A balloon-borne 620-650 GHz SIS receiver for atmospheric observations

We have developed a balloon-borne superconducting submillimeter-wave limb-emission sounder (BSMILES) to determine vertical profiles of stratospheric minor constituents like ozone and a number of key species related to ozone destruction by observing thermal emission lines from these molecules. BSMILES carries a 624-652 GHz superconductor-insulator-superconductor (SIS) receiver with the system noise temperature of 330-460 K in double sideband (DSB) during the flight. BSMILES flight experiments were conducted on August 30, 2003 and September 7, 2004 from the Pacific Coast of Japan. The system operated properly and spectra of O₃, ClO, HCl, HO₂, O₃ isotopes were successfully measured. After the observation, the gondola splashed down in the Pacific Ocean and was retrieved.