ACIS Instrument Support - Monthly Progress Report for August 2008

1.  ACIS Characterization

1.1 Characterize and model radiation damage in ACIS CCDs

  ...  Continued work on irradiation/annealing tests done at GSFC
in 2005.  Examined trailing pixel distribution.

  ...  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.  Two ObsIDs 
(57663, 57641, 57630) in August.

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.  
(http://space.mit.edu/~cgrant/monitor.html)


2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance. 
Engineering status remains normal as we continue operation with the  
Detector Housing heater disabled.

2.2 Flight software maintenance

  ...  Started development of a new software patch that will prevent
a reoccurence of the BEP crash/reboot that happened during the
NSM anomaly on day 225.

2.3 Instrument science performance

  ...  Supported investigation of and recovery from the day 225
anomaly in which Chandra went into normal sun mode and the ACIS
BEP crashed.  Reviewed telemetry and the sequence of events to
(successfully) determine why the BEP crashed.  Developed new ACIS
patch which will prevent a reoccurence of this particular crash
scenario.  Reviewed ACIS recovery CAP to reload flight software
patches, reboot and restart DEA housekeeping.  Monitored ACIS
DPA temperatures which reached their yellow low limits (due to
pitch angle and the FEPs and video boards being powered off).
Determined low temperatures are not a concern because: the DPA
temperatures leveled off, colder temperatures were reached during 
a shutdown in 2001, and a brief archeology dig found much colder 
DPA temperatures in pre-flight testing.

  ...  Continued close monitoring of ACIS focal plane 
temperatures.

  ...  Participated in monthly ACIS operations meetings.  Discussed
focal plane temperatures, ACIS support for a planned backup OCC and
lessons learned from the Chandra NSM anomaly of day 225.

  ...  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.  

  ...  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 discussing plans for a backup OCC at Cambridge 
Discovery Park and what level of functionality the ACIS team is
willing to support.

  ...  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