X-ray Imaging Spectrometer (XIS)
Suzaku at ISAS
XRS at GSFC
HXD at Tokyo U.
XRT at GSFC
This page is intended to track the performance of the XIS CCDs independent of the time-dependent response applied by the standard calibration pipeline. As such, calibration corrections have not been applied in the plots displayed below. Please take care when comparing to other XIS data, and please read these caveats.
Calibration Source Event Monitoring
The Fe55 calibration sources illuminate the far corners of quads A and D of each detector. These figure tracks measurements of all grade 02346 events in those chip regions for each detector. Black points show SCI-off data, blue points show SCI-on data, and red points show data taken at non-standard CCD temperatures (as identified in the temperature history file). The red points are excluded from the fitting. Monthly accumulations of calibration source data are also available as spectra.
Figure 1 shows shows the mean normalized energy of the Mn K alpha line, assuming a peak energy of 5.894 keV (top); the FWHM in eV of the line (middle); and the count rate in the line (bottom). Also available is the text data file from which the figure was produced.
Figure 2 shows shows the mean normalized energy of the Mn K beta line, assuming a peak energy of 6.490 keV (top); the FWHM in eV of the line (middle); and the count rate in the line (bottom). Also available is the text data file from which the figure was produced.
Current gain and FWHM change measurements at Mn K alpha (5.9 keV) and Mn K beta (6.5 keV):
The locations of the cal source extraction regions are identified below. The image shows a single CCD field (XIS2) in ACTX,ACTY coordinates, with cal sources illuminating the upper left and upper right corners. The coordinates in the table give the inside corner of the extraction boxes for each chip. The outside corners are (x,y) = (0,1024) for quad A and (1024,1024) for quad D.
This figure shows the corner pixel histogram mean (top) and sigma (middle) for all 3x3 events, and the number of hotpixels in the eventlist. The BI chip (XIS1) has different trends from the FI chips because of the difference in event thresholds, which are 100 ADU (FIs) and 20 ADU (BI). Corner pixel information is gathered from the cal source regions as defined above. Hot pixels are extracted from the full CCD field and require that at least 10% of the frames have an event in that pixel.
This figure shows the ratio between top split events and bottom split events (top), and the ratio between right split events and left split events (bottom). These can be used to track changes in parallel and serial CTI, respectively. Grades shown are ACIS 8-bit grade codes.
This figure shows the vertical trailing pixel histogram centroid (top) and 1-sigma width (bottom). These can be used to track changes in CTI.
The trends in the trailing pixel centroid:
The plots on this page are intended to characterize the XIS CCD performance, not the quality of processing or of the response calibration. The data used are raw FFF files, processed only by the mk1stfits routine to convert from RPT to FITS format. Processing such as event grading, filtering, and PHA to energy conversion are performed in a different way than the standard ISAS/GSFC Suzaku pipeline, with most calibration corrections (e.g. CTI correction) not performed at all. Therefore, please take care when comparing these trends to XIS data from other sources.
The basic steps of processing to produce these trend plots are: