Résumé: Detailed simulations of extensive air showers have been carried out with the CORSIKA program in order to evaluate the energy brought by the different shower components at ground level and transmitted underground. A special attention is given to the angular distributions and to the collimation of beams penetrating deep underground or underwater. The natural collimation of high energy particles in extensive air shower cores results mainly from the ratio between the transverse and the longitudinal momenta of secondary particles generated in the earliest interactions. This collimation is partly conserved by the high energy muons and neutrinos. It is comparable to the magnetic focusing of charged pions and kaons decaying in tunnels of suitable length after production in accelerators. Such is the case for neutrino beams of KEK J-PARC/T2K (300 km to Kamiokande), OPERA (730 km to Gran Sasso) and MINOS (735 km to Irvine Mine).

Résumé: Exposed at different altitudes (stratospheric, mountain...), X-ray emulsion chambers have given evidence for some unusual phenomena such as coplanar and halo events. These phenomena which are observed in the energy range of the Large Hadron Collider (LHC) are hard to explain with only standard physics. To understand these remarkable cosmic ray events, we have performed a set of Monte Carlo calculations using the CORSIKA code in combination with different hadronic interaction models (HDPM, QGSJET and DPMJET). The main features of these events are investigated and their physical relevancy is discussed.

Résumé: The coplanar emission of very high energy secondary cosmic rays was observed at stratospheric altitudes by the X-ray emulsion chamber experiments ECHOS-Concorde and RUNJOB. This paper treats the physical relevancy of the experimental observations using Monte Carlo calculations carried out with the help of the CORSIKA program. Different high energy hadronic interaction models have been used to study the possible dependence of this effect upon the primary particle mass number.

Résumé: The alignment of very high energy secondary cosmic rays, implying coplanar emissions, was observed at both stratospheric and mountain altitudes by several x-ray emulsion chamber experiments. This paper investigates the physical relevance of the experimental observations through detailed Monte Carlo calculations carried out with the CORSIKA program combining different models of high energy hadronic interaction. The physical factors likely to induce or to influence this phenomenon are discussed.

Résumé: Using the perturbation method (Born approximation), a theoretical model has been developed to account for the EBIC (Electron Beam Induced Current) intensities and contrasts likely to occur in an n-type polycrystalline semiconductor, as a function of the grain size. The influence of the minority charge carrier diffusion length and the primary electron beam energy have also been examined, respectively.

Résumé: We have performed, using the CORSIKA code, extensive simulations focused on the penetrating component EAS showers for p and Fe primaries in the energy band 105-109 GeV. Our analysis is concentrated on neutrinos and muons above a common energy threshold of 100 GeV. This value makes easier the observation of features which could be correlated to the characteristics of the primary interaction and possible changes at the highest energy of the LHC. The obtained results are compared for p and Fe primaries. At the lowest energies (105 GeV) we have groups of about 100 muons against 40 neutrinos, whereas we get sizes up to 6000 muons and 2000 neutrinos at 108 GeV. Muons and neutrinos contents can be enhanced by 70-80% when passing to heavy primaries, the relative neutrino muon abundance remaining in the range 0.280.29 (in the case of the same energy threshold for muons and neutrinos).

Résumé: A Monte carlo generator for coplanar emission is elaborated on the basis of partonic models and Schwinger mechanism for particle production. The very strong string tension of the valence diquark is taken as the source of very large pt's necessary to produce the alignments of secondaries. The preliminary coplanar generation is considered here in the case of small diffractive masses in the forward direction.

Résumé: X-ray emulsion chamber experiments exposed at mountain (Pamir, Chakaltaya...) and stratospheric altitude have exhibited some interesting phenomena near the LHC energy range. Among these phenomena one can quote coplanar emission and halo events which are hard to explain in the framework of the standard model. In order to understand these unusual events, we have performed Monte Carlo calculations using the CORSIKA code in combination with several standard hadronic interaction models such as QGSJET, DPMJET... The main features of these remarkable events are investigated and their physical relevancy is discussed.

Résumé: X-ray emulsion chamber experiments, exposed at mountain altitude (Pamir, Chakaltaya), have exhibited some interesting phenomena around the knee region of the primary cosmic ray energy spectrum. Among these phenomena one can quote coplanar emission and halo events which are hard to explain in the framework of the standard model. In order to understand these unusual events we have performed Monte Carlo calculations using the CORSIKA code in combination with several standard hadronic interaction models such as QGSJET, DPMJET and HDPM. The main features of these remarkable events are investigated and their physical relevancy is discussed.

Résumé: The remarkable event JF2af2 observed near 107 GeV in the emulsion chamber embarked on the Concorde shows a perfect alignment of the most energetic gamma's on the X-ray film. To investigate the origin of this phenomenon which indicates a coplanar emission, we have simulated some samples of stratospheric gamma ray families with CORSIKA code and different interaction models. Events with such common features are selected by a simple least square method. The dependance of this phenomenon on favorable geometrical circumstances (a very large transverse momentum for one very energetic secondary near the vertical plane and a large zenith angle) is investigated. The Concorde event (52° of inclination) may enter in this category (with a typical gap between the main clusters). Simulations are also carried out at Pamir altitude where such mechanism would give a probability rising with zenithal angle.