nemo – towards the km infn aims at constructing a km 3...

NEMO – Towards the km 3

INFN aims at constructing a km3 scale underwater detector forastrophysical neutrinos in the Mediterranean Sea at >3500 m

NEMO is part of the KM3NeT consortium

Activities:Search and characterization of deep sea sites

Giorgio Riccobene LNS Enrico Fermi School Summer Courses 2009

Search and characterization of deep sea sitesDetector architecture designTechnological demonstrator: NEMO Phase-1Realization of an infrastructure for the km3

The Capo Passero Site

Results from about 10 years of site seeking and monitoring ac tivitiesdemonstrate that Capo Passero Site is optimal for the instal lation of thetelescope.

• Depths of more than 3500 m are reached at about 100 km distance from the shore

• Water optical properties are the best observed in t he studied sites (L a ≈ 70 m @λλλλ = 440 nm)

• Optical background from bioluminescence is extremel y 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, allow s for possible reconfigurations of the detector layout


detector layout

The site selected for the km3 detector lies on a flat

and wide plateau

CP Site

Capo Passero Seascapes


Architecture studies

Design based on detector modularity• reduce the number of structures • reduce the underwater connections • allow operation with a ROV and reconfigurability

PJB SJB Detection Unit Example:Muon Effective area of a km3 Detector as a function ofStructure Spacing


MEOC

140 m

300 m

The NEMO Tower

Tower Height:compacted 15:20 mtotal 750 minstrumented 600 mn. beams 16 to 20

The NEMO tower is a semi-rigid 3D structure with hi gh PMT density

• easy deployment and recovery

• local trigger

• improve muon reconstruction


n. PMT 64 to 80Beams:length 20mspacing 40 m

tower

floorPMT Couple

The tower improves detector sensitivity (“bar effect ”)

String detector (ANTARES Like)

Tower Detector (NEMO Like)

8:15 m

40 m


years Ratio IceCube/ NEMO

1 2.05

3 2.47

5 2.75

Adapted from P.Sapienza, 2009And J Carr ,2009

Towards the Mediterranean km 3: technological R&D

electro optical cable: construction and

deployment

Data transmission system

Underwaterconnections

Electronics

Power Distribution


Data transmission system

Detector:design and constructiondeployment and recovery

Power transmission system

Acoustic positioning

The Catania Test Site

INFN installed a deep sea cable in the Ionian Sea, 25 km East offshore theport of Catania (East Sicily) at 2050 m depth.The infrastructures is shared with INGV for Earth and Sea Science: it is thefirst deep-sea cabled node of the European Network ESONET


The hydrophone antenna O ννννDE (Ocean noise Detection Experiment) devoted to the measurement of the acoustic noise in deep sea was also installed on the cable termination (frame)

OνDE: Ocean Noise Detection Experiment

hydrophoneselectronics

housingCable from shore

4 hydrophones (10 Hz-40 kHz bandwidth) synchronized.Acoustic signal digitization (24bit@96 kHz) at 2000m depth. Data transmission on optical fibers over 28 km.On-line monitoring and data recording on shore. Recording 5’ every hour. Data taking from Jan. 2005 to Nov. 2006 (NEMO Phase 1 deployed).


H1H2

H4

H3

connectorsHeight from seabed :

H1, H2, H4: ~ 2.6 m H3: ~ 3.2 m

North 110° Housing

Deployment of OνDE: Ocean Noise Detection Experiment

ROV


OννννDE connectionOννννDE connection

Cable Layer Vessel Pertinacia

The INFN-LNS Shore Lab infrastructure in Catania

The Shore laboratory is equipped withworkshops, a large structuresconstruction hall, a data acquisition hall acomputing room.

A 32 Mbps radio link is available totransmit data from the Shore Lab to theLaboratori Nazionali del Sud (LNS-INFN)of Catania, i.e. one of the 4 major


of Catania, i.e. one of the 4 majorlaboratores of INFN in Italy.

LNS is directly connected (1 Gbps) to thehigh speed ethernet link EumedConnectand to the main Italian Internetinfrastructure for research (GARR)

NEMO Phase-1

Phase 1 is a fully equipped deep-sea facility to testprototypes and develop new technologies for a neutrinodetector whose final scale will be 1 km 3

e.o cable

300

m


Junction Box

NEMO mini-tower(4 floors)

TSS Frame and OνDE

300

m

The Junction Box

The JB is a fiberglass container (1 m 3) filled with silicone oil, equipped with a pressure compensator (100 litres). The JB contains four cylindrical steel vessels host ing:

• the optical multiplexing and data transmission cont rol system • the underwater power control and distribution syste m• 5 electro-optical ROV mateable connectors (2 used f or NEMO Phase 1)


