Behaviour of the EAS age parameter in the knee energy region

1 Jul 2010, 09:15
15m
One West (Fermilab)

One West

Fermilab

PO Box 500 Batavia, IL 60510
Contributed Extensive air shower experiments Extensive air shower experiments

Speaker

Prof. Jean-Noël CAPDEVIELLE (APC, CNRS-University Paris Diderot)

Description

We review the different definitions of the age parameter used in the lateral and longitudinal electron distributions. In order to remove ambiguities in the interpretation of the experimental data, we have compared simulations with CORSIKA carried simultaneously with the options NKG and EGS. The effect of the positron annihilation cross section missing in the NKG approach is pointed out for small and inclined EAS, near the axis ; the consequences of the electrons coming from muon decay at large distances from axis are also underlined. Distinguishing the longitudinal, lateral and local age parameters, correspondances and conversions between the 3 categories are inferred from the simulations. Finally, the age parameter derived by fitting the lateral profile of the electron distribution, is confirmed as a good indicator of the primary composition and the hadronicity of the cascade as far as some conditions are fullfilled concerning bands of istances to the axis and zenith angle, dependant slightly on the primary energy (examples in the interpretation from Kascade and Akeno data).
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Primary author

Prof. Jean-Noël CAPDEVIELLE (APC, CNRS-University Paris Diderot)

Co-authors

Dr Artru BHADRA (University of North Bengal, Siliguri) Prof. Rajat DEY (University of North Bengal, Siliguri)

Presentation materials