Sacrificial charge and the spectral resolution performance of the Chandra Advanced CCD Imaging Spectrometer

Abstract

Soon after launch, the Advanced CCD Imaging Spectrometer (ACIS), one of the focal plane instruments on the Chandra X-ray Observatory, suffered radiation damage from exposure to soft protons during passages through the Earth's radiation belts. The ACIS team is continuing to study the properties of the damage with an emphasis on developing techniques to mitigate charge transfer inefficiency (CTI) and spectral resolution degradation. A post-facto CTI corrector has been developed which can effectively recover much of the lost resolution. Any further improvements in performance will require knowledge of the location and amount of sacrificial charge - charge deposited along the readout path of an event which fills electron traps and changes CTI. We report on efforts by the ACIS Instrument team to characterize which charge traps cause performance degradation and the properties of the sacrificial charge seen on-orbit. We also report on attempts to correct X-ray pulseheights for the presence of sacrificial charge.

9 pages, 7 figures to be published in Proc. SPIE 4851

References in corpus (1)

• An Overview of the Performance and Scientific Results from the Chandra X-Ray Observatory (CXO)

Cited by in corpus (6)

• Chandra detection of ejecta in the small-diameter supernova remnant G349.7+0.2
• A charge transfer inefficiency correction model for the Chandra Advanced CCD Imaging Spectrometer
• Long-term trends in radiation damage of Chandra X-ray CCDs
• Experimental studies on the charge transfer inefficiency of CCD developed for the soft X-ray imaging telescope Xtend aboard the XRISM satellite
• Comparing simulations and test data of a radiation damaged charge-couple device for the Euclid mission
• Temperature dependence of charge transfer inefficiency in Chandra X-ray CCDs