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 responsivities