ACIS Instrument Support - Monthly Progress Report for September 2021

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).

  ...  Purchased new desktop computer to support ACIS monitoring and operations.

2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  Engineering trending over the past 60 days indicate a stable environment.

  ...  The EEPROM checksum was verified in the SEP0621A load.   Will continue to run monthly.  MIT telemetry processing will automatically check the results and send out an alert if the checksum is unexpected.

  ...  Continued weekly physical audit of the ACIS Engineering Unit lab. 

  ...  Reviewed TDB P016 and CDB P011 files.  ACIS changes were as expected.

2.2 Flight software maintenance

  ...  Further explored the anomaly where back-to-back observations with an intervening FEP power down command did not recompute a new bias. Tests on the ACIS engineering unit have shown that the memory location being used to test for corruption of the bias map retains its contents while powered down for an unexpectedly long time, as long as 12 hours on the ground.  This explains the behavior in flight.  A flight software patch is under development which will write an invalid structure to this memory lcoation whenever a FEP is initialized, which should recover the intended FEP behavior.

  ...  Exploring improvements to the ACIS radiation monitor, txings, with the goal of improving the sensitivity of radiation triggering.  Compared high background triggers from ACIS and from HRC, to better understand the different responses.

  ...  ACIS flight software patch G-H-I (improved buscrash and new deahktrip) uploaded on January 24, 2020.  First new patch set since June 2014.  No issues to date.

  ...  We continue to monitor threshold crossing rates.  The current TXINGS parameters were last updated on July 28, 2016.  Threshold crossing rates have been decreasing, indicating the transition from solar minimum to solar maximum.  We anticipate needing to lower the trigger threshold within the next year as rates continue to drop and activity increases.

  ...  Continued work on QEMU ACIS emulator development. Used emulator to research handling of bus errors due to pathologically timed or PSMC-based FEP power-offs. Started identification of potential bus error test approaches that don't involve changing the PSMC power state

  ...  Continued team review of ACIS Flight Software User's Guide.
  
2.3 Instrument science performance

  ...  Participated in monthly ACIS operations meetings.  Discussed distribution of cold ECS time in epochs 85 and 86, upcoming BU OCC tests, the FEP power bias anomaly, and the investigation into txings modifications.

  ...  Participated in SOT radiation working group telecon.

  ...  Continued daily quick-look processing of ACIS telemetry and maintained Web interface to ACIS real-time data.  

  ...  The LETG insertion anomaly was the first time the new version of SCS106, the science instrument safing commanding, was run.  The new version powers on three FEPs to keep the electronics warmer during extended downtime and ran correctly.

  ...  Continued to publish the "annotated DOT" timeline reports.


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 PCA method for fitting ECS and Cas A data to calibrate time dependent gain and updates on contamination.

  ...  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 Wayside OCC.  Restarted both EGSE machines routinely and again after FST network maintenance. Verified telemetry reconnection after COG reboot.

  ...  Set-up an unofficial data flow pre-test from the backup OCC.  Success!

4.2 Generation of commands for ACIS observations

  ...  Continued work on assigning SI modes to cycle 23 observations. Additional email to USINT with questions to verify for the observers and problems with chip drop order.
 
  ...  Built, tested, and deployed three new SI modes for calibration observations of Cas A

  ...  Answered USINT question on reasonable chip drop order.  Worked with USINT on configuration for HETG GTO observation.

  ...  Participated in training on ACIS load review tools.

  ...  Reviewed SEP1321A command load, SEP1321 final OR list, SEP1321 preliminary schedule, and SEP2021 and SEP2721 LTS OR lists.

  ...  Assigned 2 SI modes. Dropped chips from 3 ObsIDs

  ...  Checking on automated processes associated with SACGS.