A Practical Schottky Mixer for 5 THz

摘要: The wavelength band between 60 and 120 ym is particularly important for observations of the interstellar medium, it here that cores galactic molecular clouds radiate most their energy. Both continuum radiation from warm dust grains line ions, atoms, molecules are cooling mechanisms material warmed b intense UV newly formed sfars. Velocity gradients within so small resolving power spectrometer should exceed 106, if intrinsic shapes (and information they contain) not to be degraded.. Heterodyne receivers capable such resolution have far only been operated at wavelengths >118 (2.5 THz) [1]. Of particular interest astronomers fine structure neutral oxygen (0 I) 63 jim (4.75 THz). This transition major "warm" (T 200 K) "dense" (n > 10cm -3 ) gas in cloud core. course this cannot penetrate earth's atmosphere, all must done above tropopause with aircraft or space-borne instruments. To date grating Fabry-Perot spectrometers successfully used line. albeit less spectral than possible heterodyne techniques. We can estimate some parameters by comparison another emitted these clouds: 158inn ionized carbon (C II). longer has observed a laser aboard NASA's Kuiper Airborne Observatory (K AO) over 7 years now [2]. 3 MHz (0.5 km sI shown C emission may sources optically thick, which case its function as mechanism somewhat impaired. For conditions expected cores, emission. ,um even more thick (saturated), but no direct spectroscopic evidence exists. Up theoretical analyses excitation temperatures photodissociated based simply on intensity ratio unresolved 158 lines, assumed thin. Therefore derived element abundances) could erroneous either thick. A better way determine temperature would measure peak brightness resolved 0 I II lines. If made, then yields directly.