ACIS Instrument Support - Monthly Progress Report for April 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 data telemetry. 

       * L65-68 (many ObsIDs) 3 successful runs of 16-row squeegee in cuckoo clocking mode on I3 Node 0 (focal plane temperature too warm for one run)

       * L70 (ObsIDs 61646) 1 successful run of 8-row squeegee in cuckoo clocking mode on I3 Node 3

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

  ...  Continued study of a ground-based CTI correction algorithm.  New version allows for variable trap density for each CCD column.  FWHM performance much improved.

 [...] Penn State and MIT ACIS team members met to discuss ACIS CTI correction models and methods.

       * Produced report on CTI correction approaches.  Describes and compares MIT and PSU CTI correction algorithms.  Although approaches are different (physical versus empirical), performance results are very similar.  Outlines possible implementation choices.  (CTI Correction Approaches memo)

       * Scheduled and prepared for meeting of CXC (SDS, DS, Cal, SOT), MSFC and ACIS IPI personnel to discuss CTI correction implementation by the CXC.  (Meeting took place 02 May 2001) 

1.2 Monitor scientific on-orbit performance of ACIS

  ...  Continued monitoring of ACIS CTI. Updated CTI web page (http://space.mit.edu/~cgrant/cti/cti120.html).  No significant changes detected.

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

  ...  Continued monitoring of ACIS gain stability.  Updated web page.


1.3 Update and improve CCD simulation

 [...  Began process of including our model of radiation damage into CCD simulator for FI CCDs.

 [...] Analyzed simulated and flight data to verify correctness of BI CCD simulator.


2. Engineering

2.1 Instrument hardware engineering performance

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

 [...] Reprocessed last 3 months data into canonical files of engineering housekeeping telemetry.  No untoward trends found.

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

 [...] Supported squeegee and the new cuckoo clocking mode tests including load and CAP review, and real-time command checking and data analysis.

 [...] Supported activities associated with multiple radiation related shutdowns including additional ACIS monitoring.

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


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.


New ACIS Memos:

CTI Correction Approaches

all recent memos available at http://space.mit.edu/ACIS/iacis.html

Outreach for Bautz:

Jan 11 01	San Diego AAS Poster (BAAS 19710714B)
		Chandra Observations of Lensing Clusters
		(Bautz, Malm, Arabadjis, Baganoff Jeltema, Monnelly,
		Canizares, Garmire)

Mar 7 01	Yokohama, Japan, New Century of X-ray Astronomy
		Talk: Galaxy Cluster Dynamics: Results from Chandra
		and prospects for AstroE II
		(Bautz, Malm, Machacek, Arabadjis, Jeltema, Canizares, Ricker
		Garmire)

March 27 01	MIT, for Cambridge Public School Science Teachers
		Demonstration: Dark Matter and Gravitational Lensing

April 26 01	Interview with Dirk Lorenzen of  Deutsche Welle (German
		Public Radio) on Chandra/ACIS