The SPectral IMager (SPIM) facility is a laboratory visible infrared spectrometer developed to support space borne observations of rocky bodies of the solar system. Currently, this laboratory setup is used to support the DAWN mission, which is in its journey towards the asteroid 1-Ceres, and to support the 2018 Exo-Mars mission in the spectral investigation of the Martian subsurface. The main part of this setup is an imaging spectrometer that is a spare of the DAWN visible infrared spectrometer. The spectrometer has been assembled and calibrated at Selex ES and then installed in the facility developed at the INAF-IAPS laboratory in Rome. The goal of SPIM is to collect data to build spectral libraries for the interpretation of the space borne and in situ hyperspectral measurements of planetary materials. Given its very high spatial resolution combined with the imaging capability, this instrument can also help in the detailed study of minerals and rocks. In this paper, the instrument setup is first described, and then a series of test measurements, aimed to the characterization of the main subsystems, are reported. In particular, laboratory tests have been performed concerning (i) the radiation sources, (ii) the reference targets, and (iii) linearity of detector response; the instrumental imaging artifacts have also been investigated.
The paper introduces the analysis carried out by Selex ES (SE) for the development of a third generation IRST system based on large format MWIR sensors, separable in blue and red bands. In the feasibility study, physical constraints have been evaluated relying on different optics and scanning options. The goal is a system based on distributed heads to cover 360 with a resolution better than 0.3 mrad and high frame rate that allow to take advantage of the typical atmospheric phenomena of the maritime environment as scintillation and super and sub refraction. Two critical aspects were investigated: (i) the setting of an adequate scanning mechanism to assure a high frame rate and (ii) the stitching of the collected images while maintaining the bit-depth so as to avoid abrupt changes of SNR at the seams between two subsequent images
The use of a spectrometer to measure the refractive index of a prism glass sample in the visible and near-infrared regions at cryogenic temperature is reported. The details of the measuring cell and the experimental apparatus are provided, and a specific data reduction procedure based on ray tracing is introduced. Demonstrative results on a BK7 prism sample in a temperature range from 105 to 293 K and wavelength from 480 to 894 nm are presented. The measurement uncertainty is 3 × 10−5 (2σ).
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