Any new data products (plots, tables, summaries of work done) should be posted here. I suggest a new titled section for each product or related products, and plots can be attached as PDFs (without a preview) or JPG/GIF/PNG images (which will show up inline). Plots should have some text summary about what they are. And we can link to these from the Outline and Action Items pages.
17 Feb 2011 - Catherine's attempt to duplicate Bev's monthly XIS plots for ACIS I3 (FI) and S3 (BI). Each data point is a fit to 0.1 years worth of cold ACIS calibration source data, filtered to include only the upper corner regions like XIS and grades G02346. After some testing as to which fitting procedures were less sensitive to background variations (important for ACIS probably not as much for XIS), and robust against low signal-to-noise data, I chose to use a Gaussian plus a linear background component (mpfitfun.pro with some limits to prevent non-physical fits).
24 Mar 2011 - The line normalizations that come out of the above fits. The first is a linear plot of the normalization versus time showing the obvious signature of radioactive decay.
Then comparing the data to the expected half-life of 2.737 years for Fe-55. There is clearly a slow reduction in quantum efficiency of 5-10% over the entire 11 years.
To confirm the source of the quantum efficiency reduction, here is the same plot, but for fits from the data in the lower corners of the CCD - closest to the framestore. There is no reduction in quantum efficiency for these data, indicating that the drop is due to increased CTI.
