Status of the NEMO project

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Status of the NEMO project
E. Migneco
Istituto Nazionale di Fisica Nucleare Laboratori
Nazionali del Sud
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Layout of the talk
Update on site exploration activities Recent
results on Capo Passero Some architectural issues
about the km3 Comparison of different detector
structures Angular resolution and pointing
accuracy of the km3 detector The NEMO Phase-1
project Status of the activities at the Catania
Test Site The NEMO Phase-2 project Shore and deep
sea infrastructures at Capo Passero Electro-optica
l cable Conclusions and perspectives
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The NEMO collaboration
INFN Bari, Bologna, Catania, Genova, LNF, LNS,
Napoli, Pisa, Roma Università Bari, Bologna,
Catania, Genova, Napoli, Pisa, Roma La
Sapienza CNR Istituto 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 dellInformazione (ISCTI)
More than 70 researchers from INFN and other
italian institutes
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The Capo Passero site
In a six years activity the NEMO collaboration
has selected a deep sea site offshore Capo
Passero (Sicily) with optimal oceanographycal and
environmental properties The site has been
proposed in january 2003 to ApPECas a candidate
for the km3 intallation

• Depths of more than 3500 m are reached at about
  100 km distance from the shore
• Water optical properties are the best observed in
  the studied sites (La 70 m _at_ ? 440 nm)
• Optical backgroung from bioluminescence is
  extremely low
• Stable water characteristics
• Deep sea water currents are low and stable (3
  cm/s avg., 10 cm/s peak)
• Wide abyssal plain, far from the shelf break,
  allows for possible reconfigurations of the
  detector layout

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Optical water properties
Comparison of Capo Passero and Toulon sites
Optical water properties have been mesured in the
summer 2002 in Capo Passero and Toulon in two
joint NEMO-ANTARES campaigns
Absorption lengths measured in Capo Passero are
compatible with optically pure sea water
data Large differences 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
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Optical background in Capo Passero
Data taken in collaboration with ANTARES
Background depth dependence in agreement with
biology data (bioluminescent bacteria count)

• PMT 10
• Thres .5 SPE

Dead time
Fraction of time with rate gt 200 kHz
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Distribution of bioluminescent bacteria
Autumn 2000 data
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Seasonal dependence of optical properties
March 2002 data
Winter 2003 data
Noise at 0.3 s.p.e. 28.5 ? 2.5 kHz
23/11/03 - 17/12/03 Noise at 0.25 s.p.e. 28.4 kHz
The measured value of 30 kHz is compatible with
pure 40K background
No seasonal dependence observed
Absorption length Data taken in Aug 03 (2) Aug
02 (3) Mar 02 (4) May 02 (2) Dec 99 (2)
Average values 28503250 m
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Feasibility study for the km3 detector
Detector architecture issues Reduce the number of
structures to reduce the number of underwater
connections and allow operation with a
ROV Detector modularity
Towers with non homogeneous distribution of
sensors
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The NEMO tower
Mechanical structures for the km3 studied in
order to optimize the detector performance Modular
structure composed by a sequence of 15 m long
storeys interconnected by tensioning cables. Full
height 750 m. Power and data cables are kept
separated from the tensioning ones
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Simulation of dynamical behaviour of the tower
Side view
Top view
10 m

• Complete tower
• 16 floors floor length 15 m floor spacing 40 m
  150 m between seabed and first tower floor
• Water current 10 cm/s (peak value measured in
  Capo Passero)
• Total time needed for complete tower unfurling
  16 minutes
• Displacement between buoy (top) and anchor
  (bottom) of tower about 12 m after achievement of
  static conditions
• The tower is a semi-rigid tensioned structure
  well constrained against torsion and bending

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Alternative detector geometries
NEMO_140
String-dh_140_20
String-d_125_16
5832 PMT 81 strings String height 680m (18
floors/string) V 0.88 km3
5800 PMT 100 strings String height 912 m (58
PMT/string) V 1.15 km3
20 m
16 m
5832 PMT 81 strings String height 680m
(18floors/tower) V 0.88 km3
140 m
125 m
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Comparison of tower and string detectors
Up-going muons
35 kHz background labs 70m_at_450nm
Eµ 103 104 GeV

