MAXIMA: A balloon-borne cosmic microwave background anisotropy experiment

We describe the Millimeter wave Anisotropy eXperiment IMaging Array (MAXIMA), a balloon-borne experiment which measured 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, 240, and $410GHz$⁠, with $10′$ resolution at all frequencies. The combined receiver sensitivity to CMB anisotropy was $∼40μKs$⁠. The bolometric detectors, which were cooled to $100mK$⁠, were a prototype of the detectors which will be used on the Planck Surveyor Satellite of the European Space Agency. Systematic parasitic contributions were controlled by using four uncorrelated spatial modulations, thorough cross-linking, 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 $8.5h$ of CMB observations have mapped a total of $300deg2$ of the sky in regions of negligible known foreground emission. MAXIMA results have been released in previous publications and shown to be consistent with the Wilkinson Microwave Anisotropy Probe. MAXIMA I maps, power spectra, and correlation matrices are publicly available at http://cosmology.berkeley.edu/maxima.