The Infrared Camera (IRC) for AKARI–Design and Imaging Performance

Abstract The Infrared Camera (IRC) is one of two focal-plane instruments on the AKARI satellite. It is designed for wide-field deep imaging and low-resolution spectroscopy in the near–to mid-infrared (1.8–26.5$\mu$m) in the pointed observation mode of AKARI. The IRC is also operated in the survey mode to make an All-Sky Survey at 9 and 18$\mu$m. It comprises three channels. The NIR channel (1.8–5.5$\mu$m) employs a 512 $\times$ 412 InSb array, whereas both the MIR-S (4.6–13.4$\mu$m) and MIR-L (12.6–26.5$\mu$m) channels use 256 $\times$ 256 Si:As impurity band conduction arrays. Each of the three channels has a field-of-view of about $10^\prime \times 10^\prime$, and they are operated simultaneously. The NIR and MIR-S share the same field-of-view by virtue of a beam splitter. The MIR-L observes the sky about 25$^\prime$ away from the NIR/MIR-S field-of-view. The IRC gives us deep insights into the formation and evolution of galaxies, the evolution of planetary disks, the process of star-formation, the properties of interstellar matter under various physical conditions, and the nature and evolution of solar system objects. The in-flight performance of the IRC has been confirmed to be in agreement with the pre-flight expectation. This paper summarizes the design and the in-flight operation and imaging performance of the IRC.