NESTOR – a status report
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Transcript of NESTOR – a status report
NESTOR – a status report
Presented by Petros A. RapidisNational Center foir Scientific Research “Demokritos”
Athens, GreeceOn behalf of the NESTOR collaboration
Describing the work of many, and also the work of others
Neutrino Extended Submarine
Telescope with Oceanographic
Research
Presented on April 22, 2008 at the 3rd Workshop on Very Large Volume Neutrino Telescopes (VLVnT08),
at Toulon, France, April 22-24, 2008
2
Germany
University of Hamburg University of Kiel
Greece
University of Athens
National Observatory of Athens – NESTOR Institute for Deep Sea Research, Technology and Neutrino Astroparticle Physics
University of CreteNCSR “Demokritos”
Hellenic Open University Aristotelian University of Thessaloniki
University of Patras University of Thessaloniki
Russia
Bureau of Oceanological Engineering & Institute For Nuclear Research, Russian Academy of Sciences
Sholokov Open University
Switzerland
University of BernCERN
U.S.A.
University of HawaiiLawrence Berkeley National Laboratory
Outline:
A description of the NESTOR project
A few words about the 2003 run and what we learned from this
Plans for the future :
• The NuBE proposal• Site studies• Deployment work
Toulon4500 m - 5100 m
2400 m
3500 mCapo Passero Pylos
The area off the coast of the Southern Peloponnese easternmost and deepest of the three areas under consideration
s
Also a very versatile and convenient area
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32 m diameter
30 m between floors
NESTOR TOWERNESTOR TOWER
144 PMTsEnergy
threshold as low as 4 GeV
20 000 m2
Effective Area
for E>10TeV
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Original ideas about a NESTOR full detector
~4,000m from the surface
~400m
Driven by the assumption that one has to minimize the wet-mateable connections
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• Hamamatsu PMT R2018-03 (15”)
• Benthos spheres
• μ-metal cage
• power supply
The 2003-Detector
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The Cable Deployment:The Cable Deployment:
June 2000June 2000
ElectroOptical cable to shore (18 fibers +1 conductor)
Deployed in June 2000 by the cableship MAERSK-FIGHTER (ALCATEL- TELEDANMARK)
Cable was damaged during laying because of ship’s problems.
Cable landing has been completed and first three km have been buried 2 m inside the bottom sand.
NESTOR Star Deployment (March 2003)
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Coincidence rate for OMs as measured at a depth of 3800m with 1pe thresholds The points represent the data, the solid line the Monte Carlo estimation including background and the dashed line the Monte Carlo estimation for the contribution of the atmospheric muons.4 fold rate is 0.25 Hz for this 12 PMT node.
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single p.e.
LED Run
single p.e. pulse height distribution
two p.e.s pulse height distribution
dark current pulse height distribution
sum of the above
Data from a depth of 3800 m
PMT Pulse Height Distribution
Calibration
K40 Background: A stable calibration source
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Event 1785 – Run 81 – BFile 3
c
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Event 1785 – Run 81 – BFile 3
c
The measured vertical muon intensity I0
and the index , at a depth of 3800 m water equivalent, are
Looking to the future….
What can we do before the big one comes in ?!
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Signal transmission & ControlShore Laboratory Power supply
PMT signal transmission
low voltage supply (24V) control and monitoring signal transmission
Ti-Sphere ElectronicsTi-Sphere Electronics Triggering Digitization Event Formatting Controls
Slow Controls
Calibration Unit
Theodore Athanassopoulos’ anti-talk
NuBE - NESTOR
a
• a
…meanwhile …
GRB duration is of the order of 100 seconds
300 m
Neutrino Burst Experiment – a quick look for AGN – very high energy neutrino coincidences
Two cluster NODE
This drawing is to scale
Some simple considerations : Cherenkov light produced for 1 cm in water is ~200 photons in the 350-550 nm range
Let us consider the case of a 100 TeV ( 1014 eV)Range in water (km) = 4.0 x ln (1+E(TeV)) (i.e. 10 TeV ~ 9 km, 100 TeV ~ 18 km )
Thus a on the average is accompanied by a ‘bundle’ of particles - 100 TeV / (18 km x 1 MeV/cm) ~ 60 particles (assuming they are minimum ionizing and have a de/dx of 1 ~MeV/cm) (n.b. a better simulation gives 77 particles)
In passing: a 100 TeV electron (e.g. from from NC interaction, and given Xrad = 36 cm) will give rise to a dense shower with a length of L ~ 10 m , i.e. ~40 000 particles. Also a is quite similar to an electron or muon
The Optical Module is a 37 cm diameter sphere.In a 37 cm length with 200 ph/cm there will be ~ 10^4 photons produced by a 100 TeV
Light at a node 300 m away –Project to a cylinder A=2 R(300m)L(37cm) ~ 6x106 cm2
Thus we have 0.0015 photons/cm2 and for a 15" PMT of cathode area of 1080 cm2
We expect 1.5 photoelectrons. Now let us use a quantum efficiency of 20% and an overall efficiency for transmission losses, reflections in the glass etc. of 50% and take into account that the node has 16 OM’s 2.4 photoelectrons per node, i.e. can be seen !
