A brief report on the noise characteristics of the IRS in the
two middle anneal sequences for Campaign 18

18 Feb 05

Lei Hao and Greg Sloan

Abstract:

The SURN results dropped to near-normal levels by the middle of
the campaign and appear to have stabilized in the third mid-campaign
anneal sequence.  SH continues to show SURN results under the
noise limit.  SL and LL are now at levels straddling the noise
limit, and while LH is still above its noise limit, it is at the
noise level we saw prior to Campaign 18.

Analysis:

    Noise characteristics of the modules (in DN)

           SUR data                SRS data
           noise   pre     post    noise   pre     post
   Module  limit   anneal  anneal  limit   anneal  anneal

   Campaign 18 startup

    SL      8.8     9.5    10.6    15.0    12.7    12.3
    SH      8.8     6.7     7.5    15.0    12.8    13.0
    LL     14.5    15.7    15.2    15.0    13.3    13.1
    LH     17.6    22.5    20.2    15.0    13.7    13.6

    Campaign 18 first mid-campaign anneal

    SL      8.8     8.1     9.0    15.0    12.1    12.2
    SH      8.8     7.0     6.9    15.0    12.8    12.7
    LL     14.5    14.7    13.0    15.0    12.7    12.9
    LH     17.6    19.3    19.2    15.0    13.1    13.2

    Campaign 18 second mid-campaign anneal

    SL     8.8      7.9      9.0    15.0     12.1     12.2
    SH     8.8      6.9      7.0    15.0     12.9     12.7
    LL    14.5     11.4     12.0    15.0     13.0     12.9
    LH    17.6     18.0     18.3    15.0     13.2     13.3

    Campaign 18 third mid-campaign anneal

    SL     8.8      8.8      9.5    15.0     12.4     12.3
    SH     8.8      7.2      7.1    15.0     12.8     12.9
    LL    14.5     14.8     13.6    15.0     12.9     12.8
    LH    17.6     19.8     18.8    15.0     13.2     13.2

  From the beginning of the campaign to the second mid-campaign
  anneal sequence, the noise levels in SL, LL, and LH have
  decreased.  They have risen slightly in the third mid-campaign
  anneal sequence, suggesting that we have stabilized.  SH has
  behaved well throughout the campaign.

Comparing to the average SURN in all anneal sequences in 
Campaigns 15-17 to all those in Campaign 18 gives the 
following results:

          Average for     Max for   
  Module  Camp. 15-17   Camp. 15-17  Camp. 18
  SL       8.8 +/- 0.6     10.1       9.1 +/- 0.9
  SH       7.0 +/- 0.5      8.0       7.0 +/- 0.2
  LL      12.6 +/- 0.9     14.1      13.8 +/- 1.6
  LH      18.3 +/- 0.6     19.5      19.5 +/- 1.4

  The results from the second mid-campaign anneal sequence
  are fully consistent with the averages from Campaigns 15
  to 17.  The campaign averages are still a bit higher for
  all modules but SH, but they improved significantly.