The physics of radio detection of ultra high-energy cosmic rays is the main topic of our research activities.A Codalema3 station (c) Louis-Marie.Rigalleau

Scientific context :

Their nature and their origin are some of the main unresolved questions about ultra energetic cosmic rays (at 1019eV and above). In order to overcome the extremely-low particle flux, the experiments rely on instruments deployed on the ground over very large areas such as at the Pierre Auger Observatory that cover about 3000 km2. Larger surfaces and thus a major improvement of the detection techniques are required in order to answer to these questions and to establish the astronomy of cosmic rays at extreme energies. The radio-detection of extensive air showers produced by primary cosmic ray interacting in the atmosphere is an old technique re-investigated in the early 2000 and is an experimental method possibly able to match the requirements of the next generation very large observatory.

Scientific goals :

To take fully advantage of the CODALEMA instrument is one of the main objectives of our group especially with the goal of reaching the successive milestones toward a radio detection system fulfilling the criteria of the giant ground detector of the future. Existing since 2002, the CODALEMA experiment has been recently upgraded with the deployment of an array of autonomous stations (CODALEMA 3) and will be taking data up to 2020. Two principal topics are under investigation : the physic of the radio electric field associated to the air shower and the determination of the key geometrical parameters driving the design of a very large array.
The group is also a main contributor in the international collaboration developing the AERA prototype at the Pierre Auger Observatory. On site first R&D efforts have been started in 2006 (RAuger) and pursued with the birth of a large collaboration in 2008 (AERA). Started in 2010, the installation of the AERA elements will be achieved in 2013 for a data taking period extending over several years. Observation of the cosmic rays in an hybrid mode (particle detectors, muon detectors, fluorescence telescope and radio antennas) is the most appealing advantage of the recent developments of the Pierre Auger experiment.

Since 2014 our R&D activities are taking place within the EXTASIS project. Several ideas are developped in order to improve further the extansive air shower radio detection capabilities. For instance, a smart trigger is tested in order to improve the detection efficiency of shower transients. Moreover a low frequency antenna is developed to detect a specific signal induced by the rapid disappearance of the shower particles in the ground.

 

Finally the group has accumulated a long experience in the radio detection thanks to the successive test and R&D efforts performed at the Nancay radio astronomy facility. Within this scope, we are interested in adapting the radio detection of transients to other messengers from the universe and to other observation domains.