OVERVIEW OF THE ATACAMA COSMOLOGY TELESCOPE: RECEIVER, INSTRUMENTATION, AND TELESCOPE SYSTEMS

TLDR

The Atacama Cosmology Telescope was built to measure small‑scale anisotropies in the Cosmic Microwave Background and to detect galaxy clusters via the Sunyaev‑Zel'dovich effect. It sits on Cerro Toco at 5190 m, uses a six‑meter off‑axis Gregorian telescope feeding a cryogenic Millimeter Bolometer Array Camera that houses three 1000‑element transition‑edge sensor arrays operating at 148, 218, and 277 GHz, each with a ~22′×26′ field of view. Commissioned in 2007, the telescope has completed three years of operations and its performance has been summarized in the paper.

Abstract

The Atacama Cosmology Telescope was designed to measure small-scale anisotropies in the Cosmic Microwave Background and detect galaxy clusters through the Sunyaev-Zel'dovich effect. The instrument is located on Cerro Toco in the Atacama Desert, at an altitude of 5190 meters. A six-meter off-axis Gregorian telescope feeds a new type of cryogenic receiver, the Millimeter Bolometer Array Camera. The receiver features three 1000-element arrays of transition-edge sensor bolometers for observations at 148 GHz, 218 GHz, and 277 GHz. Each detector array is fed by free space mm-wave optics. Each frequency band has a field of view of approximately 22' x 26'. The telescope was commissioned in 2007 and has completed its third year of operations. We discuss the major components of the telescope, camera, and related systems, and summarize the instrument performance.