The NEMO Project Neutrino Mediterranean Observatory P. Piattelli I - - PowerPoint PPT Presentation

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The NEMO Project Neutrino Mediterranean Observatory P. Piattelli I - - PowerPoint PPT Presentation

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The NEMO Project Neutrino Mediterranean Observatory P. Piattelli I stituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud NEMO P. Piattelli, HENA Workshop, Paris, june 16-17, 2003 NEMO Towards the km3 detector R&D phase

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SLIDE 1
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

The NEMO Project

Neutrino Mediterranean Observatory

  • P. Piattelli

I stituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud

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SLIDE 2
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

NEMO

  • R&D phase (1999 - 2002)

– Site selection and characterization

Several sites close to the italian coasts have been studied. A site close to Capo Passero (Sicily) at 3500 m with optimal water characteristics has been identified for the installation

– R&D activities

Development of specific ASICS for the underwater front end electronics Large area hybrid photomultipliers

– Feasibility study of the km3 detector

A complete feasibility study has examined all the detector critical components and the deployment procedures A preliminary project for the km3 has been developed

  • Phase 1: Advanced R&D and prototyping (2002 - 2005)

– Realization of a detector subsystem including all critical components

The system will be installed in Catania at the Underwater Test Site of the LNS

  • Km3 detector realization (2006 ? - …)

Towards the km3 detector

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SLIDE 3
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

The NEMO Collaboration

I NFN

Bari, Bologna, Cagliari, Catania, Genova, LNF, LNS, Messina, Roma

CNR

I stituto di Oceanografia Fisica, La Spezia I stituto di Biologia del Mare, Venezia I stituto Sperimentale Talassografico, Messina

I stituto Nazionale di Geofisica e Vulcanologia I stituto Nazionale di Oceanografia e Geofisica Sperimentale Universities:

Bari, Bologna, Cagliari, Catania, Genova, Messina, Roma “La Sapienza”

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SLIDE 4
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Site selection criteria

  • Proximity to the coast and to existing inf rastructures

Easy access f or sea operat ions Reduct ion of cost s f or inst allat ion and maint enance

  • Distance f rom the shelf break and f rom canyons

I nst allat ion saf et y

  • Depth

Reduct ion of at mospheric muon f lux

  • Water optical transparency

Opt imisat ion of det ect or perf ormances (ef f iciency and angular resolut ion)

  • Weak and stable deep sea currents

Reduce st resses on mechanical st ruct ures

  • Low biological activity

Low opt ical background (bioluminescence) ⇒ det ect or perf ormances Low biof ouling and sediment at ion on OM

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SLIDE 5
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Site exploration activities

  • Since 1998 continuous monitoring of a site close to the coast of Sicily
  • More than 20 sea campaigns on the site to measure

– water optical properties – optical background – deep sea currents – nature and quantity of sedimenting material

  • Other sites explored f or optical properties

– Two sites in the Southern Thyrrenian Sea (Ustica and Alicudi) – Toulon (ANTARES site), in collaboration with Antares – Lake Baikal

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SLIDE 6
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

The Capo Passero Site

  • Located in the South I onian sea
  • Selected af ter a screening of

water optical properties in several sites close to the italian coasts

  • About 50 NM f rom shore (Capo

Passero, Sicily)

  • Large and f lat area at about

3400 m depth

  • Far f rom important rivers
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SLIDE 7
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

A km3 detector in the Mediterranean

NEMO Capo Passero - 36° 16’ N, 16° 06’ E

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SLIDE 8
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Temperature Salinity Attenuation Absorption

Water optical properties

Measure of profiles of water optical properties

The setup used (AC9+CTD) measures oceanographical (temperature, salinity, pressure) and optical (absorption and attenuation coef f icients at 9 wavelengths) parameters along the whole water column Data taken in the South Thyrrenian Sea (Alicudi) Strong layering of waters

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SLIDE 9
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Water optical properties

Seasonal dependence of optical parameters in Capo Passero

  • Seasonal dependence of
  • ceanographical (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) March 02 (4) May 02 (2) December 99 (2) Data taken in

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SLIDE 10
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Water optical properties

Seasonal dependence of absorption and attenuation lenghts

  • Values averaged in the depth

region 2850÷3250 m and over several prof iles

  • No seasonal variations of

absorption and attenuation lengths are observed in deep waters in the blue region (λ = 440 nm)

