Direct measurement of the vertical component of the electric field from EAS

International audienceA three-fold antenna system has been installed nearby the center of the CODALEMA particle detector. Its goal is to measure the complete electric field produced by air showers, i.e. along the 3 polarizations East-West (EW), North-South (NS) and vertical. Indeed on all currently operating radio detection arrays, only the horizontal NS and EW polarizations or their projections are measured. This allows the vertical electric field component to be reconstructed, provided that the far-field assumption is valid, but though strong hints based on the theories of air shower radio emission tend to validate this hypothesis, it has never been verified experimentally. We present the 3D antenna and its acquisition system, and the first results obtained

Multi-scale and multi-frequency studies of cosmic ray air shower radio signals at the CODALEMA site

International audienceIn addition, CODALEMA supports the EXTASIS project, aiming at detecting the expected lowfrequency signal produced by the sudden deceleration of the air shower particles hitting the ground. Beside these dedicated arrays, the Nançay site will host the NenuFAR radio telescope (recognized as a SKA pathfinder), made of 1824 dual crossed-polarization antennas similar to the CODALEMA ones. All these arrays present different antenna density and extent, and could be operated in a joint mode to record simultaneously the radio signal coming from an air shower. Therefore, the upgraded CODALEMA facilities could offer a complete description of the air shower induced electric field at small, medium and large scale, and over an unique and very wide frequency band (from ∼ 2 to ∼ 200 MHz). The use of multi-band detectors combined with composite trigger algorithms could help boosting the radio detection technique as a candidate for an accurate composition measurement with a high efficiency, or in the frame of a further very large cosmic ray observatory. We describe the current and foreseen instrumental set-up together with the prospective developments of the radio detection technique

Multi-scale and multi-frequency studies of cosmic ray air shower radio signals at the CODALEMA site

International audienceSince 2003, the Nançay Radio Observatory hosts the CODALEMA experiment, dedicated to the radio detection of cosmic ray induced extensive air showers. After several instrumental upgrades,CODALEMA is now composed of:- 57 self-triggering radio detection stations working in the [20-200] MHz band, over 1 km2;- an array of 13 scintillators acting as a particle detector;- a compact array of 10 cabled antennas, triggered by the particle detector, to test the capabilitiesof a phased antenna cluster to cleverly select air shower events.In addition, CODALEMA supports the EXTASIS project, aiming at detecting the expected lowfrequency signal produced by the sudden deceleration of the air shower particles hitting the ground. Beside these dedicated arrays, the Nançay site will host the NenuFAR radio telescope (recognized as a SKA pathfinder), made of 1824 dual crossed-polarization antennas similar to the CODALEMA ones. All these arrays present different antenna density and extent, and could be operated in a joint mode to record simultaneously the radio signal coming from an air shower.Therefore, the upgraded CODALEMA facilities could offer a complete description of the air shower induced electric field at small, medium and large scale, and over an unique and very wide frequency band (from ~ 2 to ~ 200 MHz). The use of multi-band detectors combined with compositetrigger algorithms could help boosting the radio detection technique as a candidate for an accurate composition measurement with a high efficiency, or in the frame of a further very large cosmic ray observatory. We describe the current and foreseen instrumental set-up together withthe prospective developments of the radio detection technique