All the XMM-Newton calibration data are organized in a ``Current Calibration File" (CCF). Each constituent of the CCF is uniquely identified by its (progressive) issue number and date of validity. Access to the CCF is based on the Calibration Index File (CIF), which must be generated through the SAS task cifbuild at the beginning of an analysis session.
CCF constituents are available from the XMM-Newton Calibration Portal. This directory is frequently updated. The XMM-Newton user may consider subscribing the CCF mailing list, which notifies in real-time all changes in the CCF content, or activating an automatic update of the calibration database on her/his own disk, as specified in the XMM-Newton Calibration Portal.
The user is referred to XMM-Newton Calibration Access and Data Handbook for more information about the calibration files, and the SAS infrastructure to access/visualize the content of the CCF constituents (Calibration Access Layer, CAL). The CCF release notes (accessible also through the XMM-Newton Calibration Portal) provide information on the accuracy of the XMM-Newton calibrations. Synthetic documents, summarizing the current calibration status and associated systematic uncertainties, are available from the XMM-Newton Calibration Portal as well.