02 (4 profiles superimposed)

May 02 (2 profiles superimposed)

Dec 99 (2 profiles superimposed)

Data taken in:

temperature salinity a440 c440

Aug 03 (2 profiles superimposed)

Water optical properties: no seasonal dependence


Capo Passero 2850-3250 m

! absorption @ 440nm

Water optical properties: no seasonal dependence

! attenuation @ 440nm


Deep-Sea sites optical water properties

Comparison of Capo Passero and Toulon sites

Optical water properties have been measured in the summer 2002 in Capo Passero

and Toulon in two joint NEMO-ANTARES campaigns

Absorption lengths measured inCapo Passero site arecompatible with optically puresea water data

Large differences betweenToulon and Capo Passero areobserved in the blue region

A campaign has also beenperformed to measure waterproperties on the Baikal site


NEMO device (8’’ PMT at 0.3 spe)

! Toulon 58.0±3.0 kHz

! Capo Passero 28.5±2.5 kHz

PMT 2+power

PMT dark current 7 kHz

PMT dark current 7 kHz

Optical background in Capo Passero and Toulon

PMT 1+ DAQ

PMT 2


Optical background in Capo Passero

Data taken in collaboration

with ANTARES

Dead time:

Fraction of time with

rate > 200 kHz

" PMT: 10”

" Thres: ~.5 SPE

Background depth

dependence in

agreement with biology

data (bioluminescent

bacteria count)


Typical time sequence of Optical noise rate in Capo Passero

Measured with test 1Courtesy J.P. Schuller

Counting rate (kHz)

1

10

100

1000

10000

0 5 10 15 20 25 30

Time (mn)

.35 spe

No luminescent bacteria have been

observed in Capo Passero below

2500 m

Bioluminescence


Effect of biofouling on optical module

transparency in Capo Passero site

D

B

C

A

• Setup realized by the ANTARES collaboration

• Four glass spheres with blue LED emitters and 28 PIN

diodes

• Allows measurement at different polar angles of the

transparency loss due the bio-film growth

• Immersed at the Capo Passero site for 18 months (April

2003 - October 2004)

-100 -50 0 50 100

0.92

0.96

1.00

!

T (

t=1 y

ear)

/ T

(t=

0)

Transparency after

1 year

"

-90°

0°

+90°


Trap-KM4

0

100

200

300

Aug Oct Dec Feb Apr Jun Aug Oct Dec Feb Apr Jun Aug Oct Dec

Time

TM

F (

mg

m-2

d-1

)

1999 2000 2001

Sediment samples collected over more than 3 full years: Aug 1999-May 2000 andJuly-December 2001(analysed). Other periods under analysis

Etna eruption

July 2001

Sedimentation rate in Capo Passero site - 1


1 jan 1 mar 1 jun 1 sep 31 dec0

50

100

150

200

250

300

350

date

TM

F (

mg

m-2

day

-1)

NEMO 1999 data

NEMO 2000 data

NEMO 2001 data

ANTARES 1997 data

I1 1997 data

I1 1998 data

NorthernIonian Sea

Sedim

ent

flux (

mg m

-2 d

-1)

Sedimentation rate in Capo Passero site - 2


Two current metres and a sediment trap aremoored in Capo Passero Region since 1998 up to --> today .

Deep sea water currents are low and stable: average value=3 cm/s, max. value=10 cm/s

Seabed 3350 m

Current meter 3050 m

Current metre 2900 m

Sediment trap 3000 m

Oceanographic data measured in Capo Passero


The Capo Passero siteIn a seven year activity (1998-2005) the NEMO collaboration has selected a deep sea site

offshore Capo Passero (Sicily) (36° 16’ N, 16° 06’ E) with optimal oceanographycal and

environmental properties

The site has been proposed in January 2003 to ApPEC

as a candidate for the km3 installation

• Depths of more than 3500 m are reached at ~ 100 km

distance from the shore

• Water optical properties are the best observed in the

studied sites:

La ! 70 m @ ! = 440 nm)

• Optical background from bioluminescence is extremely

low

• Stable water characteristics

• Deep sea water currents are low and stable:

average value=3 cm/s, max. value=10 cm/s

• Wide abyssal plain, far from the shelf break, allows for

possible reconfigurations of the detector layout

Capo Passero 3400 m

Toulon 2400 m

Pylos 3800:4000 m

ANTARES

NEMONESTOR


Towards the Mediterranean km3

Electro-optical cable:

construction and

deployment

Data transmission system

Underwater

connections

Detector:

design and construction

deployment and recovery

Power transmission

system

Electronics

Power Distribution

Acoustic positioning


Feasibility study for the km3 detector

main EO cable

main Junction Box

secondary JB

“tower”

Detector architecture issues

Reduce the number of structures to reduce the

number of underwater connections and allow

operation with a ROV

Detector modularity

9 * 9 = 81 “Towers” with

3 dimensional and non

homogeneous distribution

of sensors


Possible extragalactic sources and fluxes

Learned Mannheim

AGN

GZK

p# AGN corespp AGN cores

p# blazar

GRB

WB Limit

Diffuse neutrino fluxes

Stecker

Nellen

Mannheim

Bierman

Waxman


Candidate sources of High Energy Neutrinos and

expected events

Diffuse fluxes

GZK neutrinos 0.5 / year

GRB (Waxman) 50 / year

AGN (thin) (Mannheim) few / year

(thick) >100 / year

Point-like sources

GRB (030329) (Waxman) 1-10 / burst

AGN (3C279) (Dermer) few / year

Galactic SNR (RXJ1713, Vela) (Aharonian, Vissani) few / year

Galactic MicroQuasar(Distefano, Aharonianet et al.) 1-100 / year

( )( ) ( ) ( ) ( )tot A

,min

E

,min E N Z

,min

E

N E ,dE E , P E ,E e

AT

!

