ACIS Instrument Support - Monthly Progress Report for December 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.
Submitted abstract for June SPIE meeting.

  ...  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.  Four ObsIDs
(58097, 58089, 58068, 58054) in December.

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)

  ...  Investigated counting statistics of contamination monitoring 
and estimated smallest regions that could be studied.

1.7 Produce novel data products from the MIT ACIS database

  ...  Examined XRCF continuous clocking mode data, reprocessed
from the raw data frames, that is being used to investigate the
HRMA overlayer.  Files were found to be corrupted and fixed.


2.  Engineering

2.1 Instrument hardware engineering performance

  ...  ACIS suffered an autonomous power shutdown of the DPA side B
on December 13.  Normal science operations were resumed after powering
on the side B DPA and warm booting the BEP to restore the current version
of the flight software.  This event is similar to previous autonomous 
power downs of the DPA side A and DEA presumably caused by a spurious
command from the SIM RCTU.  The average rate of occurence is once every
two years.

  ...  Reviewed CAPs for recovery after DPA-B shutdown and a generic CAP
for turning on the ACIS DH heater if SCS107 trips while heater is off.

  ...  Continue to monitor long term ACIS instrument performance.
Besides the anomalous DPA shutdown, the ACIS instrument continues 
to perform nominally.

2.2 Flight software maintenance

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.


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.

  ...  Performed cursory examination of anomalous biases identified
by standard CXC processing.

  ...  Continued to maintain ACIS calibration database of ground 
and flight data products.

  ...  Answered question regarding time constants of traps in BI
CCDs.  Due to the difficulty in decoupling fast (image-to-framestore)
and slow (framestore-to-readout) transfers, BI CCD time constants
have not been measured.  

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)


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