Exploring the physics potential of the MARTA Engineering array
IDPASC Portugal - PHD Programme 2016
2016 / 2017
Experimental Particle Physics | Astroparticle Physics
Instituto Superior Técnico
Laboratório de Instrumentação e Física Experimental de Partículas
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 that rules the shower development. Therefore, their detection at ground is an essential tool to understand the physics of extensive air showers and particle interactions at extreme energies. However, the measurement of the highest energy extensive air-showers and in particular of the produced muons at ground is not easyposes several challenges as it has to be performed in an outdoor environment, and using detectors 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 of the shower electrons and gammas. This array will measure the muons on an event-by-event basis and will collect shower events produced mainly at a center-of-mass energy compatible to those reach currently at the Large Hadron Collider, 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 MARTA 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 Engineering Array (EA), consisting of about ten MARTA stations, is planned to start to be deployed in Auger during 2016. The successful operation of the MEA 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: - Participation on the commissioning of the MARTA Engineering Array; - Validation of the detector concept and performance; - Development of data analysis tools to reconstruct showers; - Interplay of both MARTA EA and LHC data to constrain hadronic interaction properties.