ACIS Instrument Support - Monthly Progress Report for July 2003

1. ACIS Characterization

1.1 Characterize and model radiation damage in ACIS CCDs

  ...  Continued running charge injection tests on I3.  Two tests 
at a low energy to explore the energy/voltage relation.

 [...  Investigating anomaly in charge injection test taken in
June (ObsID 60674).  Significantly less charge was produced
than expected.  No conclusion yet but test will be repeated in 
August.

1.2 Monitor scientific on-orbit performance of ACIS

  ...  Continued analysis of ExtCalSrc data to study efficiency 
decrease at low energies.  Continued to explore discrepancies
between LETG and ECS measurements of the contaminant optical
depth and its time-dependence.  Verifying spatial non-uniformity
of contaminant distribution.

  ...  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/).

 [...]  Conducted ninth CTI measurement in alternating exposure mode
with frame times of 4.0 and 3.2 seconds (ObsID 60647).  Recalibrated
detrending factor used to remove influence of background on variability
of measured CTI.  (http://space.mit.edu/~cgrant/cti/altexp.html)

1.4 Update and improve CCD simulation

  ...  Continued work on improving FI and BI CCD models with a more 
physical representation of the electron traps that cause CTI.


2. Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  No
anomalies.

2.2 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 telecon.

  ...  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).

 [...] Provided support for potentially hazardous Sco X-1 observation
including checking command loads and a contingency CAP, developing quick 
look analysis tools and real-time support.  Observation ran correctly 
from the load, verified by realtime analysis, so no need for intervention.

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