ACIS Instrument Support - Monthly Progress Report for April - July 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).

  ...  Abstract accepted for a talk at the SPIE Astronomical Telescope + Instrumentation on the ACIS background correlation with AMS.  "Towards precision particle background estimation for future X-ray missions: correlated variability between Chandra ACIS and AMS".  Presentation at July meeting and proceedings paper published.

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

  ...  Supported ACIS ops solar storm library creation to provide TXings data.

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 APR0322A, MAY0922A, JUN0622A, and JUL0422B 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. Considering options of an automated EU/Image Loader liveness test.

2.2 Flight software maintenance

  ...  Completed testing and documenting ACIS FSW Patch G-I-J which includes an improved TXing radiation monitor. Internal ACIS team detailed review. Final ECO version released 4/2/22 (https://acisweb.mit.edu/pub/ACIS_Patch_G-I-J.pdf)

  ...  FSW patch presented and approved by Chandra FSW WG and the FDB.

  ...  Generating new ACIS commands to upload patch G-I-J.  Updating the patch command generation documentation in parallel.  Checked on the EU and installed in ODB.

  ...  Reviewed and validated FSW patch uplink procedures.  Reviewed script and CLD files for patch uplink.  Approved by FDB.

  ...  Organized TXing rev B parameter optimization WG.  Working on methods to select patch default and time-changing optimum parameters.  Produced history of past radiation storms and radiation triggers.  Tested and documented algorithm to select optimal TXings parameters.   Released report "Optimal Parameters for Release B of the TXings Patch"  (https://acisweb.mit.edu/pub/acis-txingsB-params-v1.5.pdf) along with many related web pages of TXing and radiation environment history.

  ...  Presented plan for selection of optimum TXing RevB parameters to radiation WG.  Approved.

  ...  Reviewed CAPs for FSW uplink and associated TXing parameter update.  CAP1621: Uplink of ACIS Flight SW Standard G, Optional I and CAP 1622: Uplink TXINGS Parameter Values. (https://acisweb.mit.edu/asc/cap/CAP1621.pdf and https://acisweb.mit.edu/asc/cap/CAP1622.pdf)

  ...  Working on process/procedure for future TXing parameter updates.  Once a range of potential future parameter values are determined, producing a small library of parameter update commands.  Selected new parameters will be uplink via SAR in the normal command load.  CLDs will be built for each selected parameter set for any anomaly uplink needs.  First library of potential TXingB parameter commands produced and tested.

  ...  Rethinking placement of TXing commands in ECS SI modes, as RevA commands will not function properly once TXing RevB is uplinked.  TXing parameter dump command moved from ECS SI mode to just before XEF1000 (belt exit).  TXing quiet command removed entirely.  Reviewed SAR for new placement of TXing parameter dump command.  Tested and installed updated ECS SI modes.  Built, tested and installed TXing parameter dump command for RevB.

  ...  Prepared updates for ACIS monitoring software PMON, to change the expected FSW version from 56 to 58.

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

  ...  We continue to monitor threshold crossing rates. Threshold crossing rates have been decreasing, indicating the transition from solar minimum to solar maximum. The TXing revA parameters were updated on June 14, 2022 to better match the current quiescent rates.

  ...  Continued work on QEMU ACIS emulator development.
	- Examined data-retention behavior during emulated board power-cycling of ACIS I-cache and D-cache
	- Determined that, by default, QEMU only clears emulated memory regions via startup memory allocation calls
	- Further memory initialization during emulated board resets/power-cycle must be specially coded
	
  ...  Released new version of documentation on ACIS data flow, from CCDs to telemetry.

2.3 Instrument science performance

  ...  Participated in monthly ACIS operations meeting.  FSW patch development and uplink plans, limit increases for 1DPAMZT and 1DEAMZT, focal plane / ACIS radiator temperatures during perigee, new 4-CCD ECS CLDs and CAP.

  ...  Participated in SOT radiation working group.

  ...  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

  ...  Wrote article on ACIS activities for Chandra newsletter

  ...  Pointed user to web page for downloading ECS data.

  ...  Answered user questions on subarrays and pileup.

  ...  Technical reviewer for HST cycle 30 joint observations and Chandra cycle 24 high count rate proposals.

  ...  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 calibration at higher temperatures, gain correction using Cas A in conjunction with the ECS, contamination measurements, and plans for AO-24.

  ...  Provided materials to calibration team on CTI correction parameters and their calibration.

  ...  Participated in virtual IACHEC meeting, May 23-25.  Organized a session on background measurement and modeling, solicited invited speakers, chaired session. 

  ...  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 pre-check and demo test.  Test was successful.  Submitted to the GOT a detailed comparison of the BU OCC telemetry feed to other sources.

4.2 Generation of commands for ACIS observations

  ...  Reviewed RTS and CLD files for new 4-chip ECS runs and END_ECS, which removes HRC commanding.  Approved by the FDB.  Reviewed template CAP to run new 4-chip ECS CLD.

  ...  Worked with USINT to change all ACIS configurations to always include at least one required FI CCD for better txings radiation monitoring.

  ...  Submitted ACIS test plan for CXC DS10.11 and RedHat 8.  Completed testing and submitted test report.

  ...  Participated in discussion on changing the ACIS default dither to improve ACA performance.  Since dither "speed" will remain the same, there is no change to ACIS data quality.  On the ground, however, CXCDS links dither changes to clearing ACIS SI mode, which is not desirable when all dither parameters will be globally changed.  DS and ArcOps are working on a solution.

  ...  Explored methods to improve DEA housekeeping sampling during long periods in format 6 with no ACIS science telemetry.  Sample rate in DEA housekeeping command is 8 bit, so maximum delay between samples is too short to be of use.  Solution would be additional ACIS commanding to start and stop DEA housekeeping run during extended format 6, but HRC real-time commanding takes precedence.  (HRC checkout steps are no longer utilizing format 6.)

  ...  Started checking ACIS configurations of cycle 24 observations to find problems.

  ...  Reviewed APR0322A, APR1822A, MAY2322A, JUN2022A, JUL1822A command loads; MAY3022, JUN2022 (x2), JUL1822 final OR lists; MAY3022, JUN2022, JUN2722 preliminary schedules; and MAY0222, JUN0622, JUL0422, AUG0122 LTS OR lists

  ...  Assigned 29 SI modes. Dropped chips from 4 ObsIDs

  ...  Checking on automated processes associated with SACGS.