ACBAR: The Arcminute Cosmology Bolometer Array Receiver

We describe the Arcminute Cosmology Bolometer Array Receiver (ACBAR); a multifrequency millimeter-wave receiver designed for observations of the cosmic microwave background and the Sunyaev-Zel'dovich effect in clusters of galaxies. The ACBAR focal plane consists of a 16 pixel, background-limited, 240 mK bolometer array that can be configured to observe simultaneously at 150, 220, 280, and 350 GHz. With 4′-5′ FWHM beams and a 3° azimuth chop, ACBAR is sensitive to a wide range of angular scales. ACBAR was installed on the 2 m Viper telescope at the South Pole in 2001 January. We describe the design of the instrument and its performance during the 2001 and 2002 observing seasons.