Charged particles of extensive air showers (EAS), mainly electrons and positrons, initiate the emission of fluorescence light in the Earth’s atmosphere. This light provides a calorimetric measurement of the energy of cosmic rays. For reconstructing the primary energy from an observed light track of an EAS, the fluorescence yield in air has to be known in dependence on atmospheric conditions, li...

The longitudinal profile of extensive air showers is sensitive to the energy and type/mass of the primary particle. One of its characteristics, the atmospheric depth of shower maximum, is often used to reconstruct the elemental composition of primary cosmic rays. In this article, the impact of the atmospheric density profile on the reconstruction of the depth of maximum, as observed in fluoresc...

We report the first direct measurement of the overall characteristics of microwave radio emission from extensive air showers. Using a trigger provided by the KASCADE-Grande air shower array, the signals of the microwave antennas of the Cosmic-Ray Observation via Microwave Emission experiment have been read out and searched for signatures of radio emission by high-energy air showers in the GHz f...

Using the large hadron calorimeter of the KASCADE experiment, hadronic cores of extensive air showers have been studied. The hadron lateral and energy distributions have been investigated in order to study the reliability of the shower simulation program CORSIKA with respect to particle transport, decays, treatment of low–energy particles, etc. A good description of the data has been found at l...

We have used Monte Carlo simulations to investigate the capabilities of a giant air shower observatory designed to detect showers initiated by cosmic rays with energies exceeding 10 19 eV. The observatory is to consist of an array of detectors that will characterise the air shower at ground level, and optical detectors to measure the uorescence light emitted by the shower in the atmosphere. Usi...

The contribution of different components of an air shower to the total energy deposit in the atmosphere, for different angles and primary particles, was studied using the CORSIKA air shower simulation code. The amount of missing energy, parameterized in terms of the calorimetric energy, was calculated. The results show that this parameterization varies less than 1% with angle or observation lev...

Understanding hadronic multiparticle production is important for deriving the composition and energy spectrum of primary cosmic rays from air shower measurements at high energy. In this article, predictions of hadronic interaction models are discussed, emphasizing uncertainties and constraints due to model assumptions and accelerator measurements. The sensitivity of shower observables to model ...

Different interaction models treating hadronic collisions below Elab<100 GeV in air shower simulations are compared within the frame of the CORSIKA program. Their behaviour is studied in isolated collisions of protons or pions with light-mass targets in comparison with experimental data. It is discussed how model properties influence air-shower parameters like the longitudinal profile or the la...

We have developed a macroscopic description of coherent electro-magnetic radiation from air showers initiated by ultra-high energy cosmic rays in the presence of the geo-magnetic field. This description offers a simple and direct insight in the relation between the properties of the air shower and the time-structure of the radio pulse. As we show the structure of the pulse is a direct reflectio...

Potential pathogens from shower water and aerosolized shower mist (i.e., shower aerosol) have been suggested as an environmental source of infection for immunocompromised patients. To quantify the microbial load in shower water and aerosol samples, we used culture, microscopic, and quantitative PCR methods to investigate four shower stalls in a stem cell transplant unit at Barnes-Jewish Hospita...