P'Auger, a major step:

1
The World's Largest Cosmic Ray Detector
The Pierre Auger Observatory is designed to
detect and study cosmic rays around and above the
GZK cutoff, i.e. at energies exceeding 1019 eV,
with an unprecedented quality and precision.
Within our present knowledge, there is no
standard explanation to the production and
acceleration of any particle in the universe at
such macroscopic energies. To solve this
astrophysical puzzle of more than 30 years, an
international scientific collaboration has
designed and is building Auger.
The puzzle of UHECR (Ultra High Energy Cosmic
Rays) Egt1019eV, particles which do
exist... But perhaps shouldnt! Ludwik M.
Celnikier

• Physics issues with Auger
• Where does the spectrum end ? Is there a GZK
  cutoff? Are the sources local (lt150 Mly)?
• Primary nature (composition) ?
• Nuclei? Protons ?
• Gamma rays? Neutrinos? Or...?
• What is the source of UHECR ?
• Bottom-Up or Top-Down scenario ?

Auger in 1 year (existing data) E gt 10 EeV
6000 events E gt 40 EeV 500 events (100) E gt
100 EeV 60 events (9)

• P.Auger, a major step
• Need high statistics
• large detection area 2 x3000 km²
• Uniform sky coverage
• 2 sites located in each hemisphere Argentina
  and USA
• Hybrid detector
• surface array (water Cerenkov tanks)
• fluorescence detector ? Good energy and
  pointing resolution, Improved sensitivity to
  composition
• Energy cross calibration

On each site 1600 SD (surface detectors) 4
FD stations (fluorescence detectors) Duty
Cycle Efficiency SD 100 gt90 above 10
EeV FD 10 Energy resolution SD
alone Hybrid mode 100 EeV 15 10 10
EeV 30 20 Angular resolution SD
alone Hybrid mode 100 EeV 0.5 0.20 10
EeV 1.0 0.35
Northern hemisphere Millard county Utah, USA
Southern hemisphere Malargüe Provincia de
Mendoza Argentina
Collaboration gt250 researchers from 56
institutions and 20 countries Argentina,
Armenia, Australia, Bolivia, Brazil, Chile,
China, Czech Republic, France, Germany, Greece,
Italy, Japan, Mexico, Poland, Russia, Slovenia,
United Kingdom, United States of America,
Vietnam US Auger groups Colorado, Colorado
State, Chicago, Fermilab, LSU, Michigan Tech,
Mississippi, Nebraska, New Mexico, Northeastern,
Penn State, UCLA, Utah
2
Building the Engineering Array at the Southern
Site
2001 Engineering Array 15 april ? 38 SD
detectors covering 70km² 15 june ? 2 FD
camera (each 30 x30) 2004 Southern site
completed
The surface detector array is on a flat plane at
1400 m altitude

• Surface Detector status
• Water purification plant operational
• Detector assembly building at Central Site is
  completed and in use. Data acquisition equipment
  (CDAS) has been installed and is operating.
• Brackets for the solar panels and electronics
  now include the 3 m communications antenna mast
  (improved previous design).
• All solar panels and battery boxes have been
  delivered.
• 18 tanks have been deployed into the field 13
  are filled with water.
• Installation of the electronics and the mounting
  of PMTs has started
• By end of March, all 40 EA tanks (38 in field
  2 control) will be deployed and filled with
  water.

The pampa amarilla, 3000 km2 of grassland
38 tanks of the Engineering Array

• Fluorescence Detector status
• Auger now has access to the Los Leones
  fluorescence building.
• The telescope alignment reference points are
  being installed.
• The mirror support systems for both telescopes
  and one set of mirrors are on site and ready for
  installation.
• Data link from Los Leones to Central Campus is
  now operational.

Central campus and Assembly Hall
Los Leones the first 2 fluorescence
detectors overlooking the EA
Filter window detail
View from one of the telescope bays
Open house for the public
Town of Malargüe
Completing the comms tower
The completed FD building will house 6 telescope/
camera arrays