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SLIDE 11
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

  • Absorption lengths

measured in Capo Passero are compatible with

  • ptically pure sea water

data

  • Large dif f erences between

Toulon and Capo Passero are observed in the blue region

  • Values measured with the

Antares Test 3’ setup are in good agreement with the AC9 data

Water optical properties

Comparison of NEMO and Antares data

Optical water properties have been mesured in the summer 2002 in Capo Passero and Toulon in two joint NEMO- ANTARES campaigns

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SLIDE 12
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Optical background

Sources of optical background

  • Decay of radioactive elements (mainly 40K) → stable f requency

noise (˜ 30 kHz on a 8” PMT at 0. 3 p. e. threshold)

  • Light produced by biological entities (bioluminescence) → random

bursts with very high counting rate No luminescent bacteria have been

  • bserved in Capo Passero below 2500 m

Data taken by I stituto Sperimentale Talassograf ico, CNR, Messina

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SLIDE 13
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Optical background

Data have been acquired with the same setup in Toulon and Capo Passero

Comparison of Toulon and Capo Passero sites Capo Passero

Noise on a 8” PMT

  • 28. 5 ± 2. 5 kHz

Toulon

Noise on a 8” PMT 58 ± 3 kHz

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SLIDE 14
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Seabed geology

Core analysis

  • All the collected cores show the

same stratigraphy

  • Some f eatures, associated to well

known geological events, allow f or a dating of the cores

  • Only one evidence of a turbidity

event is present, but it can be dated at about 60 kyr BP

  • The average sediment

accumulation rate is estimated to be 3- 4 cm/ kyr

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SLIDE 15
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

  • Two series of collected data span

an interval of about 1 year

  • The mass f lux is low (average of

62 mg m

  • 2 d- 1), as expected in an
  • ligotrophic enviroment such as

the I onian Sea, with an strong seasonal behaviour (spring bloom peak)

  • Data are comparable to those

measured in the Northern I onian which show the same f eatures

  • I nterannual variability can also
  • ccurr

Downward sediment flux

J F M A M J J A S O N D 50 100 150 200 250 300

TMF (mg m

  • 2

day

  • 1

)

NEMO 1999 data NEMO 2000 data

  • St. I1 1997 data
  • St. I1 1998 data

Seasonal dependence of the mass flux

Data analysed by I stituto di Biologia del Mare, CNR, Venezia

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SLIDE 16
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

The Capo Passero site

  • Absorption lengths (~70 m @440 nm) are compatible with optically

pure sea water values

  • Measured values are stable troughout the years (important:

variations on La and Lc will directly ref lect in changes of the detector ef f ective area)

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

rare occurrences of bioluminescence bursts)

  • The site location is optimal (close to the coast, f lat seabed, f ar

f rom the shelf break and f rom canyons, f ar f rom important rivers)

  • Measured currents are low and regular (2- 3 cm/ s average; 12

cm/ s peak)

  • Sedimentation rate is low
  • No evidence of recent turbidity events

Site optical and oceanographical characteristics

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SLIDE 17
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Development of a large area hybrid PMT

Baikal New Design

  • I. SIMION simulations show that shape of

exisiting BAIKAL PMT can be improved to provide one- one correspondence and timing improvement

  • I. SIMION simulations show that shape of

exisiting BAIKAL PMT can be improved to provide one- one correspondence and timing improvement

  • II. Coupling to a

position sensitive detector provides information on the photoelectron emission point

  • III. Coupling to a light

guide system also provides information on the detected light direction

R x

Timing Timing

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SLIDE 18
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

The LNS Underwater Test Site

SHORE SHORE LABORATORY LABORATORY UNDERWATER UNDERWATER STATION STATION

Long term tests for: underwater connections, electronics, mechanical structures, optical and acoustic detectors. Multidisciplinary laboratory (will host an on-line underwater seismic station of the I stituto Nazionale di Geofisica e Vulcanologia)

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SLIDE 19
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

The LNS Underwater Test Site

Cable features: Cable features: 10 Optical Fibres standard ITU-TG-652 6 Electrical Conductors Φ 4 mm2

2.330 m Double Armed Cable 20.595 m Single Armed Cable

Drop cable 2 Drop cable 2 5.220 m 5.220 m Drop cable 1 Drop cable 1 5.000 m 5.000 m

joint BU joint joint

GEOSTAR NEMO Phase 1 Lab

Layout of the installation

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SLIDE 20
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