The Mini tower

Floor 2

Floor 3

Floor 4

Buoy

The mini-tower is a 3D flexiblestructure designed to hold 16 opticalsensors, environmental probes (CTD,ADCP, Light Transmissometer),acoustic positioning system,compasses, data transmission andpower electronics. It is composed bya sequence of floors hostinginstrumentation interlinked by cablesand anchored on the seabed.The whole structure is kept vertical


Optical detectors

Floor Control Module

Electro optical backbone cable

Floors are mechanically interconnected and tensioned by dyneema ropes

Tower Base Module

Floor 1

Electro optical

backbonecable

Tensioningropes

Electro-optical jumper Tower - JB

CableBreak-out

The whole structure is kept verticalby appropriate buoyancy on the top.

NEMO Phase 1 Optical fiber transmission

2

3

4

Cable section

4 e.c.Optical fibers


Tower Base Module

1

The backbone cable is electro-optical (non mechanical). Mechanical stresses are applied only to the tensioning ropes

NEMO Phase 1 Optical fiber transmission

TRANSCEIVER

DROP

floor

photodiode

Next floor

Each break out contains an “add and drop” filter to add or subtract the specific optical wavelength (from/to shore) dedicated to the floor


TRANSCEIVERDWDM

laser

Previous floor

ADD

Optical Modules DAQ chain: (almost) all data to sho re

Hamamatsu 10" R7081 SEL Samples and transmits signal waveform @200 Msample/s

Optical Module (OM)


Floor Control Module Board:

Transmits OM and Slow Control data (water parametres, OM position, internal sensors) to shore through Optical Fibre (DWDM technology)

PMT tube + ISEG base FEM board

underwater electrical vable

e.o. TransceiverColored laser (DWDM)

Floor Control Module Board (FCMB)

Floor Control Module Board (implemented version)

Electro-Optical Interface:• Ser-Des (up to 1.4 Gbps)• DWDM compliant Transceiver

Acoustic data interface

Optical module datainterface

Based on DWDM e/o transceiver: low power and small dimensionsSer-Des implemented using GLink chipset: fixed laten cy and synchronous protocol


Spartan-3 FPGAbridges optics and underwater instruments

This makes the whole detector synchronous and phase d…With GPS time distributed from shore The FCM distributes the clock embedded into the stream tran smitted to off-shore)

GPS data receiver(on shore functionality)

NEMO Phase 1 Data Transmission Chain: Point to Poin t

Optical modules

Floor Control Module Board

Hydrophones

Optical Fiber + DWDM multiplexing

DWDM demultiplexing

Data

Time + controls

The whole detector is phased and synchronizes(about 1 nsec)

Time Calibration Board


Oceanographic Instrument

Acoustic positioning system board

Slow Control Interface

Internal Sensors

Floor Control Module Interface

GPS reference

Comupting

Interernet

Shore Lab

NEMO Phase 1 Data Transmission Chain: Point to Poin t

Optical modules

Floor Control Module Board

Hydrophones

Optical Fiber + DWDM multiplexing

DWDM demultiplexing

Data

Time + controls

The whole detector is phased and synchronizes(about 1 nsec)

Time Calibration Board


Oceanographic Instrument

Acoustic positioning system board

Slow Control Interface

Internal Sensors

Floor Control Module Interface

GPS reference

Comupting

Interernet

Shore Lab• The FCM collects floor data and transmit them to on -shore with a DWDM optical link.• Data are received on-shore and distributed via Ethe rnet

– Data manager: slow control– Master CPU: trigger

NEMO Phase 1 Installation

Phase 1 Installation was carried out onDecember 2006 using the Elettra Tlc- Teliri C/L.Starting from the port of Catania (logistic baseof the Elettra Tlc.)


Accident: the JB fell on the ship deck due to a shi p winch failurethe secondary power system was broken but the prima ry was ok �� JB deployed

NEMO Phase 1 Installation

Mini-tower deployment Mini-tower on the seabedJB deployment


JB connection to the tower

Mini-tower deployment Mini-tower on the seabed

Mini-tower buoy releaseMini-tower unfoding

JB deployment

Acoustic Positioning Data

After Deployment

Z= -1966 m

Tower Position reconstruction through the acoustic positioning system

But another accident happened: they buoy collapsed ! The tower started to descend and laid on the seabed from late april 2007

