ACIS Instrument Support - Monthly Progress Report for February 2004

1. ACIS Characterization

1.1 Characterize and model radiation damage in ACIS CCDs

  ...  Continued taking a series of data in full-frame raw mode for
performance verification and monitoring.  Two ObsIDs this month
with data in the ACIS-S and ACIS I configurations.

 [...] Finalized paper describing results of cold irradiation
experiment performed last fall at GSFC ("Anomalous Annealing
of a High-resistivity CCD irradiated at Low Temperature").  To
be submitted soon to IEEE Transactions on Nuclear Science.

1.2 Monitor scientific on-orbit performance of ACIS

 [...] Continued study of the step-function CTI change associated with
the Halloween CME.  Analysis is ongoing.  
(http://space.mit.edu/~cgrant/cti/change/change.html)

  ...  Continued monitoring of ACIS CTI.  Updated CTI monitoring web
page (http://space.mit.edu/~cgrant/cti/).

  ...  Continued monitoring of ACIS gain.  All CCDs stable with a slow 
decline in gain slope (ADU/eV) except for I2 which continues to vary.
(http://space.mit.edu/~cgrant/gain/).

 [...  Conducted tenth CTI measurement in alternating exposure mode
with frame times of 4.0 and 3.2 seconds (ObsID 60358).  Analysis
ongoing.

 [...] Prepared slides for Chandra Quarterly Review at MSFC in March.

1.3 Update and improve CCD simulation

  ...  Continued work on improving FI and BI CCD models and CTI simulation 
code.

  ...  Continued work on verifying new BI QE curves.  Consistent with
new XRCF data points provided by CXC.  Released test versions for CXC
verification.

 [...] Fixed bug in internal response matrix generation tools.


2. Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.
All engineering indicators remain nominal with no short term trending.

2.2 Instrument science performance

  ...  Continued daily quick-look processing of ACIS telemetry and
maintained Web interface to ACIS real-time data.

  ...  Continued to publish the "annotated DOT" timeline reports.

 [...] Participated in ACIS telecons on the possible ACIS bakeout.
Researched ACIS focal plane temperatures during belt passages to
check if ACIS has ever been warm (> -60C) as it is in some proposed
bakeout scenarios.  On one occasion very early in the mission 
(July 27, 1999 - before any doors were open) the temperature was warm
during perigee.

 [...] Reviewed ACIS instrument status in a presentation to the
ACIS IPI team.  Discussed CTI, gain, focal plane temperature and 
contamination monitoring.


3. CXC Support

3.1 Provide user support

  ...  Updated ACIS memo listing calibration ObsIDs and observation
characteristics (ACIS Memo #165).

3.2 Provide data analysis support

 [...] Participated in CXC Cal/Ops RMF discussion group.  Discussions
of validation of new BI QE curves, QE/QEU definitions and cosmic ray
dead time correction.

  ...  Continued to maintain ACIS calibration database of ground and 
flight data products


4. OCC Support

4.1 Use of MIT/ACIS EGSE at OCC

  ...  Continued support and maintenance of ACIS EGSE software and 
hardware at the OCC.


all recent memos available at http://space.mit.edu/ACIS/iacis.html