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The NEMO Status Report
M.Taiuti
on behalf of the NEMO Collaboration
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Merida, Yucatan, Mexico
30th International Cosmic Ray Conference
July 3 - 11, 2007
The NEMO Collaboration
INFN
 Bari, Bologna, Catania, Genova, LNF, LNS, Napoli, Pisa, Roma
►
Universities
 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)
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Istituto Superiore delle Comunicazioni e delle Tecnologie dell’Informazione
(ISCTI)
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more than 80 researchers involved
A Northern Telescope for High Energy Neutrinos
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The small cross section and the expected low neutrino flux
require
 large volume telescope ~ 1 km3
 long observation time ~ yrs
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The atmospheric muon background requires
 a shielding > 2000 m water equivalent
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The Mediterranean Sea provides convenient sites
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ANTARES
Toulon 2400 m
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NEMO
Capo Passero 3400 m
NESTOR
Pylos 4000 m
NEMO R&D Activity
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Site location

More than 25 sea campaigns since 1998
Catania
INFN-LNS
TSN
TSS
NEMO-KM4
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NEMO-KM4
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 80 km off-shore
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 3500 m depth
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NEMO-KM4 Properties
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High water transparency
 Data compatible with pure salt water
properties
 No seasonal variations
 10” PMT thres. 0.5 p.e.
noise rate ~ 30 kHz
 Bioluminescence almost absent
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40K
Base line rate (Threshold 1)
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2.0%
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1.5%
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1.0%
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0.5%
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Geologically
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stable
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0.0%
0
7
14
21
28
35
Date (days since the 31 st of March)
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49
Time above 200 kHz
Reduced background, mostly from
decay
Counting rates (kHz)
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NEMO km3 Conceptual Design
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NEMO km3 Conceptual Design
► Proposed
lay-out
Tower
Secondary JB
 10 junction boxes
 81 towers
 5832 PMTs
Primary JB
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140-180 m
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Electro-optical cable to shore
140-180 m
The Expected Performances
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Simulations show excellent angular
resolution
and sensitivity
 NEMO
► 81
towers 140 m spaced
► 5832 PMTs
 ICECUBE
► 80
strings 125 m spaced
► 4800 PMTs
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IceCube simulations from Ahrens et al.
Astrop. Phys. 20 (2004) 507
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Sensitivity to a E-2 neutrino
spectrum from a pointlike source
 NEMO search bin 0.3°
 IceCube search bin 1°
The NEMO Phase-1 Activity
Single armored cable
20.595 km
Double armored cable
2.330 km
North branch
5.220 km
BU
Geoseismic station
SN-1 station (INGV)
Operating since
Jan 2005
South branch
5.000 km
NEMO
Phase-1
OnDE acoustic station
Operating from
Jan 2005 till Dec 2006
NEMO Phase-1
Operating since
16 Dec 2006
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Frame
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Jumpers 300m
Junction Box
Jumper
300m
Tower
The NEMO Junction Box
Marine Alum.
external frame
Transformer
Electronics
Electro-optical
connectors
Electro-optical
splitting box
Glass reinforced
plastic container
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Innovative design to decouple
the corrosion and pressure
resistance problems
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Successfully
deployed
Dec. 10, 2006
The NEMO Prototype Tower
Buoy
br
Floor 4
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FCM
 Length 15 m
 Vertical spacing 40 m
FPM
16 Optical Modules with 10” PMT
► Acoustic Positioning
ADCP
FPM
Floor 3
FCM
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 2 hydrophones per floor
 1 beacon on the tower base
br
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OM
CTD
Floor 1
FCM
FPM
FPM
FCM
br
OM
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H
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TBM
AB
Tower
HC
Base
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Environmental instrumentation
 1 compass + tiltmeter in each Floor
C*
br
Floor 2
4 floors
H
Control Module
 CTD (Conductivity-TemperatureDepth) probe on floor 1
 C* (attenuation length meter) on
floor 2
 ADCP (Acoustic Doppler Profiler
(including compass) on floor 4
The NEMO Tower
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Semi-rigid structure provides “easy”
assembly, transportation and
deployment
The 4-floor prototype has been
successfully deployed and is
operating since Dec. 16, 2006
Successfully
deployed
Dec. 15, 2006
4 floors
“Folded” tower ready
for transportation and deployment
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Successfully
connected
Dec. 16, 2006
Calibration - Preliminary Results
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Absolute positioning
 Long Baseline acoustic positioning system based on
five Acoustic Beacons
 3 autonomous beacons battery operated
 1 beacon on the Junction Box (not operating)
 1 beacon on the Tower base
250 m
350 m
 ≈ 1.5 ns
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Time offset determination
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 network of optical fibres to flash several OMs at
one time with fast LED light pulses
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Preliminary Results
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Systematics over one month
shows good water properties:



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baseline rate
burst fraction evaluated as time
above 1.2xbaseline
burst fraction evaluated as time
above 200 kHz
The Tower can recontruct
atmospheric muon tracks!
 January 24 2007 - Run R17 file 1
Event # 366059 13 PMT hit
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The NEMO Phase-2
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Infrastructures for an -3500 m
underwater site
 Electro-optical cable (50 kW – 20 fibres)
► Deployment
scheduled in summer 2007
► Deployment of DC/DC Converter beginning
2008
NEMO-KM4
 Shore station in PortoPalo di Capo Passero
► Building
under renovation. Completion
beginning 2008
 NEMO Tower
► Deployment
forseen by middle 2008
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to NEMO-KM4
Conclusions and Perspectives
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The NEMO Collaboration is working on a long-term R&D program
toward a km3 -telescope in the Mediterranean Sea
 An optimal candidate site has been found: NEMO-KM4
 The NEMO Phase-1, aiming to validate the proposed technologies, has
been successfully conducted at the Catania Test Site
Since Jan. 2005 the geoseismic and acoustic stations are fully operative
► The Junction Box and the mini-Tower has been deployed at the end of 2006
► Data taking is in progress
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 The NEMO Phase-2, aiming to realize the deep sea station at NEMO-KM4,
is in progress
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The deployment of the electro-optical cable is scheduled in 2007
► The set-up of the onshore station is in progress
► The deployment of a full-size tower is foreseen in 2008
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Toward the -Telescope
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EU funded the joint activity for a European-scale Design
Study for a km3 -telescope in the Mediterranean Sea
 KM3NeT: ANTARES-NEMO-NESTOR consortium
http://www.km3net.org/
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The experience gained will contribute to the advancement
of the KM3NeT activities
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