2006-08-15
A 211-275 GHz SIS receiver using an ALMA Band 6 sideband-separating mixer-preamp has been installed on the Submillimeter Telescope (SMT) on Mt. Graham, Arizona, a facility of the University of Arizona. Initial observations have yielded single-sideband system noise temperatures as low as 107 K referred to outside the atmosphere. The image rejection, measured on the sky, was > 12 dB (15 dB typical) for the upper sideband, and > 20 dB for the lower sideband. Excellent baseline stability was also observed: a 4° position offset in galactic latitude yielded a peak-to-peak baseline of only 10 mK. The receiver has separate 4-8 GHz IF outputs for the upper and lower sidebands, although in the present observations the instantaneous bandwidth was limited by the available spectrometers to 2 GHz in each sideband.
View a pdf version of ALMA Memo #553.
alma-memos@nrao.edu