ACIS Instrument Support - Monthly Progress Report for April 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).

  ...  Submitted a SAR (special activity request) for new raw mode data.

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


2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  Engineering parameters remain nominal.

  ...  The EEPROM checksum was verified in the APR0521A 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.  Supported EU power-off/on during building electrical work.  Minor updates to support computer.

2.2 Flight software maintenance

  ...  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 flattened out and started decreasing, indicating the end of solar minimum. We anticipate needing to lower the trigger threshold in the next year and rates continue to drop and activity increases.

  ...  Continued work on QEMU ACIS emulator development.  Implemented some canned fixed passive analog telemetry points to emulate various temperatures, and on-going updates to the ACIS/QEMU development documentation.

  ...  Released v1.0 of "Interfaces to ACIS Emulators", describing how to use both the engineering unit and the QEMU simulator.
 
  ...  Continued team review of ACIS Flight Software User's Guide using the new version B released last April.  Reviewed newly reworked section on video board program PRAM.
  
2.3 Instrument science performance

  ...  Participated in monthly ACIS operations meetings.  Discussed thermal issues associated with upcoming low perigee in 2023 and new limits on focal plane and cold radiator temperatures.

  ...  Participated in a review of past radiation events and the Chandra response to better prepare for the upcoming solar maximum.

  ...  Reviewed proposed changes to SCS-106, the command sequence that safes ACIS.  Power command will be switched from WSPOW00000, which powers down all video boards and FEPs, to WSPOW0002A, which powers down all video boards but leaves FEPs 1,3,5 on.

  ...  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.

  ...  Answered user question on spatial features in his data.  Unlikely to be due to CCD structures, might be an artifact of ds9 binning.

3.2 Provide data analysis support

  ...  Participated in CXC Cal/Ops ACIS response discussion group.  Discussed proposed new PCA method for fitting ECS and Cas A data to calibration time dependent gain and status of cold ECS observations during the science orbit.

  ...  Continued to maintain ACIS calibration database of ground and flight data products.

  ...  Served as technical host for IACHEC virtual plenary talks.


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.  Checked and restarted both EGSE.

4.2 Generation of commands for ACIS observations

  ...  Completed bulding and testing custom SI modes for use with the ECS, allowing for more flexibility in specifying CCDs.  Installed in the ACIS tables at the OCC.

  ...  Worked with usint to correct a few more cycle 22 observations with questionable chip drop order.

  ...  Worked with USINT on ACIS configuration for a TOO.

  ...  Reviewed APR0521T command load and APR1921 LTS OR list.

  ...  Assigned 8 SI modes.

  ...  Checking on automated processes associated with SACGS.