The LNS underwater Test Site

Deployment Deployment of the

  • f the branching unit

branching unit

Cable deployed in september 2001

Optical Optical fibre fibre connections connections Electrical connections Electrical connections Electrical connections

Deployment of the Test Site cable

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SLIDE 21
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Feasibility study for the km3 detector

Aim: demonstrate that an underwater Cherenkov detector with

effective area of more than 1 km2 is technically feasible and can be constructed with a “reasonable” budget The feasibility study of the km3 detector has been developed in close contact with leader companies in the field of submarine equipment and operations: Sasp, Sonsub, Saipem for the mechanical aspects and the cable and detector deployment Nexans and Pirelli for the submarine cables Ocean Design for underwater connectors Alcatel and Pirelli for the data transmission system

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SLIDE 22
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Feasibility study for the km3 detector

Aspects that have been analysed in detail

  • Mechanical structures
  • Power distribution
  • Front end electronics
  • Data transmission to shore
  • Cable network (submarine cables and connectors)
  • Deployment of the structures and cables

The study shows that a km3 detector is presently technologically feasible at a reasonable cost

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SLIDE 23
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Detector layout

SHORE STATION SHORE SHORE STATION STATION ELECTRO OPTICAL CABLE ELECTRO OPTICAL ELECTRO OPTICAL CABLE CABLE DETECTOR STRUCTURES DETECTOR DETECTOR STRUCTURES STRUCTURES

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SLIDE 24
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Preliminary project for a km3 detector

1 main Junction Box 8 secondary Junction Boxes 64 Towers 16 storeys with 4 OM (active height 600 m) 4096 OM

˜ 180 m ˜ 180 m

Total instrumented volume ˜ 1 km3

Schematic detector layout

Detector architecture

  • Reduce number of structures

to reduce connections and allow underwater operations with a ROV ⇒ non homogeneous sensor distribution

  • Modularity

Reference layout used for the feasibility study

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SLIDE 25
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Comparison of different km3 architectures

Tower architecture (5832 OM) 18 storey towers with 4 OM per storey 20 m storey length 40 m spacing between storeys 81 towers arranged in a 9x9 square lattice 140 m spacing between towers Homogeneous lattice architecture (5600 OM) Strings with 16 OM spaced by 60 m 400 strings arranged in a 20x20 lattice 60 m spacing between strings

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SLIDE 26
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Comparison of different detector architectures

2 3 4 5 6 10-3 10-2 10-1 100

Log10 Eµ (GeV)

2 3 4 5 6 10-2 10-1 100

Log10 Eµ (GeV)

NEMO Tower detector 5832 PMTs 60 kHz NEMO Tower detector 5832 PMTs 20 kHz Homogeneous lattice detector 5600 PMTs 20 kHz

Effective areas and median angles for two different detector architectures and different optical background rates

Simulations performed with the ANTARES simulation package

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SLIDE 27
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

The NEMO Phase 1 project

A step towards the km3 detector

EO CABLE EO CABLE

Length – 25 km 10 Optical Fibres I TU- T G-652 6 Electrical Conductors Φ 4 mm2

Realization of a detector subsystem including all critical components

SHORE LABORATORY SHORE LABORATORY

1 Main Junction Box 2 Secondary Junction Boxes 2 NEMO Towers

UNDERWATER LABORATORY UNDERWATER LABORATORY

Project jointly funded by INFN and MIUR

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SLIDE 28
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

The NEMO tower

16 storeys spaced by 40 m 4 OM per storey 64 OM per tower 600 m active length Packable structure realized with 20 m long glass fibre tubes

“Tower” structure

Semi rigid structure Tensioning and electro-optical cables are kept separated The structure can be packed for transportation and deployment

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SLIDE 29
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

The NEMO tower

Deployment of the tower

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SLIDE 30
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

The NEMO tower

Study by Sonsub S.p.A.

