To enhance x-ray reflectivity of silicon micropore optics using dry etching of silicon (111) wafers, iridium coating is tested by use of atomic layer deposition. An iridium layer is successfully formed on sidewalls of tiny micropores with a pore width of 20 μm and depth of 300 μm. The film thickness is ∼20  nm. An enhanced x-ray reflectivity compared to that of silicon is confirmed at Ti K_α 4.51 keV, for what we believe to be the first time, with this type of optics. Some discrepancies from a theoretical reflectivity curve of iridium-coated silicon are noticed at small incident angles <1.3°. When a geometrical shadowing effect due to occultation by a ridge existing on the sidewalls is taken into account, the observed reflectivity becomes well represented by the modified theoretical curve. An estimated surface micro roughness of ∼1  nm rms is consistent with atomic force microscope measurements of the sidewalls.

Large-aperture focusing of Al K(α) 1.49 keV x-ray photons using micropore optics made from a dry-etched 4 in. (100 mm) silicon wafer is demonstrated. Sidewalls of the micropores are smoothed with high-temperature annealing to work as x-ray mirrors. The wafer is bent to a spherical shape to collect parallel x rays into a focus. Our result supports that this new type of optics allows for the manufacturing of ultralight-weight and high-performance x-ray imaging optics with large apertures at low cost.

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be a new probe to investigate chemical compositions of planetary atmospheres, surfaces of planets, moons or asteroids and high energy particles in planetary magnetospheres. A potential future Japanese exploration to Jupiter needs a light-weight (<10 kg) X-ray imager in order to capture X-ray auroras from Jupiter . However, limited resources, i.e., mass, power, size, have hindered exploration satellites from carrying a good angular resolution and large effective area X-ray telescope.Wolter type-I telescopes have been widely used in X-ray astronomy. X-rays are doubly reflected upon paraboloid and hyperboloid mirrors, to minimize aberrations (Wolter 1952). A few to hundreds of mirrors are conically nested to increase the effective area. Each mirror is fabricated individually with either polishing of thick mirror substrates, replication of precisely fabricated mandrels, or thermal forming of thin aluminum foils. However, these mirrors have to be heavy when a high angular resolution is sought for Bavdaz et al. (2004). Furthermore, the lightest aluminum foil mirror approximates ideal mirror surfaces with cones, which degrades the angular resolution to 10 arcmin under a short focal length less than 1 m. Therefore, a new mirror fabrication technology is needed for future X-ray astronomy missions as well as planetary explorations.A possible solution is micropore optics (Frazer 1997). Sidewalls of micro pores whose width is typically of the order of 10 to 100 µm are used for X-ray mirrors. The mirror thickness can be extremely thin, of the order of 100 µm to 10 mm. The micropore optics can thus be ultralight weight. Three types of micropore optics are proposed and being developed.The first type is silicon pore optics (SPO) (Bavdaz et al. 2004(Bavdaz et al. , 2010 which is composed of flat silicon wafers with groove structures as mirrors. The wafers are stacked and elastically bent into a conical shape. This type is being developed aiming at an angular resolution of ∼10 arcsec for the future gigantic X-ray astronomy satellite Athena. 1 1 http://www.the-athena-x-ray-observatory.eu.Abstract A light-weight Wolter type-I telescope for future space X-ray observations is prototyped by using micromachining technologies. Curvilinear micro pores with a width of 20 µ m are fabricated with deep reactive ion etching. Sidewalls of the pores are smoothed with high temperature annealing. Then, two wafers are deformed to different curvature radii, 1000 and 333 mm. The two wafers are aligned using parallel X-ray beams which are dominated by Al-K α line at 1.49 keV. High angular and positional accuracies of the order of arcsec and µm are achieved using movable stages. The first clear X-ray focusing is confirmed. Its angular resolution is 4.1 arcmin in full width half maximum while it is at least 92 arcmin in half power width. The effective area is 19.0 mm 2 which is ∼5 times smaller than a model calculation. We discuss causes of the degraded angular resolution and effective area and also future improvements.

Our development of ultra light-weight X-ray micro pore optics based on MEMS (Micro Electro Mechanical System) technologies is described. Using dry etching or X-ray lithography and electroplating, curvilinear sidewalls through a flat wafer are fabricated. Sidewalls vertical to the wafer surface are smoothed by use of high temperature annealing and/or magnetic field assisted finishing to work as X-ray mirrors. The wafer is then deformed to a spherical shape. When two spherical wafers with different radii of curvature are stacked, the combined system will be an approximated Wolter type-I telescope. This method in principle allows high angular resolution and ultra light-weight X-ray micro pore optics. In this paper, performance of a single-stage optic, coating of a heavy metal on sidewalls with atomic layer deposition, and assembly of a Wolter type-I telescope are reported.