24 July 2008 Physics of reverse annealing in high-resistivity Chandra ACIS CCDs
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After launch, the Advanced CCD Imaging Spectrometer (ACIS), a focal plane instrument on the Chandra Xray Observatory, suffered radiation damage from exposure to soft protons during passages through the Earth's radiation belts. An effect of the damage was to increase the charge transfer inefficiency (CTI) of the front illuminated CCDs. As part of the initial damage assessment, the focal plane was warmed from the operating temperature of -100° C to +30° C which unexpectedly further increased the CTI. We report results of ACIS CCD irradiation experiments in the lab aimed at better understanding this reverse annealing process. Six CCDs were irradiated cold by protons ranging in energy from 100 keV to 400 keV, and then subjected to simulated bakeouts in one of three annealing cycles. We present results of these lab experiments, compare them to our previous experiences on the ground and in flight, and derive limits on the annealing time constants.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
C. E. Grant, C. E. Grant, B. LaMarr, B. LaMarr, G. Y. Prigozhin, G. Y. Prigozhin, S. E. Kissel, S. E. Kissel, S. K. Brown, S. K. Brown, M. W. Bautz, M. W. Bautz, } "Physics of reverse annealing in high-resistivity Chandra ACIS CCDs", Proc. SPIE 7021, High Energy, Optical, and Infrared Detectors for Astronomy III, 702119 (24 July 2008); doi: 10.1117/12.789750; https://doi.org/10.1117/12.789750

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