Simulation of ultra-high energy photon showers with PRESHOWER

The new, publicly available Monte Carlo program PRESHOWER is presented. It allows detailed studies on conversion and cascading of UHE photons in the geomagnetic field. When coupled to a standard air shower simulation program, PRESHOWER enables complete simulations of UHE photon-induced showers. 1. PRESHOWER simulations The identification of primary photons or spec-ifying stringent limits on the photon flux is of major importance for understanding the origin of ultra-high energy cosmic rays (UHECR). In such a kind of studies it is necessary to simu-late thoroughly the air showers induced by UHE photons. It implies a proper treatment of pre-cascading of UHE photons in the geomagnetic field (preshower effect) [1,2]. This effect has a significant impact on observable properties of the subsequent atmospheric showers [3–6]. An ac

www.elsevier.tiocate/npe Towards the Energy Spectrum and Composition of Primary Cosmic Rays in the Knee Region: Methods and Results at KASCADE

KASCADE (KArlsruhe Shower Core and Array DEtector) is a multi-detector setup to observe the electro-magnetic, muonic and hadronic air shower components simultaneously at primary energies in the region of the “knee”. A large number of observables per single shower are registered. The main aims of the experiment are the determination of the primary energy spectrum around the “knee ” and the energy variation of the chemical composition. The measurements reveal an increasing mean mass of the primary cosmic rays above the observed kink, and a sharper knee for the light primary component than for the all-particle spectrum, and the absence of a knee for the heavy component between 1 and 10 PeV. 1