CalDB 4.11.5 Public Release Notes
Public Release Date: 16 October 2024
SDP Installation Date: 2024-10-15T12:00:00 (UTC)
I. INTRODUCTION
CalDB 4.11.5 is an upgrade to the Chandra CalDB, which includes the following items:
For the CIAO 4.16 / CalDB 4.11.5 release notes see How CalDB 4.11.5 Affects Your Analysis.
II. SUMMARY OF CHANGES
A. HRC-S Mean QE N0017 & QEU N0020 File Sets
| Location: | $CALDB/data/chandra/hrc/qe/ |
| Filenames: | hrcsD1999-07-22qeN0017.fits hrcsD2012-03-29qeN0017.fits hrcsD2021-05-14qeN0017.fits hrcsD2024-09-20qeN0017.fits |
| Location: | $CALDB/data/chandra/hrc/qeu/ |
| Filenames: | hrcsD1999-07-22qeuN0020.fits hrcsD2000-01-01qeuN0020.fits hrcsD2001-01-01qeuN0020.fits hrcsD2002-01-01qeuN0020.fits hrcsD2003-01-01qeuN0020.fits hrcsD2004-01-01qeuN0020.fits hrcsD2005-01-01qeuN0020.fits hrcsD2006-01-01qeuN0020.fits hrcsD2007-01-01qeuN0020.fits hrcsD2008-01-01qeuN0020.fits hrcsD2009-01-01qeuN0020.fits hrcsD2009-09-15qeuN0020.fits hrcsD2010-09-14qeuN0020.fits hrcsD2012-03-29qeuN0020.fits hrcsD2012-10-05qeuN0020.fits hrcsD2013-09-21qeuN0020.fits hrcsD2015-02-17qeuN0020.fits hrcsD2016-02-22qeuN0020.fits hrcsD2016-07-29qeuN0020.fits hrcsD2017-01-25qeuN0020.fits hrcsD2017-06-06qeuN0020.fits hrcsD2017-09-27qeuN0020.fits hrcsD2018-01-20qeuN0020.fits hrcsD2018-05-27qeuN0020.fits hrcsD2018-09-27qeuN0020.fits hrcsD2019-02-25qeuN0020.fits hrcsD2019-08-23qeuN0020.fits hrcsD2020-01-18qeuN0020.fits hrcsD2020-07-23qeuN0020.fits hrcsD2021-05-14qeuN0020.fits hrcsD2021-09-03qeuN0020.fits hrcsD2022-09-09qeuN0020.fits hrcsD2023-09-08qeuN0020.fits hrcsD2024-03-04qeuN0020.fits hrcsD2024-07-12qeuN0020.fits hrcsD2024-09-20qeuN0020.fits |
A new mean QE file set has been released for HRC-S, including one new file effective 2024-09-20T12:10:00, corresponding to the date of the new High Voltage (HV) setting for the HRC-S. The HV adjustment was done to compensate for the continuing gain loss suffered as the detector ages. The other three files are effective as of the previous HV adjustment dates for HRC-S.
At the same time, a new set of HRC-S QE Uniformity files have been generated for release, incorporating the most recent Calibration Observations of HZ43 using LETG and the HRC-S. As with previous releases, the secular time variations in the detector are now subsumed into the numerous QEU files.
See the HRC-S QE/QEU why page for information on the current HRC-S QE and QE Uniformity. See the technical details section below for illustrations and details of the derivation of these new QE Uniformity corrections.
SDP Pipeline / CIAO SCRIPTS/TOOLS AFFECTED:
The SDP pipeline procedure "tg_mk_responses" is used to generate single-source GARFs and GRMFs for HRC-S/LETG observations, to be ingested onto the archive. This procedure uses the HRC-S QEU library as loaded from the ARDLIB.
See the CIAO script fluximage, which uses mkinstmap.
THREADS AFFECTED:
For exposure-corrected imaging analysis with HRC-S, see the thread:
For grating spectroscopy with the LETG/HRC-S, see the thread:
B. PCAD ACA-P DARK_CURR File Updates #8
| Location: | $CALDB/data/chandra/pcad/dark_curr/ |
| Filenames: | acapD2024-08-26darkN0002.fits acapD2024-09-25darkN0002.fits |
The CXC Aspect Team has generated an eighth set of ACAP DARK_CURR files, including two new files, to support ACA background calculation and subtraction in the ASPECT L1 pipeline. The DARK_CURR files draw on an ever-growing database of ACA full field dark current data products which have been accumulated since the 1999:223 OAC dark current pixel map. Each version N0002 dark current fits file in the CALDB includes a 1024x1024 image with the processed full-field dark current map of the ACA CCD in e-/sec. Each file also includes header information with the ACA CCD temperature of the calibration, the reference date of the ACA dark current product, and the scale expected to be used to scale the calibration e-/sec to the effective e-/sec at the observed temperatures during observations.
The DARK_CURR files have effective dates (Cal Validity Start Date, or CVSD*) which are spaced ~2-6 weeks apart, as with their previously released datasets. The new files are effective as of the respective dates given above. These new files extend the date coverage for archival observations through 2024-09-25T00:00:00, with the second (last) file being the one that will be the default file in standard data processing (SDP) until the next release/extension.
PIPELINES/TOOLS AFFECTED:
PCAD L1 Pipeline tool asp_get_calib calls for the ASPECT CalDB files, including DARK_CURR.
THREADS AFFECTED:
None.
III. TECHNICAL DETAILS
A. HRC-S Mean QE N0017 & QEU N0020 File Sets
The fourth file in the QE N0017 update set is for the most recent high voltage change which occurred on Sept 20 2024. It raises the QE by 8%, across all chips and at all wavelengths.
The HRC-S QEU N0020 file set adds two additional QEU files, effective 2024-07-12T00:00 and 2024-09-20T12:10 UTC, respectively, based on the most recent HZ43 observations (28427, from June 2024, and 29452, from August 2024.) The wavelength-independent drop in QE since the previous November 2023 observation is 2-3.5%, depending on dispersed orders. The wavelength-dependent corrections required on S1 and S3 continue to follow long-observed trends.
The QEU updates the wavelength-dependent portions of S1 and S3 at the previous high voltage, based on the Aug 11 observation of HZ 43, as well as the new high voltage setting from the test observation on June 11. This latter model is labeled ObsID 78427 in the accompanying plot, but it is actually the new HV portion of ObsID 28427. The plots in Fig. 1 below give wevelength-dependent corrections applied to each file, with the black traces for S1, the red for S3.