As shown earlier at a depth of 4 km with the floor of NESTOR (12 OM) the 4-fold rate is .25 Hz for downgoing m. Thus for a 16 OM node it is ~1 Hz.For an active window of 3 s rate 1Hz x 1Hz x 3x10-6 s = 3x10-6 s-1 or 3x10-4 in 100sGRB are ~300 per year = 10-5 s-1 or 10-3 in 100 s
So for a 100 s window fake is 3x10-4 x 10-3 = 10-7 in a year long run is the fake rate.
At 100 TeV neutrinos begin to be absorbed by the earth, thus one has to start looking up.
So the crucial question is : can you handle the flux of downgoing cosmic ray induced muons ?
Waxman paper says that there should be 10-100 of 1014 eV per GRB for 1km2
So we can hope for 5-50 of such events per year (or more if the situation is more favorable).
2 node trigger with E>65 GeV for passing between stings nodes
Figure 1, LIMS Glass Housing and the steel and Etalon construction. Light source positions are shown (A')
Picture 1, LIMS Glass Housing and the steel
Figure 3
Light Absorption Measuring System
To study sedimentation – fouling …
Autonomous – complements sediment trap studies.
Continuation of Site Studies
Summary of sediment trap studies
Bioluminescence work
• 0
1000
2000
3000
4000
5000
0 1 2
Bioluminescent sources (m-3)
Dep
th (
m)
See J. Graig’s talk tomorrow
0
1000
2000
3000
4000
5000
0 10 20 30 40
Sources m-3
Dep
th (
m)
Atlantic
Antares Nestor
De
pth
[m
]
Sources [m-3]
0
5000
Pylos 4500 m deep site
Pylos 5200 m deep site
Extensive measurements of deep sea currents
The deep currents have very low velocities that rarely exceed 6 cm/s. In general, the flow at the Pylos site of 4500 m depth is northward and 90% of the time is below 4 cm/s, and at the 5200 m deep site is southward but substantially weaker, with 95% of the time the current speed being below the instrument’s measurement threshold
Light transmission in the water
Older measurements (See Uli’s talk)
Is there a significantdependence ?Published data for ‘pure’ water …
For= 460 nm
=300nm =700nm
Abs
orp
tion
Coe
ffic
ient
(m
-1)
1
.01
.01
.004
A. Psallidas , NESTOR
Light Intensity Measuring System
● 2 Sources: 8 LEDs in 2 groups 1. 375nm, 420nm, 450nm, 495nm 2. 383nm, 400nm, 470nm, 525nm● Detector: 2 Photodiodes Area: 18 mm x18 mm Type: Hamamatsu S633701● Distances between source and detector: 10 m, 15 m, 17 m, 22 m.
Data just on board of the RV Aegeon ! Looks good ! But not fully digested yet ….
The talk that was not meant to be ….
The Delta-Bereniki deployment platform
A versatile dedicated vessel
Under reconstruction – engines are mounted and she will be re-floated soon. (In a month ?)
Was built to allow assembly of towers - but she is a lot more versatile.
FREQUENCY (%) OF WIND STATE IN BEAUFORT SCALE FOR METHONI AREA. PERIOD 1956-2001
0
5
10
15
20
25
30
35
0 1 2 3 4 5 6 7 8 9 10 11
Beaufort
Fre
qu
ency
(%
) o
f w
ind
sta
te
Heave compensated crane bridge.
She will be able to hold position and allow work up to the end of Beaufort scale 4 sea (frequent white horses, 30 km/hour wind, 1 m waves)
A. Belias – Proposal for a reconfigurable data acquisition system for KM3NeT (09:30 ENG)
M. Stavrianakou - First ideas for KM3NeT on-shore data storage and distribution (12:50 PHYS)
S. Koutsoukos – NuBE Calibration from 10s to 100s of meters in an underwater neutrino telescope (15:45 ENG)
T. Athanassopoulos – Commodity , FPGA based front end electronics for an underwater neutrino telescope (09:10 ENG)
-----------------
A. Psallidas - Very recent measurements of light transmission in sea water in the Pylos area
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And the talk that was not meant to be ….