The SPIRE instrument for FIRST

摘要

SPIRE, the Spectral and Potometric Imaging Receiver, will be a bolometer instrument for ESA's FIRST satellite. Its main scientific goals are deep extragalactic and galactic imaging surveys and spectroscopy of star-forming regions in own and nearby galaxies. The SPIRE detectors are feedhorn-coupled NTD spider-web bolometers. THe instrument comprises a three-band imaging photometer covering the 250-500 mu m range, and an imaging Fourier Transform Spectrometer (FTS) covering 200-670 mu m. The photometer has a field of view of 4 x 8 arcminutes which is observed simultaneously at 250, 350 and 500 mu m, with dichroic beam dividers separating the three spectral bands. Its angular resolution is determined by the telescope diffraction limit, with FWHM beam widths of approximately 17, 24 and 35 arcseconds at 250, 350 and 500 mu m, respectively. An internal beam steering mirror can be used for spatial modulation of the telescope beam, and observations an also be made by scanning the telescope without chopping, providing better sensitivity for source confusion-limited deep surveys. The FTS has a field of view of 2.6 arcminutes and an adjustable spectral resolution of 0.04 - 2 cm~(-1) ( lambda /triangle open lambda = 20 - 1000 at 250 mu m). It employs a dual-beam configuration with novel broad-band intensity beam dividers to provide high efficiency and separated output and input ports.