ACIS Instrument Support - Monthly Progress Report for September 2002

1. ACIS Characterization

1.1 Characterize and model radiation damage in ACIS CCDs

  ...  Continued running charge injection tests on I0 from the command
load.  Accumulating more statistics with two new data sets.

  ...  Ran experiment at GSFC's particle irradiation facility to test
interaction of low energy proton radiation damage with CCD bakeout.  The CCD
was put through the same irradiation bakeout cycle as the flight instrument,
then subjected to additional bakeouts to -60C and 30C.  The initial bakeout
CTI increase measured on-orbit in September 1999 was duplicated and a second
bakeout did cause additional CTI increase.

1.2 Design and characterize alternative CCD readout modes

  ...  Supported charge injection tests on-board with lab verification and
testing.

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Continued analysis of ExtCalSrc data to search for putative QE
decrease at low energies.  Began searching for spatially varying QE,
motivated by the temperature gradient across the filter.

  ...  Continued monitoring of ACIS CTI.  No significant changes beyond the
longterm slow increase.  Updated web page
(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.
Updated web page (http://space.mit.edu/~cgrant/gain/).

 [...] Additional background measurement in HRC-I position obtained.  CXC
Cal will analyze.

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

1.4 Update and improve CCD simulation

  ...  Continued work on detailed physical model of FI CCD including CTI and
sacrificial charge.  Worked on a version of the simulator that can be
incorporated into MARX.

 ...  Continued work on improving BI CCD model.  Compared simulation with
grating data of PKS2155.

2. Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  Reviewed
past 60 days of ACIS engineering data and found no anomalies.  As predicted
in January, the PSMC has now exceeded its yellow thermal limit for the first
time in September.

 [...] Advised ACIS low energy QE telecon on ACIS thermal characteristics
for bakeout discussion.

2.2 Flight software maintainence

  ...  ACIS flight software patches in-house review conducted on August 6
(Rev C).  Addressing reviewer comments and recommendations.

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 telecons

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

 [...] Participated in ACIS science operation team meeting

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.

  ...  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


Outreach:

GSFC X-ray Astronomy School, August 2002.  Presented two lectures on CCDs in
X-ray Astronomy