SORAL's One-Element Receivers

How do submillimeter receivers work?

	SIS-230 at the SMTO: The SORAL 230 GHz single-polarization receiver is long-standing facility instrument at the SMTO. "Old Reliable" received a new SIS junction during the summer of 1997 and now exhibits a flat and very consistent DSB receiver noise temperature of 60-80K over its 210-275 GHz tuning range. The main beam efficiency on Saturn was found to be about 77% and the beam was 35.3" in azimuth and 37.0" in elevation. The SIS-230 User Manual is online!
	SIS-490 at the SMTO: The SORAL 490 GHz single-channel receiver was installed at the SMTO in early January 1998 after undergoing several improvements, including a new SIS junction that is noticably quieter at the highest frequencies. A new Zytex IR blocking filter incurs fewer losses and yields lower thermal loading. The receiver now achieves T(DSB) of 110-150 K across its 425 to 500 GHz tuning range. On Saturn, the beam was found to be 16.5" in both elevation and azimuth. The main beam efficiency on Saturn was about 45%. The forward scattering efficiency on the moon was measured at 72%. The SIS-230 and SIS-490 receivers respond to orthogonal polarizations and can therefore collect data simultaneously. The SIS-490 User Manual is online!
	SIS-492 at AST/RO: T(DSB) of 120-170K.