Development of the ATHENA mirror

Abstract

The development of the X-ray optics for ATHENA (Advanced Telescope for High ENergy Astrophysics)[1-4], the selected second large class mission in the ESA Science Programme, is progressing further, in parallel with the payload preparation and the system level studies. The optics technology is based on the Silicon Pore Optics (SPO) [5-48], which utilises the excellent material properties of Silicon and benefits from the extensive investments made in the semiconductor industry. With its pore geometry the SPO is intrinsically very robust and permits the use of very thin mirrors while achieving good angular resolution. In consequence, the specific mass of the resultant ATHENA optics is very low compared to other technologies, and suitable to cope with the imposed environmental requirements. Further technology developments preparing the ATHENA optics are ongoing, addressing additive manufacturing of the telescope structure, the integration and alignment of the mirror assembly, numerical simulators, coating optimisations, metrology, test facilities, studies of proton reflections and meteorite impacts, etc. A detailed Technology Development Plan was elaborated and is regularly being updated, reflecting the progress and the mission evolution. The required series production and integration of the many hundred mirror modules constituting the ATHENA telescope optics is an important consideration and a leading element in the technology development. The developments are guided by ESA, implemented in industry and supported by research institutions. The many ongoing SPO technology development activities aim at demonstrating the readiness of the optics technology at the review deciding the adoption of ATHENA onto the ESA Science flight programme, currently expected for 2021. Technology readiness levels of 5/6 have to be demonstrated for all critical elements, but also the compliance to cost and schedule constraints for the mission.

Measuring the atomic scattering factors near the iridium L-edges for the Athena silicon pore optics reflector

“…Athena is expected to consist of a large aperture x-ray mirror 2 with a focal length of 12 m and a goal of an on-axis angular resolution of 5 arc sec half energy width (HEW). The focal plane contains two instruments: a wide field imager 3 and an x-ray integral field unit (X-IFU).…”

“…The large aperture telescope will be composed of ∼700 SPO modules, with each mirror module containing 70 mirror plate pairs. 2 The effective area of the Athena telescope is to be determined by summing the geometrical area times the individual reflectance of each module based on the telescope design. Specifically, to define the effective area in the high-energy region, it is necessary to ensure a suitable reflectance near the iridium Ledges.…”

The Athena space X‐ray observatory and the astrophysics of hot plasma†

“…• A single telescope based an innovative silicon pore optics technology developed in Europe (Bavdaz et al 2018), with 12-m focal length, 5 in. half energy width angular resolution, and effective area ≥1.4 m 2 at 1 keV and ≥0.25 m 2 at 6 keV.…”