100 GHz Room-Temperature Laboratory Emission Spectrometer

TL;DR

This paper introduces a new room-temperature heterodyne spectrometer operating between 75 and 110 GHz, demonstrating its capability to record molecular emission spectra with potential applications in astrophysics and complex organic molecule analysis.

Contribution

The paper presents the first results of a novel, room-temperature, high-resolution spectrometer for molecular spectroscopy, with a focus on its design, performance, and potential uses.

Findings

Able to record methyl cyanide emission spectrum

Sensitivity is about ten times lower than state-of-the-art receivers

Suitable for long-term and time-dependent measurements

Abstract

We present first results of a new heterodyne spectrometer dedicated to high-resolution spectroscopy of molecules of astrophysical importance. The spectrometer, based on a roomtemperature heterodyne receiver, is sensitive to frequencies between 75 and 110 GHz with an instantaneous bandwidth of currently 2.5 GHz in a single sideband. The system performance, in particular the sensitivity and stability, is evaluated. Proof of concept of this spectrometer is demonstrated by recording the emission spectrum of methyl cyanide, CH3CN. Compared to state-of-the-art radio telescope receivers the instrument is less sensitive by about one order of magnitude. Nevertheless, the capability for absolute intensity measurements can be exploited in various experiments, in particular for the interpretation of the ever richer spectra in the ALMA era. The ease of operation at room-temperature allows for long time integration, the fast response time for integration in chirped pulse instruments or for recording time dependent signals. Future prospects as well as limitations of the receiver for the spectroscopy of complex organic molecules (COMs) are discussed.