ACIS Instrument Support - Monthly Progress Report for April 2008

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.
Will be presented at upcoming SPIE meeting.

  ...  Executed new SI modes which allow more grades to be 
telmetered.  These SI modes are being used to compare TE and CC 
mode grade rejection to help calibrate CC mode.  Three ObsIDs
(57879, 57857, 57847) in April.

1.3 Monitor scientific on-orbit performance of ACIS

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

  ...  Worked on paper for upcoming SPIE meeting comparing gain
changes due to CTI for ACIS and Suzaku XIS.  

2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.
The instrument continues to operate nominally.

  ...  Detector Housing heaters were permanently turned off on
07 April.  This has resulted in a dramatic gain in thermal control 
margin for the ACIS focal plane.  Recent science observations have 
all been able to remain within a few tenths of a degree of the 
commanded -120C set point.

  ...  Reviewed SOP for combined warm boot with starting a DEA 
housekeeping run.

2.3 Instrument science performance

  ...  Participated in monthly ACIS operations meetings.  Reported
on improvement in focal plane temperature control since turning off
the Detector Housing heaters.

  ...  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. Reported
on improvement in focal plane temperature control since turning off the
Detector Housing heaters.

  ...  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.

  ...  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)


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