The detectors in the R-array (including JFETs and preamps) have noise of
50 nv/Hz1/2, and those in the T-array about 45 nv/Hz1/2.
These measurements were made on 11/9/98 by spectrum analyzer in the lab
and recorded on pages 26 and 27 of logbook 4 (Nov. '98 - Jan. '99). The
responsivities in the T-array
are slightly lower than those of the R-array, so each array has similar Noise
Equivalent Power, about 1.2-1.5*10-16W/Hz1/2**. For
preamp gain of 10,000, data system global attenuation of 1,000, strip chart
attenuation of 8, and 2 chops/frame, the electronic noise corresponds to 1/8"
of hash on the strip chart.
A field measurement of system noise (a noisy one) was made on Feb. 9, 2000,
recorded on page 25 of logbook 6. The noisiness was due to low
3He level, but those detectors that weren't affected showed
the expected level of noise.
**Note on responsivities: The lab measurement of noise was combined with
the expected field responsivity (considering a 200K atmosphere) to get
the 1.2-1.5*10-16W/Hz1/2 NEP. These field