ACIS Instrument Support - Monthly Progress Report for March 2009

1.  ACIS Characterization

1.1 Characterize and model radiation damage in ACIS CCDs

  ...  Continued work on irradiation/annealing tests done at GSFC
in 2005.  Finalizing analysis.

  ...  Provided calibration for BI CCD temperature-dependent CTI
correction to CXC SOT.

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Continued monitoring of ACIS CTI, gain, trailing pixel 
pulseheight, detector efficiency, corner pixel distribution, spectral 
line centroid and width, and focal plane temperature.  Updated 
monitoring web pages.  (http://space.mit.edu/~cgrant/monitor.html)

  ...  Updated web page which displays raw raw frame to include most
recent data.  (http://space.mit.edu/~fergason/acis/raw.html)

  ...  Developed serial trailing monitoring for BI CCDs.  Will
post to web in April.

  ...  Examining the use of Al-K line to calibration contamination
instead of the much weaker L-complex.  Some issues with systematics
in fitting, probably due to changing background levels.  Ongoing.

2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance. 
ACIS engineering continues to report nominal operations.

  ...  Conducted two long (125 & 130 ksec) focal plane cooling tests.
Focal plane temperature dropped quickly and was regulating at -125C
(the set point).  The spacecraft was in a favorable geometry with no
Earth visible to the ACIS radiator.

2.2 Flight software maintenance


2.3 Instrument science performance

  ...  Presented ACIS SI team report at the Chandra Quarterly.  
Provided focal plane temperature data to SOT for their presentation.

  ...  Participated in monthly ACIS operations meetings.  Discussed
plan to reduce radiation belt backoff time from 6 to 5hrs from
perigee and most recent focal plane cooling test.

  ...  Participated in radiation working group telecon discussing
the radiation environment during perigee as the Chandra orbit changes.

  ...  Participated in meeting to update the MIT ACIS instrument team
on changes in EPHIN performance, required time for ECS measurements,
and possible changes in radiation belt timing.

  ...  Reviewed new parameter blocks for ACIS CTI observations which
use an alternate set of CCDs (I0-I3,S1,I3).  Will be used regularly
starting in April.

  ...  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.


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 modeling discussion group.  Discussed
updates to contamination calibration and ECS observation strategy.

  ...  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.  Replaced malfunctioning tape drive.

  ...  Continued work on improving configuration management of the
ACIS workstations in the TST area of the Chandra OCC.  Work nearly
complete.


Outreach:

none this month

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