The 1.4-m Telescope for the Q/U Imaging Experiment

The optical design of the 1.4-m telescope for the Q/U Imaging ExperimenT (QUIET) is described. The telescope is intended to image the polarization of the cosmic microwave background (CMB) with detectors at two frequencies (Q- and W-band) with unprecedented sensitivity. The RF optics uses a classical Dragonian side-fed geometry that employs a paraboloidal main reflector illuminated by a concave hyperboloidal subreflector. The relatively large offset distance and focal length of the main reflector, and the avoidance of caustics between the two reflectors, yield relatively flat reflectors with very low cross-polarization and a wide field of view capability. The antenna is fed by either a 91-element W-band or a 19-element Q-band corrugated platelet feed horn array. The telescope is installed on the CBI platform in Chile, and data taking is underway.