ACIS Instrument Support - Monthly Progress Report for February 2005

1.  ACIS Characterization

1.1 Characterize and model radiation damage in ACIS CCDs

  ...  Determined new CTI/background relation which is much more
effective at removing the background features in CTI monitoring data.
See http://space.mit.edu/~cgrant/cti/newtrend.html for details.

  ...  Planning for next set of cold irradiation and bakeout lab
tests.  Prepared data capture machine for travel.

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

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Implemented new CTI/background relation as part of our CTI 
monitoring.

  ...  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)

  ...  Did a spot check of flight raw CCD images being acquired regularly.
Images look nominal.


2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  All
engineering parameters remain stable.

  ...  The ACIS engineering team spent some time reviewing the thermal history 
of the detector housing and focal plane heater usage since launch.  We 
have seen a gradual reduction in control heater requirements, consistent 
with the rise in environmental ISIM temperatures.  Though not a problem 
for the next 10 years of operation in the case of the detector housing, 
the focal plane is becoming marginal at -120C, with certain observation 
attitudes causing the temperature to rise above the control point.  Over 
the next year or two we will have to address the science/engineering 
tradeoffs necessary to continue to run the focal plane at a consistent 
thermal set point.

2.2 Flight software maintenance

  ...  Reviewed (again) the recommendation by Peter Ford to change the
bias algorithm and split threshold for CC mode observations.  Concurred
with his analysis.  Update is forthcoming.

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 move, plans for new CCD irradiation tests and reviewed thermal
status.

  ...  Reviewed ACIS instrument status in a presentation to the
ACIS IPI team.  Discussed CTI, gain, focal plane temperature and 
contamination monitoring.


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.  Discussed
status of CTI correction calibration products.  Products for all eight
FI CCDs at -120C and -110C are in process.  The ACIS team agreed to
explore BI CTI correction

  ...  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.


Outreach:

None


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