The Raman Laser Spectrometer (RLS) on board the ESA/Roscosmos ExoMars 2020 mission will provide precise identification of the mineral phases and the possibility to detect organics on the Red Planet. The RLS will work on the powdered samples prepared inside the Pasteur analytical suite and collected on the surface and subsurface by a drill system. Raman spectroscopy is a well-known analytical technique based on the inelastic scattering by matter of incident monochromatic light (the Raman effect) that has many applications in laboratory and industry, yet to be used in space applications. Raman spectrometers will be included in two Mars rovers scheduled to be launched in 2020. The Raman instrument for ExoMars 2020 consists of three main units:(1) a transmission spectrograph coupled to a CCD detector; (2) an electronics box, including the excitation laser that controls the instrument functions; and (3) an optical head with an autofocus mechanism illuminating and collecting the scattered light from the spot under investigation. The optical head is connected to the excitation laser and the spectrometer by optical fibers. The instrument also has two targets positioned inside the rover analytical laboratory for onboard Raman spectral calibration. The aim of this article was to present a detailed description of the RLS instrument, including its operation on Mars. To verify RLS operation before launch and to prepare science scenarios for the mission, a simulator of the sample analysis chain has been developed by the team. The results obtained are also discussed. Finally, the potential of the Raman instrument for use in field conditions is addressed. By using a ruggedized prototype, also developed by our team, a wide range of terrestrial analog sites across the world have been studied. These investigations allowed preparing a large collection of real, in situ spectra of samples from different geological processes and periods of Earth evolution. On this basis, we are working to develop models for interpreting analog processes on Mars during the mission.
We evaluate the exposure during nadir observations with JEM-EUSO, the Extreme Universe Space Obser-\ud vatory, on-board the Japanese Experiment Module of the International Space Station. Designed as a mis-\ud sion to explore the extreme energy Universe from space, JEM-EUSO will monitor the Earth’s nighttime\ud atmosphere to record the ultraviolet light from tracks generated by extensive air showers initiated by\ud ultra-high energy cosmic rays. In the present work, we discuss the particularities of space-based obser-\ud vation and we compute the annual exposure in nadir observation. The results are based on studies of the\ud expected trigger aperture and observational duty cycle, as well as, on the investigations of the effects of\ud clouds and different types of background light. We show that the annual exposure is about one order of\ud magnitude higher than those of the presently operating ground-based observatories
An asynchronous phase-shifting method based on principal component analysis (PCA) is presented. No restrictions about the background, modulation, and phase shifts are necessary. The presented method is very fast and needs very low computational requirements, so it can be used with very large images and/or very large image sets. The method is based on obtaining two quadrature signals by the PCA algorithm. We have applied the proposed method to simulated and experimental interferograms, obtaining satisfactory results.
We recently presented a new asynchronous demodulation method for phase-sampling interferometry. The method is based in the principal component analysis (PCA) technique. In the former work, the PCA method was derived heuristically. In this work, we present an in-depth analysis of the PCA demodulation method.
Faraday rotation spectrum has been measured at room temperature in a magnetic nanocomposite of γ-Fe2O3/SiO2. The material consists of isolated γ-Fe2O3 nanoparticles dispersed in a silica matrix, and it was prepared through a sol-gel method. The composite contains 18% of γ-Fe2O3 in weight with an average particle size of 20 nm. It has a coercitivity of 30 Oe and an MS of 6 emu/g. The specific Faraday rotation spectrum exhibits a narrow peak centered around 765 nm, reaching a value of 110°/cm and an absorption coefficient of 64 cm−1. Faraday rotation versus applied field has also been measured, and a cycle similar to the one described by the magnetization has been found.
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