ACIS Instrument Support - Monthly Progress Report for June 2001

1. ACIS Characterization

1.1 Characterize and model radiation damage in ACIS CCDs

  ...  Continued collection of raw data in "cuckoo" clocking mode which allows for more efficient telemetry of raw data. 

       * L76-77 (ObsIDs 61602, 61597) 1 successful run of 8-row squeegee in cuckoo clocking mode on I3 Node 3 (focal plane temperature too warm for one run)

       * CR1 (ObsID 61620) first real-time test of cuckoo clocking mode without squeegee on S0 Quad D was successful.  Future runs on I-array CCDs are being planned.  These observations will be used to study the long time constant traps.

       * CL1-5 (many ObsIDs) 4 successful runs of no-squeegee cuckoo clocking on I3 Node 3 (focal plane temperature too warm for one run)

  ...  Continued analysis and modeling of cuckoo squeegee data.

 [...  Began analysis of no-squeegee cuckoo data.  These observations will be used to study the longest time constant traps (t~seconds).

 [...] Created improved trap density maps for I0-I3 and S2.  Submitted to the CXC Calibration group as part of the CTI simulator.

 [...] Modeled Mn/Fe-L complex in extCalSrc data for use as a low energy calibration line.

1.2 Monitor scientific on-orbit performance of ACIS

  ...  Continued monitoring of ACIS CTI.  No significant changes detected.

  ...  Continued effort to correlate ACIS CTI increases with attenuated fluence from Chandra Radiation Model.

  ...  Continued study of background flares for multiple SIM and grating positions.  Flares are much more common when ACIS is in the focal plane without the gratings inserted, however a small number flares have occured with the HETG inserted or when ACIS is in the HRC-S position.

1.3 Update and improve CCD simulation

  ...] Submitted FI CCD with CTI simulator to CXC Calibration group.  Included executable for undamaged FI CCD simulator, wrapper IDL code to simulate CTI degradation of event island pulseheights, calibration products (similar to the proposed CTI ARD file) and extensive documentation.  

  ...  Continued work on detailed physical model of FI CCD including CTI and sacrificial charge.

2. Engineering

2.1 Instrument hardware engineering performance

  ...  Continued to monitor hardware operations.  No problems.

2.2 Instrument science performance

  ...  Continued daily quick-look processing of ACIS telemetry.

  ...  Continued to publish the "annotated DOT" timeline reports.

  ...  Continued to test flight s/w algorithms to estimate charge lost from FI CCDs due to charge traps, using results from the ongoing series of "Squeegee-Cuckoo" tests.

  ...  Continued to support the Web interface to ACIS real-time data.

2.3 Participate in Chandra Activities

 [...  Participated in planning dark moon observations scheduled for July 26.

3. CXC Support

3.1 Provide user support

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

3.2 Provide data analysis support

  ...  Participated in CXC Cal/Ops RMF discussion group.  Tested new S3 gain tables on extCalSrc data.

  ...] Assisted the CXC in developing the specifications for a tool to correct for CTI.  Submitted to CXC-DS for eventual coding.

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.


Outreach:

"Correction of radiation damage in the Chandra X-ray CCD" presented by Gregory Prigozhin at the 2001 IEEE Workshop on Charge Coupled Devices and Advanced Image Sensors