The European Space Agency (ESA) is developing the Athena (Advanced Telescope for High ENergy Astrophysics) X-ray telescope, an L-class mission in their current Cosmic Vision cycle for long-term planning of space science missions. Silicon Pore Optics (SPO) are a new type of X-ray optics enabling future X-ray observatories such as Athena and are being developed at cosine with ESA as well as academic and industrial partners. These high-performance, modular, lightweight yet stiff, high-resolution X-ray optics shall allow missions to reach an unprecedentedly large effective area of several square meters, operating in the 0.2 to 12 keV band with an angular resolution better than 5 arc seconds. As the development of Athena mission progresses, it is necessary to validate the SPO technology under launch conditions. To this end, ruggedisation and environmental testing studies are being conducted to ensure mechanical stability and optical performance of the optics before, during and after launch. At cosine, a facility with shock, vibration, tensile strength, long time storage and thermal testing equipment has been set up to test SPO mirror module components for compliance with the upcoming Ariane launch vehicle and the mission requirements. In this paper, we report on the progress of our ongoing investigations regarding tests on mechanical and thermal stability of mirror module components such as single SPO stacks complete mirror modules of inner (R = 250 mm), middle (R = 737 mm) and outer (R = 1500 mm) radii.
Silicon Pore Optics (SPO) uses commercially available monocrystalline double-sided super-polished silicon wafers as a basis to produce mirrors that form lightweight and stiff high-resolution x-ray optics. The technology has been invented by cosine and the European Space Agency (ESA) and developed together with scientific and industrial partners to mass production levels. SPO is an enabling element for large space-based x-ray telescopes such as Athena and ARCUS, operating in the 0.2 to 12 keV band, with angular resolution requirements up to 5 arc seconds. SPO has also shown to be a versatile technology that can be further developed for gamma-ray optics, medical applications and for material research. This paper will summarise the status of the technology and of the mass production capabilities, show latest performance results and discuss the next steps in the development.
Silicon Pore Optic (SPO) is the X-ray mirror technology selected for the Athena X-ray observatory. The optic is modular; in the current design, it is made of about 700 co-aligned mirror modules. SPO is produced as stacks of 35 mirror plates, which are then paired to form X-ray Optics Units (XOUs) following a modified Wolter I geometry. A mirror module is composed of two confocal XOUs bonded in between a pair of brackets allowing interfacing to the mirror structure. Mirror modules are assembled using the XPBF 2.0 beamline of PTB at the synchrotron radiation facility BESSY II, using pencil beam and dedicated jigs. In this paper we present the challenges and solutions related to making confocal mirror modules.
Silicon Pore Optics is the X-ray mirror technology selected for the European Space Agency's Athena X-ray observatory. We describe the X-ray testing and characterization cycle that the optics are subjected to at the PTB's X-ray Pencil/Paraller Beam Facility (XPBF) 1 and 2 beamlines at the synchrotron radiation facility BESSY II. Individual stacks are measured with a pencil beam to determine their optical quality and the orientation of the optical axis. Using metrics based on X-ray and manufacturing metrology, stacks are then paired in primary-secondary Wolter-I-like systems, that are in turn characterized to determine their optical performance. Finally, four stacks, two primaries and two secondaries, are assembled into a mirror module, that is also characterized, with pencil and wide X-ray beams. At each step models, metrology, and software are combined to arrive at the relevant parameters. We describe the methods used, and illustrate how the performance of imaging pairs can be described in terms of stack-level parameters.