ACIS Instrument Support - Monthly Progress Report for December 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 at approximately 1.5 keV with two 
data sets.

 [...  Begin running charge injection tests on S2 from the command load. 
Two tests at approximately 4 and 1.3 keV.

  ...  Continued to analyze data from irradiation/bakeout test at GSFC.  
Found significant reduction of the density of the traps with short time 
constant after the warm-up from examination of trailing pixel 
pulseheights.

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

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

  ...  Continued analysis of ExtCalSrc data to search for putative QE 
decrease at low energies.  Discussed influence of F-K edge on Mn/Fe-L 
line fits with CXC colleagues.  Analysis ongoing.

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

  ...  Evaluating the correlation of the Chandra Radiation Model fluence
with CTI increase.  New CRM numbers for mission made available by CXC 
SOT.  Generally correlated, but poor correspondence for some CTI/CRM 
features.  Analysis ongoing.

  ...  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.


2. Engineering

2.1 Instrument hardware engineering performance

 [...] ACIS engineering group assisted in restarted ACIS on 12/20/02 
after a transient event turned off the primary +5V DC power to the 
instrument.  Event was symptomatically identical to that experienced in 
October 2000.  No cause yet identified.  Restart accomplished without 
incident with no loss of science or CTI data.

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

  ...  Continue to support thermal monitoring of the PSMC

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.


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

 [...] Answered CXC question about analyzing "dark" moon observations.  
Discussed analysis pitfalls due to optical loading from the bright moon.

 [...] Reviewed release notes for FI CTI-corrected matrices

 [...] Submitted Q&A for Chandra Calibration Workshop presentation

 [...] 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:

None in December