RESUMO
The Space Infrared telescope for Cosmology and Astrophysics (SPICA) mission has just been selected by the European Space Agency as one of the three candidate missions to be further studied for the medium size mission M5. B-BOP, formerly named POL, is one of the three scientific instruments of SPICA which aims, among other scientific goals, to map the galactic filamentary structures and their associated magnetic fields. With a novel interlaced-shaped design, B-BOP will contain 1344 pixels, operating within a temperature range of 50-100 mK, covering a 2.6 arcmin field of view, and delivering imaging polarimetry in three spectral bands: 100 µm, 200 µm, and 350 µm simultaneously. In this paper, we investigate by numerical simulations the mechanical, electromagnetic, and thermoelectric behaviors of B-BOP detectors and predict for the three bands (i) a sufficient mechanical stability, (ii) a good electromagnetic absorption higher than 95%, (iii) a high response value better than 1011 V/W, and (iv) especially a very low noise equivalent power reaching 1 aW/Hz1/2 at 50 mK.
RESUMO
Future missions for astrophysical studies in the submillimeter region will need detectors with very high sensitivity and large fields of view. Bolometer arrays can fulfill these requirements over a very broad band. We describe a technique that enables bolometer arrays that use quarter-wave cavities to have a high spectral response over most of the submillimeter band. This technique is based on the addition on the front of the array of an antireflecting dielectric layer. The optimum parameters (layer thickness and distance to the array) are determined by a 2D analytic code. This general principle is applied to the case of Herschel PACS bolometers (optimized for the 60 to 210 µm band). As an example, we demonstrate experimentally that a PACS array covered by a 138 µm thick silicon layer can improve the spectral response by a factor of 1.7 in the 450 µm band.
