Future soft x-ray (10 to 50 Å) spectroscopy missions require higher effective areas and resolutions to perform critical science that cannot be done by instruments on current missions. An x-ray grating spectrometer employing off-plane reflection gratings would be capable of meeting these performance criteria. Off-plane gratings with blazed groove facets operating in the Littrow mounting can be used to achieve excellent throughput into orders achieving high resolutions. We have fabricated two off-plane gratings with blazed groove profiles via a technique that uses commonly available microfabrication processes, is easily scaled for mass production, and yields gratings customized for a given mission architecture. Both fabricated gratings were tested in the Littrow mounting at the Max Planck Institute for Extraterrestrial Physics (MPE) PANTER x-ray test facility to assess their performance. The line spread functions of diffracted orders were measured, and a maximum resolution of 800±20 is reported. In addition, we also observe evidence of a blaze effect from measurements of relative efficiencies of the diffracted orders.
An x-ray spectrograph consisting of aligned, radially ruled off-plane reflection gratings and silicon pore optics (SPO) was tested at the Max Planck Institute for Extraterrestrial Physics PANTER x-ray test facility. SPO is a test module for the proposed Arcus mission, which will also feature aligned off-plane reflection gratings. This test is the first time two off-plane gratings were actively aligned to each other and with an SPO to produce an overlapped spectrum. We report the performance of the complete spectrograph utilizing the aligned gratings module and plans for future development.
Athena (Advanced Telescope for High Energy Astrophysics) is an x-ray observatory using a Silicon Pore Optics
telescope and was selected as ESA’s second L-class science mission for a launch in 2028. The x-ray telescope consists of
several hundreds of mirror modules distributed over about 15-20 radial rings. The radius of curvature and the module
sizes vary among the different radial positions of the rings resulting in different technical challenges for mirror modules
for inner and outer radii.
We present first results of demonstrating Silicon Pore Optics for the extreme radial positions of the Athena telescope.
For the inner most radii (0.25 m) a new mirror plate design is shown which overcomes the challenges of larger
curvatures, higher stress values and bigger plates. Preliminary designs for the mounting system and its mechanical
properties are discussed for mirror modules covering all other radial positions up to the most outer radius of the Athena
An X-ray spectrograph consisting of aligned, radially ruled off-plane reflection gratings and silicon pore optics (SPO) was tested at the Max Planck Institute for extraterrestrial Physics PANTER X-ray test facility. The SPO is a test module for the proposed Arcus mission, which will also feature aligned off-plane reflection gratings. This test is the first time two off-plane gratings were actively aligned to each other and with a SPO to produce an overlapped spectrum. We report the performance of the complete spectrograph utilizing the aligned gratings module and plans for future development.
Silicon Pore Optics, after 10 years of development, forms now the basis for future large (L) class astrophysics Xray observatories, such as the ATHENA mission to study the hot and energetic universe, matching the L2 science theme recently selected by ESA for launch in 2028. The scientific requirements result in an optical design that demands high angular resolution (5“) and large effective area (2 m2 at a few keV) of an X-ray lens with a focal length of 12 to14 m. Silicon Pore Optics was initially based on long (25 to 50 m) focal length telescope designs, which could achieve several arc second angular resolution by curving the silicon mirror in only one direction (conical approximation). With the advent of shorter focal length missions we started to develop mirrors having a secondary curvature, allowing the production of Wolter-I type optics, which are on axis aberration-free. In this paper we will present the new manufacturing process, discuss the impact of the ATHENA optics design on the technology development and present the results of the latest X-ray test campaigns.
We present the design and scientific motivation for Arcus, an X-ray grating spectrometer mission to be deployed on the International Space Station. This mission will observe structure formation at and beyond the edges of clusters and galaxies, feedback from supermassive black holes, the structure of the interstellar medium and the formation and evolution of stars. The mission requirements will be R>2500 and >600 cm2 of effective area at the crucial O VII and O VIII lines, values similar to the goals of the IXO X-ray Grating Spectrometer. The full bandpass will range from 8-52Å (0.25-1.5 keV), with an overall minimum resolution of 1300 and effective area >150 cm2. We will use the silicon pore optics developed at cosine Research and proposed for ESA’s Athena mission, paired with off-plane gratings being developed at the University of Iowa and combined with MIT/Lincoln Labs CCDs. This mission achieves key science goals of the New Worlds, New Horizons Decadal survey while making effective use of the International Space Station (ISS).
