Presentazione%20di%20PowerPoint

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DETECTING NEUTRINOS WITH EUSO
Sergio Bottai INFN Firenze on behalf of the
EUSO Collaboration
Paris neutrino2004
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EUSO Consortium - Institutes
The EUSO instrument consortium is truly global in
nature with gt150 researchers in 50 institutions
in 6 countries in Europe, the USA, Japan and
Brazil.
Participant Nations and Institutions
Brazil
Germany
Spain
USA
Japan
Switzerland
Portugal
Italy
France

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

• LIP, Lisbon

• Obs. Neuchatel

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

• IAG, Univ Sao Paulo

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

• IAA-CSIC, Granada
• Dpt.FTC CAFPE, Univ. Granada

• 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

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

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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
Egt1020eV particles hit the atmosphere at a rate
of lt1/(100km2year). A great experimental
challenge.
AGASA - HIRES
WE NEED NEW EXPERIMENTS CONTROLL
SYSTEMATICS -gt AUGER INCREASE STATISTICS -gt
AUGER-EUSO
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Exposure (AGASA unit)
EUSO
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EHECR FROM SPACE
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Advantage of a space-based fluorescence detector
for EECR

• Geometrical Factor (A ?) ? 6 105 km2 sr
  (FoV30 at ISS mean distance hISS?430km)
• rather constant signal attenuation 0.5
• Negligible Proximity Effect
• (?Dist./Dist. lt 1)
• (acceptance not depending on energy)
• Full Sky Coverage
• Cerenkov footprint of shower

ATMOSPHERE
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The instrument
ELECTRONICS PHOTON COUNTING TIME INFORMATION
LENSES
FOCAL SURFACE LIGHT SENSORS
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EUSO -The Optical System

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

VERY challenging
2 Double sided Fresnel lens ! Pupil diameter 2.3m
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EUSO The Focal Surface 200.000 pixels at
single PE
Support Structure
MAPMT R8900 M36
R8900 M36
Filters
Focal Surface assembly
FILLINGgt0.9
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The Atmosphering sounding
LIDAR
LIDAR IR camera

• Cloud topology survey
• Atmospheric transmission calibration

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SIMULATION The Detector Light Sensitivity
The detected signal FOR 1020eV
Signal 10
Random Noise 0.5-0.8
The trigger efficiency for a subsample 20
The trigger efficiency
Threshold reach 51019eV
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The Real Atmosphere
MCM02
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The EUSO Acceptance
In clear sky
and in real atmosphere
REALISTIC CLOUDS SCENARIO KILL 40 OF SHOWERS
The EUSO statistics Egt1020eV 1000 events/year
in SuperGZK mode gt70 events/year in
GZK-suppressed mode
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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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NEUTRINO EVENTS IN ATMOSPHERE
SHOWERS
(ne,n t,nm)

• km3we of target for EUSO
• But 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.
NEUTRINOS CC INTERACTIONS (LPM effect included)
P
n
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DOWNWARD NEUTRINO ACCEPTANCE FOR EUSO
Fluorescence only events
Golden events
Xmax Select.
Shape Select.
P
n
Neutrino domain
1600g/cm2
n
P
Rejection gt 10-4
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P
TOP ATMOSPHERE
The probability of a neutrino interaction in a
volume element dV is proportional to density
NEUTRINO
NEUTRINO
Showers
Ground level
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EFFECTIVE ACCEPTANCE (gsr) FOR NEUTRINOS
Clear sky
(duty cycle not contained)
With clouds
Shower max visible
Trigger Selection
CC
CC
300 km3we
NC
NC
duty cycle
50 km3we
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Classes of UHE n Models
p? blazar jet
log(E2 ? Flux)
pp core AGN
GZK neutrinos
Top-Down models
EUSO
GRB (WB)
3 6
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log(E/GeV)
TeV PeV EeV
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Neutrino sensitivity
Sensitivity 1 events/decade/year
EUSO has 10 times larger Aperture than Auger
above GZK energy
WB
EUSO is sensitive Z-Burst, Top Down Models and
High (MAXIMUM) GZK flux.
10 events/year detected
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UPWARD TAU SHOWERS
S. Bottai , S. Giurgola ICRC 2001 S.
Bottai,S.Giurgola Astr. Phys. 18 2003
EUSO threshold
EUSO X 20
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Just wishful thinking?
LAUNCH 2010
ESA-EUSO STARTED A PHASE A STUDY FOR ISS
PHASE A UFFICIALLY CLOSE IN JULY 2004
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
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Conclusion

• EUSO is a pioneering experiment for studying EAS
  from space
• An instantaneous aperture of 6105km2sr 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 n with Egt51019eV 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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A proposed large mirror system
Design of a mirror optics, based on the Schmidt
camera principle, with FOV up to 25
light shield
mirror
correcting plate and/or filter
FEATURES
3 identical DETECTORS ASSEMBLED INSIDETHE ISS
? Solid state detectors ?
5-7 m
focal plane
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S. Bottai, P. Spillantini, FROM THE EXTREME
UNIVERSE SPACE OBSERVATORY (EUSO) TO THE EXTREME
ENERGY NEUTRINO OBSERVATORY prooceedings of
the XIth Lomonosov Conferenceq
AUGER
EUSO
WB
q.e50 Eth3EeV D7.5m FOV EUSO X 3 GZK(A) 40
events/year
GZK(A)0.3 events/year in EUSO