Reconstruction of the muon production depth with ground array data based on the TTC (Time-Track Complementarity) approach

M Ambrosio,F Guarino,M Cilmo,L Valore,C Aramo,R Colalillo,K.-H Kampert,B Pattison,M Fukushima,R Engel

doi:10.1051/epjconf/20135308003

Abstract

The muon longitudinal profile along the shower axis depends on the nature of the primary particle and primary hadronic interaction with air nuclei. The measurement of muonic component inside showers generated by Very High Energy Cosmic Rays provides a very powerful tool for sensing high energy interactions between cosmic ray particles and air molecules. Fundamental parameters such as the interaction cross section, inelasticity, hadron production and multiplicity can be measured by comparing the development of shower electromagnetic component with that of muonic component. Since 1992 a method has been developed to combine the muon arrival direction in a ground based array for cosmic ray detection with their arrival delay with respect to the shower core. This combination permits to select high energy muons weakly scattered in the atmosphere and to reconstruct their height of production with good accuracy. In this paper we discuss the possibility to realize a dual apparatus able to detect both electromagnetic and muonic component at primary energies greater than 10 17 eV.

Highlights

There are few Ultra High Energy Cosmic Rays (UHECR) experiments operating in the energy range above 1017 eV, where the very low flux of primary particles requires the coverage of a very large area in which detectors must be scattered
The TTC technique can be applied to giant arrays at energies greater than those in the knee energy region, where complementary information coming from detection of electromagnetic components at ground level and from fluorescence radiation detection emitted along the shower axis provide information on particle distributions at the observation level and on leading particle interactions along the shower path in the atmosphere
If applied to a giant array such as the Pierre Auger Observatory it would permit to estimate the muon production depth and compare the muon longitudinal development with that of electromagnetic component depicted with fluorescence detectors

Summary

INTRODUCTION

There are few Ultra High Energy Cosmic Rays (UHECR) experiments operating in the energy range above 1017 eV, where the very low flux of primary particles requires the coverage of a very large area in which detectors must be scattered. The second technique is based on the use of fluorescence, the light generated along the shower axis from particles interacting with atmospheric nitrogen This observation permits reconstruction of the development of the electromagnetic component of the shower in the atmosphere, closely connected to the primary particle nature and nuclear cross sections. In 1995 John Linsley [1, 2] proposed a new approach to face this problem He suggested detection of muons inside the shower front and the reconstruction of their heights of production along the shower axis. Partial information has been obtained from dedicated apparatus at the knee energy region, where KASCADE experiment used muons for primary mass discrimination confirming disagreements with Monte Carlo simulations based on known cross sections and interaction parameters [3]. We suggest a possible experimental program for the Pierre Auger Observatory

THE TTC PRINCIPLE

PREVIOUS EXPERIMENTS USING TTC

POSSIBLE APPLICATIONS TO UHECR APPARATUS

CONCLUSION