alexander kappes forschungsseminar institut für physik, humboldt-universität berlin, 11. february...

Alexander KappesForschungsseminarInstitut für Physik, Humboldt-UniversitätBerlin, 11. February 2011

Fishing for Neutrinosin the Mediterranean Sea –ANTARES and KM3NeT

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 2cc

Outline

Introduction to neutrino astronomy

The ANTARES neutrino telescope

Selected results from ANTARES

The future Mediterranean neutrino telescope KM3NeT

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 3cc

1912: Discovery of Cosmic Rays (Victor Hess)• Observations before 1912:

- Elektroscopes dischargedue to natural radioactivity

• Balloon experiments since 1912: (Hess, Kolhörster)

- Discharge increases above ~1.5 km altitude

- Conclusion: Ionising radiation from outer space

Measurements Victor Hess (1912)

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 4cc

Cosmic rays:

• spectrum measured over12 orders of magnitudein energy

• power law spectrum(non thermal)

• consists of particles

Sources still unknown !

. . . 99 Years LaterCosmic ray spectrum

109 1012 1015 1018 1021

energy (eV)

10-27

10-21

10-15

10-9

10-3

103

Flu

x (G

eV-1 m

-2 s

-1 s

r-1)

LHC

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 5cc

The High-Energy Universe

gamma-ray bursts(GRB 080319B, X-ray, SWIFT)

active galactic nuclei(artist’s view)

supernova remnants(SN1006, optical, radio, X-ray)

micro-quasars(artist’s view)

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 6cc

Accelerator (source)

• Shock fronts (Fermi acceleration)

• Objects with strong magnetic fields (pulsars, magnetars)

Beam dump (secondary particle production)

• Interaction with photon and matter near the source

• Protons: pion decay

• Electrons: inverse Compton-scattering of photons

e + γ → e + γ (TeV)

High-Energy Particle Production in the Universe

p + p(γ) → π± + X μ + νμ

e + νμ + νe

p + p(γ) → π0 + X γ + γ (TeV)

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 7cc

Why Neutrino Astronomy?

• Neutrinos are produced in cosmological objects

• Neutrinos point back to the source

• Neutrinos travel cosmological distances

• Neutrinos escape from optically thick sources

• Neutrinos are a clear sign for hadron acceleration

Neutrinos provide complementary information to gamma-rays and protons

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 8cc

Principle of Neutrino Detection

muon

νμnuclearreaction

cascade43°

νμ

μTime & position of hits

μ (~ ν) trajectory Energy

PMT amplitudes

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 9cc

• Flux from above dominated by atmospheric muons

• Neutrino telescopes mainly sensitive to neutrinos from below

Background: Atmospheric Muons and Neutrinos

atmosphere

cosmicrays

μνμ

νμ

signal

background

p

p

μνμ

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Neutrino Telescope Projects

IceCubeIceCube

BaikalBaikalBaikalBaikalANTARESANTARESANTARESANTARES

NESTORNESTORNESTORNESTORNEMONEMONEMONEMO

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Sky Coverage

Visibility ANTARES (Mediterranean) > 75% 25% – 75% < 25%

TeV γ-ray sources Galactic extra-Galactic

Visibility IceCube (South Pole) 100% 0%

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The ANTARES

Neutrino Telescope

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 13

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ANTARES in the Mediterranean

Submarine cable (45km)

Shore Station

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 14

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The ANTARES Neutrino Telescope

-1995 m

-2475 m

• 12 lines (885 PMTs)+1 instrumentation line

• Instrumented volume: ~0.01 km3

2 m

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 15

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ANTARES Storey

Hydrophone:acoustic positioning

Optical Module:10” Hamamatsu PMTin 17” glass sphere photon detection

Local Control Module(in Ti cylinder):Front-endClock, tilt/compass, power distribution…

Titanium frame: support structure

Optical Beaconwith blue LEDs:timing calibration

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 16

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Construction

Milestones

• 2001 Installation of 40 km electro-optical cable

• 2002 Deployment and connection

of junction box

• 2003–2005 Installation ofprototype lines

• 2006–2008 Installation of 12 lines

• Detector completed since May 2008

Line deployment

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 17

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Line Connection

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011cc

• Light scattering + chromatic dispersion: ~ 2 ns

• TTS in PMTs: ~ 1.2 ns

→ Intrinsic angular resolution 0.2˚– 0.3˚

Requires electronics + calibration: < 0.5 ns

Timing Calibration

Signal time in OMs relative to reference PMT

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011cc

• Acoustic positioning system

• Tiltmeter and compass on each storey

Accuracy = 10 cm (0.5 ns)

Position Calibration

20 day periodMarch 2007

0 4-4-8-12 X [m]

-4

0

4

-8

Y [

m] Horizontal storey movement

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 20

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Optical Background

2005 2006 2007 2008

cable fault

2009

(Different colors correspond to different storeys)

Sin

gle

PM

T r

ate

[kH

z]

Optical background due to 40K decay and bioluminescence

• Typical rates 60-100 kHz per photomultiplier

• Occasional bursts and periods of high rates

Filtered by causality conditions between hits

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 21

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QuickTime™ and aGIF decompressor

are needed to see this picture.

