ACIS Instrument Support - Monthly Progress Report for January 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.  Two tests at approximately 1 and 8.4 keV to explore the 
energy/voltage relation.

1.2 Design and characterize alternative CCD readout modes

  ...  Supported charge injection tests on-board with lab verification 
and testing.  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 putative QE 
decrease at low energies.  Updated L/K ratio fits to the present. 
Trend seen last summer continues.  Cal source data seem to require more
absorption than edge fits from grating data.

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

  ...  Continued monitoring of ACIS gain.  Updated gain web page.  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/).

 [...] Conducted seventh CTI measurement in alternating exposure mode 
with frame times of 4.0 and 3.2 seconds (ObsID 60889).  These data are 
used to calibrate the algorithm which reduces the background influence 
on CTI measurements.  Focal plane temperature was too warm; will be 
repeated in February.

1.4 Update and improve CCD simulation

  ...  Continued work on improving FI and BI CCD models with a more 
physical representation of CTI.


2. Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  
Reviewed last 60 days of engineering housekeeping shows no anomalous 
events or trends save the increasing PSMC temperatures.

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

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

 [...] Published memo on tests of new CC mode bias parameters.  New 
method is superior to the current flight method.  
(http://acis.mit.edu/acis/ccmode/ccmode2.html)

  ...  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

 [...] Participated in ACIS Operations meeting.  Reviewed proposal for 
reducing radiation belt pad times using the Chandra Radiation Model as a 
predictor of entry and exit times. 

  ...  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).

 [...] Email discussion with HST/STIS team member about the ACIS and 
STIS CTI models.

3.2 Provide data analysis support

 [...] Participated in CXC Cal/Ops RMF discussion group.  Discussed
time-dependence of ACIS response and methods of 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.

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


Outreach:

Presentations at January AAS meeting in Seattle, WA:
  talk by Grant: "Searching for clusters and groups in the fields of 
strong gravitational lenses:  PG 1115+080 and B1422+231"