February 2007


Tower Base Z=-2100 m

Z= -2045 m

Z= -2005 m

Z= -1966 m

April 2007

Reconstructed Atmospheric Muon Tracks

Run 15 Event 11

Date 23 Jan 2007

H. 20:21

Hit = 17

Hit Selected = 14

Hit Reconstructed = 12

θ= 168°Trigger Seed = 17


Trigger Seed = 17SC = 4FC = 5CS = 8

Likelihood RED= - 8,3

Reconstructed Atmospheric Muon Tracks

Run 17 Event 38

Date 24 Jan 2007

H. 02:20

Hit = 24

Hit Selected = 17

Hit Reconstructed = 16

θ= 132°Trigger Seed = 23


Trigger Seed = 23SC = 3FC = 14CS = 6

Likelihood RED= - 6,9

NEMO Phase 1 First Results

Vertical Muon intensity as a function of depth measu red. Data are compared with Bugaev et al (1998)


The NEMO Phase-2 projectOBJECTIVES- Realization of an underwater infrastructure at 3500 m on the CP site- Test of the detector structure installation procedu res at 3500 m- Installation of a 20 storey tower (16 stories“fully equipped”)- Long term monitoring of the site

INFRASTRUCTURE- Shore station in Portopalo di Capo Passero- 100 km electro optical cable- ROV and Deep Sea Shuttle for deployment, connection and mainenance- Underwater infrastructures: Junction box containing Medium Vol tage Converter and


- Underwater infrastructures: Junction box containing Medium Vol tage Converter and ROV Operable Connectors

Shore Laboratory in Capo Passero Harbour

NEMO Phase 2 Cable Installation

The cable was deployed on July 2007Using the Elettra Tlc – Certamen C/L.

The cable fibres were continuoisly monitored from shore (using OTDR) during the installation. Monitoring continues.

The cable is suitable for the km3

Capo Passero village

Capo Passero Site

Cable route


INFN has also applied to get an opticalfibre connection (land) from the CapoPassero shore lab to LNS.

This will allow fast internet connectionfor data transmission from the shorestation and remote control.

Infrastructure for the km3 in Capo Passero

- DC/DC power converter built by Alcatel under test: installation October 2009- ROV and Deep Sea Shuttle (PEGASO) for 4000m acquir ed and under test- FullTower:

12 floors mechanical demonstrator ready: deployment in summer 200920 floors (16 instrumented): starting construction, deployment in 2010


Alcatel shore power supply Alcatel DC/DC converter

Cougar ROV (PEGASO)





Cougar ROV (PEGASO)Cougar ROV (PEGASO)

4000 m30 Ton

300 m





Tower mechanical demonstrator

The NEMO full Tower: 201075

0 m

40 m

NEMO Phase II: Installation and operation of a “ful l scale” tower in Capo Passero20 floors, 16 floors instrumented, 64 Optical Modul es, 750 m total height

Electronics and DAQ and DAT improved for faster int egrationStudies on bar length (6 to 10 m)

34 hydrophones for Acoustic Positioning …And for Aco ustic Physics / Biology

� Reduce costs and improve reliability of the tower a coustic positioning system� 750 m long antenna for feasibility studies on acous tic detection� Optical and acoustic data in the same data stream wi th the same time


750

m

10 m

2 PMTs, 1 hydrophone

2 PMTs, 1 hydrophone

� Optical and acoustic data in the same data stream wi th the same timeAll signals are phased !A viable solution for KM3NeT

Hydrophones (SMID-NATO) sensitivity -207 dBre 1uPa T ested for 4000 m Preamp (SMID-NATO) 32 dB gain, 0.8 nV/ √Hz input noiseADC-board 24 bits, 192 kHz sampling, 3 dB gain FCM all data to shore + GPS time stamp

NEMOTower

NEMO Floor

NEMO Phase II – Hydrophones

Commercial hydrophones are typically factory calibr ated:�� piston test at 250 Hz, water pool test above 5 kHz (due to reflections)�� directionality pattern

But for many hydrophones sensitivity changes as a f unction of pressure ( ∼∼∼∼ -3 dB/1000 m)

NEMO and an italian company (SMID) have developed low cost hydrophones for 4000 m depth, with no change of sensitivity as a function of dept h.

NATO has developed for/with NEMO a standard proced ure for calibration under pressure

Relative Hydrophone sensitivity variation with hydrostatic


Hydrophone

Preamplifier

variation with hydrostatic pressure (measured for 20 kHz signal)

Measured variations ≤ ±1 dB

300 Bar 400 Bar

NEMO Phase II – “Acoustic” Electronics Chain

ADCFloor Conrtol Module

Adds GPS TimeSend data to shore

On-ShoreFloor Conrtol Module

Data Parsing

Acoustic Physics / Biology

Acoustic Positioning

Acoustic Data Server

Hydros + preamps

OMs

“All data to shore” philosophy data payload: 2 Hyd ros = 1 OM, fully sustainable

opticalfiber


11 cm

Complete DAQ chain testedThe NEMO “Acou-Board”

11 cm


Acoustic neutrinoDetection

Neutrino Acoustic Detection Principle

�� Neutrino Interaction (strong Earth absorption: look upward !)

