800- to 900-GHz SIS receiver for molecular line astronomy

Recent astronomical observations of neutral carbon at 492 GHz have shown that its distribution is widespread in interstellar molecular coulds. Studies of the distribution and excitation of neutral carbon are of key importance in understanding the chemistry of such regions. Observations of CI at 809 GHz to complement those at 492 GHz would be of great importance in such studies. We are currently building as SIS receiver for the frequency band 800-900 GHz for use in observing submillimeter spectral lines, including CI. The receiver will be operated on the TIRGO infrared telescope, situated on the summit of the Gornergrat, Switzerland (altitude 10,390 ft). It is anticipated that this receiver will be mounted on the TIRGO telescope towards the end of 1996, or the beginning of 1997.