The purpose of Science Book is to set the scientific goals for CMB-S4 and specify the measurements needed to achieve them, which will then be translated into the instrument requirements. This will set the stage for defining the instrument.

This Science Book is the product of a large, global community of scientists who are united in support of proceeding with CMB-S4, which will make key advances in our understanding of the fundamental nature of space and time and the evolution of the Universe.Read more

CMB-S4 is a proposed experiment to map the polarization of the Cosmic Microwave Background (CMB) to nearly the cosmic variance limit for the angular scales that are accessible from the ground. The science goals and capabilities of CMB-S4 in illuminating cosmic inflation, measuring the sum of neutrino masses, searching for relativistic relics in the early universe, characterizing dark energy and dark matter, and mapping the matter distribution in the universe have been described in the CMB-S4 Science Book. This Technology Book is a companion volume to the Science Book. The ambitious science goals of the proposed "Stage-IV" CMB-S4 will require a step forward in experimental capability from the current Stage-III experiments. To guide this process, the community summarized the current state of the technology and identify R&D efforts necessary to advance it for possible use in CMB-S4. The book focused on the technical challenges in four broad areas: Telescope Design; Receiver Optics; Focal-Plane Optical Coupling; and Focal-Plane Sensor and Readout.Read more