Silicon Pore Optics (SPO) are the enabling technology for ESA’s second large class mission in the Cosmic Vision programme. As for every space hardware, a critical qualification process is required to verify the suitability of the SPO mirror modules surviving the launch loads and maintaining their performance in the space environment. We present recent design modifications to further strengthen the mounting system (brackets and dowel pins) against mechanical loads. The progress of a formal qualification test campaign with the new mirror module design is shown. We discuss mechanical and thermal limitations of the SPO technology and provide recommendations for the mission design of the next X-ray Space Observatory.
With the selection of “The hot and energetic Universe” as science theme for ESA's second large class mission (L2) in the Cosmic Vision programme, work is focusing on the technology preparation for an advanced X-ray observatory. The core enabling technology for the high performance mirror is the Silicon Pore Optics (SPO) [1 to 23], a modular X-ray optics technology, which utilises processes and equipment developed for the semiconductor industry. The paper provides an overview of the programmatic background, the status of SPO technology and gives an outline of the development roadmap and activities undertaken and planned by ESA on optics, coatings [24 to 30] and test facilities [31, 33].
The science requirements for the Athena X-ray mirror are to provide a collecting area of 2 m2 at 1 keV, an angular resolution of ~5 arc seconds half energy eidth (HEW) and a field of view of diameter 40-50 arc minutes. This combination of area and angular resolution over a wide field are possible because of unique features of the Silicon pore optics (SPO) technology used. Here we describe the optimization and modifications of the SPO technology required to achieve the Athena mirror specification and demonstrate how the optical design of the mirror system impacts on the scientific performance of Athena.
The characterization of large aperture (> 2 meters), long focal length (> 10 meters) X-ray mirrors for X-ray astronomy with synchrotron radiation poses signi cant problems related to the available space at synchrotron radiation facilities. Intrafocal pencil beam characterization of part of the optics is advantageous if its results can be shown to have predictive capabilities with respect to the full system.
In this paper we present the routine characterization of silicon pore optics at the X-ray Pencil Beam Facility of the Physikalisch-Technische Bundesanstalt, located at the synchrotron radiation facility BESSY II (Berlin, Germany). In particular we show how measurements taken in the standard beamline con guration (detector at ve meters from the optics) can e ectively be used to predict the optical performance of the optics at their design focal length by comparing data taken on 20-meter focal length Silicon Pore Optics unit in the 20-meter beamline con guration (available only for a few weeks every year) with extrapolated 5-meter measurements.
Silicon Pore Optics is an enabling technology for future L- and M-class astrophysics X-ray missions, which require high angular resolution (~5 arc seconds) and large effective area (1 to 2 m2 at a few keV). The technology exploits the high-quality of super-polished 300 mm silicon wafers and the associated industrial mass production processes, which are readily available in the semiconductor industry. The plan-parallel wafers have a surface roughness better than 0.1 nm rms and are diced, structured, wedged, coated, bent and stacked to form modular Silicon Pore Optics, which can be grouped into a larger optic. The modules are assembled from silicon alone, with all the mechanical advantages, and form an intrinsically stiff pore structure.
The optics design was initially based on long (25 to 50 m) focal length X-ray telescopes, which could achieve several arc second angular resolution by curving the silicon mirror in only one direction (conical approximation).
Recently shorter focal length missions (10 to 20 m) have been discussed, for which we started to develop Silicon Pore Optics having a secondary curvature in the mirror, allowing the production of Wolter-I type optics, which are on axis aberration-free.
In this paper we will present the new manufacturing process, the results achieved and the lessons learned.
Future large X-ray observatories in space will require mirrors with large effective areas and long focal lengths to
accomplish the proposed science. ESA programs for developing lightweight optics based on modules of silicon pore
optics (SPO) and slumped glass optics (SGO) were put in place for the IXO mission (f=20m, r≈1m). To test such optics
the MPE PANTER X-ray test facility has been upgraded / extended with support from ESA to accommodate in-focus
measurements of such optics modules. We describe the extension to PANTER and the first results obtained from
measuring such SPO and SGO modules during commissioning.
Silicon Pore Optics (SPO) provide a high angular resolution with a low areal density as required for future X-ray telescopes for high energy astrophysics. We present progress in two areas of ESA’s SPO development activities: Stray light baffling and environmental qualification.
Residual stray light originating from off-axis sources or the sky background can be blocked by placing suitable baffles in front of the mirror modules. We developed two different mechanical implementations. The first uses longer, tapered mirror plates which improve the stray light rejection without the need of mounting additional parts to the modules or the telescope. The second method is based on placing a sieve plate in front of the optics. We compare both methods in terms of baffling performance using ray-tracing simulations and present test results of prototype mirror modules.
