ACIS Instrument Support - Monthly Progress Report for October 2023

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).

  ...  Study on ACIS particle background variability, comparing ACIS reject rates to similar reject counters on XMM EPIC-pn and the AMS particle experiment, is nearing completion.  Paper draft is under final review (and was submitted to ApJ in November)

  ...  Compiling material for the Chandra Quarterly in November.

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 OCT0923A 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

  ...  ACIS flight software patch H-J-K uploaded on September 19, 2022.  First new patch set since August 2022.  No issues to date.

  ...  Observations of very bright source Swift J1727 occurred in OCT2323 week.  The ACIS team implemented two mitigations to prevent an unwanted TXings trigger: a) putting requirements on the timing of the maneuver to the target and the start of event data, and b) uploading an update to TXing parameters for that observation only with new parameters determined by analysis of a previous bright source observation.  Observation was performed nominally, without a false trigger.

  ...  Reviewed SAR with bright source mitigation requirements.

  ...  Created and tested new TXing parameter update command for use with the bright source. 

  ...  Confirmed normal bias maps after observation of very bright source Swift J1727.

  ...  We continue to monitor threshold crossing rates which continue to drop. New parameters were uploaded October 11. The previous set of TXing parameters were uploaded on August 14, 2023.

2.3 Instrument science performance

  ...  Participated in monthly ACIS operations meeting.  Discussed TXing mitigations during very bright source observation, status of 1CRBT, new NIL SI mode, maximum FP temperature during perigee and status of TXing parameters.

  ...  Continued daily quick-look processing of ACIS telemetry and maintained web interface to ACIS real-time data.  Updated TXing plot generation S/W to display bright-target limits.  Planned improved TXings checks.

  ...  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://acisweb.mit.edu/asc/evt-page.html), which provides the same information but is more automated.

3.2 Provide data analysis support

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

  ...  Participated in CXC Cal/Ops response discussion group.  Discussed testing of new CTI correction file, use of Cas A for tgain calibration, gain measurements at -105C, RMFs for warm focal plane temperatures and POG updates.


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.  Updated real-time procedure documentation with a better description of TXing parameter verification. Reorganized update of EGSE S/W tools.

4.2 Generation of commands for ACIS observations

  ...  Continuing to work with USINT on remaining problematic ACIS configurations in cycle 25.

  ...  Completed work on a new Next-In-Line SI mode for use during HRC observations which would telemeter TXings rates in FMT1. Built and tested on the EU.  Additional testing confirmed sufficient bandwidth in FMT1 for exposure records to be telemetered with no dropped telemetry.  Presented implementation plan to ACIS ops and to Mission Planning Constraints Working Group.  Will be implemented after load review scripts are updated.

  ...  Built a new contingency chip drop mode for the bright source TOO.

  ...  Tested preliminary schedule and final OR lists using the new OR list format.

  ...  Worked with USINT on configuring the bright source TOO observation.

  ...  Reviewed XMM/Chandra joint observations for health and safety issues.

  ...  Reviewed OCT0923A, AUG0723T, OCT2823A command loads; OCT3023 and OCT2823 final OR lists; OCT3023 and OCT2823 preliminary schedules; and OCT2323, OCT1623, NOV1323, OCT2823(x2) LTS OR lists.

  ...  Checking on automated processes associated with SACGS.