Pierre Auger Observatory
The largest in the world to unravel the mysteries of the cosmos
The Pierre Auger Cosmic Ray Observatory is located in Malargüe, in the south of the province of Mendoza, Argentina. It is an international initiative that seeks to determine the origin and identity of cosmic rays, allowing us to advance in understanding our universe.
It was built by a collaboration of 18 countries, with the participation of 500 scientists from 90 institutions, and has been operating uninterruptedly since 2004. The ITeDA (CNEA-CONICET-UNSAM) has been involved in this project since its inception, with the active participation of scientific groups and technical and engineering support.
Official website: auger.org.ar
What are cosmic rays?
Enigmatic subatomic particles that reach Earth from outer space are predominantly protons and other atomic nuclei. Some cosmic particles, or astroparticles, arrive with an enormous energy charge; they are like “messengers from space” since this energy contains information that can reveal the great mysteries of outer space.
Billions of astroparticles pass through our planet and everything on it every second. This phenomenon reaches the Earth’s atmosphere at different speeds and energy ranges. The greater their energy, the lower their abundance. Those with the highest speed and energy are a tiny fraction of the total: only a few per century impact each square kilometer of the Earth’s atmosphere, so their detection is challenging.
What does the Pierre Auger Observatory study?
This Pierre Auger Observatory is the largest in the world. The main array consists of a hexagonal grid of 1,660 surface detectors spaced 1.5 km apart, covering a total area of 3,000 km2. Around the main array are 27 fluorescence telescopes located in four buildings. On clear, moonless nights, they scan the atmosphere to observe the faint ultraviolet light produced by particle showers as they pass through the atmosphere.
AMIGA Project
The AMIGA (Auger Muons and Infill for the Ground Array) project is an extension of the Pierre Auger Observatory. Its main objective is to extend the Observatory’s energy detection range by more than an order of magnitude, reaching energies up to 1016.8 eV.
The aim is to study the so-called “transition zone” between 1016.8 and 1019 eV, where the transition from galactic to extragalactic cosmic ray sources is believed to occur.
What is AMIGA?
This project’s detection system consists of 85 pairs of surface detectors (SD) and buried detectors (BD) forming two hexagonal arrays. Of these pairs, 61 are separated by 750 meters and 24 by 433 meters. The buried detectors consist of three muon counters, each consisting of 64 plastic scintillators, a multi-pixel light sensor (SiPM), and data acquisition electronics. These counters work with the surface detectors (SD), which detect Cherenkov radiation in water produced by particle showers.
The muon counters are buried approximately 2.3 meters underground, allowing only the muon component of the particle showers to be detected, thus filtering out other lower-energy secondary particles. This configuration accurately measures the muon component, a key feature for understanding the nature of cosmic rays in the energy range of interest.
AUGER PRIME
Pierre Auger Observatory Upgrade Project
In recent years, the Observatory team has worked hard to upgrade, install, and commission new systems for the surface detectors. This included replacing all the electronics and the solar panels with more efficient and higher-power ones. Two new detection systems were incorporated into each surface detector: a scintillator on the top and a radio antenna. A small phototube was also installed inside each surface detector, expanding its dynamic range.
The AMIGA muon detectors have been included in AugerPrime, as they are another of the new detection systems added to the Observatory’s basic design. ITeDA developed its technology entirely in Argentina. It consists of underground detectors for the direct measurement of muons, a high-energy and highly penetrating elementary particle that could help us understand the nature of cosmic rays. This is important for studying the transition between cosmic rays of galactic and extragalactic origin.
