Measurements with a Diffusion-Cooled Nb Hot-Electron Bolometer Mixer at 1100 GHz

In this paper we report receiver sensitivity measurements with a diffusion-cooled niobium hot-electron bolometer around 1100 GHz. The lowest receiver noise temperature was 1670 K DSB, with approximately 40 nW of local oscillator power being dissipated in the device. The intermediate frequency bandwidth of this device, due to its short length (0.15 gm) and low normal resistance (43 a), exceeded the 1.8 GHz bandwidth of the measurement setup. The receiver was used to detect the sulfur dioxide gas absorption line at 1102 GHz in a heterodyne mode.