ACIS Instrument Support - Monthly Progress Report for August 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.

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)

  ...  Examined focal plane temperatures in detail.  Reducing
radiation belt backoff time from 6hrs to 5hrs in May has slightly
increased the number of warm observations.  Going to exclusive
tail-sun orientation during the MUPS anomaly significantly increased
the number of warm observations.  As a test, the SIM FA6 heater was
turned off August 14 which has reduced the number of warm observations.

  ...  Prepared slides for Chandra Quarterly Review in September.
Included plots and statistics on focal plane temperatures.

  ...  Collected raw data frames.  Raw frames can be helpful with 
diagnosing future problems and better understanding cosmic ray 
artifacts.  Plan is to take raw data a few times a year.

  ...  Submitted abstract for the Chandra Calibration Review in
September on the ACIS instrument team monitoring effort.

2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance. 
ACIS engineering parameters continue to be stable.

2.2 Flight software maintenance

2.3 Instrument science performance

  ...  Examined ObsID 56866, ECS dataset that was mistakenly allowed
to continue for ~2.5-hrs beyond the normal stop science.  Provides
interesting data on particle background count rates at lower altitudes.

  ...  Conducted meeting of MIT ACIS instrument team to review available
data since the reduction of the radiation belt backoff time from 6hrs
to 5hrs that happened in May.

  ...  Participated in monthly ACIS operations meeting.  Discussed
ACIS focal plane temperatures and MUPS news.

  ...  Monitored MUPS anomaly telecons.

  ...  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

  ...  Answered user question on data analysis problems with measuring 
Fe-55 decay in the ACIS calibration source.

  ...  Updated ACIS memo listing calibration ObsIDs and 
observation characteristics (ACIS Memo #165).

3.2 Provide data analysis support

  ...  Examined anomalous biases for ObsID 11799.  Suggested features
were most likely due to a light leak during the observatory slew and
that data should be reprocessed using a different bias.

  ...  Tested temperature-dependent CTI correction tool for future
inclusion as user-contributed software.  Results seem promising.
Co-author on abstract submitted to the Chandra Calibration Review 
in September.

  ...  Participated in CXC Cal/Ops modeling discussion group.  Discussed
proposed update to the ACIS contamination model and plans for the upcoming
Chandra Calibration Review.

  ...  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.


Outreach:

none this month

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