September 1999 Anneal Report for Program 8410

There was an anneal of the CCD on Sept 26, 1999, 34 days after the 
previous anneal of August 23.   A homogeneous set of data was obtained from
proposal 8410: The Continuing Monthly Anneal Monitor. 

For the most part, past trends continue.  Howver, comparison of the last few
monts data suggests a noticable flattening of the growth rate in hot pixels
(see the figure post_plot_sep99.ps).  The post-anneal dark now shows 12065 hot
pixels.

1) The *raw* post-anneal dark countrate for this anneal is 0.0192 cts/pixel.
   This compares with 0.01879 cnts/pixel in Sept and 0.014820
   cts/pixel in Feb 99, consistent with a growth rate of 0.0066
   cnts/pixel/year.  This continues past trends.
   
2) The iterated median count rate (after iterating up to 30 times by
   eliminating pixels +/- 5*sigma) is 0.00349.

3) the creation rates for hot pixels over this anneal period were within
   the normal range found in recent anneals, although the rate for the 0.1
   e/s cut is near the low end of the previously observed range.

   > 0.1 e/s:  32.8 pixels/day in September
   > 1.0 e/s:
   > 10  e/s:

   > 0.1 e/s: 52.2 pixels/day in August
   > 1.0 e/s:  5.2
   > 10  e/s:  0.5

   > 0.1 e/s: 47.5 pixels/day in early July
   > 1.0 e/s:  5.2
   > 10  e/s:  0.5

4) The rate at which new hot pixels annealed out was also within the normal
   range of fluctuations.

   > 0.1 e/s: 80.3% annealed away in September 99 anneal.
   > 1.0 e/s: 99.0
   > 10  e/s:-29.6%

   > 0.1 e/s: 80.7% annealed away in August anneal
   > 1.0 e/s: 54.1%
   > 10  e/s: 89.9%  

   > 0.1 e/s: 83.7% annealed away in early July anneal
   > 1.0 e/s: 25.6%
   > 10  e/s:200.0%  


   Cumulative plots of total post-anneal hot pixels, and the new pixel
   anneals are attached.