Pierre Auger Observatory for UHE Cosmic Rays

Gianni Navarra (INFN-University of Torino)for the Pierre Auger Collaboration

XXXXth Rencontres de MoriondElectroWeak Interactions and Unified TheoriesLa Thuile 5-12th March 2005

•• Science CaseScience Case: the need for Auger: the need for Auger•• Principles and Advantages ofPrinciples and Advantages of aa Hybrid DetectorHybrid Detector•• Present StatusPresent Status of the Observatoryof the Observatory•• First First preliminary preliminary DataData•• PerspectivesPerspectives

Pierre Auger Collaboration

Spokesperson: Alan Watson

16 Countries 50 Institutions~350 Scientists

Italy ArgentinaCzech Republic Australia France BrazilGermany Bolivia* Greece MexicoPoland USASlovenia Vietnam* Spain United Kingdom

*Associate Countries

UHE Cosmic Rays

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

Surface particle detectors

atmosphericfluorescence detectors

UHE Cosmic Rays

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

Atmospheric fluorescence detectors

HiRes vs AGASA

AGASA

HiReS

D. Bergmann

~ 30 %Syst. Error

Atmospheric fluorescence detectors

Surface particle detectors

GZK?

pair production energy loss

pion production energy loss

pion production rate

eV1044

2 192

th

mmm

E N

Cosmic ray sources are close by (<100 Mpc)

1021 eV

3 Gpc

B = 1 nG

B intergalactic

-

~ degree Sources !!!

Astrophysics?

Relic Particles in Galactic Halo ?

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

2

8

16

+ Composition (p,…Fe)+ Astronomy (point sources)

Sakar & Toldrà, Nucl.Phys.B621:495-520,2002Toldrà, astro-ph/0201151

Fundamental

Physics ?

Required to solve EHECR-Puzzle:

• • Better understanding of Syst. ErrorsBetter understanding of Syst. Errors• • Better Resolution in Energy and DirectionBetter Resolution in Energy and Direction

• • Much more StatisticsMuch more Statistics

Hybrid Approach:Hybrid Approach: Independent EAS-observation techniquesIndependent EAS-observation techniques Shower-by-Shower Shower-by-Shower in one Experimentin one Experiment

Much larger ExperimentMuch larger Experiment

Atmospheric fluorescence detectorsAtmospheric fluorescence detectors

UHE Cosmic Rays with Auger

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

Surface particle detectorsAtmospheric fluorescence detectors

70 km

Southern SitePampa Amarilla; Province of Mendoza3000 km2, 875 g/cm2, 1400 m

Lat.: 35.5° southSurface Array:1600 Water Tanks1.5 km spacing3000 km2

Surface Array:1600 Water Tanks1.5 km spacing3000 km2

Fluorescence Detectors:4 Sites6 Telescopes per site (180° x 30°)24 Telescopes total

Fluorescence Detectors:4 Sites6 Telescopes per site (180° x 30°)24 Telescopes total

LOMA AMARILLA

View of Los LeonesFluorescence Site

Six Telescopes viewing 30°x30° each

Schmidt corrector ring

2

.2 m

opt. Filter(MUG-6)

UV optical filter(also: provide protectionfrom outside dust)

Camera with 440 PMTs (Photonis XP 3062)

Schmidt Telescope using 11 m2 mirrors

Coihueco(fully operational)

Lomo Amarilla(in preparation)

Moradoshanded to Collaboration 1.9.04

Los Leones(fully operational)

Aligned Water Tanksas seen from Los Leones

Water Tank in the Pampa

Solar PanelElectronics enclosure40 MHz FADC, local triggers, 10 Watts

Communication antenna

GPS antenna

Batterybox

Plastic tank with 12 tons of water

three 9”PMTs

receiving tanks

Tank Preparation and Assembly

Transportation into fieldWater deployment

installation of electronics

Installation Chain

650 Water Tanks (out of 1600)

+ 12 Telescopes

Los Leones

Coihueco

AGASA

> 10 x AGASA

Southern Site as of Febr. 2005

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%

VEMPeak

Sum PMT 1

PMT 2 PMT 3

Local EM Shower

SD calibration & monitoringsingle muons

Noise

Base-Temperaturevs Time

Signal-Height vs Time

Signal-Height vs Base-Temp

Single tank response

Huge Statistics!Systematic error ~5%

± 3%

All agreed within 10%for the EA

Alternative techniques for cross checks• Scattered light from laser beam• Calibr. light source flown on balloon

