  We used integrated-light medium-resolution spectra of six Galactic globular
clusters and model stellar atmospheres to carry out population synthesis and to
derive chemical composition and age of the clusters. We used medium-resolution
spectra of globular clusters published by Schiavon et al. (2005), as well as
our long-slit observations with the 1.93 m telescope of the Haute Provence
Observatory. The observed spectra were fitted to the theoretical ones
interactively. As an initial approach, we used masses, radii and log g of stars
in the clusters corresponding to the best fitting isochrones in the observed
color-magnitude diagrams. The computed synthetic blanketed spectra of stars
were summed according to the Chabrier mass function. To improve the
determination of age and helium content, the shape and depth of the Balmer
absorption lines was analysed. The abundances of Mg, Ca, C and several other
elements were derived. A reasonable agreement with the literature data both in
chemical composition and in age of the clusters is found. Our method might be
useful for the development of stellar population models and for a better
understanding of extragalactic star clusters.
