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This paper presents the modeling and the comparison of two acquisition systems developed at the Test Centre Division, European Space and Technology Centre, of the European Space Agency in the frame of two investigations: 1) on microelectromechanical-systems-based sensors for the detection of very low-g accelerations and 2) on the feasibility of a compact and low-power multisensor acquisition platform for environmental tests of spacecrafts or subsystems. A Simulink-based approach is proposed for fast, accurate, and reconfigurable modeling of both systems, taking into consideration the sensors and the acquisition chain. This paper aims to highlight the importance of the models as key tools to predict the distortion and noise sources, to allow fast setup of the experiments, and to manage the signal conditioning process. The validity of the proposed technique, applied to the two acquisition systems, is assessed by comparing the predicted results with tests on the real system. Finally, this paper aims to prove, by comparing the two approaches (dedicated acquisition system and multisensor acquisition platform), the importance of the characterization of the whole acquisition system when high performances need to be achieved.

During the last decade, III–VI layered semiconductors (GaSe, InSe, GaS, etc.) have emerged as potential candidates for various applications, such as FET and optoelectronic devices. The properties of this class of layered materials are strongly dependent on their structure, and the existence of different polytypes makes it necessary the identification of the structural phase. In this work, we have performed a detailed investigation of the crystal structure and morphology of bulk InSe, by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy. The combination of the employed techniques allowed to identify the structural phase of InSe samples ( ϵ polytype). Most importantly, we show that only by crossing the information of each technique it is possible to unambiguously discern between similar polytypes.

A commercial variable angle spectroscopic ellipsometer from J. A. Woollam Company is modified in order to make possible measurements in guiding structures. The half leaky guided mode technique is realised for liquid crystal optical dispersion measurements. Features and problems related to experimental data interpretation and error sources in the refractive index measurements are carefully analyzed, achieving a final accuracy of 0.0002. We present the measured optical dispersion curves in the wavelength range from 0.5 to 1.7 mu m for two widely studied liquid crystals, namely E7 and 5CB.