Atmospheric Noise in the Far Infrared (300–3000 µm)

Noise measurements in the frequency regions 5–200 Hz and 5.2 × 10⁻⁴−8.3 × 10⁻³ Hz have been performed in the wavelength region between 300 and 3000 µm from the high altitude observatory of Testa Grigia, Italy (3.500 m). In the high frequency region a specially designed Ge bolometer operating in background-limited-infrared-photoconductor conditions matched to a 1.5-m telescope has been used, while at low frequency a radiometer designed for atmospheric transmittance measurements was employed. In both regions no excess noise with respect to the photon noise relative to 300-K blackbody has been detected.