Isabella Amore Laboratori Nazionali del Sud - INFN, Catania International School of Cosmic Ray...
Transcript of Isabella Amore Laboratori Nazionali del Sud - INFN, Catania International School of Cosmic Ray...
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
International School of Cosmic Ray Astrophysics15th Course: "Astrophysics at Ultra-high Energies"
NEMO: a project for a km3 underwater detector for astrophysical neutrinos in the
Mediterranean Sea
Isabella Amore
20-27 June 2006, EriceEttore Majorana Centre
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
Why Neutrino Astronomy?
gammas 0,01-1 Mpc
protons E>1019 eV10 Mpc
High energy neutrinos
Astrophysicalsource
We want to measure neutrinos coming from astrophysical sources
1 parsec (pc) 3 ligth years
5 Gpc
Closest AGNs
Galactic radius (15 kpc)
TeV PeV EeV
Neutrinos traverse space without being deflected or absorbed:
– They can reach the Earth from cosmological sources– They point back to their sources– They allow to view into dense environments
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
Status of collaborationsBAIKAL, AMANDA: taking dataNESTOR, ANTARES, NEMO R&D: under constructionICECUBE: completion expected in 2010KM3NET – Mediterranean : EU Design Study 2006-2008
AMANDAICECUBE
BAIKAL
ANTARES
2400 m
NESTOR
3800 m
NEMO
3500 m
• In order to obtain the whole sky coverage 2 telescopes must be built
• The Galactic Centre is observable only from the Northern Hemisphere
Small scale detectors and demonstrators
km3 scale telescopes
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
The NEMO collaboration
INFNBari, Bologna, Catania, Genova, LNF, LNS, Napoli, Pisa, RomaUniversitiesBari, Bologna, Catania, Genova, Napoli, Pisa, Roma “La Sapienza”
CNRIstituto di Oceanografia Fisica, La SpeziaIstituto di Biologia del Mare, VeneziaIstituto 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 dell’Informazione (ISCTI)
More than 70 researchers from INFN and other Italian Institutes
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
NEMO R&D activities towards the Mediterranean km3
Site selection and long term monitoring
Feasibility study of the km3 detector
Installation of small scale prototypes
Realization of a marine infrastructure for the km3
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
The Capo Passero deep sea site
• It is located in a wide abyssal plateau far from shelf breaks and geologically stable.
• The average depth is 3500 m, the distance from shore is about 100 km.
• Optical properties of deep sea water are the best measured among investigated sites (absorption length close to optically pure water astro-ph\0603701)
• Optical background is low (30 kHz on 10’’ PMT at 0.3 s.p.e. threshold) and mainly due to 40K decay since the bioluminesce activity is extremely low.
• Underwater currents are very low (2.5 cm/s) and stable.
After eight years of activity in seeking and monitoring abyssal sites in the Mediterranean Sea the NEMO collaboration has chosen a deep sea site about 100 km SE of Capo Passero, in Sicily.The site has been proposed to ApPEC on january 2003 as candidate site for the installation of the km3.
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
Seawater optical properties
Optical properties have been measured in Capo Passero since 1998
Profiles as a function of depth of oceanographic and optical properties in Capo Passero
• Seasonal dependence of oceanographical
(Temperature and Salinity) and optical
(absorption and attenuation) properties
has been studied in Capo Passero
• Variations are only observed in shallow
water layers
• Seasonal dependence of oceanographical
(Temperature and Salinity) and optical
(absorption and attenuation) properties
has been studied in Capo Passero
• Variations are only observed in shallow
water layers
• Absorption lengths measured in Capo Passero are close to the optically pure sea water data
• Differences between Toulon and Capo Passero are observed for the blue light absorption
• Absorption lengths measured in Capo Passero are close to the optically pure sea water data
• Differences between Toulon and Capo Passero are observed for the blue light absorption
temperature
salinity
a440 c440
absorption @ 440nm absorption @ 440nm
attenuation @ 440nm attenuation @ 440nm
Lc=35.5 m
La=66.5 m
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
Optical background was measured
in Capo Passero @ 3000 m depth.
Data are consistent with 30 kHz background on
10”PMT at 0.3 spe
(mainly 40K decay, very few bioluminescence).
