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Pierre Auger Observatory for UHE Cosmic Rays. Gianni Navarra (INFN-University of Torino) for the Pierre Auger Collaboration. • Science Case : the need for Auger • Principles and Advantages of a Hybrid Detector • Present Status of the Observatory • First preliminary Data • Perspectives.

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Pierre Auger Observatory for UHE Cosmic Rays

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Pierre Auger Observatoryfor UHE Cosmic Rays

Gianni Navarra (INFN-University of Torino)

for the Pierre Auger Collaboration

•Science Case: the need for Auger

•Principles and Advantages ofaHybrid Detector

•Present Statusof the Observatory

•First preliminary Data

•Perspectives

XXXXth Rencontres de Moriond

ElectroWeak Interactions and Unified Theories

La Thuile 5-12th March 2005


16 Countries

50 Institutions

~350 Scientists

Pierre Auger Collaboration

ItalyArgentina

Czech RepublicAustralia

FranceBrazil

Germany Bolivia*

GreeceMexico

PolandUSA

SloveniaVietnam*

Spain

United Kingdom

*Associate Countries

Spokesperson: Alan Watson


UHE Cosmic Rays

Surface particle detectors

Eo >1020 eV: 1 part / (km2 century sr)  102 – 103 km2 collecting areas


atmospheric

fluorescence detectors

UHE Cosmic Rays

Atmospheric fluorescence detectors

Eo >1020 eV: 1 part / (km2 century sr)  102 – 103 km2 collecting areas


HiRes vs AGASA

Surface particle detectors

~ 30 %

Syst. Error

AGASA

HiReS

??

Atmospheric fluorescence detectors

D. Bergmann


B intergalactic

pair production energy loss

B = 1

nG

3

Gpc

pion production energy loss

pion production rate

-

10

eV

21

Astrophysics?

GZK?

Cosmic ray sources are close by (<100 Mpc)

Dq ~ degree

 Sources !!!


Relic Particles in Galactic Halo ?

Fundamental

Physics ?

2

Sakar & Toldrà, Nucl.Phys.B621:495-520,2002

Toldrà, astro-ph/0201151

8

16

+ Composition (p,…Fe,g,n)

+ Astronomy (point sources)

Mrelic = 1022 eV; SUSY evolution, n-body decay


Required to solve EHECR-Puzzle:

• Better understanding of Syst. Errors

• Better Resolution in Energy and Direction

• Much more Statistics

  • Hybrid Approach:

    Independent EAS-observation techniques Shower-by-Shower in one Experiment

  • Much larger Experiment


Atmospheric fluorescence detectors

Atmospheric fluorescence detectors

UHE Cosmic Rays with Auger

Surface particle detectors

Atmospheric fluorescence detectors

Eo >1020 eV: 1 part / (km2 century sr)  102 – 103 km2 collecting areas


LOMA AMARILLA

Southern Site

Pampa Amarilla; Province of Mendoza

3000 km2, 875 g/cm2, 1400 m

Surface Array:

1600 Water Tanks

1.5 km spacing

3000 km2

Lat.: 35.5° south

Fluorescence Detectors:

4 Sites

6 Telescopes per site (180° x 30°)

24 Telescopes total

70 km


View of Los LeonesFluorescence Site


Six Telescopes viewing 30°x30° each


Schmidt Telescope

using 11 m2 mirrors

UV optical filter

(also: provide protection

from outside dust)

Schmidt corrector ring

 2.2 m

opt. Filter

(MUG-6)

Camera with 440 PMTs

(Photonis XP 3062)


Lomo Amarilla

(in preparation)

Morados

handed to Collaboration 1.9.04

Los Leones

(fully operational)

Coihueco

(fully operational)


Aligned Water Tanksas seen from Los Leones


Communicationantenna

GPSantenna

Electronics enclosure

40 MHz FADC, local triggers, 10 Watts

Solar Panel

three 9”

PMTs

Plastic tank with 12 tons of water

Battery

box

Water Tank in the Pampa


installation of electronics

receiving tanks

Water deployment

Transportation into field

Tank Preparation and Assembly

Installation Chain


Coihueco

> 10 x AGASA

AGASA

Los Leones

Southern Site as of Febr. 2005

650 Water Tanks (out of 1600)

+ 12 Telescopes


Calibration


SD Calibration by Single Muon Triggers

Agreement with GEANT4 Simulation up to 10 VEM (Vertical Equivalent Muons).

