The MIDAS experiment: A prototype for the microwave emission of Ultra-High Energy Cosmic Rays

Recent measurements suggest that extensive air showers initiated by ultra-high energy cosmic rays (UHECR) emit signals in the microwave band of the electromagnetic spectrum caused by the collisions of the free-electrons with the atmospheric neutral molecules in the plasma produced by the passage of the shower. Such emission is isotropic and could allow the detection of air showers with 100% duty cycle and a calorimetric-like energy measurement, a significant improvement over current detection techniques. We have built MIDAS (MIcrowave Detection of Air Showers), a prototype of microwave detector, which consists of a 4.5 m diameter antenna with a cluster of 53 feed-horns in the 4 GHz range. The details of the prototype and first results will be presented.Comment: To appear in the proceedings of 12th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD10), Siena, Italy, 7 - 10 June 201

Multi-scale failure for heterogeneous materials: link with morphological modeling – COMPLAS XI

A 3D meso-scale model for failure of heterogeneous quasi-brittle materials is presented. At such scale, concrete can be represented as an heterogenous material with two phases, where aggregates are included within the concrete. The model problem of heterogeneous materials that is adressed in detail here is based, on the one hand, on FE models with embedded discontinuities and, on the other hand, on a morphological representation using Gaussian or Gaussian related random field excursion sets