FD Calibration Absolute: End to End Calibration

A Drum device installed at the aperture uniformly illuminates the camera with light from a calibrated source (1/month)

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

N Photons at diaphragm FADC

counts

MirrorCamera Calibrated

light source

Diffusely reflective drumDrum from Drum from outside telescope outside telescope buildingbuilding

Atmospheric Monitoring

Balloon probes (T,p)-profiles

LIDAR at each FD building

Central laser facility (fibre linked to tank)

light attenuation lengthAerosol concentration

steerable LIDAR facilities located at each FD eye

• LIDAR at each eye

• cloud monitors at each eye

• central laser facility

• regular balloon flights

Performancedemonstrated

by

First Preliminary Data

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

Energy ~ (6-7) 10 19 eV

35 tanks

~ 13 km

14 km

14 tanks

~ 7 km

Young & Old Shower‘‘young’ showeryoung’ shower

‘‘old’ showerold’ shower

density falls by factor ~150

… by factor ~4

Vertical vs Horizontal Showers

‘young’ showers • Wide time distribution• Strong curvature• Steep lateral distribution

‘old’ showers• Narrow time distribution• Weak curvature• Flat lateral distribution

Only a neutrino can induce a young horizontal shower !Only a neutrino can induce a young horizontal shower !

~ 0.2 µs

(m)

~11020eV~1020eV

Lateral Distribution Function

~ 14 km

~ 8 km

A Big One: ~1020 eV, ~60°34 tanks

~60°~60°

propagation time of 40 µs

EAS as seen by FD-camerasEAS as seen by FD-cameras

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

Two-Mirror event

EAS as seen by FD-cameras

Energy Reconstruction

Integral ofLongitudinal Shower Profile

Energy

preliminarypreliminary

~ 4.8 Photons / m / electron(~ 0.5 % of dE/dx)

A Stereo Hybrid; ~70°

CoihuecoFluores. Telescope

Los LeonesFluores. Telescope

~8·1019eV

Lateral Distribution Function

~37 km

~24km

~70°~70°global view

…zoom

A stereo hybrid; ~70°~37 km

~24km

A stereo hybrid; ~70°Shower Profile

~7·1019eV(SD: ~8·1019eV)

The Power of Hybrid Observations

y

yx

SD times

FD times

Mono vs Hybrid: uncertainties ofShower core & angle of incidence

Verified by using central laser facility

monohybrid

Mono 26.15 ± 0.55 km

Hybrid 25.96 ± 0.02 km

Some numbers:data taking from Jan. 2004

SD: number of tanks in operation 650fully efficient above ~ 3.1018 eVnumber of events ~ 120,000 reconstructed ( > 3fold, >1018 eV) ~ 16,500at present ~ 600 events/day

FD: number of sites in operation 2SD+FD: number of hybrids 1750

~ 350 “golden”

Preliminary Sky Plot

Auger-S >85o

Auger-S >60o

no energy cut applied

Distribution of Nearby Matter

Auger-S >60o

Auger-N >60o

Jim Cronin, astro-ph/0402487

7-21 Mpc

Two Candidate Sites

UtahColorado

“Standard”3,100 km2

10,000km2

15,000km2

TA(800km2)

Auger North(3,100 km2)

AUGER NORTH

CONCLUSIONS

Auger construction in rapid progress in southAuger construction in rapid progress in south Physics data taking since January 2004Physics data taking since January 2004

Stable operation, excellent performance

Hybrid approach is a great advantage!

Neutrino sensitivity

First physics results by summer 2005First physics results by summer 2005Energy spectrum

Sky map

Auger North proposal in progressAuger North proposal in progress

Pampa Amarilla