September 2001 anneal report for program 8841.

There was an anneal of the CCD on Sep 21, 2001, 31 days after the
previous anneal on Aug 21, 2001.  A homogeneous set of data was obtained
from proposal 8841:  The CCD Hot Pixel Annealing.

Previous trends continue.  The growth rate of hot pixels continues within the
range seen for previous months.

1) The number of post-anneal hot pixels has increased, except for the very hot
   pixels, which have decreased by a couple.

   > 0.1 e/s: 15230 pixels on Sep 21, 2001
   > 1.0 e/s:  3228
   > 10. e/s:   361
   
   > 0.1 e/s: 15093 pixels on Aug 21, 2001
   > 1.0 e/s:  3215
   > 10. e/s:   363
   
   > 0.1 e/s: 15140 pixels on Jul 28, 2001
   > 1.0 e/s:  3240
   > 10. e/s:   370
   
   > 0.1 e/s: 15866 pixels on Jul 11, 2001
   > 1.0 e/s:  3278
   > 10. e/s:   379


2) The *raw* post-anneal dark countrate for this anneal is 0.02391 cts/pixel.
   This compares with 0.02430 cts/pixel a month ago, and 0.02423 cts/pixel  a
   year ago.

3) The iterated median count rate (after iterating up to 30 times by
   eliminating pixels +/- 5*sigma) is 0.00373, down from last month.

4) The creation rates for hot pixels over this period were within the normal
   range of fluctuations.

   > 0.1 e/s:   4.3 pixels/day in Aug 2001
   > 1.0 e/s:  -2.1
   > 10  e/s:  -0.9

   > 0.1 e/s: -13.4 pixels/day on July 28, 2001
   > 1.0 e/s:   0.2
   > 10  e/s:  -0.4

   > 0.1 e/s: -205.8 pixels/day on July , 2001
   > 1.0 e/s: -53.0
   > 10  e/s: -10.6


   > 0.1 e/s:  20.7 pixels/day 1 year ago
   > 1.0 e/s:   2.5
   > 10  e/s:  -0.5


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

   > 0.1 e/s: 147.0% annealed away in the Aug 21, 2001 anneal
   > 1.0 e/s:  47.9%
   > 10  e/s:    65%
   
   > 0.1 e/s: -237.7% annealed away in the Jul 28, 2001 anneal
   > 1.0 e/s:   1366%
   > 10  e/s:    -50%
   
   > 0.1 e/s:  29.4% annealed away in the Jul 11, 2001 anneal
   > 1.0 e/s:  45.9%
   > 10  e/s:    53%


   The usual plots are attached.