Status of the PAO, JC Arteaga V., R. L

1
Status of the Pierre Auger Observatory
J. C. Arteaga-Velázquez1 , Rebeca López2, Rodrigo
Pelayo1 and Arnulfo Zepeda1 1Departamento de
Física, Cinvestav, Apartado Postal 14-740, 07000,
México, D.F., México . 2Benemérita Universidad
Autónoma de Puebla, 72570, Puebla,
Puebla. Abstract The quest for the origin,
composition and acceleration mechanism of the
ultrahigh energy cosmic rays, the particles with
the highest energy (E ? 1018 eV) so far detected
from outer space, has led an international
collaboration to design and built a gigantic
cosmic ray detector called the Pierre Auger
Observatory which, once finished, will address
the main questions behind these enigmatic
particles. The construction of the Pierre Auger
Observatory began in March 1999, and now, it is
the first and the only one existing hybrid cosmic
ray detector in the world. In addition, it has
become the largest running surface array on the
Earth, altough it has not been completed yet.
In the following lines, the present
status of the Pierre Auger Observatory will
be described .
The central data acquisition system is in the
central building, at the Auger campus.
The detector assembly building at the Auger
campus, which is located in the town of Malargüe.

• The second and present stage Preproduction
• The project is now in the pre-production
  phase, which is on
• the way to be completed. After this, the
  project will move into
• the full-production phase, under which the
  complete FD and SD
• will be finished.
• Description In this stage, 2 fluorescence
  buildings and 100 final
• design Cherenkov detectors are expected
  to be deployed and
• tested, checking, in this way, the
  performance of the final design.
• Status of the Surface detector
• On Octuber 3rd of 2003, the 100th running
  Cherenkov detector
• joinned the surface array. In this
  way, the Pierre Auger
• Observatory, in its present stage,
  has become the largest
• running array of the world.
• There are about 180 Cherenkov detectors
  deployed in the field,

• Introduction
• What are the ultra high energy cosmic
• rays (UHECR)?
• What we know is that they are very
  energetic particles
• ( E ? 1018 eV) which arrive to the Earth
  from the outer
• space.
• But, their origin, composition and
  acceleration mechanism
• remain still a mystery.
• The Pierre Auger Observatory (PAO) and the quest
  for the UHECR
• To shed light on the mystery of the UHECR, it
  is necessary
• to have a detector of kilometric size,
  such as the Pierre
• Auger Observatory, since the flux of
  cosmic rays with
• energy above 1020 eV it is too low
  of the order of
• 1 particle/( km2 century).

• Status of the southern PAO
• The construction of the southern Pierre Auger
  Observatory began
• in March 1999. From that date, several
  advances have been
• accomplished in its construction. The main stages
  of the project, up
• to now, are shown below
• The first stage The Engineering Array (EA)
• The first phase was finished during 2001 with
  the deployment of
• a prototype detector called the
  Engineering Array (EA).
• Description The EA is a subset of the PAO and
  is composed by
• 40 water Cherenkov detectors, and two
  prototype fluorescence
• telescopes, the latter ones overlooking the
  Cherenkov detectors
• from Los Leones hill.
• Size The surface detectors cover an area of 46
  km2.

The full planned Southern PAO (left) and
the EA (right).

• Goal This prototype was constructed to help
  the Pierre Auger
• Collaboration to test several aspects of
  the observatory and
• improve them. For example
• Performance of the initial design.
• Deployment strategy.
• Communication and data acquisition systems.
• Components and subsystems, etc.
• Status Accomplished. Now, the Cherenkov
  detectors of the EA
• are part of the Observatory and the two
  prototype telescopes
• have been dismantled to allow installation
  of the final design
• telescopes.

The SD at the beginning of Octuber 2003.
The EA is shown inside the shaded
region in gray.

• Status of the Fluorescence detectors
• Two fluorescence buldings have already been
  constructed at Los
• Leones and Coihueco hills, and planning
  for the construction of
• the third one at Los Morados has begun.
• There are three final design fluorescence
  telescopes in operation
• at Los Leones. A new one is about to
  become operational at
• Coihueco.
• In order to perform atmospheric and calibration
  measurements it
• was constructed a Central Laser Facility
  (CLF). This instrument is
• located almost equidistantly from the
  Coihueco, Los Leones and
• Los Morados hills.
• Data acquisition and performance of the PAO
• The observatory has been taking data since
  the construction of

Detector Description Detection technique
Surface Detector (SD) Array of 1600 water Cherenkov detectors separated by 1.5 km from each other and spread over an area of 3000 km2. It will sample the lateral distribution of muons, electrons and photons at ground level.
Fluorescence detectors (FD) Set of 4 FDs detectors overlooking the SD array. Each FD composed by 6 telescopes. It will observe the atmospheric fluorescence emission induced by the shower.
Upper figure final design fluorescence
telescope (left) at Los Leones building
(right).
The Central Laser Facility (left).
Spectacular hybrid event recorded on Octuber
2003 (right). The event, which struck 11 tanks
in the array, was reconstructed with
an energy of 25.4 Eev.