�� Hadronic shower formation at interaction vertex(ννννe e.m. shower)

�� H shower carries (on average) ¼ E νννν

� Shower Development(LPM must be taken into account for EHE)

� Sudden deposition of heat through ionization

neutrino

Weak interaction

Hadronic shower


�� Thermo-acoustic process:Increase of temperature (C p), Volume Expansion ( ββββ)

� The “pen shaped” energy deposition region (20 m dep th, 10 cm diameter) produces a pancake shaped acoustic wave peak wavelength

22

λ ≈ = ≈ 10 kHzscd f

d� Acoustic wave propagation in the

medium: near field ( ) 1∝maxp rr

Hadronic shower

ννννee.m.shower

Basics of thermo-acoustics mechanism

( )22

1 ∂∇ − = − ⋅

∂

..

s p

r, tp p

c c t

εεεεββββ

A pressure wave is generated instantaneous followi ng a sudden deposition of energy in

the medium (neglecting absorption: O(10 km) at 10 kHz )

≈ ≈ -7 -8 / 10 :10 secdepositiont D c

Istantaneous deposition of heat through ionization

Thermo-acoustic process:increase of temperature (specific heat capacity C p), expansion (expansion coeff ββββ)

≈ ≫-5

expansion deposition 10 sect t


∂s pc c t

( ) 0

4

−

∂ ∝∂

s

p

rt

cEp r , t

c t r

δδδδββββ

ππππ

1

4

∂∝∂ ∫

p

p(r, t) dV c t r

ββββ εεεεππππ

For a point like source (micropulse):

For a shower heating a volume of matter (macropulse ): Sum of pointlike sources: wavefront and signal shape depend on the energy density distribution

Learned

Bipolar pulsespherical expansion

Acoustic pulse amplitude in Salt, Water, and Ice

Conversion of ionization energy into acoustic energy

Med Sea S.P. ice NaCl

T [ºC] 14º -51º 30º

cs [m s -1] 1545 3920 4560

ββββ [ K -1] 25.5x10 -5 12.5x10-5 11.6x10-5

CP [J kg -1 K-1] 3900 1720 839


2116 10

4− ≈ × × ≈ ⋅

max

Pap E E

eVν νν νν νν νγγγγ

0.12:0.13 1.12 2.872 βγ = s

p

cC

Gruneisen coefficient

The Size of Neutrino Acoustic Detectors

( ) 410

2 100

−

−

= =

= ≈⋅

A Tot Earth

min eff

CC A

D(N )

2

eff

P E ,E R N

N events P e

A T km y

νµ ν µ µνµ ν µ µνµ ν µ µνµ ν µ µ

σ ρσ ρσ ρσ ρν νµν νµν νµν νµ

σσσσ

Φ πΦ πΦ πΦ π

Eνννν = 1020 eV

in water: p = 0.6 Pa @ 1 km �� 20 mPa (neglecting attenuation)

in Ice : p = 6 Pa @ 1 km �� 200 mPa (neglecting attenuation)

Underwater Cherenkov detectorsUpgoing events – 100 TeV

WB flux


Underwater Acoustic detectorsDowngoing events – 10 20 eV

3

3

10

10

−

−

= ≈

≈⋅

eff

det min det Tot A

2

eff

P (E ,p ) H N

N events

A T km y

νννν σσσσ

Sound absorption length in ocean O(10 km), noise O (10 mPa)

Several groups developing and improving simulation codes for large acoustic detectors What we can do with 1 km 3 filled with hydrophones ?

WB flux

Acoustic Detector Sensitivity

1100 hydros in 1 km 3

1 year, threshold 35 mPa, 95% CL(random geometry)Acoustics

.. with cuts- No cuts

Largely spaced detectors for GZK neutrino detection


1500 km3, 200 hydros per km 3

5 yearsthreshold 5 mPa

A “complementary” km 3-scale detector ?

10 years, threshold 5 mPa, 90% CL (random geometry)

km3 regular geometries5 years, 15 mPa, 95% CL

Just a personal idea: possible neutrino calorimetry ?


Bioacustic: Sperm-whale click analysis


2

s

LIPI

c=

L

i

nose

Air

Depth = 560 ± 5 m

L = 3.41 ± 0.05 mSize = 9.72 - 10.50 m

Young male or female

Final Note

Dolphins use sound !

They’re the second most evoluted species on Planet Earth

… Mankind is only the third one !


nemo – towards the km infn aims at constructing a km 3...

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