Any optics for space telescopes needs to be compliant with the harsh conditions of the launch and in-orbit operation. We present new work in improving the mechanical and thermal ruggedness of SPO mirror modules and show recent results of qualification level tests, including tests of modules with externally mounted sieve plate baffles.
Cosine has developed the technology to bend and directly bond Si mirror plates in order to produce stiff, lightweight Xray optics which are used for large area space based X-ray telescopes. This technology, Silicon Pore Optics (SPO), also allows us to produce other types of high energy optics. Here we present the latest developments in the design and manufacture of a new generation of soft gamma-ray Laue lenses made using SPO technology named Silicon Laue lens Components: SiLC.
The bending and bonding of 300 μm thin Si single crystals allows us to fabricate a single crystal with radially curved crystal planes, which strongly improves the focusing properties of a Laue lens. The size of the focal spot is no longer determined by the size of the individual single crystals, but by the accuracy of the applied curvature, which is as low as a few seconds of arc. Furthermore, a wedge is incorporated in each individual Si crystal to ensure that all crystals are confocal in the radial direction. A secondary curvature in the axial direction can be used to improve the reflectivity of each crystal, and increase the reflected energy bandwidth.
We present the first SiLC crystals which will be manufactured in the fall of 2013. These are technology demonstrators designed for 125 keV radiation, 3.4m focal length and 600mm2 frontal area. The first measurements at synchrotron radiation facilities are planned for November 2013. With these first prototype lenses we want to demonstrate that the SPO stacking technology can be successfully applied to non-ribbed Si wafer plates and subsequently demonstrate the correct focusing in Laue geometry of both the wedges and radial curvature.
We report on the status of the Laue lens development effort led by UC Berkeley, where a dedicated X-ray beamline and a Laue lens assembly station were built. This allowed the realization of a first lens prototype in June 2012. Based on this achievement, and thanks to a new NASA APRA grant, we are moving forward to enable Laue lenses. Several parallel activities are in progress. Firstly, we are refining the method to glue quickly and accurately crystals on a lens substrate. Secondly, we are conducting a study of high-Z crystals to diffract energies up to 900 keV efficiently. And thirdly, we are exploring new concepts of Si-based lenses that could further improve the focusing capabilities, and thus the sensitivity of Laue lenses.
A slatted mirror is a unique and crucial component in a particular design for an astronomical X-ray interferometer (Willingale 20041). The slats must be thin, < 300 μm, flat and co-planar to a very high precision. We describe the manufacture and characterisation of a prototype slatted mirror produced using a modified form of Silicon pore optics technology.
Future high energy astrophysics missions will require high performance novel X-ray optics to explore the Universe beyond the limits of the currently operating Chandra and Newton observatories. Innovative optics technologies are therefore being developed and matured by the European Space Agency (ESA) in collaboration with research institutions and industry, enabling leading-edge future science missions.
Silicon Pore Optics (SPO) [1 to 21] and Slumped Glass Optics (SGO) [22 to 29] are lightweight high performance X-ray optics technologies being developed in Europe, driven by applications in observatory class high energy astrophysics missions, aiming at angular resolutions of 5” and providing effective areas of one or more square meters at a few keV.
This paper reports on the development activities led by ESA, and the status of the SPO and SGO technologies, including progress on high performance multilayer reflective coatings [30 to 35]. In addition, the progress with the X-ray test facilities and associated beam-lines is discussed .
Silicon pore optics (SPO)1 were originally designed to provide very large collecting areas combined with good angular resolution in narrow field X-ray telescopes. We describe modifications to the geometry and manufacture of SPO to facilitate wide field X-ray imaging applications. Modest changes can greatly improve the vignetting function and off-axis angular resolution of SPO in the Wolter I geometry. Reconfiguring SPO to form Kirkpatrick- Baez stacks in the Schmidt geometry can provide very large fields of view with high angular resolution and large collecting area.
In this paper we present several novel applications using X-ray mirrors based on Silicon Pore Optics
technology, the present baseline technology for large effective area space based X-ray telescopes. By
cutting, bending and direct bonding of mirrors cut from silicon wafers we can create a variety of
structures in a number of well-defined shapes. One novel application is an X-ray half-mirror for X-ray
interferometry applications based on flat, structured Si mirrors bonded to a glass support structure with
a large open area ratio. A second application is to use bent silicon single crystals as a focusing Laue
lens for soft gamma rays.
