ACIS Instrument Support - Monthly Progress Report for October 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.  Five ObsIDs 
(58179, 58169, 58160, 58150, 58144) in October.

  ...  Presentation at Chandra Calibration Workshop on the
temperature-dependent CTI correction algorithm.

  ...  Preparing CTI-temperature calibration data for inclusion
in the Penn State CTI correction software.

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Continued investigation of bias artifacts believed to be
due to long-lived cosmic ray afterglows.  Presentation
on bias artifacts and "superbiases" at 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)


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.

  ... Five Detector Housing cooling tests were conducted in October.
Testing of instrument response to turning off the Detector Housing  
heaters has shown close correlation to thermal model predictions.   
Although the margin on focal plane thermal control (the bottom line  
reason for changing our operating strategy) cannot be measured  
directly, the model correlations that have been done give us  
confidence that we can predict the magnitude of the benefit gained by  
operating in this mode.

  ...  Planning new Detector Housing cooling test during perigee.
Temperature should drop much lower and may trigger survival heaters.

2.2 Flight software maintenance

2.3 Instrument science performance

  ...  Reviewed documents and CAPs related to Detector Housing cooling
tests.

  ...  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 questions about calibration at -100C.  Provided
suggestions for how to test the validity of scientific conclusions.

  ...  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 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)

Participated in Cambridge Girls' Science Club meeting (C. Grant, B. LaMarr)


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