About Chandra Archive Proposer Instruments & Calibration Newsletters Data Analysis HelpDesk Calibration Database NASA Archives & Centers Chandra Science Links


ACIS Calibration Presentation from April HEAD Meeting:
Section 3

Last updated: 06/07/2002, G. E. Allen


Section 3: CTI correction for FI CCDs.

We describe changes to the CIAO software that permit a user to mitigate the affects of CTI for the observations that use the ACIS-I array of CCDs. The document briefly describes the three adverse affects of CTI (a degraded energy resolution, an apparent gain shift, and "GRADE migration"), outlines the algorithm used to compensate for CTI, shows how to use the CIAO tool acis_process_events to mitigate the affects of CTI, compares the formats of regular and CTI-adjusted event data files, and shows how the CTI mitigation code improves the problems of a degraded energy resolution, an apparent gain shift, and "GRADE migration." A list of selected CTI references is included for users interested in obtaining more information about CTI.


Comments/Questions/Changes to mraley@cfa.harvard.edu