ACIS Instrument Support - Monthly Progress Report for August 2005

1.  ACIS Characterization

1.1 Characterize and model radiation damage in ACIS CCDs

  ...  Continued test to measure CTI at different focal plane temperatures.
These results will be used to both understand the discrepancies between
the 2002 and 2005 ground radiation tests, which may be at least partially
due to different baseline temperatures, and to update our knowledge of 
CTI temperature dependence from 1999 to the present.  Three observations
this month at set point temperatures of -90C, -105C, and -115C.  Final
observation at -95C interrupted by SCS107 shutdown and rescheduled for
September.  Preliminary analysis will be distributed in September.

  ...  Submitted abstract to Six Years of Science with Chandra symposium
on the recent ACIS CCD irradiation experiments.

1.3 Monitor scientific on-orbit performance of ACIS

  ...  Presentation at SPIE describing long-term trends in ACIS radiation
damage.  Paper will be published in Proc. SPIE 5898 and is posted on
astro-ph.

  ...  Co-author on presentation at SPIE describing Chandra radiation
management.  Paper will be published in Proc. SPIE 5898.

  ...  Continued monitoring of ACIS CTI, gain, trailing pixel pulseheight,
detector efficiency and spectral line centroid and width.  Updated 
monitoring web pages.  (http://space.mit.edu/~cgrant/monitor.html)

  ...  Updated CTI monitoring to match SPIE paper.  Now includes 
corrections for both background and temperature variations.

  ...  Improved automation of monitoring analysis scripts.

  ...  Discussed and compared ACIS and Suzaku/XIS monitoring with
instrument team.

  ...  Began preparing memo for the operations team on the consequences
of a future, unprotected radiation belt transit by ACIS.  Motivated
by recent Chandra safe mode simulation. 

1.4 Update and improve CCD simulation

  ...  Investigated anomaly in the shape of the response 
function in the new version of the BI CCD simulator.  The bug was 
found and fixed. The tests were run at large selection of energies, 
fixed version seems to work well.


2.  Engineering

2.1 Instrument hardware engineering performance

  ...  Continue to monitor long term ACIS instrument performance. The 
ACIS instrument continues to operate nominally.

2.3 Instrument science performance

  ...  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).

3.2 Provide data analysis support

  ...  Working with CXC SDS on implementation of serial CTI
correction.  Confirmed that current version of acis_process_events
does not produce correct results.  Ongoing.

  ...  Participated in CXC Cal/Ops modelling discussion group.

  ...  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 OCC.

  ...  Continued work on improving configuration management of the ACIS
workstations in the TST area of the Chandra OCC.  


Outreach:

Presentation at SPIE conference 5898, "UV, X-ray and Gamma-ray Space 
Instrumentation for Astronomy XIV", 2 Aug 2005
     * Grant, et al., "Long-term trends in radiation damage of 
       Chandra X-ray CCDs"
     * O'Dell, et al., "Managing radiation degradation of CCDs on 
       the Chandra X-ray Observatory II"

Lecture at 4th Annual X-ray Astronomy School, 16 Aug 2005
     * Grant, "CCDs for X-ray Astronomy"


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