ACIS Instrument Support - Monthly Progress Report for October 2001

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. 

       * CL25-28 (many ObsIDs) 2 successful runs of no-squeegee cuckoo clocking on I3 Node 3 (focal plane temperature too warm for two runs)

  ...  Continued analysis of no-squeegee cuckoo data.  These observations will be used to study the longest time constant traps (t~seconds).  Limited currently by photon statistics.

1.2 Design and characterize alternative CCD readout modes

  ...  Continued study of charge injection to measure CTI using ACIS electronics in the lab.  Charge can be injected from 100 eV to 6 keV with reasonable precision and can be used to calculate CTI on a pixel by pixel basis.  (see http://space.mit.edu/ACIS/cti_charge_inj.html)  

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Continued monitoring of ACIS CTI.  Two radiation events required SI safing (SCS 107).  No significant changes detected. Updated CTI web page (http://space.mit.edu/~cgrant/cti/cti120.html)

  ...  Continued study of ACIS background, both quiescent and flares, for multiple SIM and grating positions.

1.4 Update and improve CCD simulation

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

 [...] Delivered improved version of empirical ACIS CTI simulator to CXC calibration group.

2. Engineering

2.1 Flight software maintenance

 [...  Investigation of ACIS t-plane latchup anomaly which took place on Oct. 29.  This is the second occurence since launch (first was June 27, 2000).  Analysis of dumped BEP memory and flight software is ongoing.

2.2 Instrument hardware engineering performance

  ...  Continued to monitor hardware operations.  No problems.

 [...] Performed tri-monthly reduction of engineering data and scanned for trends and irregular events - none found.

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.

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

 [...] Participated in ACIS operations meetings

 [...] Participated in ACIS telecon

 [...] Participated in Chandra Calibration Review

2.4 Participate in Chandra Activities

 [...] Supported real-time activities during ACIS t-plane latchup anomaly including CAP review, commanding checking and real-time data analysis

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.

 [...] Assisted CXC SOT in specifying limits for ACIS engineering telemetry checking

 [...] Continued to maintain computers containing ACIS calibration database 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.