ACIS Instrument Support - Monthly Progress Report for May 2011

1.  ACIS Characterization

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 examining bias data before and after Crab
  observations to include most recent ones (ObsIDs 13207,
  13150-13154).  No changes observed.

  ...  Continued work on a paper combining CTI, FWHM and background
  monitoring results from ACIS and Suzaku.  Submitted abstracts to
  present results at Suzaku meeting in July and HEAD meeting in
  September.  Examining FWHM as a function of particle background
  rate.

  ...  Presented poster at the May AAS meeting on the ACIS instrument
  team's monitoring program.

  ...  Requested new raw frames for periodic monitoring.


2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  All
  ACIS engineering parameters continue to operate within predicted
  limits.

  ...  Continued work on the ACIS Engineering Unit.  Developed plans
  to move the EU into a more secure, semi-clean space with protection
  against future water leaks.

2.2 Flight software maintenance

2.3 Instrument science performance

  ...  Parameter blocks to test potential new values for CCD video
  offsets ready to be run on the spacecraft.  The results of the
  planned June tests will inform future global changes to prevent
  bias-uncorrected pulseheights from going below zero at higher
  detector temperatures.

  ...  Continued investigation into whether ACIS can act as it's own
  radiation monitor, prompted by action from the thermal working group
  which is concerned about the continued degradation of EPHIN.
  Reviewing new, hopefully final, version of patch.

  ...  Participated in monthly ACIS operations meetings.  Topics
  included status of the engineering unit, thermal issues, reducing
  perigee backoff times, and the threshold crossings patch. 

  ... Participated in radiation working group telecon.

  ... Prepared plots of ACIS CTI history, specifically looking for
  changes due to the reduction in perigee backoff times.  None seen.

  ...  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 CC mode calibration and the recent IACHEC meeting.

  ...  Attended meeting called by CXC SDS discussing best practices in
  finding and correcting bias anomalies.

  ...  Started compiling statistics on ACIS subarray usage.  Most
  commonly used configurations will be used in future tests to
  determine whether the current CTI correction is adequate for
  subarray modes.

  ...  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.



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