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Last modified: 14 December 2009

URL: http://cxc.harvard.edu/caldb4/index.html
Introduction
Header Keywords
Directory Structure
Indexing System
Versioning
Download the CALDB4
Download Version 4.2.0
Release Notes
Caveats for the Chandra CALDB4
ACIS N0005 Responses Suite Caveat
Querying the CALDB4
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Analysis Notes

Matching CIAO and CALDB Versions

CALDB 4.2.0 should not be used unless you are running CIAO 4.2 or later versions. CIAO 3.4 requires CalDB 3.5.5, available here.

Are your versions mismatched? Time to ugrade CIAO and CALDB!

News

Previous Items

15 Dec 2009 [New]

CalDB4.2.0, an important (decimal) upgrade of the Chandra CalDB, and necessary to run CIAO 4.2, has been released. See the release notes for more information.

17 Sep 2009

CalDB4.1.4, a patch to all previous CalDB4 versions, has been released. It includes the acis Epoch 38 T_GAIN upgrades (May through Jul 09). See the CalDB 4.1.4 release notes for more information.

07 Jul 2009

CalDB4.1.3, a patch to all previous CalDB4 versions, has been released. It includes the acis Epoch 37 T_GAIN upgrades (Feb through Apr 09). See the CalDB 4.1.3 release notes for more information.

27 Mar 2009

CALDB 4.1.2, a patch to CalDB 4.1.0 or 4.1.1, has been released. It includes the ACIS Epoch 36 T_GAIN updates for Nov 08 through Jan 09. See the CalDB 4.1.2 release notes for more information.

21 Jan 2009

CalDB 4.1.1 was released. It includes upgrades to the HRMA Effective Area and the HETG 1st-order grating efficiencies. See the CalDB 4.1.1 for more information on this upgrade.

15 Dec 2008

CalDB 4.1.0, a new CalDB structure for CIAO 4.1, which includes ACIS -120C EPOCH 35 (Aug - Oct 08) T_GAIN updates, was released. See the CalDB 4.0 and CalDB 4.1.0 release notes for more information on this new installation.

Welcome to the
Chandra Calibration Database Website

The Chandra X-Ray Center introduced version 4.2.0 of the Chandra Calibration Database (CALDB) on 15 DEC 2009.

CALDB 4 is a brand new, newly-configured, newly-supported calibration database for Chandra, in particular for CIAO 4.1. The directory structure, caldb configuration (index files), and the software interface are all changed/upgraded.

The CalDB 4.2.0 upgrade is a major (decimal) upgrade to CalDB 4.1.x. CIAO 4.2 and CalDB 4.2.0 are mutually required to implement several of the upgrades in 4.2.0 correctly. CalDB 4.2.0 includes the following items, amoung several others:

  • ACIS CONTAM version N0005, important for all ACIS-S observations, with or without gratings, taken since 2005.
  • HRC-I SUMAMPS-based GMAP (gain) files and an associated new RMF for HRC-I. The new SAMP-based GMAPs require CIAO 4.2 or later to work properly in hrc_process_events.
  • HRC-S SUMAMPS-based time-dependent GMAP (T_GMAP) and an associated LETG PIMASK filter file to reduce backgrounds. This is a major improvement in LETG/HRC-S background reduction. This upgrade also requires CIAO 4.2 or later version, to work properly.

Users are strictly cautioned that CalDB 4.2.0 is totally incompatible with CIAO 3.4. CalDB 4.2.0 is required by CIAO 4.1.x and later versions, but will not work at all if you install it with or in CIAO 3.4.

See details in the link CalDB 4.2.0 Release Notes.

CalDB version 3.5.5, for use only with CIAO3.4, is still maintained by the CXC, and may be accessed and downloaded from the CALDB3 main and download pages. Compatible upgrade files will be added to CalDB 3.5.5 for at least throughout calendar year 2009. See the caldb3 web page for details and upgrades for CalDB 3.5.5.

The CALDB is the directory and indexing structure that stores and provides access to all calibration files that are required for standard processing and analysis.

These files are used in standard data processing, as well as for analysis with software packages such as CIAO. When you apply a gain map, create an exposure map, or build response files (RMFs and ARFs) - among many other things - you are using the Chandra CALDB to apply the necessary calibration files.

The CALDB serves many functions:

  • Storing and archiving calibration files.

  • Maintaining a naming convention and header structure for all calibration files.

  • Indexing calibration data, based on FITS header keywords, for software access.

  • Permitting updates of calibration data independent of software updates, while maintaining configuration control.

  • Providing a traceable history of calibration data in the database by maintaining versioning.

  • Translating calibration products into formats suitable for processing and/or analysis.

These webpages contain information about each of these topics. They are also designed to help you (or your system manager) understand how the CALDB is assembled and how it works in the Chandra software system.

Please email the CXC Helpdesk with any questions or comments on the CALDB and this website.

Last modified: 14 December 2009

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