Continuous Clocking Mode Calibration with HETG and X-Ray Binaries

One of the outstanding issues with the performance of the Chandra CCDs
is the calbration of the continuous clocking (cc) mode.
High resolution X-ray spectra of bright X-ray sources are now commonly
performed using the ACIS cc-mode in order to avoid spectral degradation
because of photon pile-up. While ths clearly is a favorable mode to allow
the detection of discrete emission and absorption features in the spectra,
the calibration to allow a consistent analysis of the spectral continua
needs to be addressed. We demonstrate our current capability to perform
such observations and showcase  current problem areas. Gain drift s due to
CTI seem to be quite similar to what has been observed in TE mode.
The Si K edge in the current effective area calculation seems
fundamentally flawed and needs to be recalibration. Other problem areas
appear to be a systematic difference in spectral slope in MEG and HEG at
the soft end and hard end. We highlight how these issues affect the
interpretation of X-ray binary spectra.