X-Ray Pore Optics Technologies and Their Application in Space Telescopes

Abstract

Silicon Pore Optics (SPO) is a new X-ray optics technology under development in Europe, forming the ESA baseline technology for the International X-ray Observatory candidate mission studied jointly by ESA, NASA, and JAXA. With its matrix-like structure, made of monocrystalline-bonded Silicon mirrors, it can achieve the required angular resolution and low mass density required for future large X-ray observatories. Glass-based Micro Pore Optics (MPO) achieve modest angular resolution compared to SPO, but are even lighter and have achieved sufficient maturity level to be accepted as the X-ray optic technology for instruments on board the Bepi-Colombo mission, due to visit the planet Mercury. Opportunities for technology transfer to ground-based applications include material science, security and scanning equipment, and medical diagnostics. Pore X-ray optics combine high performance with modularity and economic industrial production processes, ensuring cost effective implementation.

The mirror module design for the cryogenic x-ray imaging spectrometer on-board ORIGIN

“…For our application we have to stack shorter wafers with an inner bending radius of 0.3 m. The smaller bending radius has been studied by finite element modeling and has been demonstrated by bending and bonding of two mirror plates with this radius (Cosine Research (NL) private communication). An angular resolution (HEW) < 20" has been repeatedly demonstrated by X-ray pencil beam measurements performed at PTB in Berlin for a set up to 45 plates of an IXO mirror module, mounted in representative flight configuration [10] [13]. These results indicate that in the case of ORIGIN, the 30″ HEW requirement on-axis, being dominated by the conical approximation to the Wolter-I optics, is achievable.…”

“…The scientific requirement of an angular resolution of 30" HEW on-axis can be achieved using a conical approximation to the Wolter-I geometry for the outer mirror module, where the replication of Wolter-I mandrels has not yet been fully developed although it has been considered within the IXO development program [10]. The inner mirror module has been designed according to the Wolter-I geometry since its implementation with the Ni electroforming technology is mature and has already been proven in space.…”

X-ray telescope mirrors made of slumped glass sheets

“…2 describes a complete telescope system made of slumped glass sheets [8], meeting the requirements for the future X-ray telescope ATHENA which has recently been selected by ESA as the next large mission to be launched in 2028 [4]. The current baseline for ATHENA is the silicon pore optics (SPO) [9], based on thin silicon wafers with an etched structure on one side. The wafers are bonded together to form an approximation of a Wolter-I profile and the radiation travels through the etched spaced, the pores, to the focal plane.…”

Silicon pore optics for future x-ray telescopes

“…The details of manufacturing the mirror plates, the coating process and the robotic stacking can be found elsewhere [4,5,6], this paper concentrates on presenting the currently achieved optical performances, the environmental qualification status and some recent updates of the robotic stacking tools, the SPO mirror module design and X-ray beamlines.…”