ACIS Instrument Support - Monthly Progress Report for October 2021

1.  ACIS Characterization

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Following Chandra safing action on Oct 23 due to IU reset, verified ACIS was safe, and supported recovery from NSM.

  ...  Automous radiation shutdown shutdown on Oct 28 instigated by the ACIS txings monitor shortly after an X-1 class flare.  This was the third ACIS initiated radiation shutdown since the patch was activated in 2012. ACE proton rates remained high, even after science observations were resumed, but stayed just below the 2e9 orbital fluence budget.

  ...  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).

  ...  Setting up 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 OCT0421B 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. 

2.2 Flight software maintenance

  ...  New ACIS flight software patch, fepbiasrec has been written and tested.  ECO is being reviewed by the ACIS team. This patch forces the FEP to recompute its bias map after being power-cycled, to prevent the anomaly that occurred over the summer with consecutive event histogram runs.

  ...  Exploring improvements to the ACIS radiation monitor, txings, with the goal of improving the sensitivity of radiation triggering. First will be an update to the parameter file to better match the dropping quiescent rate.  

  ...  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 plan to lower the trigger threshold early in 2022.

  ...  Continued team review of ACIS Flight Software User's Guide, with sections on example scenarios of a warm instrument re-start and TE mode science runs. Updates to the FSW UG are being made in response to these reviews.

  ...  Reviewed documentation on ACIS data flow, from CCDs to telemetry.

2.3 Instrument science performance

  ...  Participated in monthly ACIS operations meeting. Discussed potential future focal plane heating test, the BU OCC tests, and possibly txings modifications.

  ...  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.


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 collecting cold ECS data, PCA method for fitting ECS and Cas A data to calibrate time dependent gain, and a proposed new observation of G21.5.

  ...  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.

  ...  Participated in backup OCC demo shadow pass test.  Test was successful.  Submitted to the GOT a detailed comparison of the BUOCC to the Wayside telemetry feed.

4.2 Generation of commands for ACIS observations

  ...  Continued work on assigning SI modes to cycle 23 observations and clearing problematic configurations.

  ...  Reviewed XMM-Chandra joint proposals for health and safety issues

  ...  Built, tested, and deployed two new SI modes for science observtions, including an observation of the Crab coordinated with IXPE.

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

  ...  Reviewed OCT1121A command load, and OCT1821, OCT2521, and OCT1121 LTS OR lists.

  ...  Assigned 3 SI modes.

  ...  Checking on automated processes associated with SACGS.