The detectors in the R-array (including JFETs and preamps) have noise of 50 nv/Hz^1/2, and those in the T-array about 45 nv/Hz^1/2. 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/Hz^1/2**. 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/Hz^1/2 NEP. These field responsivities