A three photon noise SIS heterodyne receiver at submillimeter wavelength

• Published in: IEEE transactions on applied superconductivity 1999-06, Vol.9 (2), p.4456-4459
• Main Authors: Karpov, A., Blondel, J., Voss, M., Gundlach, K.-H.
• Format: Article
• Language: English
• Subjects: Astronomical observations; Astronomy; Earth, ocean, space; Exact sciences and technology; Fundamental astronomy and astrophysics. Instrumentation, techniques, and astronomical observations; Josephson junctions; Niobium; Noise; Noise figure; Noise measurement; Noise temperature; Optical receivers; Photons; Radio astronomy; Radio telescopes; Receivers; Single sideband; Submillimeter (300 μm - 1 mm); Superconducting device noise; Superconducting devices; Telescopes; Temperature; Wavelengths
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/77.784014

An ultra-low noise single sideband SIS receiver has been prepared for radio astronomy at the sub millimeter wavelength /spl lambda//spl ap/0.85 mm. The minimum single sideband receiver noise temperature of 48 K corresponds to 3 h/spl omega//k or equivalent number of 3 photon of noise. The minimum single sideband SIS mixer noise temperature is about 20 K, close to 1.2 h/spl omega//k, or one photon of noise. The Nb/AlOx/Nb junctions with a Josephson critical current density of 9 KA/cm/sup 2/ and with the area of about 0.9 /spl mu/m/sup 2/ were used. The receiver has been tested at the 30 meter IRAM radio telescope in the winter seasons of 1997 and 1998. The observations at the radio telescope are speeded up by a factor of two to three with the new receiver.