Thesis

Design of a next-generation detector for gamma-ray astrophysics in South America

• Call:

  IDPASC Portugal - PHD Programme 2019

• Academic Year:

  2019 / 2020

• Domains:

  Experimental Particle Physics | Astroparticle Physics

• Supervisor:

  Ruben Conceição

• Co-Supervisor:

  Bernardo Tomé

• Institution:

  Instituto Superior Técnico

• Host Institution:

  Laboratório de Instrumentação e Física Experimental de Partículas

• Abstract:

  Very-high-energy (VHE) cosmic gamma rays are messengers of violent processes in the universe. In particular, their production is closely connected with the particle acceleration of the very-high-energy cosmic rays detected on Earth. VHE photons are thus key to understand the long-standing mystery of the mechanism by which cosmic rays are accelerated. Also, their intergalactic propagation across vast distances is sensitive to possible modifications of the structure of space-time on the Planck scale. Moreover, the detection of VHE gamma rays may also provide a clue to the nature of the dark matter (DM). In fact, weakly interacting massive particles (considered the most plausible form of DM) are expected to mutually annihilate, giving rise to the creation particles, among them VHE gamma rays. Dark matter particles tend to accumulate at the centers of the galaxies. As such the center of our galaxy is a preferred spot to look for these DM signals. While most VHE gamma-ray detectors currently in operation are located in the northern hemisphere, several of the next-generation detectors are planned to be installed in the southern hemisphere, to have a privileged view of the galactic center. LIP is currently involved in an international project involving teams from different countries such as, Brazil, Italy, Germany, and the USA, to develop and optimize a new concept for a large field-of-view gamma-ray observatory to be installed in South America. The region of the Atacama Desert in northern Chile, at an altitude above 5000 meters, is one of the most promising sites. One of the biggest challenges in the design of this novel detector concept is to bridge the gap between gamma-ray observations using satellites such as Fermi, sensitive up to several tens of GeV and the present and planned gamma ray ground-based experiments, which start to be sensitive at only several hundreds of GeV. This would allow to observe the southern sky with high duty-cycle in an energy region where serendipitous events from, e.g., VHE gamma-ray flares from Active Galactic Nuclei or Gamma-ray bursts are expected to occur. The observatory would thus also play an essential role in issuing alerts to other observatories, thus contributing in an important way to the multi-messenger observations network. The interested candidate will participate in the activities of the LIP team. The works to be performed include: The simulation of the detector concept using the Geant4 toolkit and air-shower simulation tools such as CORSIKA; The development of data analysis tools and studies of the performance of the full-scale detector; The participation on the commissioning of the prototype detector to be installed in South America;