ACIS Instrument Support - Monthly Progress Report for March 2002

1. ACIS Characterization

1.1 Characterize and model radiation damage in ACIS CCDs

  ...  Continued collection of raw data in "cuckoo" clocking mode which allows for more efficient telemetry of raw data. 

       * CL41-42, 1 successful run of no-squeegee cuckoo clocking on I3 Node 3 (focal plane temperature too warm for one run)

  ...  Continued analysis of no-squeegee cuckoo data.  Work continues on defining filters and corrections factors that would improve over-all performance.  Preliminary results will be presented at HEAD meeting in April.

1.2 Design and characterize alternative CCD readout modes

  ...  Supported charge injection tests on-board with lab verification.
 
1.3 Monitor scientific on-orbit performance of ACIS

  ...  Analyzed ExtCalSrc data to search for putative QE decrease at low energies including comparison to pre-launch measurements.  Data are suggestive of a long-term slowly increasing layer of contamination on ACIS at a rate much higher than pre-launch estimates.  Analysis ongoing.

 [...  Testing calibration sources in the lab to determine is any of the change in the Mn+Fe-L/Mn-K ratio measured onboard could be due to intrinsic changes in the source.

 [...] Prepared report on ACIS flight experience with bakeouts (ACIS Memo #197) to support discussion of removal of possible ACIS contamination.

  ...  Continued monitoring of ACIS CTI.  No significant changes detected. Updated CTI web page (http://space.mit.edu/~cgrant/cti/)

 [...] Updated plots of ACIS gain in the bottom twenty rows of each CCD as a function of time.  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/)

1.4 Update and improve CCD simulation

  ...  Continued work on detailed physical model of FI CCD including CTI and sacrificial charge.

  ...  Reanalyzing HIREFS calibration data of S3 to compare to CCD simulator output and to better understand gain function at very low energies.

  ...]  Corrected bugs in addCti.pro - FI CCD CTI simulator used in conjunction with CCD simulator to produce CTI degraded data.  Verified that simulated data is well matched to external calibration souce data.  Released to CXC/Cal.


2. Engineering

2.1 Instrument hardware engineering performance

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

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.

  ...  Continued to develop flight s/w algorithms to implement "Squeegee" clocking mode and to report precursor charge from ACIS CCDs.

  ...  Participated in ACIS telecons

2.3 Participate in Chandra activities

 [...] Supported testing of CAP #785 - a test of charge injection on S0 run on 14 March 2002.  Including,
	* CAP review
	* Real-time support, both command checking and data analysis
	* Post-test analysis of data compression anomaly

 [...] Supported preparation for charge injection test in the load (to be run 10 April 2002).

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.

 [...] Sent comments on January 2002 memo on HRC-I location background histograms to Beth Biller concerning effects of the event and split thresholds on lowest energies.

  ...  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.



New ACIS Memo:

197 - Flight experience with bakeouts

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


Outreach for Bev LaMarr:

Provided pointers to CXC's online resources for a 
teacher at Hill and Plain Elementary School in New Milford, 
Connecticut.  Several of her third grade students have 
been asking about black holes, and I suggested that she 
might want to "Ask an Astrophysist" to answer some of the 
tougher ones.