Thermal detection radiometry at short millimeter wavelengths

Details concerning the design, construction, and operation of thermal detection radiometers for wavelengths near one mm are given. The sensitivity of these systems greatly exceeds that of more conventional radiometers at short millimeter wavelengths. Although the present designs are shown to be far from optimum, they have made possible a considerable number of astronomical observations that were previously beyond the state of the art. Measurements of atmospheric attenuation in the one-mm window as a function of total precipitable water vapor are presented, and methods of reducing the effects of varying sky background are discussed.