Thesis

Exploring the physics potential of the MARTA prototype array

• Call:

  IDPASC Portugal - PHD Programme 2015

• Academic Year:

  2015 / 2016

• Domain:

  Astrophysics

• Supervisor:

  Carlos M Correia

• Co-Supervisor:

  Paulo Garcia

• Institution:

  Universidade do Porto

• Host Institution:

  Laboratório de Instrumentação e Física Experimental de Partículas

• Abstract:

  Keywords for this thesis: - Performance and optimization studies for the MARTA prototype array; - Development of air-shower reconstruction tools; - Analysis of data from RPC detectors installed in the Pierre Auger Observatory; Detailed description: The nature and arrival direction of cosmic rays at the highest energies can only be inferred indirectly through the analysis of the air shower induced by their interaction with the atmosphere. The understanding of the shower development relies on our knowledge about the hadronic interactions that can occur at energies well above those reachable at accelerators on Earth. Muons, being long-lived particles, carry important information about these hadronic interactions. Therefore, their detection at ground is an essential tool to understand the physics of extensive air showers. However, their measurement is not easy as it has to be done in an outdoor environment and covering a very large area. Engaging this challenge, the LIP group is leading the MARTA project, which proposes an innovative concept for the muon detection in air-shower experiments. MARTA (Muon Array of RPCs for Tagging Air showers) consists basically of robust RPCs (Resistive Plate Chambers) deployed under a Water Cherenkov Tank, which is sensitive to all kind of charged particles and is also used as an absorber. This array will measure the muons on an event-by-event basis and will collect shower events produced mainly at a centre-of-mass energy compatible with those of the LHC. The unique characteristics of MARTA RPCs (high efficiency, and high timing and spatial accuracy) will further allow to measure simultaneously the muon signals in the tanks and in MARTA, providing a powerful tool to inter-calibrate both detectors and to monitor important parameters of the tanks on the field. Several full-scale prototypes are already installed and taking data in the Pierre Auger Observatory - currently the biggest cosmic ray observatory in the world - situated in Argentina. A MARTA Prototype Array (MPA), consisting of about ten MARTA stations, is planned to start to be deployed in Auger during 2015. The successful operation of the MPA will be of the utmost importance for the proof-of-concept of MARTA. The selected candidate will be involved in the activities of the LIP/Auger group, in particular those related with the Prototype Array. Performance and optimization studies will be carried out by using state-of-the-art Monte Carlo simulations of the air-showers propagation (CORSIKA) and of the detectors at ground (Geant4, Auger Offline software). An important part of the work will consist in the analysis of the data taken by the MPA and the comparison with the simulation results. This interplay between simulations and real data will be of great relevance both in the validation of the existing MARTA simulations and for possible improvements in the final detector design. Moreover, the data taken with the MPA can be also used to test our physical knowledge about the shower. Hence, the candidate is also expected to participate in the creation of data analysis tools to reconstruct showers.