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Deep-sea neutrino telescopes Prof. dr. Maarten de Jong Nikhef / Leiden University.
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Transcript of Deep-sea neutrino telescopes Prof. dr. Maarten de Jong Nikhef / Leiden University.
contents
Neutrino astronomy
Antares
‒ prototype
KM3NeT
‒ next generation neutrino telescope
issues, ideas
neutrinos
p
Scientific motivation:– origin cosmic rays– creation& composition relativistic jets– mechanism cosmic particle acceleration– composition dark matter neutrino telescope
Why neutrinos?– no absorption– no bending
Neutrino astronomy
1960 Markov’s idea:
range of muon
detect Cherenkov light
transparency of water
Use sea water as target/detector
How?
muon
wavefront1 2 3 4 5
~few km
~100 m
muon travels with speed of light (300,000 km/s) → ns (10 cm) @ km
neutrino
interaction
1.5deg.
θTeVE
General layout
lightdetection
transmissionof (all) data
datafilter
real-time event
distribution
shore station
3-5 km 800 m
50-100 km
1-2 km>1000 km
Antares
1997‒2005– R&D– site explorations– measurements of water properties
2005‒2008– construction-operation
2008‒2017– operation
prototype neutrino telescope ‒ 100 persons ‒ 25 M€
Hydrophoneacoustic positioning
10” PMTphoton detection
Electronicsreadout
titanium framemechanical support
Optical beacontiming calibration
~1 m
Detection unit
PMT100 Mb/s
e/o
Ethernetswitch
1 Gb/se/o e/o
optical fiber (21)
DWDMfilter
optical fiber (4)
40 km
5x15 m
5‒25x15 m
CPUFPGA
container
container
container
deep-sea network
penetrator (3)
connector (3)
penetrator (2)
wet-matable connector (2)
1 km
(40)
junctionbox
data filter data filter data filter
time
Ethernet switch
off-shore
on shore
CPU CPU CPU CPU CPU CPU
data flow
data filter data filter data filter
time
Ethernet switch
off-shore
on shore
CPU CPU CPU CPU CPU CPU
data flow
data filter data filter data filter
time
Ethernet switch
off-shore
on shore
CPU CPU CPU CPU CPU CPU
data flow
Antares deep-sea infrastructure
– 1 km3
• 900 PMTs, hydrophones, ADCP, seismometers, etc.• 10 kW, 1 GB/s
– one main electro-optical cable • 50 km, AC, 1 cupper conductor + sea return
‒ network• active multiplexing locally (Ethernet standard)• passive multiplexing based on DWDM technology
– low number of channels for reliability of offshore transceiver stability)
‒ operation• 10 years (some maintenance’• data transmission signal recovery by amplification
KM3NeT
2005‒2008– design study
2008‒2012– preparatory phase
2013‒2017– construction
definitive neutrino telescope ‒ 300 persons ‒ 200 M€
deep-sea network
j+1
j
optical modulator
laser
laser
receiver
receiver
integrate timing system (GHz = ns) minimise offshore electronics
DWDM shore station
DWDM
penetrator (1)
wet-matable connector (1)
6 m
Mechanical cable connection
Data cable storage
Mechanical cable storage
Frame
Optical module
Mechanical holder
Needs new deployment technique
Storey
1 Digital Optical Module = Dom2 Dom’s on 1 bar = Dom-bar
20 Dom-bar’s on 1 tower = Dom tower
suddenEddie currents
Temperature
Earth & Sea sciences
France
observatoryfood supply
Bioluminescence
short lived (rare) eventsdominate deep-sea life
permanent observatory
time profile
KM3NeT
deep-sea infrastructure– 10 km3
• >100,000 PMTs, hydrophones, ACDP, seismometers, etc.
• <100 kW, 100 GB/s– two main electro-optical cables
• 100 km, DC, 1 cupper conductor + sea return‒ network
‒ PON, point-to-point + amplification‒ new Ethernet standard
• Precision-Time-Protocol (”White Rabbit”)‒ operation
• 10 years without maintenance
Deep-sea infrastructure materials
– containers (glass, Ti, Al) mechanics
– drag, deployment, etc. cables
– dry versus oil-filled– little experience with vertical orientation
wet-matable connectors– expensive (combined fiber and cupper wires)– bulky (problems with handling)
penetrators– source of single-point-failures (error propagation)
data taking & processing network
– high-bandwidth & long haul• integration of data transmission & timing (PTP)
– (real-time) data distribution• monitoring• archival• offline analysis (astronomy, etc.)
– external triggers• satellites, other infrastructures
computing– (real-time) data processing
• algorithms (reduction of complexity & parallelization of problem)• implementation (state-of-the-art OO-programming)• hardware (multi-core, GPUs)
Fiber technology data transmission
– laser/[A]PD• flexible (2 x transceiver = point-to-point link)• active feedback loop (intrinsically instable power, )• non-negligible electrical power consumption
– modulators• wavelength, phase, intensity, polarization• very low power• reliable
– amplification• long-haul communication
Energy transmission– ?
sensor– e.g. Bragg reflectrometer as deep-sea hydrophones
• sensitivity low weight…