New laboratory techniques using heterodyne receivers

Abstract

Two laboratory emission spectrometers have been designed and described previously. Here, we present a follow-up study with special focus on absolute intensity calibration of the new SURFER-spectrometer (SUbmillimeter Receiver For Emission spectroscopy of Rotational transitions), operational between 300 and 400 GHz and coincident with ALMA (Atacama Large Millimeter/submillimeter Array) Band 7.Furthermore, we present a feasibility study to extend the detection frequencies up to 2 THz. First results have been obtained using the SOFIA (Stratospheric Observatory for IR Astronomy) upGREAT laboratory setup which is located at the University of Cologne. Pure rotational spectra of the complex molecule vinyl cyanide have been obtained and are used to give an estimate on the sensitivity to record ro-vibrational transitions of molecules with astrophysical importance at 2 THz.

Laboratory spectroscopy for astrophysics: Festschrift for Stephan Schlemmer

“…In addition, the arsenal of mm-wave spectrometers has been enriched with state-of-the art modern equipment over the years, driven by Stephan and Nadine Wehres. One route were emission spectrometers that use radio astronomical heterodyne receiver technology to capture the instantaneous room-temperature emission of molecules, and operate in the range 270-390 GHz (coincident with Band 7 of the ALMA telescope) [42,43] and 75-110 GHz (Band 3 of ALMA) [44]. Another route were the construction of several chirped pulse spectrometers [45], the highest frequency one now operating in the range 70-110 GHz.…”