Development of four-stage X-ray telescope for wide field fine spectroscopic mission

We are developing the new type of X-ray telescope with short focal length for small satellite to perform the fine spectroscopic study of diffuse soft X-rays with very low surface brightness. Point of the design of such system is to use four-stage reflection to reduce focal length. For this purpose, techniques developed for the fabrication of high throughput X-ray telescope for ASTRO-E/E2 satellite can be applied. Though the energy range is restricted below 1 keV, a combination with X- ray micro-calorimeter can provide us powerful tool for the study such as the detection of warm-hot intergalactic medium with the temperature of several millions degree, which should exist in the peripheral region around clusters of galaxies. We will report on the the design of such system, results of performance estimation by ray tracing program.