Deployment of the tower

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SLIDE 31
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Junction Boxes

Preliminary design of the JB container pressure-compensated with

  • il

Pressure vessel for electronics devices Internal cable layout Fiberglass container and it’s components

Alternative design to the Titanium container (Antares-like)

Aim

Decouple the two problems of pressure and corrosion resistance

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SLIDE 32
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Junction Boxes

Design specifications

  • electronics device dimensions
  • material with high stiffness/cost ratio
  • finite element analisys to check stress

concentration

Electronics steel container

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SLIDE 33
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Junction Boxes

JB internal layout

Fibreglass container ˜ 1 m side

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SLIDE 34
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Data transmission

Objective

  • 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

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SLIDE 35
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Data transmission system

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 8 7 6 5

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 tower couple. All the fibres coming from the secondary JB go directly to shore (connection to the main electro-

  • ptical cable inside the main JB)

Mostly passive components Very low power consumption

Tower Secondary JB Primary JB

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SLIDE 36
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Data transmission system

B1

Interleaver

… 1 16 17 32 33 48 49 64 65 80 81 96 97 112 113 128

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

200/100

A1

…

D1

…

200 GHz 200 GHz

200/100

C1

…

F1

…

200 GHz 200 GHz

200/100

E1

…

H1

…

200 GHz 200 GHz

200/100

G1

…

Secondary Secondary JB JB

Tower Tower base base

STM1 flux, 155 MB per channel

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SLIDE 37
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Power budget

Storey power load (4 OM + storey electronics + additional sensors) 20 W x 16 storeys 320 W + additional power load at the tower base (electronics, sensors, …) 100 W

Total power load per tower 420 W x 64 towers 27 kW Power losses

AC/CD conversion Cable losses Transformers

η ˜ 0.5 Total power needed ˜ 60 kW

+ JB power load (electronics, sensors, …), 300 W per JB 3 kW

Total power load 30 kW

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SLIDE 38
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Power distribution system

NEMO PHASE 1 POWER SYSTEM NEMO PHASE 1 POWER SYSTEM

Main electro – optical cable 25 km - 4x4 mm2 Primary JB

Frame

Secondary JB Secondary JB Primary JB – Secondary JB electro – optical cable 600 m - 4x4 mm2 Secondary JB – Secondary JB electro – optical cable 400 m – 4x4mm2 Secondary JB – tower base electro – optical cable 300 m - 4x4 mm2 Wet-mateable connector

Tower base Tower base

Transmission Primary Distribution Secondary Distribution

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SLIDE 39
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Power distribution system

sensors

electronics

PMT

∼ =

PMT PMT PMT

Storey box ac/dc converter Electro-optical cable ac monophase

dc

SECONDARY DISTRIBUTION SYSTEM STOREY DISTRIBUTION SYSTEM

Storeys

∼ ∼ =

Electric load storey 16

∼ ∼ = ∼ ∼ = ∼ ∼ =

Base Tower CONNECTION

Secondary JB

JB second. - base tower Electro-optical cable Electric load storey 1 Electric load storey 2 Electric load storey 3

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SLIDE 40
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Power distribution system

Avaliable connectors Avaliable connectors

PRIMARY JB SECON D. JB SECON D. JB

MAIN FEEDING 4 fibre optical 4 electrical wires

Tower

SECURITY FEEDING 2 fibre optical 2 electrical wires

Control system

Tower

Control system Control system

The power control system should be able to:

  • monitor physics parameters

(temperature, humidity, current, voltage, etc.) inside the boxes,

  • switch the power on and off,

individually, to the feeding lines both under ordinary and fault conditions,

  • reveal the electric fault and

remotely control the breakers in

  • rder to continue feeding the JB

interested by the fault. The communication among the field control levels will be realized using electrical wires (there aren’t optical fibers available), while, the communication between field control systems and shore will be realized with optical fibres.

Control system

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SLIDE 41
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Connectors

Part of the connections (all those inside the tower) will be performed in air during the tower assembling Some connections (link of the tower with the Junction Box) must be performed underwater Wet mateable connectors that can be ROV

  • perated exist (Ocean Design)

These hybrid connectors can be configured for up to 8 optical fibres and/or electrical circuits Well tested technology - Solution adopted in Antares Expensive connections must be minimized

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SLIDE 42
  • P. Piattelli, HENA Workshop, Paris, june 16-17, 2003

NEMO

Summary and outlook

  • Site selection

– The Capo Passero site close to the coast of Sicily has been deeply studied – The results show that it is an excellent location f or the km3

  • Feasibility study

– All the critical detector components and their installation has been analysed in detail – Technologies and costs (120 M€) af f ordable

  • Present activity

– Phase 1 project to realize a subset of the detector including all the critical components

  • Future plans

– Construction of the km3 within a large international collaboration