Archeops:: a high resolution, large sky coverage balloon experiment for mapping cosmic microwave background anisotropies

Archeops is a balloon-borne instrument dedicated to measuring cosmic microwave background (CMB) temperature anisotropies at high angular resolution (similar to8') over a large fraction (similar to25%) of the sky in the millimetre domain. Based on Planck high frequency instrument technology, cooled bolometers (0.1 K) scan the sky in total power mode with large circles at constant elevation. During the course of a 24-h Arctic-night balloon flight, Archeops will observe a complete annulus on the sky in four frequency bands centered at 143, 217 353 and 545 GHz with an expected sensitivity to CMB fluctuations of similar to100 muK for each of the 90 thousand 20' average pixels. We describe the instrument and its performance obtained during a test flight from Trapani (Sicily) to Spain in July 1999. (C) 2002 Elsevier Science B.V. All rights reserved.