ACIS Instrument Support - Monthly Progress Report for July 2013

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)

  ...  Continued work on a paper combining CTI, FWHM and background monitoring results from ACIS and Suzaku.  Final edits on paper continuing.  Added a temperature filter to the XIS data which resulted in much smoother time evolution.

  ...  Ran two ECS measurements at warmer focal plane temperatures (-115C and -110C).  Analyzed data and presented initial results to ACIS team.  As expected, S/N is much worse now than in 2005 due to radioactive decay.  Recommended changes in the commanding for the second set in August.

2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance.  Reviewing the engineering housekeeping data for the past 60 days reveals no unexpected trends.  

  ...  Use of bakeout heater during warm CTI measurement caused an undervoltage which has been seen before and should have been expected.

  ...  ObsID 15474 ended early due to an anomaly in which all five active FEPs reset.  The data is consistent with a recurrence of the DEA Sequencer Anomaly seen in 2004 - a spurious signal on the BEP-to-DEA command line caused the DEAs to stop sequencing.

2.2 Flight software maintenance

  ...  Engineering Unit currently running on a reasonably modern Solaris workstation.  Continued work on testing the interfaces under Linux.
 
  ...  Produced Engineering Change Order 36-1047 on an update to the buscrash2 patch which prevents trickle-bias anomalies and BEP crashes.  Currently under review by the ACIS team.

  ...  A trickle-bias anomaly occurred on July 24 and was detected by the buscrash2 patch which clobbered the process which telemeters bias maps.  No science data was lost and the CXC pipeline was able to proceed using replacement bias maps.

2.3 Instrument science performance

  ... Participated in monthly ACIS operations meetings.  Discussed recent anomalies, updates to the buscrash2 and txings patches, and new warm CTI measurements.

  ...  Re-examining the TXINGs triggering algorithm.  Fully tested a wide range of parameters and adjustments to make the algorithm more sensitive, also tested triggering on decreasing rates.  Results are being examined to determine whether updates are significantly better than the current version.  The ACIS radiation detection and safing team received a NASA Group Achievement Award in July.

  ...  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

  ...  Updated ACIS memo listing calibration ObsIDs and observation characteristics (ACIS Memo #165).

  ...  Answered CXC SDS question on the status of CTI correction at -110C.  Work is considered low priority and is on hold.

3.2 Provide data analysis support

  ...  Participated in CXC Cal/Ops ACIS response discussion group.  Discussed contamination analysis and initial results from new warm CTI measurements.

  ...  Re-examining ECS data taken before launch at Ball Aerospace.  Has been used for contamination calibration but there have always been unexplained offsets.

  ...  Continued to maintain ACIS calibration database of ground and flight data products.  Primary backup machine for ACIS ECS eventlists required a replacement RAID controller card.

  ...  Upgraded OS on primary monitoring computer.

  ...  Answered questions from Swift XRT calibration scientist on ACIS RMF generation.

4.  OCC Support

4.1 Use of MIT/ACIS EGSE at OCC

  ...  Continued support and maintenance of ACIS EGSE software and hardware at the OCC.  Plan for broken EGSE backup machine is to do nothing for now, but proceed with upgrades to Linux.

  ...  Migration of MIT realtime telemetry software to Linux continues.