CalDB Public Release Notes
Installed in Standard Data Processing (SDP) as of (UTC)
Effective Date: (UTC) 2006-05-03T15:00:00
Release to public (anticipated) Tuesday 2006-05-09.
CalDB 3.2.2 is a small patch to CalDB 3.2.1 which includes three new
T_GAIN files corresponding to two new epochs (to wit, quarter years) of
the mission timeline. These are Epochs 23 and 24, which cover the August
2005 - Jan 2006 time period.
II. Summary of Changes
A. T_GAIN files for EPOCHs 23 and 24.
(Flat, non-interpolating file, will be current in SDP)
ECS data collected from May 01 2005 through Nov 01 2006 have been
reduced to determine the chip-by-chip T-Gain or time-dependent gain
correction factors for those periods. The Chandra Data System team has
produced the resultant CalDB FITS files for use in CIAO/SDP ACIS Level
1 tool acis_process_events that are effective on the dates in the
These new files upstage and demote the previous standard processing
default file, acisD2005-05-01t_gainN0002.fits for all observations
taken on or after UTC=2005-05-01T00:00:00.
ACIS L1 pipeline tool acis_process_events.
CIAO tools affected:
ACIS L1 events file generator acis_process_events.
New Level=2 Event File
Time-Dependent ACIS Gain Correction
III. Technical Details
An improved means of filtering the input ECS data to exclude
out-of-bounds temperatures has been employed for these epochs relative
to the preceding T_GAIN data releases. For the files in question, the
time-dependent gain correction has the following disposition versus
energy for chips ACIS-I3 and ACIS-S3, respectively. The previous
default file, namely acisD2005-05-01t_gainN0002.fits, a
non-interpolating file released in CalDB 3.2.0, Nov. 15, 2005, is
included in the plot for reference. Note that for the FI chip I3, the
T_GAIN correction is not monotonically increasing versus epoch during
Fig 1: ACIS-I3 aim point time-dependent
gain correction in eV.
Fig 2: ACIS-S3 (BI chip)
time-dependent gain corrections derived from the new data files.