February 2002 anneal report for program 8841.

There was an anneal of the CCD on Feb 4, 2002, 26 days after the previous
anneal on Jan 9, 2002.  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 at all levels.

   > 0.1 e/s: 15803 pixels on Feb 4, 2002
   > 1.0 e/s:  3330
   > 10. e/s:   376
   
   > 0.1 e/s: 15800 pixels on Jan 9, 2002
   > 1.0 e/s:  3295
   > 10. e/s:   353
   
   > 0.1 e/s: 15801 pixels on Dec 15, 2001
   > 1.0 e/s:  3340
   > 10. e/s:   387
   
   > 0.1 e/s: 15839 pixels on Nov 19, 2001
   > 1.0 e/s:  3250
   > 10. e/s:   346


2) The *raw* post-anneal dark countrate for this anneal is 0.02500 cts/pixel.
   This compares with 0.02451 cts/pixel a month ago, and 0.02521 cts/pixel 
   a year ago.
   
3) The iterated median count rate (after iterating up to 30 times by
   eliminating pixels +/- 5*sigma) is 0.00415, 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:  25.2 pixels/day in Feb 2002
   > 1.0 e/s:   4.4
   > 10  e/s:   0.7

   > 0.1 e/s:  48.1 pixels/day in Jan 2002
   > 1.0 e/s:   3.7
   > 10  e/s:   0.0

   > 0.1 e/s:  31.0 pixels/day in Dec 2001
   > 1.0 e/s:   7.8
   > 10  e/s:   2.3


   > 0.1 e/s:  49.6 pixels/day 1 year ago
   > 1.0 e/s:  13.2
   > 10  e/s:   2.1


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

   > 0.1 e/s:  99.5% annealed away in the Feb 4, 2002 anneal
   > 1.0 e/s:  67.9%
   > 10  e/s:   -35%
   
   > 0.1 e/s: 100.1% annealed away in the Jan 9, 2002 anneal
   > 1.0 e/s: 151.1%
   > 10  e/s:  9999%
   
   > 0.1 e/s: 104.9% annealed away in the Dec 15, 2001 anneal
   > 1.0 e/s:  53.8%
   > 10  e/s:    28%


   The usual plots are attached.