  We present an optimised galaxy cluster finder, 3D-Matched-Filter (3D-MF),
which utilises galaxy cluster radial profiles, luminosity functions and
redshift information to detect galaxy clusters in optical surveys. This method
is an improvement over other matched-filter methods, most notably through
implementing redshift slicing of the data to significantly reduce line-of-sight
projections and related false positives. We apply our method to the
Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) Deep fields, finding ~170
galaxy clusters per square degree in the 0.2 <= z <= 1.0 redshift range. Future
surveys such as LSST and JDEM can exploit 3D-MF's automated methodology to
produce complete and reliable galaxy cluster catalogues. We determine the
reliability and accuracy of the statistical approach of our method through a
thorough analysis of mock data from the Millennium Simulation. We detect
clusters with 100% completeness for M_200 >= 3.0x10^(14)M_sun, 88% completeness
for M_200 >= 1.0x10^(14)M_sun, and 72% completeness well into the 10^(13)M_sun
cluster mass range. We show a 36% multiple detection rate for cluster masses >=
1.5x10^(13)M_sun and a 16% false detection rate for galaxy clusters >~
5x10^(13)M_sun, reporting that for clusters with masses <~ 5x10^(13)M_sun false
detections may increase up to ~24%. Utilising these selection functions we
conclude that our galaxy cluster catalogue is the most complete CFHTLS Deep
cluster catalogue to date.
