ACIS Instrument Support - Monthly Progress Report for September 2017

1.  ACIS Characterization

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Continued monitoring of ACIS CTI, gain, trailing pixel pulseheight, detector efficiency, corner pixel distribution, spectral line centroid and width, and focal plane temperature.  Updated monitoring web pages. (http://space.mit.edu/~cgrant/monitor.html).

  ...  There were two autonomously commanded radiation shutdowns on September 7 and 11.  Both were triggered by the HRC.  During ObsID 18997 on September 6, the ACIS TXINGS filter did not trigger because although the threshold crossing rate exceeded the alert threshold for almost an hour, it didn’t match the criteria for a genuine background event.  During ObsID 49790 on September 10, the TXINGS filter triggered within 15 minutes of exceeding the alert threshold, but no safing action was taken since the observatory was in perigee passage and radiation alerts were disabled.  When Chandra came out of perigee during CTI ObsID 49785, the ACIS threshold crossing rates were above the alert threshold by an order of magnitude.  The TXINGS filter didn’t trigger because the rate was descending and therefore didn’t match the criteria.  After each of the radiation safing actions, the ACIS science team verified that ACIS was safe and undamaged, monitoring housekeeping data, and support safing action recovery.

  ...  Developing updates to PMON, the ACIS telemetry monitor, which would produce alerts for unexpected FEP resets.  Ran entire telemetry database through the new pmon.  Released new listing of ACIS S/W Housekeeping channels showing which would trigger alerts in the new, improved, pmon, with suggestions for interpreting the causes.

  ...  Installed new pmon limit table for FEP and BEP component temperatures.  New limits are based on pre-flight ground testing.

  ...  Analyzing ACIS raw data frames to better understand particle interaction in the CCDs and the non-X-ray-background.

  ...  Prepared slides for the Chandra Quarterly in October.

1.5 Analyze data from engineering unit ACIS CCDs

  ...  Verified continued ability to run an ACIS detector (CCD plus DEA electronics) in the lab.  Creating more complete and consolidated documentation of the required steps to do so.


2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  All engineering data remains nominal.
  
  ...  The EEPROM checksum was verified in the SEP0917 load.   Will continue to run monthly.  MIT telemetry processing will automatically check the results and send out an alert if the checksum is unexpected.

2.2 Flight software maintenance

  ...  Flight software patch F-G-H (improved buscrash2) uploaded in June 2014.
  
  ...  We continue to monitor threshold crossing rates.  The current TXINGS parameters, which were last updated on July 28, 2016, were checked in June and August and were found to still be valid.  The major solar storm in early September did reduce the quiescent particle background rates by ~10% (Forbush decrease), which may push the need for a parameter update towards the end of this year.
2.3 Instrument science performance

  ...  Participated in monthly ACIS operations meeting.  Reviewed status of updated SOPs, DEA relay documentation, solar activity, the OCC move, and SI involvement in FOT simulations.

  ...  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.

  ...  Attended State of the ACA briefing.


3.  CXC Support

3.1 Provide user support

  ...  ACIS memo listing calibration ObsIDs and observation characteristics (ACIS Memo #165) will no longer be updated.  Functionality is replaced by new web page (http://acis.mit.edu/asc/evt-page.html), which provides the same information but is more automated.

3.2 Provide data analysis support

  ...  Participated in CXC Cal/Ops ACIS response discussion group.  Discussed updates to the ACIS QEU, and potential changes to tgain epochs in light of the radiation shutdown in early September.

  ...  Provided FITS eventlists for the ground ECS data taken at Ball Aerospace to ACIS Cal.
  
  ...  Participated in planning telecon for upcoming IACHEC meeting (April in Italy).

  ...  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.  Performed monthly check of all ACIS hardware and software in the TST room at the OCC.  Working on updating documentation.

4.2 Generation of commands for ACIS observations

  ... Completed global SI mode assignment for all observations in AO-19.  Ran initial steps to uncover problematic configurations.  Built 5 new TE modes and 2 new CC modes.  Installed new ACIS tables at the OCC.

  ...  Contacted CXC USINT about AO-19 observations with configurations that produced warnings during initial assignment.

  ...  Completed building SI modes for potential future chip drops.  This covers all 1-chip drop contingencies down to two CCDs.  Built 3 new TEmodes, 1 new CC mode, and a new power command.  Installed new ACIS tables at the OCC.  (Remaining chip drop contingency modes were built in October.)

  ...  Worked with SOT MP to allow them access to the ACIS ops chip drop check tool.  Will allow them to see ahead of time the SI mode for a chip drop candidate.

  ...  Continued review and updating of SACGS documentation (SACGS = SOT ACIS Command Generation System).

  ...  Continuing familiarization with SACGS operation and under-the-hood functioning.

  ...  Reviewed SEP2517A and SEP12517B command loads.  Reviewed SEP1117, SEP2517 and OCT0217 preliminary schedules and final OR lists.  Reviewed OCT0917 Long Term Schedule OR lists.

  ...  Assigned 8 SI modes.  Dropped chips from 5 ObsIDs.  Built one chip drop contingency SI mode.

  ...  Checking on automated processes associated with SACGS.