Multimuon detector for quasi horizontal EAS

University and INFN, Firenze, Italy

Abstract

Quasi horizontal showers produced by charged CR and gammas are constituted exclusively by muons, the other components being absorbed in the thick layer of the atmosphere they must cross to reach a detection system on the Earth surface. Their transverse dimensions are increased by the distance they must travel as well by the terrestrial magnetic field which extends muon cloud and separates positive muons from negative ones. The extended wide transverse dimensions allow increasing the rate of detection of EAS produced by high energy CR by means of a single detector which samples the muon density in the shower. This concept has been already applied in the NEVOD-DECOR experimental complex at MEPhI in Moscow that could detect local muon density (LMD) of showers produced by very high energy CR up to more than 10¹⁸eV. By adding to the LMD the measurement of the local energy density (LED) the determination of the primary energy E₀ can be substantially improved. A few embodiments of such a device can be envisaged and one of them is discussed. The substantial rate increase of the area explored by a multimuon detection system measuring LMD and LED allows to conceive an array constituted by a relatively small number of such stations for measuring UHECR up to 10¹²eV and higher.