ACIS Instrument Support - Monthly Progress Report for November 2022

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).

  ...  Prepared and presented materials on ACIS status for November Chandra Quarterly Review.

  ...  Submitted abstract for HEAD meeting on the ACIS background correlation with AMS.

2.  Engineering

2.1 Instrument hardware engineering performance

  ...  On November 6, there was a trip of the ACIS thermal monitor in the OBC, when the temperature of the DPA box exceeded its red limit. First trip of the monitor since it was activated in 2021 and behavior was nominal. FEP and BEP board temperatures stayed below their yellow limits. The cause of the thermal excursion is understood, due to a long dwell in a state with poor calibration of the ACIS thermal model. 

  ...  Continue to monitor long term ACIS instrument performance.  Engineering trending over the past 60 days is nominal.

  ...  The EEPROM checksum was verified in the NOV1422A loads. 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

  ...  Thermal monitor trip and subsequent SCS107 shutdown of science observing on November 6 exposed a bug in the ACIS response as the science run failed to terminate properly. The initial FEP power cycle at the start of the return to science commanding clobbered the offending run and science observing after that point was nominal.  The bug only appeared after SCS107 was switched from powering down all FEPs, to leaving three FEPs on for thermal reasons.  Tests on the EU confirmed the problem. Opened SW Problem Report 161 (acisweb.mit.edu/axaf/spr/prob0161.html)

  ...  In response to SPR161, started development and testing of updated standard patch "buscrash".  Will be added to the HJK patch level release.

  ...  Released final version of ObsID 25140 anomaly report which includes description of the biasphase3 patch that prevents the problem. (http://acisweb.mit.edu/pub/acis-25140-anomaly-v1.2.pdf).

  ...  ACIS flight software patch G-I-J (improved TXings) uploaded on August 11, 2022.  First new patch set since January 2020.  No issues to date.

   ...  Next ACIS flight software patch level HJK has undergone internal MIT review.  Includes three standard patches.  fepbiasrec and biasphase3 address software anomaly reports that pointed to errors in FEP flight software, and mostfatal assists in preserving BEP register contents in the event of an unexpected hardware interrupt. Responded to reviewer comments which were all minor. After initial HJK review it was decided to add the new update to the standard buscrash patch to this release.

  ...  We continue to monitor threshold crossing rates. Threshold crossing rates have flattened, during a period of low solar activity.  The last parameter update was September 12, 2022.

  ...  Continued work on QEMU ACIS emulator development.
	- continued examination of QEMU's CPU "throttle" start-up parameter that changes the emulated CPU speed;


2.3 Instrument science performance

  ...  Participated in monthly ACIS operations meeting. Discussed OpsGenie alert system, new CLDs for ECS runs in real-time, SPR161 - the BEP in science active after SCS107, and plans for the next flight software patch release.

  ...  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

  ...  Corrected two 1-bit telemetry corruption in ObsID 45049 bias maps.  Repaired EHS file made available to CXC.

  ...  Participated in CXC Cal/Ops ACIS response discussion group. Discussed initial results of -105C calibration observations.

  ...  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.

4.2 Generation of commands for ACIS observations

  ...  Checking cycle 24 long term schedule and pool targets for configuration issues and chip drop assignment problems.

  ...  Worked with USINT on a particularly tricky ACIS configuration.

  ...  Worked on procedure for re-assigning large groups of SI modes as mission planning updates the "spectra_max_counts" parameter needed for FP temperature limit decisions.

  ...  Built, tested, and installed new SI mode for calibration observation of E0102.

  ...  Built, tested, and installed new NIL event histogram modes to support HRC return-to science.  New modes use fewer CCDs, to allow for TXings radiation monitoring while minimizing thermal impact on HRC. Working with mission planning on implementing the new NIL modes. Working with MP and HRC on radiation protection timing issues.

  ...  Built, tested, and installed new ECS mode to complement the one in use for long measurements during shutdowns.

  ...  Started updated "or2simodes" tool which is used for ACIS review of OR lists. Removing outdated warnings, and adjusting dither parameter warnings with the new default settings.  Fixing a few bugs.

  ...  Reviewed NOV0722A and NOV2822A command load; NOV0722, NOV1422(x2), NOV2822, DEC0522 final OR lists; NOV0722, NOV1422, NOV2822, DEC0522 preliminary schedules; and NOV2122(x2), DEC1222 LTS OR lists.
 
  ...  Assigned 18 SI modes. Dropped chips from 18 ObsIDs

  ...  Checking on automated processes associated with SACGS.