!

µ

µ µ "# $

! ! ! !µ ! µ

$= % $ & &'

Neutrino fluxProbability to produce a

detectable muon (E" >Emin)Earth transparency

Expected

events in a

1 km2

underwater

Cherenkov

Neutrino

Telescope


The NEMO “Tower”

Optical Modules

Electronics container

Mechanical structures for the km3 studied in order to optimize

the detector performance.

Modular structure composed by a sequence of 15 m long

arms (storeys) interconnected by tensioning cables. Full

height 750 m.

Power and data cables are kept separated from the

tensioning ones.


Tower detector performance

Sensitivity

Sensitivity to point-like sources (Ev-2 spectrum)

NEMO 81 towers 140m spaced - 5832 PMTs

IceCube 80 strings 125m spaced - 4800 PMTs

Reconfigurability

Effective areas with different element spacing

Tower Floor

spacing spacing

Black line 140 m 40 m

Red square 300 m 60 m

Black points 300 m 40 m

NEMO search bin 0.3°

IceCube search bin 1°

IceCube simulations from Ahrens et al. Astrop. Phys. 20 (2004) 507


Angular resolution and pointing accuracy

2659 8deg

0.19 0.02deg

k

!

"= ±

= ±

(Simulated time = 1 year)

2

22

2 212

moondN

k ed

!µ "

!

! "

#$ %& '= #& '( )

100 days needed to observe a 3$ effect

Observation of the Moon

shadowing effect on the flux

of atmospheric muons


Effects of environmental properties on detector

performance

0 1 2 3

0.9

1.0

Log10 Eµ (TeV)

Aef

f (t

) /

Aef

f (t=

0)

6 months

1 year

5 years

10 years

Aeff µ vs Eµ

Optical background rate Biofouling

# 20 kHz

# 60 kHz

# 120 kHz

Effective areas for different

background rates

Upgoing muons with E-1 spectrum

Trigger + Quality Cuts

Reduction of effective area due to loss of

transparency of the Optical Modules

Transparency loss as measured in Capo

Passero


The NEMO Phase-1 project

Double armed cable

2.330 m

Single armed cable

20.595 m

North branchNorth branch

5.220 m5.220 m

South branchSouth branch

5.000 m5.000 m

BU

SN-1Shore stationShore station

NEMO Phase-1

Underwater infrastructure realized by the

Laboratori Nazionali del Sud to test

detector prototypes

A seismic and environmental observatory

of INGV has been installed and connected

to the EO cable

• Realization of a subsystem of the km3

including all the key elements of the detector

• Shore and deep sea infrastructures already realized

• Project jointly funded by INFN and MIUR

• Realization of main components completed

• Integration and test under way

See G. R

iccobene talk


The NEMO Phase 2 project

A deep sea station on the Capo Passero site

OBJECTIVES

- Realization of an underwater infrastructure at 3500 m on

the CP site

- Test of the detector structure installation procedures at

3500 m

- Installation of a 16 storey tower

- Long term monitoring of the site

INFRASTRUCTURE UNDER CONSTRUCTION

- Shore station in Portopalo di Capo Passero

- 100 km electro optical cable

- Underwater infrastructures

STATUS

- Electro-optical cable (>50 kW, 20 fibres) ordered

- A building (1000 m2) located inside the harbour area of

Portopalo has been acquired. Procedures for its renovation

started

- Project completion planned in 2007

CapoPassero

site


The Phase-2 electro-optical cable

DC solution with sea return

Working Voltage 10 kV

Power > 50 kW


Phase-2 Electro Optical cable termination

To shore

Cable In

VDC 10 kV

Cable Out

VDC 10 kV

DC/DC

5-10 kW

400 V-DC Out

Fibre Out

400 V-DC Out

Fibre Out

ROV connector

ROV connector

DC/DC

5-10 kW

JB

DC/AC

TowerTower

380 V-AC Out

Fibre Out

main EO cablemain Junction Box

secondary JB

“tower”


View of the cable landing area

Shore Station


The Shore Station (project)

View from the north side


NEMO: status and perspectives

Site choiceThe site selected offshore Capo Passero shows optimal characteristics for the installation

of the km3-scale Deep-Sea Cherenkov Neutrino Telescope

Proof of the technical and budgetary feasibility of the km3

Checked in a complete feasibility study performed in collaboration with some companies

with well proven experience in underwater operations

Validation of the proposed technologies for the km3

Realization of Phase-1 (2006) and Phase-2 (2007) projects

Realization of shore and deep sea infrastructures at Capo Passero

Future developmentsEurope funded (10M#) the KM3NeT Design Study. ANTARES, NEMO and NESTOR

physicists working together … towards the realization of a km3 detector


Summary: the km3Neutrino Telescope in the

Mediterranean Sea: a long effort …

for (hopefully) a great result

… let’s realize the “forbidden dream” …”


Muon fluxes and depths in water

%µ

(cm

-2 s

r-1 s

ec-1

)

AMANDA

Toulon

Capo Passero

Methoni

%µ

(cm

-2 s

r-1 s

ec-1

)


Seismic activities in Mediterranean area

Earthquakes registered if magnitudo > 4-5 Richter


ANTARES & NEMO measurements

NEMO project: towards the km Cherenkov Neutrino … project: towards the km3 Cherenkov Neutrino...

Documents

Transcript of NEMO project: towards the km Cherenkov Neutrino … project: towards the km3 Cherenkov Neutrino...