Up-going Neutrino Candidate

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 22

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Selected Resultsfrom ANTARES

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 23

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Atmospheric Muons & Neutrinos

Up-going:ν-induced muons (~1000)

ANTARES (341 days)

Down-going:atm. muons

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 24

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Muon Intensity vs. Depth (90 days, 5 Lines):

2.5km6km Astropart. Phys. 34 (2010) pp. 179-184

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 25

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Upper Limit on Diffuse Flux (334 days)

IceCube 40 Strings

Physics Letters B 696 (2011) 16–22

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 26

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Full-Sky Search for Point Sources (295 days)

Most significant cluster

• Cluster of 8 events:Unbinned likelihood fit: Nsig = 5.16p-value = 0.024 (2.0 σ)

• Also no significant excess for selected sources

Equatorial coordinates

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 27

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Flux Limits and Sensitivity

25

preliminarypublication in preparation

Best limits on neutrino fluxes from southern-sky sources

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 28

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• Neutralino (χ) good WIMP candidate

• ANTARES data:No excess

Long term investigation necessary

Dark Matter Searches (WIMPs)

χ

ν

-ν

hard (W+W–)

soft (bb)ANTARES (5-line data, ~70 days)

preliminary

Neutralino mass [GeV]0 100 200 300 400 500 600 700

Φ(ν

μ+

νμ)

(>1

0 G

eV

) fr

om

Su

n [

km

-2 y

r-1]

109

1010

1011

1012

1013

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 29

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More Physics

Point sources:

• Gamma-ray bursts

• Flaring sources (e.g. AGNs)

• Use coincidences in neutrino telescopes to trigger optical follow-up

Other topics:

• Neutrino oscillations (atmospheric neutrinos 10 - 100 GeV)

• Exotic physics (Lorentz violation, monopoles, . . .)

• Cosmogenic neutrinos (E 10≳ 17 eV)

• Cosmic-ray anisotropy

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 30

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The Future Mediterranean

Neutrino Telescope KM3NeT

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 31

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Current Upper Limits on Point Sources

90% C.L. upper flux limits for E-2 spectra (preliminary)

⇒ km3-class detector in Northern Hemisphere needed

Galactic sources with TeV γ-ray emission

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 32

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KM3NeT

Artist’s view

• Future cubic-kilometer-class Mediterraneanneutrino telescope(joint effort of ANTARES, NEMO, NESTOR)

• Supported by ESFRI, ASPERA, ASTRONET

• Objectives:

- Exceed Northern-hemisphere telescopes by factor ~50 in sensitivity

- Exceed IceCube sensitivity by substantial factor

- Provide node for earth and marine sciences

- Budget: ~220 MEuro

EU-funded Design Study (2006–09) and Preparatory Phase (2007–11)

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 33

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Objective: Support 3D-array of photodetectors andconnect them to shore (data, power, slow control)

• Optical Modules

• Front-end electronics

• Readout, data acquisition, data transport

• Mechanical structures, backbone cable

• General deployment strategy

• Sea-bed network: cables, junction boxes

• Calibration devices

• Shore infrastructure

• Assembly, transport, logistics

• Risk analysis and quality control

Technical Design

Design rationale:cost-effectivereliableproducibleeasy to deploy

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 34

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OM with Many Small PMTs

• 31× 3” PMTs in 17-inch glass sphere(total ~140 mW)

• Front-end electronics (B,C)

• Al cooling shield and stem (A)

• Advantages:

- autonomous detection unit with single penetrator

- same photocathode area as 3 large PMTs

- directional information

- reduced afterpulsing

- improved 1-vs-2 photo-electron separation better sensitivity to coincidences⇒

A

B

CC

PMT

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 35

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• 20 storeys

• Each storey supports 2 multi-PMTs

• Power and data cables separated from ropes;single backbone cable with breakouts to storeys

• Distance between DU base and first storey = 100m

Flexible Towers with Horizontal Bars

2 km

Footprint “building block”(optimization ongoing)

• 2 “building blocks” required toachieve objectives

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 36

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Point Source Sensitivities (1 year)

ANTARES: 1 yr (pred. sensitivity)

Predicted fluxesHalzen, AK, O’Murchadha, PRD (2008)AK, Hinton, Stegmann, Aharonian, ApJ (2006)Kistler, Beacom, PRD (2006)Costantini & Vissani, App (2005) . . .

KM3NeT: 1 yr (pred. sensitivity)KM3NeT

IceCube 80: 1 yr (pred. sensitivity)

ANTARES

IceCube

90% CL sensitivity for E-2 spectra (preliminary)

• Vision of a worldwide neutrino observatory (IceCube + KM3NeT)

• Large overlap region (enhanced sensitivity + cross check)

SNR RX J1713 @ 5σ in 8 years

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 37

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Next steps: Prototyping and design decisions

• TDR public since June 2010

• final decisions require site selection

• expected to be achieved by end of 2011

Timeline:

Next Steps and Timeline

nownow

Feb

2006

Feb

2006

Mar

200

8

Mar

200

8

Jun

2010

Jun

2010

Mar

201

2

Mar

201

2

TDRTDRCDRCDR

Design StudyDesign Study

Preparatory phasePreparatory phase

Prototyping and constructionPrototyping and construction

Data takingData taking

2014

2014

2018

2018

Design and site decision

Design and site decision

Alexander Kappes, Forschungsseminar, Humboldt-Universität, 11.02.2011 38

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Summary

• Neutrino provide complementary information to gamma-rays and protons of the high-energy universe

• ANTARES completed since May 2008

- First results published and further analyses in full swing

- No deviations from background observed

- Detector likely too small to detect cosmic neutrinos

• KM3NeT: km3-class neutrino telescope in Northern Hemisphereneeded to complement IceCube

- In prototyping phase

- Substantially improved sensitivity compared to IceCube

- First data could be available in 2014