Optical data are consistent with biological measurements:
No luminescent bacteria have been observed in Capo Passero
below 2500 m
Optical background in Capo Passero
40K
Baseline rate~ 30 kHz
15
20
25
30
35
0 7 14 21 28 35 42 49
Co
un
tin
g r
ates
(kH
z)
0.0%
0.5%
1.0%
1.5%
2.0% Tim
e abo
ve 200 kHz
Days
30 kHz
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
Feasibility study for the km3 detector
main EO cablemain Junction Box
secondary JB
“tower”
Detector architecture has been studied in order to
Reduce the number of structures to reduce the number of underwater connections and allow operation with a ROV
Detector modularity
9 x 9 = 81 “Towers” with 3 dimensional and non homogeneous distribution of sensors
Conceptual detector layout
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
The NEMO tower
Height:compacted 15:20 mtotal 750 minstrumented 600 mn. beams 16 to 20n. PMT 64 to 80Beams:length 15 mspacing 40 m
The tower is a semi-rigid 3D
structure designed to allow easy
deployment and recovery.
High local PMT density is designed
to perform local trigger.750
m
10’’ PMTs
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
Expected detector performaces
SensitivitySensitivity to a Ev
-2 neutrino spectrum from point like sources
NEMO 81 towers 140m spaced - 5832 PMTsIceCube 80 strings 125m spaced - 4800 PMTs
Geometry “flexibility”Effective area for different detector geometries
spacing spacingtowers floors140 m 40 m
300 m 40 m
C. Distefano, NEMO, astro-ph/0605067 R. Coniglione, NEMO astro-ph/0605068
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
Validation of technologies: NEMO Phase 1
The NEMO Collaboration is undergoing the Phase 1 of the project, installing a fully equipped
deep-sea facility to test prototypes and develop new technologies for the km3 detector.
Shore laboratory port of Catania
e.o. cable from shore
TSS Frame
To be completed in 2006
Junction Box
NEMO mini-tower(4 floors)
Deployed on Jan 2005
underwater e.o. cable10 OF 6 conductors
Underwater test site: 25 km E offshore Catania at 2000 m depth
Realizaton of a system hosting all key elements for the km3 detector:
Mechanical structures; Optical and environmental sensors; Electronics; Data
transmission system; Power distribution system; Acoustic positioning
system;Time calibration system
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
Sea operations January 2005
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
The NEMO test site: a multidisciplinary laboratory
The ODE stationGEOSTAR SN-1 deep sea station
First data from 2000 m• GEOSTAR SN-1, a deep sea station for on-line seismic and environmental monitoring by
INGV. The NEMO test site is the Italian site for ESONET (European Seafloor Observatory
NETwork);
• ODE (Ocean noise Detection Experiment), for on-line deep sea acoustic signals
monitoring (4 hydrophones hydrophones 30 Hz - 40 kHz measurement of noise bkg for
neutrino acoustic detection ).
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
The NEMO Phase 1: the underwater station
TSS Frame
Junction Box
NEMO mini-tower(4 floors, 16 OM)
300
m
Mini-Tower compacted
Mini-Tower unfurled
15 m
Al alloy
Buoy
e.o. connection
The mechanical structure is
under final assembly at the
NEMO Test Site shore
laboratory
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
The Junction Box
Fiberglass external vessel
Power vesselselectro-optical
connectors
The Junction Box hosts the data transmission and power distribution system.
The JB is made of an Al cage, an extrenal fiberglass vessel and 4 steel pressure vessels: PV1, PV2, PV3 and Trafo Vessel.The space between fiberglass and PV will be filled with silicone oil.This solution permits to separate the corrosion and the pressure resistance problems.
1 m
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
NEMO Phase 1: Floor DAQ chain
Hamamatsu 10" R7081 SEL 200 Msample/s
Floor Control Module Board:
Transmit OM and slow Control data (water parametres, OM position, internal sensors) to shore through Optical Fibre (DWDM technology)
Optical Module (OM)
PMT tube FEM board
Underwater electrical Cable
e.o. transceiver
Floor Control Module Board (FCMB)
Optical modules
Floor control module
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
The NEMO Phase 2 project in Capo Passero
Objectives- Realization of an underwater infrastructure at
3500 m on the Capo Passero site- Test of the detector structure installation
procedures at 3500 m- Installation of a 16 storey tower- Long term monitoring of the site
Status
- The EO cable (≈48 optical fibres, 30÷40 kW) will
be deployed within 2007- The shore laboratory acquired, now in
restoration
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
Summary and outlook
• Site selection– The Capo Passero site has been deeply studied: the results show that it is an excellent location for a km3 telescope
• Feasibility study
– All the critical detector components and their installation have been analysed in detail
• Present activity
– NEMO-Phase 1 in Catania: installation of a subset of the detector including all the critical components
• Future plans
– NEMO-Phase 2 : Underwater infrastructure @ 3500 m in Capo Passero
… A large international collaboration will build the Mediterranean km3
Isabella Amore Laboratori Nazionali del Sud - INFN, Catania
We are eagerly waiting for the start-up !