VEM ~ 100 PE /PMT

Huge Statistics!

Systematic error ~5%

Sum

PMT 1

VEM

Peak

Local

EM Shower

PMT 2

PMT 3


SD calibration & monitoring

Base-Temperature

vs Time

Single tank response

single muons

Noise

Signal-Height vs Time

Signal-Height vs Base-Temp

± 3%

Huge Statistics!

Systematic error ~5%


FD Calibration

Absolute:End to End Calibration

N Photons at diaphragm  FADC counts

A Drum device installed at the aperture uniformly illuminates the camera

with light from a calibrated source (1/month)

Mirror

Calibrated

light source

Camera

Diffusely reflective drum

Drum from outside telescope building

Relative: UV LED + optical fibers (1/night)

  • Alternative techniques for cross checks

    • Scattered light from laser beam

    • Calibr. light source flown on balloon

All agreed within 10%

for the EA


•LIDAR at each eye

•cloud monitors at each eye

• central laser facility

• regular balloon flights

Atmospheric Monitoring

steerable LIDAR facilities

located at each FD eye

Central laser facility (fibre linked to tank)

LIDAR at each FD building

  • light attenuation length

  • Aerosol concentration

Balloon probes  (T,p)-profiles


PerformancedemonstratedbyFirst Preliminary Data


Vertical (q~35o) & Inclined (q~72o)

35 tanks

14 tanks

14 km

~ 13 km

Energy ~ (6-7) 10 19 eV

~ 7 km


density falls by factor ~150

… by factor ~4

Young & Old Shower

‘young’ shower

‘old’ shower


n

Only a neutrino can induce a young horizontal shower !

Vertical vs Horizontal Showers

~ 0.2 µs

‘young’ showers

• Wide time distribution

• Strong curvature

• Steep lateral distribution

‘old’ showers

• Narrow time distribution

• Weak curvature

• Flat lateral distribution


A Big One: ~1020 eV, q ~60°

34 tanks

~60°

~ 8 km

(m)

~ 14 km

propagation time of 40 µs

Lateral Distribution Function

~1020eV

~11020eV


EAS as seen by FD-cameras

EAS as seen by FD-cameras

Two-Mirror event

Only pixels with ≥ 40 pe/100 ns are shown

(10 MHz FADC  ≤ 4 g/cm2;12 bit resol., 15 bit dynamic range)

Pixel-size = 1.5° ; light spot: 0.65° (90%)

1019 eV events trigger up to ~ 30 km


Energy Reconstruction

Integral of

Longitudinal Shower Profile Energy

~ 4.8 Photons / m / electron

(~ 0.5 % of dE/dx)

preliminary


…zoom

A Stereo Hybrid; q ~70°

~70°

global view

Coihueco

Fluores. Telescope

~37 km

Lateral Distribution Function

~8·1019eV

~24km

Los Leones

Fluores. Telescope


A stereo hybrid; q ~70°

~37 km

~24km


A stereo hybrid; q ~70°

Shower Profile

~7·1019eV

(SD: ~8·1019eV)


 SD times

Verified by using central laser facility

 FD times

x

y

Mono vs Hybrid: uncertainties of

Shower core & angle of incidence

Mono 26.15 ± 0.55 km

Hybrid 25.96 ± 0.02 km

mono

hybrid

The Power of Hybrid Observations

y


Some numbers:

data taking from Jan. 2004

SD: number of tanks in operation 650

fully efficient above ~ 3.1018 eV

number of events ~ 120,000

reconstructed ( > 3fold, >1018 eV) ~ 16,500

at present ~ 600 events/day

FD:number of sites in operation 2

SD+FD:number of hybrids 1750

~ 350 “golden”


Preliminary Sky Plot

no energy cut applied

Auger-S >85o

Auger-S >60o


Distribution of Nearby Matter

7-21 Mpc

Auger-S >60o

Auger-N >60o

Jim Cronin, astro-ph/0402487


15,000km2

10,000km2

Utah

Colorado

“Standard”3,100 km2

Auger North

(3,100 km2)

TA

(800km2)

AUGER NORTH

Two Candidate Sites


CONCLUSIONS

Auger construction in rapid progress in southPhysics data taking since January 2004

  • Stable operation, excellent performance

  • Hybrid approach is a great advantage!

  • Neutrino sensitivity

    First physics results by summer 2005

  • Energy spectrum

  • Sky map

    Auger North proposal in progress


Pampa Amarilla


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