solving the mystery of the ultra-high energy cosmic rays the pierre auger observatory pablo bauleo...
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Solving the Mystery of the
Ultra-High Energy Cosmic Rays
The Pierre Auger Observatory
Pablo BauleoPhysics DepartmentColorado State UniversityFort Collins CO 80523
Southern Site: Malargue, Argentina Northern Site: Southeast Colorado, USA
http://www.auger.org.ar
Historical high pointsHistorical high points1912
Victor Hess discovers
“penetrating radiation” from space
1938Pierre Auger discoversExtensive air showers
DAuger varied distance and lead covering
Fast electronic counters
Pb
For energy > 5 * 1019
Greisen, Zatsepin-Kuzmin (GZK) Cut OffParticles > 5 * 1019 eV
must be < ~ few*50 Mpc away
1962: Penzias-Wilson: Cosmic Microwave Background
p + CMB p + 0
n + +
Energy (eV)
Flu
x (
m2 s
r s e
V)-
1
Highest energy event:3.2 x 1020 eV
Fly’s Eye in Utah in 1991
Today a lot is known about the cosmic ray flux…
The Auger project is focused on the highest energies.
At the high end of the spectrum the energies are macroscopic
Highest energy events are around 2*1020 eV 30 Joules
…dropping my laptop computer from shoulder height
This energy is concentrated in, say, one proton. It corresponds to kinetic energy of…
…a tennis ball at 40 miles per hour
…a person walking slowly, deep in thought.
Flux @ 1020 eV 1 CR/(km2 sr century)
Cosmic MysteriesCosmic MysteriesWhere do Ultra High Energy Where do Ultra High Energy Cosmic Rays Come From?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:
(1) Particles reach ground
(2) Nitrogen fluorescence10% duty factor – dark nights
Up to order 1011 particles
Height ~20 km.a.s.l
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 EnergyRedundant measurement for cross-checks
Animation of an eventmeasured in Argentina
The Auger Collaboration• 18 Participating Countries - 50 Institutions, >280 ScientistsArgentina MexicoAustralia NetherlandsBolivia* PolandBrazil Slovenia Czech Republic SpainFrance South KoreaGermany United Kingdom Greece USAItaly Vietnam*
• Participating US institutions:
UCLA Michigan TechCase Western MinnesotaChicago NebraskaColorado New MexicoColorado State NortheasternFermilab (and ANL) Penn StateLouisiana State Utah
Auger north is planned in Colorado
Malargue is a small town on the high plains not far from a ski area in the Andes.
Auger south is here.
View of Los LeonesView of Los LeonesFluorescence SiteFluorescence Site
Six Telescopes viewing 30°x30° Six Telescopes viewing 30°x30° eacheach
Schmidt corrector ring
2
.2 m
opt. Filter(MUG-6)
UV optical filter(also: provide protectionfrom outside dust)
Camera with 440 PMTs (Photonis XP 3062)
Schmidt Telescope using 11 m2 mirrors
Atmospheric MonitoringAtmospheric Monitoring
Balloon probes (T,p)-profiles
LIDAR at each FD building
Central laser facility (fiber linked to tank)
light attenuation lengthAerosol concentration
steerable LIDAR facilities located at each FD eye
•• LIDARLIDAR at each eye at each eye
•• cloud monitorscloud monitors at each eye at each eye
•• central central laserlaser facility facility
•• regular regular balloon flightsballoon flights
Aligned Water TanksAligned Water Tanksas seen from Los Leonesas seen from Los Leones
Water Tank in the PampaWater Tank in the Pampa
Solar PanelElectronics enclosure
40 MHz FADC, local triggers, 10 Watts
Communication antenna
GPS antenna
Batterybox
Plastic tank with 12 tons of water
three 9”PMTs
receiving ~20 tanks/week
Tank Preparation and Assembly
Transportation into fieldWater deployment
installation of electronics
Installation Installation ChainChain
Central campus with visitors center
Assembly building, yard
Coihueco(fully operational)
Loma Amarilla(in preparation)
Los Leones(fully operational)
Los Morados(fully operational)
Proposed Layout in Southeast ColoradoProposed Layout in Southeast Colorado
http://www.auger.org.ar