Ultra high throughput four-reflection x-ray telescope for high resolution spectroscopy

The first application of four-times reflection X-ray optics is planned for the DIOS mission, in which very soft X-ray observation is expected. On the other hand, effective area of the telescope for higher X-ray energy (E 2 for assumed several meter focal length. However, if we introduce four-reflection optics to this energy range, we can get several times large effective area for single telescope with same several meter focal length. To prove this possibility, we performed ray tracing simulation for four-reflection telescope with 6 m focal length and found that effective area of 3100 cm 2 at 6 keV can be obtained for single telescope. In this paper, we will discuss about other telescope performances, mechanical properties and application to fine spectroscopic mission using X-ray micro-calorimeter.