Silicon Pore Optics (SPO) is a lightweight high performance X-ray optics technology being developed in Europe, driven by applications in observatory class high energy astrophysics missions. An example of such application is the former ESA science mission candidate ATHENA (Advanced Telescope for High Energy Astrophysics), which uses the SPO technology for its two telescopes, in order to provide an effective area exceeding 1 m2 at 1 keV, and 0.5 m2 at 6 keV, featuring an angular resolution of 10” or better [1 to 24].
This paper reports on the development activities led by ESA, and the status of the SPO technology. The technology development programme has succeeded in maturing the SPO further and achieving important milestones, in each of the main activity streams: environmental compatibility, industrial production and optical performance. In order to accurately characterise the increasing performance of this innovative optical technology, the associated X-ray test facilities and beam-lines have been refined and upgraded.
We present initial novel coating design for ATHENA. We make use of both simple bilayer coatings of Ir and B4C
and more complex constant period multilayer coatings to enhance the effective area and cover the energy range
from 0.1 to 10 keV. We also present the coating technology used for these designs and present test results from
Silicon pore optics is a technology developed to enable future large area X-ray telescopes, such as the
International X-ray Observatory (IXO) or the Advanced Telescope for High ENergy Astrophysics (ATHENA),
an L-class candidate mission in the ESA Space Science Programme 'Cosmic Visions 2015-2025'.
ATHENA/IXO use nested mirrors in Wolter-I configuration to focus grazing incidence X-ray photons on a
detector plane. The x-ray optics will have to meet stringent performance requirements including an effective area
of a few m2 at 1.25 keV and angular resolution between 5(IXO) and 9(ATHENA) arc seconds. To achieve the
collecting area requires a total polished mirror surface area close to 1000 m2 with a surface roughness better than
0.5 nm rms. By using commercial high-quality 12" silicon wafers which are diced, structured, wedged, coated,
bent and stacked, the stringent performance requirements can be met without any costly polishing steps. Two of
such stacks are then assembled into a co-aligned mirror module, which is a complete X-ray imaging system.
Included in the mirror module are the isostatic mounting points, providing a reliable interface to the telescope.
Hundreds of such mirror modules are finally integrated into petals, and mounted onto the spacecraft to form an
X-ray optic. In this paper we will present the silicon pore optics mass manufacturing process and latest X-ray test
The establishment of Silicon Pore Optics (SPO) as the technology of choice for the implementation of future large
X-ray space optics has opened up the road to its use in all classes of X-ray missions with varying scientific goals.
This interest has given us the possibility to broaden the design parameter space which is normally considered
for SPO optics. In doing so a number of classical space X-ray optics design issues (e.g., field of view, stray
light, baffling, aberrations) have been tackled. In this paper we report on recent results achieved in this effort.
Particular attention will be given to the issues of stray light and baffling, a topic upon which a combination of
analytical, simulation, and data analysis means can be effectively brought to bear. Missions considering the use
of SPO optics have requirements spanning more than two orders of magnitude in energy, and a factor 20 in focal
length. The possibilities that can be considered and the trade offs that must be made when applying SPO to
such a wide range of optical designs will be illustrated, and some of the possible solutions discussed.
In this paper we present the latest developments on the ruggedisation of the Silicon Pore Optics (SPO) mirror
modules. SPO is one of the candidate technologies for producing the X-ray optics for the future space based Xray
telescope, the International X-ray Observatory (IXO). To produce SPO mirror modules, Si mirrors are first
bonded together using direct Si bonding to form a stack. These stacks are the glued into brackets, which then
connect to the supporting optical bench by invar pins. The combination of brackets and invar pins now forms a
full isostatic mount, and is rugged enough to allow the mirror module to survive the high loads of a launch. The
mounting system furthermore allows for a certain level of manufacturing tolerances for the support structure, and
ensures interchangeability of the mirror modules within one single ring of the optical bench. To prove this, a test
interface has been designed and manufactured, on which a single, full fledged mirror module will be mounted to
be exposed to environmental tests.
