ACIS Instrument Support - Monthly Progress Report for July 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.  Four ObsIDs 
(58327, 58318, 58309, 58300) in July.  Differences in flight 
grade distribution between TE and CC mode are roughly 
consistent with our understanding of ACIS trap properties.  
Continuing to investigate performance differences.

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Continued investigation of bias artifacts believed to be
due to long-lived cosmic ray afterglows.  Created superbiases
for CC-mode data.  Developed and tested bias artifact detection 
code.

  ...  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)

1.7 Produce novel data products from the MIT ACIS database

  ...  Retrieved XRCF continuous clocking mode raw data frames 
from tape archive and reprocessed to restore the full 3x3 event 
island.  Data will be used to study the HRMA overlayer.


2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.
ACIS continues to perform nominally.

2.2 Flight software maintenance

  ... Tested the next ACIS patch release (standard "C", optional 
"C", certification "D"), which will include the "tlmbusy" and 
"buscrash" patches.  These patches address the issues reported 
in Software Problem Reports 138 and 140.
(http://acis.mit.edu/axaf/spr/prob0138.html and 
http://acis.mit.edu/axaf/spr/prob0140.html)

2.3 Instrument science performance

  ...  Participated in monthly ACIS operations meeting.  
Discussed new flight software patch, thermal issues, further 
analysis of data with bias artifacts and updates to ACIS 
parameters in the OBSCAT.

  ...  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.

  ...  Provided list of epoch 1 bias artifacts in ECS data to 
study effect of artifacts on calibration

  ...  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)

None

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