Silicon Pore Optics is the optic technology selected for the production of the hundreds of mirror modules that will comprise the European Space Agency’s NewAthena X-ray mirror assembly. Each mirror module starts from pristine silicon wafers that are taken through many physical, mechanical and chemical steps to produce the about 160 individual mirror plates that are needed for its construction. At each step in the production chain, data are used to tune the details of each process, and new data are collected to assess the quality of the output. In this paper we describe how the different pieces of data that become available during the production of the optics are brought together in a system of data bases and software pipelines that is meant to serve both the scientific and the production quality needs associated with such a large effort. A few examples will be described to illustrate the current status of these efforts.
The European Space Agency (ESA), cosine and its partners have been developing for 20 years the Silicon Pore Optics (SPO) technology. SPO enables the next generation of space x-ray telescopes, with increased sensitivity and resolution. NewAthena, the New Advanced Telescope for High Energy Astrophysics, has just been endorsed by ESA as one of its Lclass mission, to launch around 2037. NewAthena’s optic is modular and consists of up to 600 mirror modules that form together a ~2.5 m diameter X-ray mirror with a focal length of 12 m and an angular resolution of 9 arc-seconds half-energy width. The total polished mirror surface is ~300 m2, which will focus X-rays with an energy of about 0.3 – 10 keV onto two detectors, a wild-field imager (WFI) and an imaging spectrometer (XIFU). Building hundreds of such SPO mirror modules in a cost-efficient and timely manner is a formidable task and subject of a dedicated ESA technology development program.
We present in this paper the status of the optics production and illustrate not only recent X-ray results but also the progress made on the environmental testing, manufacturing and assembly aspects of SPO based optics.
Silicon Pore Optics (SPO) have been invented and developed to enable x-ray optics for space applications that require a combination of high angular resolution while being light-weight to allow achieving a large mirror surface area. In 2005, the SPO technology development was initiated by the European Space Agency (ESA) for a flagship x-ray telescope mission and is currently being planned as a baseline for the NewATHENA mission scheduled for launch in the 2030s. Its more than 2m diameter mirror will be segmented and comprises of 492 individual Silicon Pore Optics (SPO) grazing-angle imagers, called mirror modules. Arranged in concentric annuli and following a Wolter-Schwartzschild design, the mirror modules are made of several tens of primary-secondary mirror pairs, each mirror made of silicon, coated to increase the collective area of the system, and shaped to bring the incoming photons to a common focus in 12 m distance. The mission aims to deliver an angular resolution of better than nine arc-seconds (Half-energy width) and effective area of about 1.1 m2 at an energy of 1 keV. We present in this paper the status of the optics production and illustrate not only recent x-ray results but also the progress made on the environmental testing, manufacturing and assembly aspects of SPO based optics.
Athena is the European Space Agency’s next flagship telescope, scheduled for launch in the 2030s. Its 2.5 m diameter mirror will be segmented and comprise more than 600 individual Silicon Pore Optics (SPO) mirror modules. Arranged in concentric annuli and following a Wolter-Schwartzschild design, the mirror modules are made of several tens of grazing incidence primary-secondary mirror pairs, each mirror made of silicon, coated to increase the effective area of the system, and shaped to bring the incoming photons to a common focus 12 m away. The mission aims to deliver a half-energy width of 5" and an effective area of about 1.4 m2 at 1 keV. We present the status of the optics technology, and illustrate recent X-ray results and the progress made on the environmental testing, manufacturing and assembly aspects of the optics.
Athena is the European Space Agency’s next flagship x-ray telescope, scheduled for launch in the 2030s. Its 2.5-m diameter mirror will be segmented and comprise more than 600 individual Silicon Pore Optics (SPO) grazing-incidence-angle imagers, called mirror modules. Arranged in concentric annuli and following a Wolter-Schwartzschild design, the mirror modules are made of several tens of primary-secondary mirror pairs, each mirror made of mono-crystalline silicon, coated to increase the collective area of the system, and shaped to bring the incoming photons to a common focus 12 m away. Aiming to deliver a half-energy width of 5”, and an effective area of about 1.4 m2 at 1 keV, the Athena mirror requires several hundred m2 of super-polished surfaces with a roughness of about 0.3 nm and a thickness of just 110 µm. SPO, using the highest-grade double-side polished 300 mm wafers commercially available, were invented for this purpose and have been consistently developed over the last several years to enable next-generation x-ray telescopes like Athena. SPO makes it possible to manufacture cost-effective, high-resolution, large-area x-ray optics by using all the advantages that mono-crystalline silicon and the mass production processes of the semiconductor industry provide. Ahead of important programmatic milestones for Athena, we present the status of the technology, and illustrate not only recent x-ray results but also the progress made on the environmental testing, manufacturing and assembly aspects of the technology.
The mirror modules composing Athena’s X-ray optics are made with the Silicon Pore Optics (SPO) technology.
