  We present an analysis of the X-ray point source populations in 182 Chandra
images of galaxy clusters at z>0.1 with exposure time >10 ksec, as well as 44
non-cluster fields. Analysis of the number and flux of these sources, using a
detailed pipeline to predict the distribution of non-cluster sources in each
field, reveals an excess of X-ray point sources associated with the galaxy
clusters. A sample of 148 galaxy clusters at 0.1<z<0.9, with no other nearby
clusters, show an excess of 230 cluster sources in total, an average of ~1.5
sources per cluster. The lack of optical data for these clusters limits the
physical interpretation of this result, as we cannot calculate the fraction of
cluster galaxies hosting X-ray sources. However, the fluxes of the excess
sources indicate that over half of them are very likely to be AGN, and the
radial distribution shows that they are quite evenly distributed over the
central 1 Mpc of the cluster, with almost no sources found beyond this radius.
We also use this pipeline to successfully reproduce the results of previous
studies, particularly the higher density of sources in the central 0.5 Mpc of a
few cluster fields, but show that these conclusions are not generally valid for
this larger sample of clusters. We conclude that some of these differences may
be due to the sample properties, such as the size and redshift of the clusters
studied, or a lack of publications for cluster fields with no excess sources.
This paper also presents the basic X-ray properties of the galaxy clusters, and
in subsequent papers in this series the dependence of the AGN population on
these cluster properties will be evaluated.
  In addition the properties of over 9500 X-ray point sources in the fields of
galaxy clusters are tabulated in a separate catalogue available online.
