ANTENNA-COUPLED BOLOMETER ARRAYS FOR ASTROPHYSICS

We are developing arrays of feedhorn-coupled, silicon nitride micromesh (‘spider web’) bolometers for the ESA/NASA Planck Surveyor and Herschel Space Observatory for millimeter to far-infrared wavelengths. These detector systems realize high end-to-end optical efficiency, essentially fill the available focal surface, and achieve background-limited sensitivity. The Planck/HFI detectors in particular approach the fundamental sensitivity set by the photon noise from the cosmic microwave background. The silicon nitride micromesh architecture realizes low areal heat capacity. NTD Ge thermistor readouts and DC-stable electronics provide low-frequency noise stability appropriate for slow-scanned space-borne platforms. A novel Si JFET amplifier package allows us to operate large numbers of bolometers for Herschel/SPIRE with moderate power dissipation (~50 uW/JFET). We are developing a new antenna-coupled architecture appropriate for the next-generation astrophysics applications such as CMB polarimetry and far-infrared/sub-millimeter spectral line surveys. Compared to bolometers with extended area radiation absorbers, antenna-coupled bolometers offer active volumes that are orders of magnitude smaller, promising further gains in sensitivity and speed of response. We are developing a focal plane architecture for CMB polarimetry consisting of a distributed array of slot antenna