MARTIN PHILIPP, MICHAEL CARIS, THOMAS GIESEN AND STEPHAN SCHLEMMER, University of Cologne, I. Institute of Physics, 50933 Cologne, Germany.
We report on the setup of a supersonic jet spectrometer allowing measurements of rot-vibrational transitions in cold carbon clusters in the frequency range of 1.75 to 1.95 THz. The spectrometer consists of a multi reflection Herriott cell and uses a frequency tripled backward-wave oscillator source. It is the result of the combination of the existing Cologne Supersonic Jet Spectrometer for THz Application (SuJeSTA) with the 1.9~THz portable and stand-alone local oscillator of the German Receiver for Astronomy at Terahertz frequencies (GREAT). Due to the oscillator's frequency stabilization system, a spectral resolution of 13 kHz is achieved. An overview of the functional setup of the spectrometer and first measurements of the Q(10) bending vibration of the 12C3 carbon cluster at 1935.87~GHz are reported. Ongoing projects for the measurement of submillimeter transitions in the 13C3 and C7 carbon clusters in the accessible terahertz region will be discussed.