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Manuscript Title: A program for the analytic simulation of extensive air showers.
Authors: L. Goorevich
Program title: CASCADE
Catalogue identifier: AAYF_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 7(1974)344
Programming language: Fortran.
Computer: CDC 6600.
Operating system: SCOPE.
RAM: 28K words
Word size: 60
Keywords: Astrophysics, Elementary, Particle physics, Cosmic rays, Extensive air showers, Simulation, Hadrons, Cascade.
Classification: 1.1, 11.3.

Nature of problem:
Air shower simulations allow one to compare the predictions of various models with experimental results of extensive air shower (EAS) arrays. Direct Monte Carlo methods are not practical, in terms of computing time, for the ultra-high primary energy(approx10*20eV) and low thresholds(approx 1GeV)now detectable. An analytic method is therefore used to predict the mean values of observables such as hadron energy spectra, muon shower size and electron shower size.

Solution method:
The diffusion equations for nucleons and charged pions are solved bythe method of "sucessive generations". This involves an iterative procedure in which the energy spectra of nucleons and charged pions, as a function of depth, are found by numerical integration. Other observables are derived from these basic spectra.

Restrictions:
Fluctuations in the characterists of particle interactions are not taken into account. Cascade development is assumed to be in one dimension. Production of K-mesons is not considered. The electron component secondary to the muons is not considered.

Unusual features:
The particle production spectra include delta-function components representing the decay products of isobars.

Running time:
This depends on the required accuracy of integration but is typically about 1.5 minutes for one test set of parameters.