Transcript ppt

Status of the ANTARES
Neutrino-Telescope
Alexander Kappes
Physics Institute
University Erlangen-Nuremberg
for the ANTARES Collaboration
WIN´05, 6.–11. June 2005
Delphi, Greece
 Introduction
 The ANTARES Detector
 First Results from Test-Lines
 Outlook
Cosmic accelerators
Supernova Remnant
(RX J1713.7-3946)
H.E.S.S.
Active Galactic Nuclei
Hubble
Gamma Ray Burst
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
(Bepposax)
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Detection of Cosmic Neutrinos
Čerenkov light:
Čerenkov angle: 42o
wave lengths used:
350 – 500 nm
Earth used as shield against
all other particles
 A !  X
low  cross section requires
large detector volumes

key reaction:
 +A! +X
Detector deployed in deep water / ice to
reduce downgoing atmospheric muons
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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Physics with Neutrino Telescopes

Searching for point-like neutrino sources

Measurement of diffuse neutrino flux

Search for Dark Matter (WIMPs)

Search for exotic particles:
e.g. magnetic monopoles
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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Why a Neutrino Telescope in the Mediterranean Sea?


Sky coverage complementary to telescopes at South Pole
Allows to observe the region of the Galactic Centre
South Pole
Mediterranean Sea
Mkn 421
Mkn 501
Crab
SS433
Not seen
Mkn 501
Crab
SS433 GX339-4 VELA
Galactic
Center
Not seen
Sources of VHE  emission (HESS 2005)
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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The ANTARES Collaboration
20 institutions from
6 European countries
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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The ANTARES Detector
Hostile environment:
 pressure up to 240 bar
 sea water (corrosion)
Buoy
Optical
Module
Submersible
Junction
Box
artist´s view
(not to scale)
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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One of 12 ANTARES Strings
 Buoy

keeps string vertical
(horizontal displacement < 20 m)
 Storey


3 optical modules (45o downwards)
electronics in titanium cylinder
 EMC
cable

copper wires + glass fibres
 mechanical connection between storeys
 Anchor

connector for cable to junction box
 control electronics for string
 dead weight
 acoustic release mechanism
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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Optical Module
optical module
B-screening
Alexander Kappes
University Erlangen-Nuremberg
Glass spheres:
 material: borosilicate glass (free of 40K)
 diameter: 43 cm; 1.5 cm thick
 qualified for pressures up to 650 bar
Photomultipliers (PMT):
 Ø 10 inch (Hamamatsu)
 transfer time spread (TTS) = 1.3 ns
 quantum efficiency:
> 20% @ 1760 V (360 <  < 460 nm)
6. - 11. June 2005
WIN´05 Delphi, Greece
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DAQ and Online Trigger

Data acquisition:
 signals digitized in situ
(either wave-form or single photo-electron (SPE))
 all data above low threshold (0.3 SPE)
sent to shore
 no hardware trigger

Online trigger:
 computer farm at shore station (~100 PCs)
 data rate from detector ~1GB/s
(dominated by background)
 trigger criteria: hit amplitudes,
local coincidences, causality of hits
 trigger output ~1MB/s = 30 TB/year
Control room
Computer Centre
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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Online Trigger



Level 1: coincidences at one storey (Dt < 20 ns)
or large individual signal (> 2.4 SPE)
Level 2: causality condition
Dt < n / c · Dx
Level 3: accept if sufficiently many
causally related hits exist
Efficiency
cos C = 1 / n
Advanced algorithms
under development
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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Calibration devices (Overview)
 Time
calibration system

1 LED in each optical module
 Optical beacons
- LED beacons at 4 different storeys
- Laser beacon at anchor
 Acoustic
positioning

receivers (hydrophones) at 5 storeys
 1 transceiver at anchor
 autonomous transceivers on sea floor
 Tiltmeter
and compass
at each storey
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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Time-Calibration Systems

timing resolution of PMT signals determines pointing accuracy
limited by intrinsic TTS of PMTs (1.3 ns)
) resolution of time calibration has to be better than 0.5 ns

expected variations of individual time offsets of PMT signals ~10 ns

complete calibration performed prior to deployment

two independent in situ calibration systems for PMTs available:
Flashed LEDs in optical modules:

blue LED attached to back of each PMT
 illuminates only local PMT
OM
PMT
Flashed optical beacons:

illuminate mainly PMTs on neighbouring strings
 each beacon contains PMT for recording of emission time
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
13
Positioning System


motion of lines due to sea current (up to 30 cm/s)
0.5 ns timing resolution requires 10 cm position accuracy for each PMT
Acoustic system:
 transmitter frequencies: 8–16 kHz (long distance)
40–60 kHz (short distance)
 distance measurements via run time of acoustic signals
 reconstruction of storey positions via triangulation
Tiltmeters and compasses:
o
o
 resolutions: tiltmeters = 0.2 , compasses = 1
System designed to provide
PMT position accuracy better than 10 cm.
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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Environmental Parameters
Continuously measured with various instruments on a
dedicated string (Instrumentation Line) or at string anchors

quantities directly influencing reconstruction
 attenuation length (25–60 m, depending on wave length and time)
resolution ¼ 4 m
 sound velocity ) acoustic positioning system
resolution = 0.1 m/s

other quantities measured
 direction/speed of water current (via Doppler effect)
precision: Dv = 0.5 cm/s, D = 0.5o
 temperature, salinity (via conductivity)
 water pressure (device attached to anchor)
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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Muon Reconstruction
Angular resolution (simulation)
 E < 10 TeV: dominated by
kinematics (Æ[,])
 E > 10 TeV: dominated by
 reconstruction accuracy
Energy resolution (simulation)
Muon momentum
 low E: muon track length
 E > 1 TeV: Čerenkov light from
radiative losses (small elm.
showers)
D < 0.3o (E > 10 TeV)
Alexander Kappes
University Erlangen-Nuremberg
D(log E) ¼ 0.3 (E > 1 TeV)
6. - 11. June 2005
WIN´05 Delphi, Greece
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Detector Infrastructure and Prototype Lines

