ACIS Instrument Support - Monthly Progress Report for April 2003

1. ACIS Characterization

1.1 Characterize and model radiation damage in ACIS CCDs

  ...  Continued running charge injection tests on S2 from the command 
load.  Two tests repeating earlier runs with warm focal plane 
temperatures.

 [...  Preliminary analysis of charge injection tests shows a linear 
dependence of CTI measured from cal source lines and measured from 
charge injection.  Working on better determining measurement errors.

 [...  Preparing new set of charge injection tests on I3.

1.2 Monitor scientific on-orbit performance of ACIS

  ...  Continued analysis of ExtCalSrc data to search for efficiency 
decrease at low energies.  Worked on improving analysis of 1.5 keV line,
to reduce systematic errors.  

  ...  Continued monitoring of ACIS CTI.  No significant changes beyond 
the long term slow increase.  (http://space.mit.edu/~cgrant/cti/)

  ...  Continued monitoring of ACIS gain.  All CCDs stable with a slow 
decline in gain slope (ADU/eV) except for I2 which continues to vary.
(http://space.mit.edu/~cgrant/gain/).

1.4 Update and improve CCD simulation

  ...  Continued work on improving FI and BI CCD models with a more 
physical representation of the electron traps that cause CTI.


2. Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  A 
review of the past 60 days of engineering data reveals no new trends or
anomalous behaviour within ACIS.

  ...  Continue to support thermal monitoring of the PSMC.  Ongoing 
monitoring of thermal conditions on the SIM has resulted in 
recommending a new set of thermal warning limits for the instrument.

 [...] Reviewed DEA housekeeping temperatures.  No large deviations.  
Based on previous history, new warning limits are being determined.  

2.2 Flight software maintainence

 [...]  The ACIS engineering team released Rev C of the Flight Software 
Optional Patches.  This release added two new diagnostic timed-exposure 
modes (patches ctireport1 and ctireport2), a fix to a hardware race 
condition (patch untricklebias), and a fix to a logical bug in raw data 
compression (patch compressall).

2.3 Instrument science performance

 [...] Finalized new CC mode bias parameters.  New parameters will be 
tested on board during a CTI run and then implemented for all CC mode 
science observations.

  ...  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 telecon.

 [...] Participated in ACIS Operations meeting.

  ...  Continued to support charge injection operations by reviewing 
loads and comparing flight data to ground data to select new settings.

 [...] Participated in Chandra quarterly review.  Presented ACIS status 
report.


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 RMF discussion group.

 [...] Checked magnitude of pulseheight evolution from CTI and
instrumental gain changes for I2.  Instrumental gain change dominates!

  ...  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.


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


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