CCD x-ray detectors: on-board data processing

Laura J. Cawley, John Andrew Nousek, David Nelson Burrows, Gordon P. Garmire, Diego Janches, David H. Lumb

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We present the results of a comparison of data processing algorithms to be used with space- borne x-ray CCD cameras such as those aboard ASCA, CUBIC and AXAF. The goal is to optimize efficiency and accuracy based upon the capabilities and limitations of the on-board processors. We examine the two main components of processing: determination of the bias (or zero) -level, and event recognition. An algorithm to generate a pixel-by-pixel bias by on-board processing is developed and tested. The on-board bias frame is compared to a bias created from a standard laboratory pixel-by-pixel averaging of dark frames. We show that an accurate pixel-by-pixel bias frame can be created with an on-board algorithm in as few as 15 frames. We show that a bias frame created from that algorithm performs as well as meanframes created in the laboratory. On-board algorithms that handle bias determination and event selection simultaneously are also developed. We show that several types of these algorithms successfully process the CCD data, although the algorithm should be chosen according to the specific capabilities of the processors. The procedures were evaluated by examining event quality and single/split event ratios, and more importantly by the determination of spectral energy resolution (e.g., the FWHM of 55Fe). The algorithms were compared and evaluated for laboratory data from several different cameras and types of CCD devices.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsOswald H. Siegmund, John V. Vallerga
Number of pages9
StatePublished - Dec 1 1995
EventEUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy VI - San Diego, CA, USA
Duration: Jul 12 1995Jul 14 1995


OtherEUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy VI
CitySan Diego, CA, USA

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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