Deep-sea cable to shore station deployed

Junction box deployed and connected to deep-sea cable

Prototype lines deployed, connected to junction box
and successfully recovered after 5 months
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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Results from Prototype Lines (2003)

Long term measurements of optical background in the deep sea:
Baseline rate
0.4 seconds

3.5 months
Technical problems:
damaged optical fibre inside cable + water leak in electronics container
) no data with ns time resolution + loss of a storey
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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New Test-Lines: MILOM and Line0
Deployed March 2005, connected April 2005
MILOM: Mini Instrumentation Line
with Optical Modules
Alexander Kappes
University Erlangen-Nuremberg
Line0: full line without electronics
(test of mechanical structure)
6. - 11. June 2005
WIN´05 Delphi, Greece
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MILOM setup
Optical components:
 equipped with final electronics
 3+1 optical modules at two storeys
 timing calibration system:
 two LED beacons at two storeys
 Laser Beacon attached to anchor
 acoustic positioning system:
 receiver at 1 storey
 transceiver (transmitter + receiver)
at anchor
allows to test all aspects of optical line
Instrumentation components:
 current profiler (ADCP)
 sound velocimeter
 water properties (CSTAR, CT)
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
20
First results from MILOM
Timing calibration with LED beacons:
 Measured relative offset of 3 optical modules on same storey
 Large light pulses used ) TTS of PMT small
Optical beacon signal
Amplitude
=0.75ns

=0.68ns
beacon signal
Time (ns)

Time difference between optical modules
Dt OM1 – OM0
Dt OM2 – OM0
electronics contribution to resolution around 0.5 ns
investigations in progress to separate various contributions
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
21
First results from MILOM
Acoustic positioning:
 Several acoustic transponders installed
 Currently only results from 1D measurements available
Distance (m)
distance from transponder (anchor)
to receiver (first storey) vs. time
distribution around
daily average
96.61
96.60
96.59
96.58
2
4
6
8 10 12 14 16 18 20
Time (day)
8
6
4
2
0
2
4
6
8
Distance (mm)
Systematic effects under control on the level of 2 mm.
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
22
First Results from MILOM
Compass headings from all three MILOM storeys:
mostly synchronous movement of all storeys
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
23
First results from MILOM
Environmental data:
Water temperature
+ sound velocity

Temperature almost
constant at 13.2oC
Water temperature
determines sound
velocity
(at given depth)
Alexander Kappes
University Erlangen-Nuremberg
Velocity (m/s)

Water temperature
Sound velocity
6. - 11. June 2005
WIN´05 Delphi, Greece
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First results from MILOM
Environmental data: Sea current (current profiler)


Most times sea current < 15 cm/s
Significant changes of direction over periods from hours to days
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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First results from MILOM
MILOM is a big success:

Data readout (waveforms + SPE) is working as expected
and yields ns timing information

In situ timing calibration and acoustic positioning
reach expected resolution

All environmental sensors are working well

Continuous data from Slow Control
(monitoring of various detector components)

Lots of environmental and PMT data available;
intensive studies ongoing
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
26
Line0


deployed to test mechanical structure
equipped with autonomous recording devices

water leak sensors
 sensors connected to electrical and fibre loops
for attenuation measurements

recovered in May 2005
Results:
 no water leaks occurred
 optical transmission losses at various points on fibres
evidently all losses occur inside electronics container
at entry and exit from cylinder
On first prototype strings
presently under intense investigations
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
fibres inside cables were
damaged
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ANTARES: further schedule

First full string (Line1) to be deployed and
connected end of 2005

Full detector installed in 2007

From 2006 on: physics analysis !
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
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The future: KM3NeT
km3 detectors required to exploit
full physics potential of neutrino telescopes

common effort of European  telescope groups
(ANTARES, NEMO, NESTOR) + associated sciences

aim: build and operate a km3 neutrino telescope
in the Mediterranean Sea

complementary to IceCube at the South Pole

expect to get EU funding (10 MEuro) for a design study
(total budget 24 MEuro) by beginning of 2006

Technical Design Report early 2009
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
29
Conclusions

MILOM proved to be a big success
 data readout is working as expected
 in situ timing and position resolution sufficient to reach
angular resolution < 0.3o for neutrinos with E > 10 TeV
 many more data to analyse

Line0 results
 mechanical structure water tight and pressure resistant
 optical losses in fibres currently under
intense investigation

First full string expected to be deployed this year;
Full detector in 2007
Well prepared for physics data to come in 2006
Alexander Kappes
University Erlangen-Nuremberg
6. - 11. June 2005
WIN´05 Delphi, Greece
30