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Solving the Mystery of the Ultra-High Energy Cosmic Rays The Pierre Auger Observatory. Southern Site: Malargue, Argentina Northern Site: Southeast Colorado, USA. Pablo Bauleo Physics Department Colorado State University Fort Collins CO 80523. http://www.auger.org.ar.
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Solving the Mystery of the Ultra-High Energy Cosmic Rays The Pierre Auger Observatory Southern Site: Malargue, Argentina Northern Site: Southeast Colorado, USA • Pablo Bauleo • Physics Department • Colorado State University • Fort Collins CO 80523 http://www.auger.org.ar
Historical high points 1912 Victor Hess discovers “penetrating radiation” from space 1938 Pierre Auger discovers Extensive air showers Auger varied distance and lead covering D Pb Fast electronic counters
1962: Penzias-Wilson: Cosmic Microwave Background p + CMB p + 0 n + + • For energy > 5 * 1019 Greisen, Zatsepin-Kuzmin (GZK) Cut Off Particles > 5 * 1019 eV must be < ~ few*50 Mpc away
Today a lot is known about the cosmic ray flux… Highest energy event: 3.2 x 1020 eV Fly’s Eye in Utah in 1991 Flux (m2 sr s eV)-1 The Auger project is focused on the highest energies. Energy (eV)
At the high end of the spectrum the energies are macroscopic Highest energy events are around 2*1020 eV 30 Joules This energy is concentrated in, say, one proton. It corresponds to kinetic energy of… …a tennis ball at 40 miles per hour …dropping my laptop computer from shoulder height …a person walking slowly, deep in thought. Flux @ 1020 eV 1 CR/(km2 sr century)
Cosmic MysteriesWhere do Ultra High Energy Cosmic Rays Come From? No convincing acceleration process for explaining particle energy > 1020 eV A handful of super-GZK events have been reported. Sources of particles > 1020 eV 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: Height ~20 km.a.s.l Up to order 1011 particles (2) Nitrogen fluorescence 10% duty factor – dark nights (1) Particles reach ground Height ~ 1500 m.a.s.l
Extracting information from an EAS • Tank timing • Arrival direction • Number of particles in tanks • Total Energy • Telescope image (digital camera like) • Arrival direction • Light detected • 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 • Australia Netherlands • Bolivia* Poland • Brazil Slovenia • Czech Republic Spain • France South Korea • Germany United Kingdom • Greece USA • Italy Vietnam* • Participating US institutions: • UCLA Michigan Tech • Case Western Minnesota • Chicago Nebraska • Colorado New Mexico • Colorado State Northeastern • Fermilab (and ANL) Penn State • Louisiana State Utah
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.
Schmidt Telescope using 11 m2 mirrors UV optical filter (also: provide protection from outside dust) Schmidt corrector ring 2.2 m opt. Filter (MUG-6) Camera with 440 PMTs (Photonis XP 3062)
•LIDAR at each eye •cloud monitors at each eye • central laser facility • regular balloon flights Atmospheric Monitoring steerable LIDAR facilities located at each FD eye Central laser facility (fiber linked to tank) LIDAR at each FD building • light attenuation length • Aerosol concentration Balloon probes (T,p)-profiles
Water Tank in the Pampa Communication antenna GPS antenna Electronics enclosure 40 MHz FADC, local triggers, 10 Watts Solar Panel Plastic tank with 12 tons of water Battery box three 9” PMTs
installation of electronics receiving ~20 tanks/week Water deployment Transportation into field Tank Preparation and Assembly Installation Chain
Central campus with visitors center Assembly building, yard
Loma Amarilla (in preparation) Los Leones (fully operational) Coihueco (fully operational) Los Morados (fully operational)