Chandra Announcement: CXC Announces the Release of Chandra CalDB version 4.11.1

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Tingle, Evan

Apr 18, 2024, 2:32:49 PMApr 18

CXC Announces the Release of Chandra CalDB version 4.11.1

This upgrade includes the following items:

ACIS CTI correction files version N0012

  • Includes new "warm" corrections for ACIS-S2, S3.
  • Retains the same warm corrections for the ACIS-I array.
  • New upper limit TEMP_HI for the highest band (188.96 K, or -84.19 C) for all chips.

HRC-S QE Uniformity data sets version N0018 (33 files)

  • Replaces the N0017 file set.
  • Includes one additional new file effective 2023-09-08.
  • 1-2% decrease in net HRC-S QE since June 2023.

PCAD ACA-primary DARK_CURR (dark current) file periodic additions #6.

  • Does not affect CIAO users.

For details, please see the CalDB 4.11.1 Release Notes located at:

NOTE: CalDB 4.11.1 is only compatible with CIAO 4.16.0 and later versions; CIAO 4.15.x and earlier versions will generate an error in and termination of acis_process_events due to the new CTI file formats.

See also "How CalDB 4.11.1 Affects Your Analysis" at:

To download and install CalDB 4.11.1 on you system with CIAO 4.16.0, using the preferred Conda package, see the following link:

Alternatively, to use the ciao-install script to install or upgrade your CIAO 4.16.0 CalDB to version 4.11.1, please see the following link:

Manual download and installation instructions are also available at:

Users who do not wish to download the full CalDB, but would rather access it via the web for their specific observations only, may use the CIAO contributed script "download_obsid_caldb". Note that the web-accessible CalDB may take a day or two to be upgraded to this latest CalDB release.

As always, please send questions and requests for enhancements to the CXC HelpDesk (

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