为了普查缺失的重子，理解星系吸积和反馈对星系演化的影响，需要对近邻宇宙中星系际介质和邻近星系的紫外OVI和HI Lyα发射线成像，所覆盖的波长为1020－1080Å 和 1240-1300 Å。这个紫外窗口在科学上非常独特和重要。纵观空间天体物理现状和未来发展，现在也是这个空间窗口最好的研究时机。基于申请人组织的科学和技术团队所提出的小型紫外空间项目（CAFE），申请人在这个天文联合重点基金项目申请中将完备这个小卫星窄带成像仪（OVI 和HI Lyα）的光学设计和优化，并进行国际评估；此外完成HI Lyα窄带成像仪原理样机的研制(其中MCP探测器将由国际合作伙伴德国提供），并完成样机实验室检验。

In order to make a complete census of warm-hot intergalactic medium (WHIM) where is the missing baryons, understanding one of the fundamental astrophysical topics, that is, how accretion and feedback affect the galaxy evolution, we have proposed a small space UV mission (CAFE, stands for Census of WHIM, Accretion, and Feedback Explorer) for the mapping of UV line emission of highly ionized oxygen (OVI) and neutral hydrogen (HI Ly α) from the Intergalactic Medium(IGM) and nearby galaxies. There is unique and groundbreaking science to be done in this field. It is a great opportunity at present to develop techniques for such a small mission. Based on two-years investigations for CAFE, we now propose to complete the optics design for two imagers, and make assessment internationally. In addition, we will make a prototype for HI Lyα imager with MCP and possible testing offered by German collaborators .