First light with the Hot-electron Bolometric Mixer Receiver at 810 GHz and 690 GHz !

The CfA Submillimeter Receiver Lab's Niobium Nitride (NbN) phonon-cooled Hot-electron Bolometric (HEB) Mixer Receiver, operating in the 690 GHz and 810 GHz bands, was successfully installed and tested at the SMTO in early March 1998. Superconducting HEB mixers are an alternative to SIS systems, especially for the high frequency range around and above 1 THz (for details about the HEB technology see the list of recent publications of the CfA Submillimeter Receiver Lab).

The tunerless waveguide receiver has a receiver noise temperature of 1300 K (DSB) at 810 GHz and 650 K at 690 GHz across the 1.2 to 1.8 GHz IF. The local-oscillator source is a frequency-multiplied Gunn oscillator.

It was the first time a HEB system has been used at a telescope and it is the first spectral line run in the 690 GHz window at the SMTO. First results include the detection of the CO 7-6 (807 GHz) and 6-5 (691 GHz) lines as well as CI 2-1 (809 GHz) towards several sources.

Here is an example of a CO 7-6 5-point map of IRC+10216:

(click on thumbnail to get a larger image)
(Image courtesy of R. Blundell, J. Kawamura, T. Hunter & E. Tong)