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EExtreme UUniverse SSpace OObservatory

Sergio Bottai

INFN Firenze

on behalf of the EUSO Collaboration

DETECTING NEUTRINOS WITH EUSO

Paris neutrino2004

2#2

EUSO Consortium - Institutes

Participant Nations and Institutions

Brazil Germany Spain USA Japan Switzerland PortugalItaly France

– APC, Paris– CdF, Paris– IAP, Paris– LPSC, Grenoble– LPTHE, Paris– OdP, Paris

– IASF, Palermo– ISAC-CNR, Bologna– INFN & Univ. Genova– INFN & Univ. Firenze– INFN & Univ. Torino– INFN & Univ. Trieste– INFN Catania & Univ. Palermo– Univ. Roma “La Sapienza”– Scuola Normale Sup. Pisa– Oss. Astrofisico Arcetri– Oss. Astrofisico Catania– CARSO– INOA

– LIP, Lisbon

– MSFC & NSSTC, Huntsville– UAH, Huntsville– UCB, Berkeley– UCLA, Los Angeles– Vanderbilt Univ.

– Obs. Neuchatel

– RIKEN– ICRR– Konan Univ.– ISAS– Rikkyo– KEK– NAO– Tokyo Univ.– Saytama– Aoyama– Kinki– Seikei– Kanazawa

– MPIfP, Munich– MPIHLL, Munich– MPIfRA, Bonn– Univ. Wuerzburg

– IAG, Univ Sao Paulo

– IAA-CSIC, Granada– Dpt.FTC & CAFPE,

Univ. Granada

The EUSO instrument consortium is truly global in nature with >150 researchersin 50 institutions in 6 countries in Europe, the USA, Japan and Brazil.

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BASIC GUIDELINE

EUSO is an experiment devoted to measure the cosmic ray spectrum above 1020eV with high statistic

EUSO is at present in a phase of ‘feasibility study’

EUSO has also some potentiality to detect extraterrestrial neutrinos of energy close to 1020eV. The sensitivity for such neutrino discover will be discussed in the presentation

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UHECR Observational Situation as today E>1020eV particles hit the atmosphere at a rate of <1/(100km2•year). A great experimental challenge.

P

γ3K

Δ

Ｎ

　

π

GZK mechanism

WE NEED NEW EXPERIMENTS :

CONTROLL SYSTEMATICS -> AUGER INCREASE STATISTICS -> AUGER-EUSO

AGASA - HIRES

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Exposure

1

10

100

1000

10000

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

2012

2014

Year

Expo

sure AGASA

HiResAugerEUSO

Exposure (AGASA unit)

EUSO

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EHECR FROM SPACEPhotons per misotropic

330 – 400 nm

Euso Area vs Auger

EUSO

Pierre-Auger

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• Geometrical Factor (A · ) 6 · 105 km2 sr (FoV=±30° at ISS mean distance hISS430km)

• rather constant signal attenuation ~0.5

• Negligible Proximity Effect

(Dist./Dist. < 1%)

(acceptance not depending on energy)

• Full Sky Coverage

• Cerenkov “footprint” of shower

Advantage of a space-based fluorescence detector for EECR

ATMOSPHERE

8#8

ELECTRONICS :PHOTON COUNTINGTIME INFORMATION

FOCAL SURFACELIGHT SENSORS

LENSES

The instrument

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Optics Requirements–FoV 30° –Pupil entrance pupil 2 m–F/# 1.15–Spot dimension ~ 0.1°–Spectral range 300-400 nm– Limited mass !!

11:26:05

EUSO:f/1.25 Monochromatic Double Fresnel Scale: 0.05 DJL 01-Nov-01

490.20 MM

EUSO -The Optical System

VERY challenging

2 Double sided Fresnel lens !Pupil diameter 2.3m

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Support Structure

Focal Surface assembly

Microcell

Macrocell

EUSO – The Focal Surface 200.000 pixels at single PE

R8900 – M36

Filters

MAPMT R8900 – M36

FILLING>0.9

11G. D’Alì Staiti, Bologna, May 24, 2004 #11#11

The Atmosphering sounding

Cloud topology surveyAtmospheric transmission calibration

LIDAR

+

IR camera

LIDAR

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The detected signal FOR 1020eV

