Superconducting Tunnel Junctions for Radioastronomical Receivers

摘要: The extension of astronomical observations into the millimeter and sub-millimeter wavelength region has yielded exciting discoveries; numerous molecules have been detected in comets, stellar atmospheres, circumstellar shells, proto-planetary nebulae interstellar clouds. Most are observed rotational emission lines. excitation usually occurs through collision with H2 He atoms kinetic temperatures 10 to 200 K. Fig. 1 shows (1-0) (2-1) rotation lines isotope C180 from center a spiral galaxy, 13.5 million light years away us [1]. brightness temperature TB (vertical scale) is Rayleigh-Jeans an equivalent black body that would give same signal power as source. horizontal frequency scale converted velocity scale. In laboratory, maxima located at 109.8 GHz for 219.6 transitions this isotope. offset zero indicates galaxy moves about 30 km/s.