The Physikalisch-Technische Bundesanstalt (PTB) has used synchrotron radiation for the characterization of optics and
detectors for astrophysical X-ray telescopes for more than 20 years. At a dedicated beamline at BESSY II, a
monochromatic pencil beam is used by ESA and cosine Research since the end of 2005 for the characterization of novel
silicon pore optics, currently under development for the International X-ray Observatory (IXO). At this beamline, a
photon energy of 2.8 keV is selected by a Si channel-cut monochromator. Two apertures at distances of 12.2 m and
30.5 m from the dipole source form a pencil beam with a typical diameter of 100 μm and a divergence below 1". The
optics to be investigated is placed in a vacuum chamber on a hexapod, the angular positioning is controlled by means of
autocollimators to below 1". The reflected beam is registered at 5 m distance from the optics with a CCD-based camera
This contribution presents design and performance of the upgrade of this beamline to cope with the updated design for
IXO. The distance between optics and detector can now be 20 m. For double reflection from an X-ray Optical Unit
(XOU) and incidence angles up to 1.4°, this corresponds to a vertical translation of the camera by 2 m. To achieve high
reflectance at this angle even with uncoated silicon, a lower photon energy of 1 keV is available from a pair of W/B4C
multilayers. For coated optics, a high energy option can provide a pencil beam of 7.6 keV radiation.
The requirements for the IXO (International X-ray Observatory) telescope are very challenging in respect of angular
resolution and effective area. Within a clear aperture with 1.7 m > R > 0.25 m that is dictated by the spacecraft envelope,
the optics technology must be developed to satisfy simultaneously requirements for effective area of 2.5 m2 at 1.25 keV,
0.65 m2 at 6 keV and 150 cm2 at 30 keV. The reflectivity of the bare mirror substrate materials does not allow these
requirements to be met. As such the IXO baseline design contains a coating layout that varies as a function of mirror
radius and in accordance with the variation in grazing incidence angle. The higher energy photon response is enhanced
through the use of depth-graded multilayer coatings on the inner radii mirror modules. In this paper we report on the first
reflectivity measurements of wedged ribbed silicon pore optics mirror plates coated with a depth graded W/Si multilayer.
The measurements demonstrate that the deposition and performance of the multilayer coatings is compatible with the
SPO production process.
Silicon pore optics is a technology developed to enable future large area X-ray telescopes, such as the
International X-ray Observatory (IXO), a candidate mission in the ESA Space Science Programme 'Cosmic
Visions 2015-2025'. IXO uses nested mirrors in Wolter-I configuration to focus grazing incidence X-ray photons
on a detector plane. The IXO optics will have to meet stringent performance requirements including an effective
area of >2.5 m2 at 1.25 keV and >0.65 m2 at 6 keV and angular resolution better than 5 arc seconds. To achieve
the collecting area requires a total polished mirror surface area of ~1300 m2 with a surface roughness better than
0.5 nm rms. By using commercial high-quality 12" silicon wafers which are diced, structured, wedged, coated,
bent and stacked, the stringent performance requirements of IXO can be attained without any costly polishing
steps. Two of these stacks are then assembled into a co-aligned mirror module, which is a complete X-ray
imaging system. Included in the mirror module are the isostatic mounting points, providing a reliable interface to
the telescope. Hundreds of such mirror modules are finally integrated into petals, and mounted onto the
spacecraft to form an X-ray optic of approximately 4 m in diameter.
In this paper we will present the silicon pore optics mass manufacturing process and latest X-ray test results of
mirror modules mounted in flight configuration.
We present the latest results of X-ray metrology performed on Silicon Pore Optics, a novel type of lightweight X-ray
optics made from silicon and developed for future, large area space based X-ray telescopes. From these so-called pencil
beam measurements, performed at the PTB laboratory of the BESSY synchrotron radiation facility, the overall
performance in terms of half energy width (HEW) of the optics has been calculated. All measurements are performed at
an intrafocal distance, but due to the nature of this measurement method, the results in terms of HEW can be
extrapolated to the focal plane. In the near future, upgrades of the X-ray facilities will allow measuring the performance
of the optics in the actual focal plane. We also present the newest development of our X-ray tracer tool, which is used to
retrieve performance and imaging prediction from single plate level up to a full optic by use of the mirror figure, as
recorded during the fabrication process. We furthermore present results of AFM imaging and X-ray reflectivity
measurements performed to determine the surface roughness of the base material (polished Si wafers) and of fully
processed and coated mirror plates.
For the International X-ray observatory (IXO), a mirror module with an effective area of 3 m2 at 1.25 keV and at least
0.65 m2 at 6 keV has to be realized. To achieve this goal, coated silicon pore optics has been developed over the last
years. One of the challenges is to coat the Si plates and still to realize Si-Si bonding. It has been demonstrated that
ribbed silicon plates can be produced and assembled into stacks. All previously work has been done using uncoated Si
plates. In this paper we describe how to coat the ribbed Si plates with an Ir coating and a top C coating through a mask
so that there will be coating only between the ribs and not in the area where bonding takes place. The paper includes
description of the mounting jig and how to align the mask on top of the plate. We will also present energy scans from Si
plates coated through a mask.
