CalDB 4.11.6 Public Release Notes

I. INTRODUCTION

CalDB 4.11.6 is an upgrade to the Chandra CalDB, which includes the following items:

• HRC-I QE vN0016 File Set (40 new files)
• PCAD ACA-P DARK_CURR File Update #9
• Proposal Cycle 27 PIMMS Effective Areas

For the CIAO 4.17 / CalDB 4.11.6 release notes see How CalDB 4.11.6 Affects Your Analysis.

II. SUMMARY OF CHANGES

A. HRC-I QE vN0016 File Set (40 new files)

Location:

$CALDB/data/chandra/hrc/qe/

Filenames:

hrciD1999-07-29qeN0016.fits hrciD2000-07-23qeN0016.fits hrciD2001-04-17qeN0016.fits hrciD2001-10-12qeN0016.fits hrciD2002-04-12qeN0016.fits hrciD2002-10-23qeN0016.fits hrciD2003-04-23qeN0016.fits hrciD2003-10-06qeN0016.fits hrciD2004-04-05qeN0016.fits hrciD2004-11-05qeN0016.fits hrciD2005-05-15qeN0016.fits hrciD2005-11-01qeN0016.fits hrciD2006-04-25qeN0016.fits hrciD2006-11-19qeN0016.fits hrciD2007-09-15qeN0016.fits hrciD2008-09-11qeN0016.fits hrciD2009-09-15qeN0016.fits hrciD2010-09-16qeN0016.fits hrciD2011-09-29qeN0016.fits hrciD2012-09-29qeN0016.fits hrciD2013-10-03qeN0016.fits hrciD2014-09-29qeN0016.fits hrciD2015-08-05qeN0016.fits hrciD2016-06-11qeN0016.fits hrciD2017-02-16qeN0016.fits hrciD2017-08-16qeN0016.fits hrciD2018-02-12qeN0016.fits hrciD2018-08-24qeN0016.fits hrciD2019-02-27qeN0016.fits hrciD2019-08-24qeN0016.fits hrciD2020-02-20qeN0016.fits hrciD2020-08-27qeN0016.fits hrciD2021-01-09qeN0016.fits hrciD2021-02-16qeN0016.fits hrciD2021-04-05qeN0016.fits hrciD2021-08-29qeN0016.fits hrciD2022-09-04qeN0016.fits hrciD2023-09-27qeN0016.fits hrciD2024-03-30qeN0016.fits hrciD2024-09-20qeN0016.fits

The HRC calibration team has generated an update (version 16) to the HRC-I time-dependent QE file set in CalDB, to include data derived from recent HRC-I/LETG HZ 43 observations. The new file set includes two additional files, the first effective as of 2024-03-30T00:00:00 (UTC) which includes the calibrations for the previous HV settings, and the second effective 2024-09-20T12:00:00 UTC, the date and time of the newly adjusted HV setting for HRC-I.

See the Technical Details section below for the HRC-I QE N0016 updates.

PIPELINES/TOOLS AFFECTED:

CIAO tools/scripts fluximage and mkgarf

THREADS AFFECTED:

HRC-I Exposure Map and Exposure-corrected Image
LETG/HRC-I Grating ARFs

B. PCAD ACA-P DARK_CURR File Update #9

Location:	$CALDB/data/chandra/pcad/dark_curr/
Filenames:	acapD2024-10-05darkN0002.fits acapD2024-10-18darkN0002.fits acapD2024-11-12darkN0002.fits

The CXC Aspect Team has generated a ninth set of ACAP DARK_CURR files, including three new files, to support ACA background calculation and subtraction in the ASPECT L1 pipeline. The DARK_CURR files draw on an evergrowing 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 in the filnames in the Description of Change Item 2 section below. These new files extend the date coverage for archival observations through 2024-11-12T00:00:00, with the final 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:

PIPELINES/TOOLS AFFECTED:

None.

C. Proposal Cycle 27 PIMMS Effective Areas

Location:	$CALDB/data/chandra/pimms/acis/
Filenames:	acisiD2024-11-06pimmsN0027.fits acisihetg0D2024-11-06pimmsN0027.fits acisiletg0D2024-11-06pimmsN0027.fits acissD2024-11-06pimmsN0027.fits acissheg1D2024-11-06pimmsN0027.fits acisshegmeg1D2024-11-06pimmsN0027.fits acisshetg0D2024-11-06pimmsN0027.fits acissleg1D2024-11-06pimmsN0027.fits acissletg0D2024-11-06pimmsN0027.fits acissmeg1D2024-11-06pimmsN0027.fits
Location:	$CALDB/data/chandra/pimms/hrc/
Filenames:	hrciD2024-11-06pimmsN0027.fits hrciletg0D2024-11-06pimmsN0027.fits hrcsD2024-11-06pimmsN0027.fits hrcsleg1D2024-11-06pimmsN0027.fits hrcsleghiD2024-11-06pimmsN0027.fits hrcsletg0D2024-11-06pimmsN0027.fits

The Chandra Cycle 27 PIMMS effective areas have been generated and loaded into the DS10.13.1 software for release with the Cycle 27 Call for Proposals. These files are maintained in CalDB for use by the DS when it is ready to load the PIMMS files, and convert them into the usual PIMMS ASCII format for implementation and distribution to HEASARC, annually. See the links below for information on this cycle's PIMMS EAs:

Cycle 27 PIMMS Effective Areas

Cycle 27 PIMMS Effective Area Public Information

PIPELINES/TOOLS AFFECTED:

PIMMS Effecive Area Viewer

PIMMS Count Rate Calculator

THREADS AFFECTED:

None.

III. TECHNICAL DETAILS

A. HRC-I QE vN0016 File Set (40 new files)

From Vinay Kashyap, HRC calibration scientist:
These [N0016 QE files] include the effects of QE decline after the previous voltage increase as well as the updated QE after the latest voltage increase that was tested on June 6, 2024 and implemented on Sep 20, 2024. Attached are some figures illustrating the verification of count rate prediction after folding the QE into an effective area, and a plot showing the evolution of the QE over the years.

Fig. 1: HRC-I QE traces from each of the new QE N0016 files in the new 40-file set.