  The HST/ACS Survey of Galactic globular clusters (GGCs) is a HST Treasury
project aimed at obtaining high precision photometry in a large sample of
globular clusters. The homogeneous photometric catalogs that has been obtained
from these data by Anderson et al. (2008) represents a golden mine for a lot of
astrophysical studies.
  In this paper we used the catalog to analyse the properties of MS-MS binary
systems from a sample of fifty GGCs. We measured the fraction of binaries
(divided in different groups), studied their radial distribution and
constrained the mass ratio distribution. We investigated possible relations
between the fraction of binaries and the main parameters of their host GGCs.
  We found a significant anti-correlation between the binary fraction in a
cluster and its absolute luminosity (mass).
