Astron. Astrophys. 363, L37-L39 (2000)

2. Experimental

HNC was synthesized in situ in a flow system via dc glow discharge of 2-10 Pa methyl cyanide, , and up to 20 Pa Helium. Two different spectrometers were employed: In the lower submm-range ( 913 GHz), the Cologne terahertz spectrometer (Winnewisser et al. 1994 , Winnewisser 1995) was used with its phase-stabilized backward-wave oscillators (ISTOK Research and Production Company, Moscow region, Russia) (Lewen et al. 1998) as sources. Measurements near two terahertz were carried out using the Cologne sideband spectrometer for terahertz applications (COSSTA) (Gendriesch et al. 2000) employing a double modulation technique: modulating the discharge by 11 Hz and the source frequency by 27 kHz. Two different absorption cells of 2 and 1 m length, respectively, were used. Magnetically tuned, liquid-He-cooled InSb hot electron bolometers were employed as detectors.

© European Southern Observatory (ESO) 2000

Online publication: December 5, 2000
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