Future X-ray astrophysics missions, such as the International X-ray Observatory, IXO, require the development of novel
optics in order to deliver the mission's large aperture, high angular resolution and low mass requirements. A series of
activities have been pursued by ESA, leading a consortium of European industries to develop Silicon Pore Optics for use
as an x-ray mirror technology.
A novel process takes as the base mirror material commercially available silicon wafers, which have been shown to
possess excellent x-ray reflecting qualities. These are ribbed, curved and stacked concentrically in layers that have the
desired shape at a given radii of the x-ray aperture. Pairs of stacks are aligned and mounted into doubly reflecting mirror
modules that can be aligned into the x-ray aperture without the very high angular and position alignment requirements
that need to be achieved for mirror plates within the mirror module. The use of this silicon pore optics design
substantially reduces mirror assembly time, equipment and costs in comparison to alternative IXO mirror designs.
This paper will report the current technology development status of the silicon pore optics and the roadmap expected for
developments to meet an IXO schedule. Test results from measurements performed at the PTB lab of the Bessy
synchrotron facility and from full illumination at the Panter x-ray facility will be presented.
Silicon pore optics is a technology developed to enable future large area X-ray telescopes, such as the International Xray
Observatory (IXO), a candidate mission in the ESA Space Science Programme 'Cosmic Visions 2015-2025'. IXO
uses nested mirrors in Wolter-I configuration to focus grazing incidence X-ray photons on a detector plane. The IXO
mirrors will have to meet stringent performance requirements including an effective area of ~3 m2 at 1.25 keV and ~1 m2
at 6 keV and angular resolution better than 5 arc seconds. To achieve the collecting area requires a total polished mirror
surface area of ~1300 m2 with a surface roughness better than 0.5 nm rms. By using commercial high-quality 12" silicon
wafers which are diced, structured, wedged, coated, bent and stacked the stringent performance requirements of IXO can
be attained without any costly polishing steps. Two of these stacks are then assembled into a co-aligned mirror module,
which is a complete X-ray imaging system. Included in the mirror module are the isostatic mounting points, providing a
reliable interface to the telescope. Hundreds of such mirror modules are finally integrated into petals, and mounted onto
the spacecraft to form an X-ray optic of four meters in diameter.
In this paper we will present the silicon pore optics assembly process and latest X-ray results. The required metrology is
described in detail and experimental methods are shown, which allow to assess the quality of the HPOs during
production and to predict the performance when measured in synchrotron radiation facilities.
Silicon pore optics are currently under development for missions such as the International X-ray Observatory (IXO) as
an alternative to the glass or nickel shell mirrors that were used in previous generation X-ray telescopes. The
unprecedented effective area requirement of the IXO requires a modular optics design suitable for mass production. In
this paper we discuss the current state-of-the-art in plate manufacturing technology. We provide examples of process
innovations that have directly impacted the cost per mirror plate and have reduced the manufacturing cost of a mirror
module. We show how a switch from silicon to silica as the reflective surface results in a simplified process flow without
a corresponding change in the optical performance. We demonstrate how standard photolithographic techniques, applied
in the semiconductor industry, can be used to pattern a reflective layer. The 5 arc-second angular resolution requirement
of the IXO has stimulated a theoretical analysis of engineering tolerances in relation to angular resolution. We prove that
improved control of the wedge angle by means of etch rate monitoring results in improved angular resolution. The
results of this investigation will be used as the basis for future development in design for mass production.
Silicon pore optics have been developed over the last years to enable future astrophysical X-ray telescopes and have now
become a candidate mirror technology for the XEUS mission. Scientific requirements demand an angular resolution
better than 5" and a large effective area of several square meters at photon energies of 1 keV. This paper discusses the
performance of the latest generation of these novel light, stiff and modular X-ray optics, based on ribbed plates made
from commercial high grade 12" silicon wafers. Stacks with several tens of silicon plates have been assembled in the
course of an ESA technology development program, by bending the plates into accurate shape and directly bonding them
on top of each other. Several mirror modules, using two stacks each, have been aligned and integrated to form the
conical approximation of a Wolter-I design. This paper presents the status of the technology, addresses and discusses a
number of activities in the ongoing ESA technology development and shows latest results of full area measurements at
the MPE X-ray test facility (PANTER).