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Crockett NR, Bergin EA, Wang S, Lis DC, Bell TA, Blake GA, et al. Herschel observations of EXtra-Ordinary Sources (HEXOS): The Terahertz spectrum of Orion KL seen at high spectral resolution. Annual Rev. Astron. Astrophys.. 2010;521:L21 (1 to 5).
Abstract: We present the first high spectral resolution observations of Orion KL in the frequency ranges 1573.4–1702.8 GHz (band 6b) and 1788.4–1906.8 GHz (band 7b) obtained using the HIFI instrument on board the Herschel Space Observatory. We characterize the main emission lines found in the spectrum, which primarily arise from a range of components associated with Orion KL including the hot core, but also see widespread emission from components associated with molecular outflows traced by H2O, SO2, and OH. We find that the density of observed emission lines is significantly diminished in these bands compared to lower frequency Herschel/HIFI bands.
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Burke PJ, Schoelkopf RJ, Prober DE, Skalare A, Karasik BS, Gaidis MC, et al. Spectrum of thermal fluctuation noise in diffusion and phonon cooled hot-electron mixers. Appl Phys Lett. 1998;72(12):1516–8.
Abstract: A systematic study of the intermediate frequency noise bandwidth of Nb thin-film superconducting hot-electron bolometers is presented. We have measured the spectrum of the output noise as well as the conversion efficiency over a very broad intermediate frequency range (from 0.1 to 7.5 GHz) for devices varying in length from 0.08 μm to 3 μm. Local oscillator and rf signals from 8 to 40 GHz were used. For a device of a given length, the spectrum of the output noise and the conversion efficiency behave similarly for intermediate frequencies less than the gain bandwidth, in accordance with a simple thermal model for both the mixing and thermal fluctuation noise. For higher intermediate frequencies the conversion efficiency decreases; in contrast, the noise decreases but has a second contribution which dominates at higher frequency. The noise bandwidth is larger than the gain bandwidth, and the mixer noise is low, between 120 and 530 K (double side band).
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Burke PJ, Schoelkopf RJ, Prober DE, Skalare A, Karasik BS, Gaidis MC, et al. Mixing and noise in diffusion and phonon cooled superconducting hot-electron bolometers. J. Appl. Phys.. 1999;85(3):1644–53.
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Karpov A, Miller D, Rice F, Zmuidzinas J, Stern JA, Bumble B, et al. Low noise 1.2 THz SIS receiver. In: Jet Propulsion Laboratory CIit.u.t.e of T, editor. Proc. 12th Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. p. 21–2.
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Karpov A, Miller D, Stern JA, Bumble B, LeDuc HG, Zmuidzinas J. Low noise NbTiN 1.25 THz SIS mixer for Herschel Space Observatory. In: Proc. 16th Int. Symp. Space Terahertz Technol. Göteborg, Sweden; 2005. 450.
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