Transcript ATARES: a system of underwater sensors looking for neutrinos

ANTARES: a system of underwater
sensors looking for neutrinos
Miguel Ardid
IGIC- Universitat Politècnica de València
on behalf of the ANTARES Collaboration
• Introduction
• Detector overview
• Optical modules
• Data acquisition system
• Calibration system
• Construction milestones & schedule
• Summary and conclusions
UNWAT – SENSORCOMM
Valencia, 18th October 2007
ANTARES
• ANTARES (Astronomy with a Neutrino Telescope and Abyss
environmental RESearch) Collaboration is deploying a 2500 m
deep 0.1 km2 underwater neutrino telescope in the Mediterranean
Sea
• It is the largest neutrino telescope under construction in the
northern hemisphere.
• The aim of the telescope is to detect high energy neutrinos,
which are elusive particles expected from a multitude of
astrophysical sources.
• ANTARES also aims to provide a research infrastructure for
deep sea scientific observations.
Introduction
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
ANTARES Collaboration
NIKHEF, Amsterdam
KVI,Groningen
IFREMER,Toulon
& Brest
DAPNIA, Saclay
IReS, Strasbourg
GRPHE, Mulhouse
CPPM Marseille
IGRAP, Marseille
COM, Marseille
ITEP
Moscow
Bucharest
Genova
Pisa
IFIC
Valencia
IGIC- UPV
Gandia
Introduction
Erlangen
Bari
Roma
LNSCatania
Bologna
23 Institutions from 7 European countries
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
Why neutrino astronomy?
protons E>1019 eV (10 Mpc)
Cosmic accelerator
neutrinos
gammas (0.01 - 1 Mpc)
protons E<1019 eV
1 parsec (pc) = 3.26 light years (ly)
Photons: absorbed on dust and radiation
Protons/nuclei: deviated by magnetic fields, reactions with radiation
Introduction
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
Why neutrino astronomy?
•
Neutrinos (ν’s) are elementary particles:
– Extremely small mass, no electric charge, very small interaction
difficult to detect
– Are produced in nuclear fusion (e.g. stars) or fission (e.g. nuclear power plants) processes
– From Sun reaching Earth ~ 1011 ν/cm2
•
Neutrinos traverse space without deflection or attenuation
– they point back to their sources (Search for astrophysical point sources)
– they allow for a view into dense environments
– they allow us to investigate the universe over cosmological distances (Search for Big Bang
relics)
•
Neutrinos are produced in high-energy hadronic processes
→ distinction between electron and proton acceleration.
•
Neutrino is a good key for particle physics & cosmology
– Magnetic monopoles, topological defects, Z bursts, nuclearites, …
Introduction
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
Detection Principle
p, a
nm
m
p Cherenkov light
from m
nm
g
Sea floor
g
3D
PMT
array
43°
m
interaction
n
Introduction
Reconstruction of m trajectory (~ n)
from timing and position of PMT hits
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
Why so large? so deep? Why …?
• Why so large? Neutrino detection requires huge target masses
due to the low probability of interaction → use naturally
abundant materials (water, ice)
• Why so deep? A large shield is needed in order to avoid masking
from other cosmic particles → deep inside the earth
• Why so many optical elements? In order to reconstruct the muon
track, the Cherenkov light should be detected. Attenuation length
of light in water = 52 m.
• Why calibration systems? For the muon reconstruction a good
accuracy of the position of the optical sensors is needed (~ 10
cm) together with a good timing resolution (< 1 ns)
Introduction
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
Site
ANTARES shore station
Toulon
40 km
submarine cable
-2475m
Detector overview
8
Design
•
•
•
•
2500m
900 PMTs
12 lines
25 storeys / line
3 PMTs / storey
9 lines + IL deployed (675 PMTs)
m
5 lines connected and taking data (375450
PMTs)
40 km to
shore
Junction
Box
~70 m
Interlink cables
Modular detector
Modular detector  easily expandable to larger dimensions
Nearby Large Infrastructures and Scientific Laboratories
Detector overview
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
Storey: Basic detector element
Optical
Beacon
for timing
calibration
(blue LEDs)
1/4 floors
Optical Module in
17” glass sphere
Hydrophone RX
Local Control Module
(in the Ti-cylinder)
Detector overview
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
Optical Modules
Optical Modules
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
Optical Modules
Blow-up of an Optical Module
Main specs
 Sensitive area  500 cm2
 Transit time spread < 3.6 ns
(FWHM)
 Dark count (@ 1/3 SPE) < 10 kHz
 Peak/valley > 2
Base
4
3
P/V
LED
PMT
m-metal
cage
TTS (ns)
PMT: 10”
Hamamatsu R7081-20
4
2
3
1
2
0
TTS
Specs: < 3.6 ns
0
Gel
100
200
300
400
500
600
700
800
P/V
Specs: > 2
1
0
0
100 200 300 400 500 600 700 800 900
The 900 PMT’s have been fully characterized
900
Data Acquisition System
Main processes in the DAQ system
DAQ Hardware
main hardware components in the
electronics module of a storey
Local Control Module
Inside a Local Control Module
POWER_BOX
LCM_DAQ
LCM_CLOCK
ARS_MB
x3
x 4 in case
of LED
beacon
COMPASS_MB
For some LCM’s,
additional cards for:
 LED beacon
 Hydrophone
UNIV1
Front-end: ARS & Motherboard
The PMT signals (anode and dynode D12) are processed by the Analogue Ring Sampler
In the same chip are gathered
 A comparator  Flash ADC (up to 1GHz sampling)
 An integrator  Pipe-line memory
 A clock
 Fast output port (20 Mb/s)
ASIC full custom chip
4 x 5 mm2, 68000 transistors
200 mW under 5 V
 A Pulse Shape Discriminator