SPO is produced as stacks of 38 mirror plates, which are paired to form X-ray Optics Units (XOUs) following a
modified Wolter I geometry. In the current design, a mirror module is composed of two confocal XOUs glued in
between a pair of brackets that freeze the configuration and provide interfaces to the mirror structure. Mirror
modules are assembled at the XPBF2 beamline of PTB at the synchrotron radiation facility BESSY II, using
dedicated jigs. In this paper we present the latest developments regarding the assembly of confocal mirror
modules for Athena with an emphasis on alignment tolerances and gluing accuracy.
The Silicon Pore Optics (SPO) technology has been established as a new type of X-ray optics and will enable future X-ray observatories such as Athena and Arcus. SPO is being developed at cosine Research B.V. together with the European Space Agency (ESA) and academic as well as industrial partners. For Athena, about 150,000 mirror plates are required. With the technology spin-in from the semiconductor industry, mass production processes can be employed to manufacture rectangular SPO mirror plates in high quality, large quantity and at low cost. Over the last years, several aspects of the SPO mirror plates have been reviewed and undergone further developments in terms of effective area, intrinsic behavior of the mirror plates and mass production capability. The paper will provide an overview of most recent SPO plate designs, mirror plate production status and plan forward including reflective coating process as well as mass production developments.
Athena, the largest space-based x-ray telescope to be flown by the European Space Agency, uses a new modular technology to assemble its 2.5 m diameter lens. The lens will consist of several hundreds of smaller x-ray lenslets, called mirror modules, which each consist of up to 76 stacked mirror pairs. Those mirror modules are arranged in circles in a large optics structure and will focus x-ray photons with an energy of 0.5 to 10 keV at a distance of 12 m onto the detectors of Athena. The point-spread function (PSF) of the optic shall achieve a half-energy width (HEW) of 5” at an energy of 1 keV, with an effective area of about 1.4 m2, corresponding to several hundred m2 of super-polished mirrors with a roughness of about 0.3 nm and a thickness of down to 110 µm. This paper will present the status of the technology and of the mass production capabilities, show latest performance results and discuss the next steps in the development.
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 unprecedented combination of large effective area, good angular resolution and low mass. As the development of the 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. In this paper, we report on the results of our completed environmental testing campaigns on mirror modules of middle radius (about 700 mm) of curvature. In these campaigns, each mirror module is first integrated then submitted to sine and random vibration tests, as well as shock tests, all in accordance with the upcoming Ariane launch vehicle and the mission requirements. Additionally, the mirror modules are characterized with X-ray before and after each test to verify the optical performance remains unchanged.
Athena, the largest space-based x-ray telescope to be flown by the European Space Agency, uses a revolutionary new modular technology to assemble its 2.6 m diameter lens. The lens will consist of several hundreds of smaller x-ray lenslets, called mirror modules, which each consist of about 70 mirror pairs. Those mirror modules are arranged in circles in a large optics structure and will focus x-ray photons with an energy of 0.5 to 10 keV at a distance of 12 m onto the detectors of Athena. The point-spread function (PSF) of the optic shall achieve a half-energy width (HEW) of 5” at an energy of 1 keV, with an effective area of about 1.4 m2, corresponding to several hundred m2 of super-polished mirrors with a roughness of about 0.3 nm and a thickness of only 150 µm. Silicon Pore Optics (SPO), using the highest grade double-side polished 300 mm wafers commercially available, have been invented to enable such telescopes. SPO allows the cost-effective production of high-resolution, large area, x-ray optics, by using all the advantages that mono-crystalline silicon and the mass production processes of the semi-conductor industry provide. 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 present the status of the technology and of the mass production capabilities, show latest performance results and discuss the next steps in the development.
The X-ray parallel beam facility XPBF 2.0 in the laboratory of the Physikalisch-Technische Bundesanstalt at the synchrotron radiation facility BESSY II provides a parallel beam of very low divergence, and adjustable beam sizes between about 100 μm and at least 5 mm. Further, XPBF 2.0 is equipped with a vacuum chamber with a hexapod system for accurate positioning of all silicon pore optic (SPO) sizes to be investigated, and a vertically movable CCD-based camera system to register the direct and the reflected beam at a sample to CCD distance of 12 m corresponding to the envisaged focal length of ATHENA (Advanced Telescope for High ENergy Astrophysics). Since its installation in 2016, the beamline has been constantly upgraded to improve performance and implementing the changing requirements. To accurately and constantly measure the 12 m distance, between the center of the sample (i.e. mirror module) and the CCD detector, a laser-tracker has been installed. Additionally, the cleanroom, housing the vacuum chamber, was upgraded with a cooling unit keeping the temperature at 20°C. The original phosphor screen in front of the CCD has been replaced with a new phosphor screen with different grain size and material. The next upgrade of the XPBF 2.0 is the installation of a new monochromator mirror to operate the beamline at 1.0 keV instead of 1.6 keV. This paper will present the upgrades of the X-ray parallel beam facility XPBF 2.0 and discuss next steps for characterizing SPOs with synchrotron radiation.
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.
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