Astronomy and Astrophysics – Astronomy
Scientific paper
Jan 2010
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010aas...21546208m&link_type=abstract
American Astronomical Society, AAS Meeting #215, #462.08; Bulletin of the American Astronomical Society, Vol. 42, p.494
Astronomy and Astrophysics
Astronomy
Scientific paper
The Advanced Camera for Surveys (ACS) has been continuously exposed to the space radiation environment since being installed during Hubble Servicing Mission 3B in March 2002. We have been monitoring and calibrating the effects of radiation damage in the CCDs during this 7-year period, which includes several changes in operating temperature and procedures for annealing at +20C. Radiation damage on-orbit leads to an increase of the mean dark current, a continuous growth of permanent hot pixels (defined to be greater than 0.08 e-/sec), and loss of charge transfer efficiency (CTE, see related paper by Chiaberge). In July 2006, coincident with the switch to the redundant side 2 electronics, the operating temperature of the CCDs was lowered from -77 C to -81 C, which caused the dark current rate and the hot pixel contamination to be reduced by more than 50%. Following the ACS failure in January 2007, the camera experienced a relatively warm 28-month "pseudo-annealing" period at -10 C. We summarize the radiation damage history of the two Wide Field Channel (WFC) CCDs, and our corresponding bias and dark calibration strategy for ACS science data, with results following the on-orbit installation of the new controller electronics box (CEB-R) during Hubble Servicing Mission 4 in May 2009. In general, we have found the effects of ongoing radiation damage, and its impact on our bias and dark calibration, to be largely predictable given the inflight age of the CCDs -- as if our repaired camera had been working all along. The horizontal striping issue (see related paper by Grogin) is based in the new electronics -- it is not an effect of radiation damage -- but we are investigating how to mitigate its impact on our calibration reference files.
Golimowski Dave
Lucas Ray A.
Mutchler Maximilian J.
Sirianni Marco
No associations
LandOfFree
ACS After SM4: Bias And Dark Calibrations For Revitalized But Aging CCDs does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with ACS After SM4: Bias And Dark Calibrations For Revitalized But Aging CCDs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and ACS After SM4: Bias And Dark Calibrations For Revitalized But Aging CCDs will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-972116