Pierre Auger Observatory for UHE Cosmic Rays Gianni

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 XXXXth Rencontres de Moriond Electro. Weak Interactions and Unified Theories La Thuile 5 -12 th March 2005

Pierre Auger Collaboration 16 Countries 50 Institutions ~350 Scientists Italy Czech Republic France Germany Greece Poland Slovenia Spain United Kingdom Spokesperson: Alan Watson Argentina Australia Brazil Bolivia* Mexico USA Vietnam* Associate Countries *

UHE Cosmic Rays Surface particle detectors Eo >1020 e. V: 1 part / (km 2 century sr) 102 – 103 km 2 collecting areas

UHE Cosmic Rays atmospheric fluorescence detectors Atmospheric fluorescence detectors Eo >1020 e. V: 1 part / (km 2 century sr) 102 – 103 km 2 collecting areas

Hi. Res vs AGASA ~ 30 % Syst. Error Surface particle detectors Hi. Re. S Atmospheric fluorescence detectors D. Bergmann AGASA

? s c i s ophy Astr GZK? Cosmic ray sources are close by (<100 Mpc) pair production energy loss B intergalactic B = 1 n. G 3 Gpc pion production energy loss pion production rate 1021 e. V Dq ~ degree Sources !!! -

Relic Particles in Galactic Halo ? l a t n e m a d Fun ? s c i s Phy Sakar & Toldrà, Nucl. Phys. B 621: 495 -520, 2002 Toldrà, astro-ph/0201151 2 8 16 + Composition (p, …Fe, g, n) + Astronomy (point sources) Mrelic = 1022 e. V; SUSY evolution, n-body decay

Required to solve EHECR-Puzzle: • Better understanding of Syst. Errors • Better Resolution in Energy and Direction ðHybrid Approach: Independent EAS-observation techniques Shower-by-Shower in one Experiment • Much more Statistics Much larger Experiment

UHE Cosmic Rays with Auger Atmospheric fluorescence detectors Surface particle detectors Atmospheric fluorescence detectors Eo >1020 e. V: 1 part / (km 2 century sr) 102 – 103 km 2 collecting areas

Southern Site Pampa Amarilla; Province of Mendoza 3000 km 2, 875 g/cm 2, 1400 m Surface Array: Lat. : 35. 5° south LOMA AMARILLA 1600 Water Tanks 1. 5 km spacing 3000 km 2 Fluorescence Detectors: 4 Sites 6 Telescopes per site (180° x 30°) 24 Telescopes total 70 km

View of Los Leones Fluorescence Site

Six Telescopes viewing 30°x 30° each

Schmidt Telescope using 11 m 2 mirrors UV optical filter (also: provide protection from outside dust) 2. 2 m Schmidt corrector ring opt. Filter (MUG-6) Camera with 440 PMTs (Photonis XP 3062)

Los Leones (fully operational) Morados handed to Collaboration 1. 9. 04 Coihueco (fully operational) Lomo Amarilla (in preparation)

Aligned Water Tanks as seen from Los Leones

Water Tank in the Pampa Communication antenna GPS antenna Electronics enclosure 40 MHz FADC, local triggers, 10 Watts Battery box Solar Panel three 9” PMTs Plastic tank with 12 tons of water

Installation Chain installation of electronics receiving tanks Tank Preparation and Assembly Transportation into field Water deployment

Southern Site as of Febr. 2005 Coihueco 650 Water Tanks (out of 1600) > 10 x AGASA + 12 Telescopes AGASA Los Leones

Calibration

SD Calibration by Single Muon Triggers Agreement with GEANT 4 Simulation up to 10 VEM (Vertical Equivalent Muons). VEM ~ 100 PE /PMT Huge Statistics! Systematic error Sum PMT 1 PMT 2 PMT 3 VEM Peak Local EM Shower

tank response& monitoring SDSingle calibration Base-Temperature vs Time single muons Noise Signal-Height vs Time Signal-Height vs Base-Temp ± 3% Huge Statistics! Systematic error ~5%

Absolute: End to End Calibration FD 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 Camera Calibrated light source Diffusely reflective drum Relative: UV LED + optical fibers (1/night) Alternative techniques for cross checks • Scattered light from laser beam • Calibr. light source flown on balloon Drum from outside telescope building All agreed within 10% for the EA

Atmospheric Monitoring • LIDAR at each eye • cloud monitors at each eye • central laser facility • regular balloon flights steerable LIDAR facilities located at each FD eye Central laser facility (fibre linked to tank) LIDAR at each FD building Älight attenuation length ÄAerosol concentration Balloon probes (T, p)-profiles

Performance demonstrated by First Preliminary Data

Vertical (q~35 o) & Inclined (q~72 o) 14 tanks 35 tanks 14 km ~ 7 km Energy ~ (6 -7) 10 19 e. V ~ 13 km

de ns i ty fa lls Young & Old Shower by fa ct or ‘young’ shower ~ 15 0 … ‘old’ shower by fa ct or ~ 4

Vertical vs Horizontal Showers n Only a neutrino can induce a young horizontal shower~ 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 e. V, q ~60° 34 tanks ~60° ~ 8 km (m) ~ 14 km Lateral Distribution Function ~102020 e. V ~1 10 e. V propagation time of 40 µs

EAS as seen by FD-cameras Two-Mirror event EAS as seen by FD-cameras Only pixels with ≥ 40 pe/100 ns are shown (10 MHz FADC ≤ 4 g/cm 2; 12 bit resol. , 15 bit dynamic range) Pixel-size = 1. 5° ; light spot: 0. 65° (90%) 1019 e. V events trigger up to ~ 30 km

Energy Reconstruction Integral of Longitudinal Shower Profile Energy ~ 4. 8 Photons / m / electron (~ 0. 5 % of d. E/dx) preliminary

A Stereo Hybrid; q ~70° …zoom ~70° Coihueco global Fluores. Telescope ~37 km ateral Distribution Function ~8· 1019 e. V ~24 km Los Leones Fluores. Telescope view

A stereo hybrid; q ~70° ~37 km ~24 km

A stereo hybrid; q ~70° Shower Profile ~7· 1019 e. V (SD: ~8· 1019 e. V)

The Power of Hybrid Observations SD times x y y Verified by using central laser facility Mono 26. 15 ± 0. 55 km Hybrid 25. 96 ± 0. 02 km Mono vs Hybrid: uncertainties of Shower core & angle of incidence mono hybrid FD times

Some numbers: data taking from Jan. 2004 SD: number of tanks in operation 650 fully efficient above ~ 3. 1018 e. V number of events ~ 120, 000 reconstructed ( > 3 fold, >1018 e. V) ~ 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 >85 o Auger-S >60 o

Distribution of Nearby Matter 7 -21 Mpc Auger-S >60 o Auger-N >60 o Jim Cronin, astro-ph/0402487

AUGER NORTH Two Candidate Sites 15, 000 km 2 Utah Colorado Auger North (3, 100 km 2) TA (800 km 2) 10, 000 km 2 “Standard ” 3, 100 km 2

CONCLUSIONS Auger construction in rapid progress in south Physics data taking since January 2004 üStable operation, excellent performance üHybrid approach is a great advantage! üNeutrino sensitivity First physics results by summer 2005 üEnergy spectrum üSky map Auger North proposal in progress

Pampa Amarilla