Maxima: a Balloon-borne Cosmic Microwave Background Anisotropy Experiment

We describe the Millimeter wave Anisotropy eXperiment IMaging Array (maxima), a balloon-borne experiment designed to measure the temperature anisotropy of the Cosmic Microwave Background (CMB) on angular scales of 10 to 5. maxima mapped the CMB using 16 bolometric detectors in spectral bands centered at 150 GHz, 240 GHz, and 410 GHz, with 10 resolution at all frequencies. The combined receiver sensitivity to CMB anisotropy was ∼40 μK √ sec. Systematic parasitic contributions were minimized by using four uncorrelated spatial modulations, thorough crosslinking, multiple independent CMB observations, heavily baffled optics, and strong spectral discrimination. Pointing reconstruction was accurate to 1 , and absolute calibration was better than 4%. Two maxima flights with more than 8.5 hours of CMB observations have mapped a total of 300 deg of the sky in regions of negligible known foreground emission. maxima results have been released in previous publications. maxima-i maps, power spectra and correlation matrices are publicly available at http://cosmology.berkeley.edu/maxima. Subject headings: cosmic microwave background