ACIS Instrument Support - Monthly Progress Report for March 2005

1.  ACIS Characterization

1.1 Characterize and model radiation damage in ACIS CCDs

  ...  Planning for next set of cold irradiation and bakeout lab
tests.  Scheduled for May 9-20.  Draft of experimental plan and
equipment setup forwarded to GSFC contact.

  ...  Began adapting current CTI correction process to ACIS-S3.  The
original correction algorithm only treated parallel CTI in the imaging
array as is appropriate for FI CCDs, while BI CCDs have additional
CTI in the framestore and serial array.  A first attempt yielded
encouraging results.  Calibration products will be fine-tuned and
turned over to CXC.

  ...  Continued taking a series of data in full-frame raw mode for
performance verification and monitoring.  Three ObsIDs this month with
data in both the ACIS-I and ACIS-S configurations.

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Continued monitoring of ACIS CTI, gain, trailing pixel pulseheight,
detector efficiency and spectral line centroid and width.  Updated 
monitoring web pages.
(linked from http://space.mit.edu/~cgrant/monitor.html)

1.4 Update and improve CCD simulation

  ...  Modified BI CCD simulator used for generating calibration
products.  Analysis of LETG data on S3 showed the model had a much
stronger low-energy tail for low energy lines than is seen in the
data.  After changing the surface charge collection efficiency the
data and model match very well.  The improved model will be handed
over to the CXC.


2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  A review 
of the engineering housekeeping for the past 60 days reveals no unexpected 
events or trends.  The instrument continues to operate nominally.

2.2 Flight software maintenance

  ...  Reviewed new memo on CC mode bias parameters by Nancy Adams-Wolk.  
Concurred with her analysis.

2.3 Instrument science performance

  ...  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.

  ...  Participated in ACIS operations meeting.  Discussed status of
ACIS EGSE Squirt telemetry feed, plans for GSFC irradiation experiments,
focal plane cooling tests and new RPS forms and help documents for
window filters.


3.  CXC Support

3.1 Provide user support

  ...  Reviewed the much improved new RPS form and help documentation 
for window filters.

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

3.2 Provide data analysis support

  ...  Working with CXC Cal on CTI correction calibration.  Tested
new maps for all FI CCDs at -110C.  Results are good and are posted
on the web:  http://space.mit.edu/~cgrant/cticorr/

  ...  Participated in CXC Cal/Ops modeling discussion group.  Discussed
new CTI correction calibration products for -110C, using LETG data
to improve the BI CCD model and changes to CC mode bias algorithm.

  ...  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.  

  ...  ACIS EGSE move is essentially complete.  Old machines continue
to run in parallel for the time being.  Some issues with Squirt are
being evaluated.


Outreach:

None


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