  A 50 ksec observation of the Supernova Remnant Cas A was taken using the
Chandra X-Ray Observatory High Resolution Camera (HRC) to search for periodic
signals from the compact source located near the center. Using the HRC-S in
imaging mode, problems with correctly assigning times to events were overcome,
allowing the period search to be extended to higher frequencies than possible
with previous observations. In an extensive analysis of the HRC data, several
possible candidate signals are found using various algorithms, including
advanced techniques developed by Ransom to search for low significance periodic
signals. Of the candidate periods, none is at a high enough confidence level to
be particularly favored over the rest. When combined with other information,
however (e.g., spectra, total energetics, and the historical age of the
remnant), a 12 ms candidate period seems to be more physically plausible than
the others, and we use it for illustrative purposes in discussing the possible
properties of a putative neutron star in the remnant. We emphasize that this is
not necessarily the true period, and that a follow-up observation, scheduled
for the fall of 2001, is required.
  A 50 ksec Advanced CCD Imaging Spectrometer (ACIS) observation was taken, and
analysis of these data for the central object shows that the spectrum is
consistent with several forms, and that the emitted X-ray luminosity in the 0.1
-10 keV band is 10^{33}-10^{35}erg cm^{-2}sec^{-1} depending on the spectral
model and the interstellar absorption along the line of sight to the source.
