ACIS Instrument Support - Monthly Progress Report for November 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).

  ...  Setting up new desktop computer to support ACIS monitoring and operations.  Finished installation of necessary software.

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

2.  Engineering

2.1 Instrument hardware engineering performance

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

  ...  The EEPROM checksum was verified in the NOV0821B 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.

  ...  Reviewed a SAR (Special Activity Request) that would disable txings during an observation of a known bright source, to prevent false positive triggering.

  ...  Continued team review of ACIS Flight Software User's Guide, with sections on example scenarios of timed exposure and continuous clocking science runs.

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.


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 plans for a test of calibration below -120C.

  ...  As part of the IACHEC working group summary meeting, presented recent work by Suzuki et al. on ACIS background modeling

  ...  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 in response to COG work.

4.2 Generation of commands for ACIS observations

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

  ...  Testing and review of new python based command generation wrapper scripts.

  ...  Started designing a plan for powering on more FEPs during 1 CCD observations to keep the electronics warmer.

  ...  Reviewed NOV1521A command load, NOV1521(x2), NOV2221 final OR lists, NOV1521(x2), NOV2221 preliminary schedules, and NOV2921 LTS OR list.

  ...  Assigned 2 SI modes. Dropped chips from 13 ObsIDs

  ...  Checking on automated processes associated with SACGS.