Development and Construction of the Cosmic Background Imager

本项目支持宇宙背景成像仪（Cosmic Background Imager， CBI）的研制和建设，用于研究2′-20′角尺度上的宇宙微波背景辐射，灵敏度Trms/T = 2 × 10-6。CBI是一种工作频率为28 GHz - 36 GHz的四元干涉仪。每个单元都有三个主反射镜，大小分别为0.75 m， 1.5 m和3m，将根据要成像的角度尺度选择。该仪器在一个16米× 16米的“光学工作台”上运行，元件可以被放置在各种各样的配置中。中频和本振信号通过光纤传输。CBI将拍摄宇宙微波背景辐射的图像，从而能够确定2 × 1012太阳质量到2 × 1015太阳质量范围内的质量波动谱。这将为宇宙结构形成的理论提供基础，并可能在早期宇宙中的量子涨落与已知的最大结构之间提供联系。此外，CBI将能够对星系团中的Sunyaev-Zel'dovich效应进行观测，并将允许我们在与高分辨率x射线观测相结合时对星系团中的热气体进行详细研究。CBI还将成为研究漫射星系前景辐射的工具。＊＊＊

9413935 Readhead This project supports the development and construction of a research instrument -- the Cosmic Background Imager (CBI) -- to study the cosmic microwave background radiation on angular scales from 2'-20' with sensitivity Trms/T = 2 x 10-6. The CBI is a four element interferometer operating at 28 GHz - 36 GHz. Each element has a complement of three primary reflectors, of sizes 0.75 m, 1.5 m and 3 m, which will be selected according to the angular scale to be imaged. The instrument operates on a 16 m x 16 m "optical bench" on which the elements can be placed in a wide variety of configurations. The intermediate frequency and local oscillator signals are distributed via optical fibres. The CBI will make images of the cosmic microwave background radiation and hence enable determination of the spectrum of mass fluctuations on scales of 2 x 1012 solar mass to 2 x 1015 solar mass. This will provide foundation for theories of the formation of structure in the universe, and could provide a link between quantum fluctuations in the very early universe and the largest structures known. In addition, the CBI will be capable of making observations of the Sunyaev-Zel'dovich effect in clusters of galaxies, and will allow us to carry out detailed studies of the hot gas in clusters when used in combination with high resolution X-ray observations. The CBI will also be a tool for the study of diffuse galactic foreground emission. ***