Parameters adjustable via SC
Gain
Gauge for PSD
Integration timing
Thresholds …
The motherboard is equipped with 3 ARS’s.
 By mean of a token ring, 2 of them are
activated in turn
reduction of dead time
 3rd one used for complementary trigger
purposes
Data Acquisition system
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
DAQ Board & Data Transmission
The main functions of the DAQ board are:
RISC m-processor
 Readout and packing of the data produced by the ARS’s.
 Ethernet node
 Transmission of the resulting data through the line network.
 Processing of slow control messages.
Cf. next slide
 Conversion to optical signals on 1 fiber (100 Mb/s)
Bi-directional transceiver
LCM
100 Mb/s link
1 Gb/s link
LCM
M
U
X
MLCM 1
LCM
MLCM 2
optical bi-directional signals are merged
 2 fibers (Rx and Tx) ensure the
communication with the SCM
 The color is different for each sector
Data Acquisition system
JB
MLCM 4
At the level of the MLCM (i.e. sector level):

Line 1
d
e
M
U
X
MLCM 3
LCM
To shore
(MEOC)
SCM
MLCM 5
At the level of the SCM
(i.e. line level):
 colors are (de)multiplexed by DWDM’s
 the communication with shore is done via
two fibers per line through the Junction Box
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
Slow control
Managed by the main processor
Messages (requests and answers) are interleaved with ARS data (same fiber)
Main tasks:
 Configuration of the detector (for instance ARS’s)
 Supervision of the state of the detector: temperature, voltages, consumption …
Dedicated m-controller with ADC’s and DAC’s




to measure temperatures and humidity
to command/monitor high voltages on PMT
formatting of data
an interface with compass/inclinometers
TCM2 Dedicated circuit with:
 2-D inclinometers for roll and pitch measurements
 3-D magnetometers for compass bearing
Main performances:
 .5 to 1 for compass bearing
 .2 for tilt angles
 1 mT for magnetic field
In combination with the acoustic positioning:
Data Acquisition system
reconstruction of the line shape
positions in space of the optical modules
Calibration systems
• Main calibration systems are presented in other talks:
– Positioning Calibration (P. Keller’s talk)
• To determine and monitor the position of optical modules
– Timing Calibration (F. Salesa’s talk)
• To know the time offsets and get a good timing resolution
– Instrumentation Line + Acoustic detection (R. Lahmann’s
talk)
• Monitor environmental and physical variables that could play a role
in any system of the telescope
• Equipment for marine science research
• Study the viability of the acoustic detection of neutrinos
Calibration systems
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
Construction milestones
• 1996-1999: R&D and site evaluation period.
• 1999-2004: Prototype lines
• 2004-2005: Final design line evaluation: Line0 (test of
mechanics) & MILOM (Mini Instrumentation Line with
Optical Modules)
• February 2006-October 2007: 9 lines + IL deployed, 5 lines
connected and operational, starts standard operation
• March 2008: The whole detector will be finished and ready
to work at full efficiency for science operation
Construction Milestones
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
Line 1 deployment
Construction Milestones
ROV connection of Line 1
Construction Milestones
M. Ardid for ANTARES Collaboration
Pictures courtesy of IFREMER
UNWAT – SENSORCOMM
Valencia, 18th October 2007
Hundreds of neutrino candidates
already detected
Upward going muon track reconstructed (height vs. time, q = 69º) during shift 07/09
Track predicted depending on
orientation
Downgoing muon
Construction Milestones
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
Summary and conclusions
• ANTARES Collaboration pursued the challenge of
building an undersea neutrino telescope as a sophisticated
and precise system of underwater sensors in a hostile
environment
• The design, construction and first results have been shown
• After a hard job, there is now almost half neutrino
telescope operational and working within specifications,
and will be completed early next year.
• For the first time, an undersea neutrino detector
(ANTARES) “sees” neutrinos (most likely atmospherics)
• New challenge: KM3NeT, a cubic kilometre undersea
neutrino telescope (see C. Bigongiari’s talk)
Summary and conclusions M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007
ANTARES: a system of underwater sensors
looking for neutrinos
Thank you for the attention
The End
M. Ardid for ANTARES Collaboration
UNWAT – SENSORCOMM
Valencia, 18th October 2007