Solving the Mystery of the UltraHigh Energy Cosmic

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Solving the Mystery of the Ultra-High Energy Cosmic Rays The Pierre Auger Observatory Southern

Solving the Mystery of the Ultra-High Energy Cosmic Rays The Pierre Auger Observatory Southern Site: Malargue, Argentina Pablo Bauleo Physics Department Colorado State University Fort Collins CO 80523 Northern Site: Southeast Colorado, USA http: //www. auger. org. ar

Historical high points 1912 Victor Hess discovers “penetrating radiation” from space 1938 Pierre Auger

Historical high points 1912 Victor Hess discovers “penetrating radiation” from space 1938 Pierre Auger discovers Extensive air showers D Pb Auger varied distance and lead covering Fast electronic counters

1962: Penzias-Wilson: Cosmic Microwave Background p+ CMB p + 0 n + + For

1962: Penzias-Wilson: Cosmic Microwave Background p+ CMB p + 0 n + + For energy > 5 * 1019 Greisen, Zatsepin-Kuzmin (GZK) Cut Off Particles > 5 * 1019 e. V must be < ~ few*50 Mpc away

Flux (m 2 sr s e. V)-1 Today a lot is known about the

Flux (m 2 sr s e. V)-1 Today a lot is known about the cosmic ray flux… Highest energy event: 3. 2 x 1020 e. V Fly’s Eye in Utah in 1991 The Auger project is focused on the highest energies. Energy (e. V)

At the high end of the spectrum the energies are macroscopic Highest energy events

At the high end of the spectrum the energies are macroscopic Highest energy events are around 2*1020 e. V 30 Joules This energy is concentrated in, say, one proton. It corresponds to kinetic energy of… …dropping my laptop computer from shoulder height …a tennis ball at 40 miles per hour …a person walking slowly, deep in thought. Flux @ 1020 e. V 1 CR/(km 2 sr century)

Cosmic Mysteries Where do Ultra High Energy Cosmic Rays Come From? No convincing acceleration

Cosmic Mysteries Where do Ultra High Energy Cosmic Rays Come From? No convincing acceleration process for explaining particle energy > 1020 e. V A handful of super-GZK events have been reported. Sources of particles > 1020 e. V must be closer than about 50 Mpc because of CMB No likely acceleration sites have been found nearby. The highest energy cosmic rays should point back to possible sources Point sources or uniform on the sky?

The primary cosmic ray initiates a shower. There are two basic detection techniques: Up

The primary cosmic ray initiates a shower. There are two basic detection techniques: Up to order 1011 particles (1) Particles reach ground Height ~20 km. a. s. l (2) Nitrogen fluorescence 10% duty factor – dark nights Height ~ 1500 m. a. s. l

Extracting information from an EAS • Tank timing Ø Arrival direction • Number of

Extracting information from an EAS • Tank timing Ø Arrival direction • Number of particles in tanks Ø Total Energy • Telescope image (digital camera like) Ø Arrival direction • Light detected Ø Total Energy Redundant measurement for cross-checks Animation of an event measured in Argentina

The Auger Collaboration • 18 Participating Countries - 50 Institutions, >280 Scientists Argentina Mexico

The Auger Collaboration • 18 Participating Countries - 50 Institutions, >280 Scientists Argentina Mexico Australia Netherlands Bolivia* Poland Brazil Slovenia Czech Republic Spain France South Korea Germany United Kingdom Greece USA Italy Vietnam* • Participating US institutions: UCLA Case Western Chicago Colorado State Fermilab (and ANL) Louisiana State Michigan Tech Minnesota Nebraska New Mexico Northeastern Penn State Utah

Auger north is planned in Colorado Auger south is here. Malargue is a small

Auger north is planned in Colorado Auger south is here. Malargue is a small town on the high plains not far from a ski area in the Andes.

View of Los Leones Fluorescence Site

View of Los Leones Fluorescence Site

Six Telescopes viewing 30°x 30° each

Six Telescopes viewing 30°x 30° each

Schmidt Telescope using 11 m 2 mirrors UV optical filter (also: provide protection from

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)

Atmospheric Monitoring • LIDAR at each eye • cloud monitors at each eye •

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 (fiber linked to tank) LIDAR at each FD building Älight attenuation length ÄAerosol concentration Balloon probes (T, p)-profiles

Aligned Water Tanks as seen from Los Leones

Aligned Water Tanks as seen from Los Leones

Water Tank in the Pampa Communication antenna GPS antenna Electronics enclosure 40 MHz FADC,

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 ~20 tanks/week Tank Preparation and Assembly Transportation into

Installation Chain installation of electronics receiving ~20 tanks/week Tank Preparation and Assembly Transportation into field Water deployment

Central campus with visitors center Assembly building, yard

Central campus with visitors center Assembly building, yard

Los Leones (fully operational) Coihueco (fully operational) Los Morados (fully operational) Loma Amarilla (in

Los Leones (fully operational) Coihueco (fully operational) Los Morados (fully operational) Loma Amarilla (in preparation)

Proposed Layout in Southeast Colorado

Proposed Layout in Southeast Colorado

http: //www. auger. org. ar

http: //www. auger. org. ar