CMB-S4 Technology Book, First Edition

CMB-S4 is a proposed experiment to map the polarization of the Cosmic\nMicrowave Background (CMB) to nearly the cosmic variance limit for angular\nscales that are accessible from the ground. The science goals and capabilities\nof CMB-S4 in illuminating cosmic inflation, measuring the sum of neutrino\nmasses, searching for relativistic relics in the early universe, characterizing\ndark energy and dark matter, and mapping the matter distribution in the\nuniverse have been described in the CMB-S4 Science Book. This Technology Book\nis a companion volume to the Science Book. The ambitious science goals of\nCMB-S4, a "Stage-4" experiment, require a step forward in experimental\ncapability from the current Stage=II experiments. To guide this process, we\nsummarize the current state of CMB instrumentation technology, and identify R&D\nefforts necessary to advance it for use in CMB-S4. The book focuses on\ntechnical challenges in four broad areas: Telescope Design; Receiver Optics;\nFocal-Plane Optical Coupling; and Focal-Plane Sensor and Readout.\n