Methods of determination of the energy and mass of primary cosmic ray particles at extensive air shower energies

Abstract

Abstract. Measurements of cosmic ray particles at energies above E > ∼ 5 · 10 14 eV are performed by large area ground based air shower experiments. Only they provide the collection power required for obtaining sufficient statistics at the low flux levels involved. In this review we briefly outline the physics and astrophysics interests of such measurements and discuss in more detail various experimental techniques applied for reconstructing the energy and mass of the primary particles. These include surface arrays of particle detectors as well as observations of Cherenkov-and of fluorescence light. A large variety of air shower observables is then reconstructed from such data and used to infer the properties of the primary particles via comparisons to air shower simulations. Advantages, limitations, and systematic uncertainties of different approaches will be critically discussed.

Cosmic Ray Energy Spectra and Mass Composition at the Knee – Recent Results from KASCADE –

“…It is well known [13] that for given energy, primary Fenuclei result in more muons and fewer electrons at ground as compared to proton primaries. Specifically, in the energy range and at the atmospheric depth of KASCADE, a Fe-primary yields about 30 % more muons and almost a factor of two fewer electrons as compared to a proton primary.…”

“…For a brief review about EAS observables and their experimental techniques the reader is referred to Refs. [13,14,12].…”

Hybrid simulations of extensive air showers

“…The combination of these and occasionally additional shower features, calculated in simulations with a particular hadronic model, is used as the basis for the determination of the energy and mass of the primary particle. Reviews of air shower experiments and observed features are given, for example, in [1,2].…”

Cosmic Rays from the Knee to the Ankle – Status and Prospects

“…However, this is probably the most difficult task in EAS physics, both because of the level of dependence on hadronic interaction models used in EAS simulations and because of the significant (mass dependent) fluctuations of EAS observables. A large variety of methods is used to infer the primary energy and mass [28], most notably the ratio of electron to muon numbers. At energies and heavy (all the rest) primaries from EAS-TOP and MACRO using TeV muons [29]).…”

“…Such studies have provided important information about the origin and transport properties of CRs in the interstellar medium. Two prominent examples are ratios of secondary to primary elements, such as the B/C-ratio, which are used to extract the average amount of matter CR-particles have traversed from their sources to the solar system, or are relative abundances radioactive isotopes, such as 10 Be to stable 9 Be or 26 Al to stable 27 Al, which carry information about the average 'age' of CRs. With many new complex experiments taking data or starting up in the near future and with a possibly new gener- * email: kampert@uni-wuppertal.de ation of long flying balloons, this remains a vital field of research.…”