1. (NEutrino Mediterranean Observatory): Toward a km3 Neutrino Telescope
NEMO
(NEutrino Mediterranean Observatory):
Toward a km3 Neutrino Telescope
in the Mediterranean Sea
Marco Circella
Istituto Nazionale di Fisica Nucleare
Bari, Italy
on behalf of the NEMO Collaboration
Il “Toward” è stato aggiunto dopo la conferenza... (perciò non figura nel titolo dell’abstract né nei proceedings)

2. (NEutrino Mediterranean Observatory): Toward a km3 Neutrino Telescope
NEMO
(NEutrino Mediterranean Observatory):
Toward a km3 Neutrino Telescope
in the Mediterranean Sea
What we will be talking about:
a km3 Neutrino Telescope in the Mediterranean Sea?
R&D for a km3 Neutrino Telescope
the site selection
the NEMO apparatus: the “tower” approach
Prototyping activity: NEMO-Phase 1 and 2

3. Motivations for a km3 Neutrino Telescope in the Mediterranean Sea
No doubt we need a km3 detector for -astrophysics! Then:
a Mediterranean detector will complement the ICECUBE sky survey
crosschecks between the two detectors will be possible
it will be possible to observe the Galactic center

4. Constraints for a km3 Neutrino Telescope in the Mediterranean Sea
detector installation is an issue
optical background in sea-water due to 40K-decay and bioluminescence
the apparatus is not rigid in the sea currents
high-pressure salted water is not a friendly environment...

5. Solutions for a km3 Neutrino Telescope in the Mediterranean Sea
detector installation is an issue
keep the number of structures to a minimum, prepare structures which can be easily transported and deployed (the “tower” approach!)
optical background in sea-water due to 40K and bioluminescence
choose a suitable site!!!
the apparatus is not rigid in the sea currents
position monitoring system needed
high-pressure salted water is not a friendly environment...
low-cost solutions need to be developed for mechanical structures

6. NEMO R&D activities toward a km3 Detector
R&D for selected items:
low-consumption Front-End electronics
large area hybrid photomultiplier
material choice and design of mechanical structures
time calibration through a dedicated optical fibre system
Commercial solutions when available:
high-bandwidth SDH data communication system
Dense Wavelength Division Multiplexing (DWDM)
cables and connectors
power distribution
acoustic positioning system

7. see Tommaso Chiarusi’s presentation
NEMO km3 Optimal site
80 km
NEMO-KM4
80 km at SE of Capo Passero, Sicily
3500 m depth
more than 25 sea campaigns for characterization since 1998
very good characteristics as to: water optical properties, sea currents, optical background, sedimentation,...
1 primary Junction Box
8-9 secondary Junction Boxes
64-81 towers
140 m grid pitch
64-72 PMT on each tower
PMT in total
Huge apparatus of more than
1 km side and 800 m tall
see Tommaso Chiarusi’s presentation

8. NEMO km3 Telescope layout
Tower
Secondary JB
Electro-optical cable to shore
Primary JB m
NEMO km3 proposal: 10 junction boxes, 81 towers, 5832 PMTs

9. The tower approach (and design)
Semi-rigid structures, which can be “easily” assembled and packed
4 PMTs on each floor (two looking downwards, two looking horizontally)
after installation, floors are kept mutually perpendicular
PMT arrangement extensively investigated through simulations
“Folded” tower
for transportation and deployment
A tower floor
16 m
2 PMTs at each edge
NON mostrata per mancanza di tempo

10. The NEMO simulated performance
106107 GeV
103104 GeV
104105 GeV
105106 GeV
NON mostrata per mancanza di tempo
Muon effective area
Neutrino effective area
Median angle between muon simulated and reconstructed track

11. The Tower deployment
Remark: the tower design has been performed in tight connection
with leading underwater operation companies

12. The Tower deployment: tests
Installation and recovery test of a 1:5 4-floor tower performed in Spring 2004
mechanical properties of the tower and installation/recovery procedures extensively simulated
installation and recovery test of a full-size 4-floor tower will be performed in Fall 2005

13. The NEMO prototyping activities
Shore station in the port of Catania
2.5 km e.o. Cable with double steel shield
21 km e.o. Cable with single steel shield
Branching Unit
5 km e.o. cable
5 km
e.o. cable
Geoseismic station SN-1 (INGV)
The Catania test site:
25 km off the coast of Catania
2000 m depth
already equipped with a double-termination cable
80 km
25 km
Catania
TSS
TSN
NEMO-KM4
NEMO Phase 1
Il progetto prevede la realizzazione del dimostratore tecnologico di km3 al largo delle coste di Catania. Nel sito di installazione di Catania verranno depositati sul fondo del mare le 3 jb e la minitorre.
La torre modello nemo di 16 piani verrà installata a capo passero dopo il deployment del cavo

14. Installation of the cable termination panels at the test site
(January 2005)
Recovery of the two terminations of the cable
Installation of the termination panels
Deployment of the termination panels
ROV-connection of the acoustic monitoring system ONDE
ROV-connection of the geoseismic platform SN-1
(Remark: ONDE and SN-1 fully operational since January)
(see Giorgio Riccobene’s presentation)

15. Installation of the cable termination panels at the test site
(January 2005)
ROV connection

16. schedule: to be completed in 2006
NEMO Phase 1
Purpose: to test all critical components for the construction of the km3 detector
Structure: it comprises a junction box and a reduced-size tower (4 floors with 16 PMTs)
schedule: to be completed in 2006

17. The NEMO Phase 2 project:
building the infrastructures for a 3500 m deep-sea apparatus (& testing a full-size NEMO tower)
-3500 m
Interdisciplinary activities
NEMO-KM4
Long-distance electro-optical cable:
purchase in 2005, deployment in 2006
shore station in the port
(acquired; work in progress)

18. Conclusions & perspectives
The NEMO Collaboration is working on a long-term R&D program toward the construction of a km3 neutrino telescope in the Mediterranean Sea
The NEMO Phase 1 project is ongoing at an underwater test site offshore Catania:
- infrastructure (cable to shore, shore station) ready
- junction box to be deployed in early 2006
- a reduced-size tower to be deployed in 2006
The NEMO Phase 2 project has also started at the optimal km3 site:
- work to equip the onshore station started
- electro-optical cable to be purchased by the end of 2005, deployed in 2006
- full-size tower to be deployed in 2007
Working for the future neutrino telescope in the Mediterranean:
- ANTARES-NEMO-NESTOR consortium in the KM3Net EU Design Study:
- EU-sponsored activity for a European-scale Design Study for a km3 neutrino telescope in the Mediterranean Sea: project accepted for funding
- negotiations with EU about to start activity expected to start in early 2006
- 2nd VLVnT (Very Large Volume -Telescope) workshop to be held in Catania,
8-11 Nov. 2005
Probabilmente converrebbe aggiungere una riga all’ultimo punto “Working for...” dove si parla della collaborazione in atto con ANTARES