Design of the South Pole imaging Fabry-Perot interferometer (SPIFI)

The South Pole Imaging Fabry-Perot Interferometer (SPIFI) is a direct detection, imaging, submillimeter spectrometer. The spectral resolving elements are a pair of cryogenic, scanning Fabry-Perot interferometers which use a free- standard Ni mesh for the etalon mirrors. The detectors for SPIFI are a 5 X 5 array of bolometers coupled to the focal plane with Winston cones. An adiabatic demagnetization refrigerator cools the bolometers to approximately 60 mK while a 3 He system operates simultaneously as a thermal guard. SPIFI is intended to operate on the ASO/RO submillimeter telescope at the South Pole and on the JCMT telescope on Mauna Kea and will be used to study the gas- phase reservoirs of carbon in star-forming regions in our own and near-by galaxies. SPIFI takes advantage of three things: (1) Advanced bolometers that achieve background limited performance at very high resolving powers. (2) The imaging capability and high spectral resolving power of Fabry-Perot interferometers. (3) The superb atmospheric transmission in submillimeter bands possible from the South Pole. The SPIFI uses state-of-the-art monolithic silicon bolometers fabricated at the NASA Goddard Space Flight Center. The cryogenic, scanning Fabry-Perots in SPIFI were designed and built at Cornell and are an evolution of the design used with great success for the Kuiper Wide Field Camera. The 1.7 m Antarctic Submillimeter Telescope/Remote Observatory exploits what is thought to be the best submillimeter observing site in the world.