• ? string-dh_140_20
• ? string-d_125_16
• ? NEMO_140

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Tower detector performance
Sensitivity Sensitivity to point-like sorces
(Ev-2 spectrum)
Reconfigurability Effective areas with different
element spacing
IceCube simulations from Ahrens et al. Astrop.
Phys. 20 (2004) 507
tower floor spacing spacing Black line 140 m 40
m Red square 300 m 60 m Black points 300 m 40 m
NEMO 81 towers 140m spaced - 5832 PMTs IceCube 80
strings 125m spaced - 4800 PMTs
NEMO search bin 0.3 IceCube search bin 1
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Determination of the angular resolution
Observation of the Moon shadowing effect on the
flux of atmospheric muons
(Simulated time 1 year)
100 days needed to observe a 3? effect
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Absolute pointing accuracy
Check of the detector pointing accuracy with the
shadow of the Moon performed by introducing a
rotation around the z axis of the detector
coordinate system
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The NEMO Phase-1 project
Validation of the technological solution proposed
for the realization and installation of the km3
detector Realization of a system including all
the key elements of the km3 Mechanical structures
(talk by M. Musumeci) Optical end environmental
sensors (talk by E. Leonora) Read out electronics
(talks by C.A. Nicolau, D. lo Presti) Data
transmission system (talk by G. Bunkheila) Power
distribution system (talk by R. Cocimano) Acustic
positioning system Time calibration system (talk
by M. Ruppi) System will be installed at a depth
of 2000 m at the LNS Test Site offshore
Catania Realization of main components completed.
Integration starting Project completion may 2006
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The NEMO Phase-1 project
Underwater infrastructure realized by the
Laboratori Nazionali del Sud to test detector
prototypes A seismic and environmental
observatory of INGV has been istalled and
connected to the EO cable
SN-1
Shore station
North branch 5.220 m
Double armed cable 2.330 m
BU
Single armed cable 20.595 m
NEMO Phase-1

• Realization of a subsystem of the km3 including
  key elements of the detctor
• Shore and deep sea infrastructures already
  realized
• Project jointly funded by INFN and MIUR
• Completion planned in the first half of 2006 with
  the deployment and connection of a junction box
  and a fully instrumented four storey tower

South branch 5.000 m
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NEMO Phase-1 scheme and deployment schedule
Mini-Tower unfurled
NEMO mini-tower (4 floors, 16 OM)
Deployment of JB and minitower april-may 2006
Deployedjanuary 2005
Junction Box
TSS Frame
300 m
Mini-Tower compacted
15 m
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January 2005 deployment
Deployment of two cable termination frames
equipped with EO wet mateable connectors Deploymen
t and connection of an acoustic detection
station Deployment and connection of the SN-1
seismic and environmental monitoring station
Validation of ROV connection operations System
operative and in data taking since january
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The NEMO Test Site a multidisciplinary laboratory

• Submarine Network-1, a deep sea station for
  on-line seismic and environmental monitoring by
  INGV. The NEMO-SN1 is the first active node of
  ESONET (European Seafloor Observatory NETwork)
• O?DE (Ocean noise Detection Experiment), for
  on-line deep sea acoustic signals monitoring (4
  hydrophones 30 Hz - 40 kHz ? measurement of
  background noise for neutrino acoustic detection )

The O?DE station
SN-1 deep sea station
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OnDE first results
Fluctuations of noise level are strong below 20
kHz. At higher frequency PSD 25?2 ?Pa2/Hz
(H1 sensitivity -175 db)
April 10 July 17 2005 from 040000 - to
040230
All Hydrophones (except H4) measure the same
noise level at all frequencies.
The exact position of the four hydrophones is
known, this information will be used to locate
the source position (direction)
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Tower mechanics
Floors (marine aluminum)
All mechanical components ready and in
house Starting integration
Anchor (iron)
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Junction Box

• Data transmission electronics
• Power distribution and control system
• Optical fibre splitters

