  (ABRIDGED)
  This dissertation concerns the use of CCDs for for X-ray astronomy. Part I of
this thesis focuses on the calibration of the Advanced CCD Imaging Spectrometer
(ACIS), one of the two primary focal plane instruments on the Chandra X-ray
Observatory. I begin by presenting a series of measurements made using
undispersed synchrotron radiation. I analyzed the results of these experiments
to extract parameters necessary to model the absolute detection efficiency of
CCDs used as reference standards for ACIS characterization. I also discuss a
novel "mesh" technique I pioneered to non-destructively measure the sub-pixel
structure of CCDs, including the channel stops and gates. Guided by the results
of the mesh experiments, I performed additional measurements to constrain
recombination effects in the channel stops.
  Part II of this thesis concerns the X-ray properties of rotation- powered
(radio) pulsars. High energy observations serve as a powerful diagnostic of the
energetics and emission mechanisms of neutron stars. I analyze ASCA and ROSAT
observations of three young pulsars which are particularly well-suited for
addressing these issues. I also present observations of the rotation-powered
pulsar with the highest known magnetic field, and describe how the results
relate to anomalous X-ray pulsars, another type of neutron star. Finally, I
analyze Chandra observations of the supernova remnant Cas A. These data fully
demonstrate the capabilities of ACIS and reveal a previously unknown point
source at the center of the remnant.
