ACIS Instrument Support - Monthly Progress Report for August 2007

1.  ACIS Characterization

1.1 Characterize and model radiation damage in ACIS CCDs

  ...  Continued work on a paper presenting the results of the 
radiation damage/reverse annealing tests done at GSFC in 2005.

  ...  Executed new SI modes which allow more grades to be 
telmetered.  These SI modes will be used to compare TE and CC 
mode grade rejection to help calibrate CC mode.  Three ObsIDs 
(58291, 58259, 58250) in August.

  ...  Prepared abstract on temperature-dependent CTI-correction
for Chandra Calibration Workshop.

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Continued investigation of bias artifacts believed to be
due to long-lived cosmic ray afterglows.  Prepared abstract
on bias artifacts for Chandra Calibration Workshop.

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

  ...  Prepared abstract on ACIS instrument monitoring for Chandra 
Calibration Workshop.

1.7 Produce novel data products from the MIT ACIS database

  ...  To futher explore the differences between CC and TE mode
grade ratios, hunted for and found CC mode data taken in the lab.
Analysis ongoing.

2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.
The ACIS instrument continues to operate in nominal fashion.  A  
review of the past 60 days of engineering telemetry shows no unusual  
trends.

2.2 Flight software maintenance

  ... Work continues on the next ACIS patch release, which will 
include the "tlmbusy" and "buscrash" patches (SPR 138 and 140).
Two Engineering Change Orders (ECOs) began the review
process.

2.3 Instrument science performance

  ...  Reviewed a proposed set of tests which would turn off the 
ACIS detector housing heater.  Assessed the potential risks to
ACIS and found none.  Submitted a memo to the Chandra FDB.

  ...  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).

  ...  Summarized calibration changes to the ACIS effective area 
at the Si-K edge for Suzaku XIS team members.

3.2 Provide data analysis support

  ...  Participated in CXC Cal/Ops modeling discussion group.

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

  ...  Assisted in characterizing ACIS afterglow events for SDS tool
testing.

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.

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


Outreach:

Mentor to high school students participating in the Chandra 
Astrophysics Institute (C. Grant)

Lecture on "CCDs for X-ray Astronomy" at 5th International X-ray
Astronomy School (C. Grant)


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