CalDB 4.10.5 Public Release Notes

I. INTRODUCTION

CalDB 4.10.5 is an upgrade to the Chandra CalDB, which includes the following items:

• HRC-S GTI_LIM Updates Effective 2021-05-14

Note: The HRC-S GTI_LIM file in CalDB is called by the standard processing MTL pipeline only, and not CIAO, which instead uses the existing standard mtl1 file as input. Hence there will be no immediate public release of CalDB 4.10.5. Instead, it will be subsumed within a later public CalDB release.

II. SUMMARY OF CHANGES

A. HRC-S GTI_LIM Updates Effective 2021-05-14

Location:	$CALDB/data/chandra/hrc/gti_lim/
Filenames:	hrcsD2021-05-14gtilimN0001.fits (for OBS_MODE=(POINTING,RASTER,SCAN,SLEW)) hrcsD2021-05-14gtilim_secN0001.fits (for OBS_MODE=SECONDARY only)

With the recent restart of the HRC in a modified operational mode, there has been a modification of one the high voltage settings for HRC-S, which will require an adjustment in the GTI Limits tables in CalDB in order for any GTIs (Good Time Intervals) to be obtained (and hence any events to be delivered in L2 event lists).

Specifically, the limit on the parameter SPHBLV must be reset from 79 to 78, with tolerance of +/-1, to be effective as of (UTC) 2021-05-14T00:00:00. The change has been formally recommended by the HRC Instrument Scientist. No other limits need to be changed, as they are already appropriately set in the existing files.

The need for the change was recognized when HRC-S DDT OBS_ID 27452 came through with no GTIs or L2 events, and it was determined that the SPHBLV limit setting was off by +1 relative to the new operational value.

The SPHBLV setting (at 79) exists in the two currently active GTI_LIM files for HRC-S, and hence two new files must be added to upstage them as of the above date. The new filenames are given in the table above.

STANDARD DATA PIPELINES/TOOLS AFFECTED:

(SDP) Mission Time Line (MTL) tool mtl_build_gti, first run-through, in which the CalDB GTI_LIM file is called for as input.

CIAO THREADS AFFECTED:

None. While the tool mtl_build_gti is included in CIAO, it is not used to call CalDB for the GTI limits; Instead, the limits table has aready been included in the mtl1 FITS file (See the extension LIMITS) with the standard data products.