SIMULATION : The Detector Light Sensitivity

The trigger efficiency

Random Noise 0.5-0.8

Signal ~10

The trigger efficiency

for a subsample

20%

Threshold reach ~5*1019eV

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The Real Atmosphere

no triggerno triggerclearclear

MCM’02

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The EUSO AcceptanceIn clear sky… …and in real atmosphere

GoldenCerenkov only

Fmax only

The EUSO statistics E>1020eV

~1000 events/year in SuperGZK mode>70 events/year in GZK-suppressed mode

REALISTIC CLOUDS SCENARIO KILL ~40% OF SHOWERS

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EUSO resolution

Angular res = 1o – 4o

Energy res = 20% (RMS)+..(with Lidar info)

Xmax res = 50 g/cm2

(with Lidar info)

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SHOWERS

NEUTRINO EVENTS IN ATMOSPHERE

(e)

2000 km3we of target for EUSOBut : duty cycle, efficiency, very high energy threshold

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Proton – neutrino discrimination

The probability of neutrino interaction in atmosphere is proportional to the atmospheric density.

NEUTRINOSCC INTERACTIONS(LPM effect included)

P+

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DOWNWARD NEUTRINO ACCEPTANCE FOR EUSO

Rejection > 10-4

Golden events Fluorescence only events

XmaxSelect.

ShapeSelect.

P+

P+

1600g/cm2

Neutrinodomain

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TOP ATMOSPHERE

P+

NEUTRINO

Ground level

Showers

The probability of a neutrino interaction in a volume element dV is proportional to density

NEUTRINO

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EFFECTIVE ACCEPTANCE (g*sr) FOR NEUTRINOS

Clear skyWith clouds

(duty cycle not contained)

CC

CC

NC NC~300 km3we

+ Shower max visibleTrigger + Selection

~50 km3we

dutycycle

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log(E2 Flux)

log(E/GeV)TeV PeV EeV

3 6 9

pp core AGN

p blazar jet

Top-Down models

GRB (W&B)

Classes of UHE Models

GZK neutrinos

EUSO

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Neutrino sensitivity

Auger

EUSO

Sensitivity1 events/decade/year

EUSO has 10 times largerAperture than Auger aboveGZK energy

EUSO is sensitive Z-Burst, Top Down Models and High (MAXIMUM) GZK flux.

~ 10 events/year detected

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EUSOthreshold

UPWARD TAU SHOWERS

EUSO X 20

S. Bottai , S. Giurgola ICRC 2001S. Bottai,S.Giurgola Astr. Phys. 18 2003

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EUSO2003 2004 2005 2006 2007 2008 2009 2010 201320122011

A C/DB

Just wishful thinking?

on June 2004 ESA ‘SCIENCE DIRECTORATE’ DID NOT INCLUDED EUSO IN THE PRIORITY LIST OF CANDIDATE EXPERIMENT UP 2012 . (“wait AUGER results”)

The possibility to mantain the time schedule is under investigation

ESA-EUSO STARTED A PHASE A STUDY FOR ISS

PHASE A UFFICIALLY CLOSE IN JULY 2004

LAUNCH 2010

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Conclusion

EUSO is a pioneering experiment for studying EAS from space:

An instantaneous aperture of 6×105km2sr with a duty cycle ~20% is a technically achievable goal with up-to-date technology;The acceptance reduction due to cloud effect has been evaluated to be ~0.5.

50.000 km2sr effective acceptance

~103 events/year can be expected according to AGASA findings;~102 events/year can be expected according to GZK-suppressed spectrum due to uniform source distribution.

for with E>5*1019eV EUSO will have a competitive sensitivity (50 km3 we effective) TOP DOWN MODELS CAN BE SEEN IF THEY EXISTS

TIME SCHEDULE 2010 ???????

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Design of a mirror optics, based on the Schmidt camera principle, with FOV up to 25°

A proposed large mirror system

correcting plate and/or filter

mirrorlight shield

focal plane

FEATURES

3 identical DETECTORS ASSEMBLED INSIDETHE ISS ?

Solid state detectors ?

5-7 m

27GZK(A)~0.3 events/year in EUSO

EUSO

AUGER

q.e=50%Eth=3EeVD=7.5mFOV= EUSO X 3

GZK(A)~ 40 events/year

S. Bottai, P. Spillantini, “ FROM THE EXTREME UNIVERSE SPACE OBSERVATORY(EUSO) TO THE EXTREME ENERGY NEUTRINO OBSERVATORY “ prooceedings of the XIth Lomonosov Conferenceq

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