ACIS Instrument Support - Monthly Progress Report for March 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.  Four tests at new energies to explore the energy/voltage 
relation.

 [...  Reanalyzed some of the results of the cold irradiation 
experiment, including trailing charge.  Worked on paper summarizing
results of the cold irradiation experiment.

1.2 Design and characterize alternative CCD readout modes

  ...  Suported charge injection tests on-board.  Determined new set 
of DAC values for use with upcoming tests on S2.

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Continued analysis of ExtCalSrc data to search for efficiency 
decrease at low energies.  Confirmed that change can be measured as
high as 1.5 keV.  Preliminary results presented at ACIS telecon.
Analysis ongoing.

  ...  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 CTI.  Wrote code that generates a map of 
traps containing full description of all properties of every trap in a 
CCD.


2. Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  

  ...  Continue to support thermal monitoring of the PSMC.  Trend 
remains moderate.

2.2 Flight software maintainence

 [...] ACIS flight software patches review conducted on March 20 (Rev C).
In-house review of changes made since first initial August review found
no problems.  All reviewed patches are optional.

2.3 Instrument science performance

 [...] Further discussions of implementing new CC mode bias parameters.
Decision hopefully forthcoming.

  ...  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.  Presented preliminary results
on QE change at 1.5 keV.

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


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.

 [...] Participated in discussion of calibration plan for a possible
ACIS bakeout.  Provided statistics for typical cal source observations. 

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

 [...] Discussed software spec for new hot pixel finder with CXC/SDS.


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:

Presentations at HEAD meeting
  Bautz, et al., "Effects of Room-Temperature Bakeout on the CTI of 
an ACIS CCD Irradiated at -100C"
  Grant, et al., "Detection of X-rays from galaxy groups associated 
with the gravitationally lensed systems PG 1115+080 and B1422+231"