Electro-optical connections
Pressure vessels
Fibreglass container
The design decouples the corriosion and pressure
resistance problems
1 m
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Floor readout chain
Inside Optical Module (OM)
200 Msample/s 8bit (logarithmic compression)
Underwater electrical Cable
Hamamatsu 10"  R7081 SEL
DAQ board
Inside Floor Control Module (FCM)
Floor Control Module Interface Transmit OM and
Slow Control data (water parametres, OM position,
internal sensors) to shore through Optical Fibre
(DWDM technology)
e.o. transceiver
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NEMO Phase-1 Optical Module electronics
Data Acquisition
- 200Msample/s - 8bit (pseudo-logarithmic
compression) - User programmable digital
threshold level
Floor Control Module
On-board sensors
- Temperature - Humidity
Final version successfully tested - Production in
progress
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New low power electronics for the Optical Module

• Sampl .Freq. 200MHz
• Trigger level remote controlled
• Max Power dissipation less than 200 mW
• Input dynamic range 10 bit
• Dead time lt 0.1.
• Time resolution lt 1 ns

New full custom VLSI ASIC Presently under final
laboratory testing Will be tested in some optical
modules in Phase 1
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Data transmission
FEM1
FEM0
FEM1
Sea
Optical Module data come from 4 (up to 8) Front
End Modules (FEM)
Off-shore floor data concentration is carried out
by a Floor Control Module (FCM)
One floor data is received on-shore by a twin FCM
board, plugged on a host machine (FCM Interface)
FEM2
FEM3
At the FCMI, data are made available on memory
buffers (Front End Buffers, or FEBs). Each FEB
contains formatted data issued from the
corresponding Front End Module
Shore
FCMI
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NEMO phase-1 DWDM data transmission system
Very low power consumption (mostly passive
components)

• First Stage (Multiplation Tower Floor)
• 8 Channels coming from the even/odd tower floors.
  The channels are multiplexed in one fibre by
  means of AddDrop modules.

Tower B
Tower A

• Second Stage (Multiplation Junction Box)
• Even and Odd channels Bands coming from a tower
  are multiplexed by means of Band Coupler modules

• Third Stage (Demultiplation on Shore Station)
• 16 channels coming from 1 tower are demultiplexed
  by means of a single Demux module.

mux-demux
All the fibres coming from the Junction Box go
directly to shore, the same path is dedicated to
slow control signals (16 channels) in the
opposite direction.
mux-demux
Junction Box
System realized by TELCON and tested and
certified by ISCTI
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NEMO phase-1 DWDM data transmission system
The system, coupled with the Floor Control
Module, has been successfully tested and
certified by an external agency (ISCTI) on July
2005
Tower B
Transceivers mux-demux
Tower A
Transceiver
mux-demux
Bit error rate lt 10-9 (for a single channel,
after transmission over 100 km fibre optical
cable)
FCM board with transceiver
Junction Box
mux-demux
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NEMO Fase 1 sistema di calibrazione temporale
To upper floor
Pulser
From lower floor
Optical pulsers are used to illuminate the
Optical Modules at scheduled times An optical
fibre network is used to convey the light
efficiently to the Optical Modules Reliable
solution for km3 detectors where sensors can be
spaced by several tens of meters.
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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
• Purchase of the electro-optical cable (gt50 kW)
  under way
• A building (1000 m2) located inside the harbour
  area of Portopalo has been acquired. It will be
  renovated to host the shore station
• Project completion planned in 2007

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The Phase-2 electro-optical cable
DC solution with sea return
Working Voltage 10 kV Power gt 50 kW
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Phase-2 Electro Optical cable termination
To shore
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View of the cable landing area
Shore Station
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The Shore Station building (present status)
Existing building Total surface 800 m2

• Building acquired
• Renovation project defined and under approval
  procedure by the Sovraintendenza ai Beni
  Culturali
• Start of construction work for renovation in
  2006
• Station completion in 2007

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The Shore Station (project)
View from the north side
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The Shore Station (project)
View from the east side
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The Shore Station (project)
600 m2 for laboratories, data acquisition and
guest house 400 m2 for assembling area
Plan of ground floor
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The Shore Station (project)
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NEMO status and perspectives
Site choice The site selected offshore Capo
Passero shows optimal characteristics for the
installation of the km3
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 techologies for the
km3 Realization of Phase-1 (2006) and Phase-2
(2007) projects Realization of shore and deep sea
infrastructures at Capo Passero
Future developments RD in the KM3NeT Design
Study towards the realization of a km3 detector