Interferometer instrumentation

The Far-infrared Interferometer Instrument Simulator, FllnS, is an instrument simulator for a Far-infrared Spectro-Spatial Interferometer. The main goal is to simulate both the input and the output of such a system, and compare the input sky map with the synthesised one after data processing algorithms have been applied. With a modular design, intermediate outputs are also available. In this chapter the different modules created to build FllnS are described, from the sky map generator to the raw data on the detectors module. In Chap. 5 the data processing algorithms are presented and the simulator is verified via the Cardiff-UCL FIRI testbed described in Chap. 3. 

The second and third year have focused in the development and testing of the Far Infrared Interferometer Instrument Simulator FllnS, and preliminary results have been presented at international Conferences (Juanola-Parramon et al. 2012 Juanola-Parramon and Savini 2013). 

R. Juanola-Parramon, G. Savini, FllnS The far-infrared interferometer instrument simulator, in Fourier Transform Spectroscopy (Optical Society of America, 2013)... 

FIGURE 3 Thermal emission spectra of Earth measured by the IRIS Michelson interferometer instrument on the Nimbus 4 spacecraft Shown also are the radiances of blackbodies at several temperatures. (top) Sahara region, (middle) Mediterranean, (bottom) Antarctic. 

As can be seen from Fig. 8a, a mirror displacement of x cm results in an optical path difference of 2x cm for instruments with Michel son interferometers. Instruments with Genzel interferometers, achieve an optical path difference of 4x. Resolution is inversely proportional to optical path differences, so it can be seen that the Genzel interferometer achieves the same resolution for only half the mirror travel of a Michel son interferometer, an important feature when mechanical tolerance is considered. The schematic diagram of the Genzel interferometer is depicted in Fig. 8b. The detector then measures the amount of energy at discrete intervals of mirror travel. 

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