  Observational studies of cluster evolution over moderate redshift ranges (to
z ~ 1) are a powerful tool for constraining cosmological parameters, yet a
comprehensive knowledge of the properties of these clusters has been hitherto
unattained. Using a highly efficient optical selection technique, the
Red-Sequence Cluster Survey (RCS) has unearthed a large sample of high redshift
cluster candidates. All six of the clusters from this sample which have been
observed with the Chandra X-Ray Observatory were detected in the X-ray. These
Chandra follow-up observations (0.64 < z < 1.0) indicate that the clusters are
systematically less luminous than their similarly rich, X-ray selected
counterparts at lower redshifts, though they are consistent with standard Lx-Tx
relationships. Comparisons with X-ray selected samples suggest that the
discrepancy may be due in part to systematic differences in the spatial
structure of the X-ray emitting gas. Our initial results from Chandra follow-up
observations of six RCS clusters are presented, including beta model parameters
and spectral information.
