TErahertz and submm LImb Sounder (TELIS), Development and characterization a cryogenic THz heterodyne receiver for TELIS

Abstract

In order to understand the ozone destruction, TELIS (TErahertz and sum Limb Sounder) has been developing by utilizing a new state-of-the-art balloon borne with three channel (500, 625, 1800 GHz for RAL, SRON and DLR consecutively) cryogenic heterodyne spectrometer. The state-of-the-art super¬conducting heterodyne technology and is designed to be compact and lightweight, while providing broad spectral coverage within the submillimeter and far-infrared spectral range, high spectral resolution and long flight duration (~24 hours duration during a single flight campaign). Measurements with the1.8 THz receiver will focus on the OH specie at 1.8 THz ±40GHz. The weaker emission at 1.8 THz is partly compensated by the higher sensitivity of the HEB mixer. The cryogenic receiver will utilize 2 Martin-Puplett interferometers as single-side-band filter and diplexer, a solid state local oszillator and a hot electron bolometer (HEB) as mixer. Recently, a simplified setup of the cryogenic heterodyne receiver in double-side-band (DSB) mode using a far-infrared laser source as LO was successfully tested within the frame of the PhD thesis of Ulrich Mair. Within the present PhD thesis the complete 1.8 THz channel will be finalised and characterised. The backend equipped with an autocorrelator spectrometer will also be characterised. Then the integration in the flight module and the radiometric characterisation of the entire instrument follows. Finally, data from the first flight will be analysed.