This PDF file contains the front matter associated with SPIE Proceedings Volume 6688, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

As NASA's next major x-ray astronomical mission following the James Webb Space Telescope, Constellation-X requires technology advances in several areas, including x-ray optics, x-ray detectors, and x-ray gratings. In the area of x-ray optics, the technology challenge is in meeting a combination of angular resolution, effective area, mass, and production cost requirements. A vigorous x-ray optics development program has been underway to meet this challenge. Significant progress has been made in mirror fabrication, mirror mount and metrology, and mirror alignment and integration. In this paper we give a brief overview of our development strategy, technical approaches, current status, and expectations for the near future and refer interested readers to papers with an in-depth coverage of similar areas.

Hard X-ray telescopes using depth-graded multilayer is a key technology for future satellite programs. Developments are underway by many groups, and balloon experiments have also been carried out. We have developed light-weight hard X-ray telescopes using Pt/C multilayer and high-throughput thin-foil optics. They have been aboard on InFOCμs and SUMIT balloon flights. As a next development efforts, especially for Japan's NeXT satellite program, we focus on improvement of image quality. Among three equally-contributing error factors (figure error, positioning error and off-roundness), figure errors and off-roundness have been reduced significantly, by screening of replication mandrels and active and iterative tuning of support bars. Further studies are in progress, such as suer-polished metal mandrels and better positioning of reflector edges, to meet the baseline requirement of the NeXT mission.

The Constellation-X mission concept has been streamlined to a single Atlas V 551 configuration. This decision was reached by the project team after considering the increases in launch costs announced in 2006 coupled with the constrained budget environment apparent with the release of the NASA 2007 budget. Along with the Spectroscopy X-ray Telescopes, this new configuration continues to carry a Hard X-ray Telescope (HXT) component, with some modifications to the original requirements to adjust to the new configuration. The total effective area requirement in the 7 - 40 keV band has been reduced, but at the same time the angular resolution requirement has been increased from 1 arcmin to 30 arcsec. The Smithsonian Astrophysical Observatory, Marshall Space Flight Center and Brera Observatory (Italy) have been collaborating to develop and HXT which meets the requirements of Constellation-X. The development work we have been engaged in to produce multilayer coated Electroformed-Nickel-Replicate (ENR) shells is well suited for this new configuration. We report here on results of fabrication and testing of a prototyped optic for the HXT. Full beam illumination X-ray tests, taken at MPE-Panter Test Facility, show that these optics meet the new requirement of 30 arcsec for the streamlined Constellation-X configuration. This report also presents preliminary results from studies using titanium nitride as a release agent to simplify and improve the nickel electroforming replication process.

How structures of various scales formed and evolved from the early Universe up to present time is a fundamental question of astrophysics. EDGE will trace the cosmic history of the baryons from the early generations of massive stars by Gamma-Ray Burst (GRB) explosions, through the period of galaxy cluster formation, down to the very low redshift Universe, when between a third and one half of the baryons are expected to reside in cosmic filaments undergoing gravitational collapse by dark matter (the so-called warm hot intragalactic medium). In addition EDGE, with its unprecedented capabilities, will provide key results in many important fields. These scientific goals are feasible with a medium class mission using existing technology combined with innovative instrumental and observational capabilities by: (a) observing with fast reaction Gamma-Ray Bursts with a high spectral resolution (R ~ 500). This enables the study of their (star-forming) environment and the use of GRBs as back lights of large scale cosmological structures; (b) observing and surveying extended sources (galaxy clusters, WHIM) with high sensitivity using two wide field of view X-ray telescopes (one with a high angular resolution and the other with a high spectral resolution). The mission concept includes four main instruments: a Wide-field Spectrometer with excellent energy resolution (3 eV at 0.6 keV), a Wide- Field Imager with high angular resolution (HPD 15") constant over the full 1.4 degree field of view, and a Wide Field Monitor with a FOV of ¹/₄ of the sky, which will trigger the fast repointing to the GRB. Extension of its energy response up to 1 MeV will be achieved with a GRB detector with no imaging capability. This mission is proposed to ESA as part of the Cosmic Vision call. We will briefly review the science drivers and describe in more detail the payload of this mission.

The Gamma-Ray Imager (GRI) is a novel mission concept that will provide an unprecedented sensitivity leap in the soft gamma-ray domain by using for the first time a focusing lens built of Laue diffracting crystals. The lens will cover an energy band from 200 - 1300 keV with an effective area reaching 600 cm². It will be complemented by a single reflection multilayer coated mirror, extending the GRI energy band into the hard X-ray regime, down to ~10 keV. The concentrated photons will be collected by a position sensitive pixelised CZT stack detector. We estimate continuum sensitivities of better than 10^-7 ph cm^-2s^-1keV^-1 for a 100 ks exposure; the narrow line sensitivity will be better than 3 x 10^-6 ph cm^-2s^-1 for the same integration time. As focusing instrument, GRI will have an angular resolution of better than 30 arcsec within a field of view of roughly 5 arcmin - an unprecedented achievement in the gamma-ray domain. Owing to the large focal length of 100 m of the lens and the mirror, the optics and detector will be placed on two separate spacecrafts flying in formation in a high elliptical orbit. R&D work to enable the lens focusing technology and to develop the required focal plane detector is currently underway, financed by ASI, CNES, ESA, and the Spanish Ministery of Education and Science. The GRI mission is proposed as class M mission for ESA's Cosmic Vision 2015-2025 program. GRI will allow studies of particle acceleration processes and explosion physics in unprecedented detail, providing essential clues on the innermost nature of the most violent and most energetic processes in the Universe.

Gamma ray bursts have become as important as supernova in astrophysics and cosmology and they should be studied with the same amount of diligence and continuity. Most of the types of telescopes and detectors needed already exist and in fact have already been in space. The addition of a very wide field, high angular resolution X-ray telescope would open a much larger window to bursts whose spectra are soft, either intrinsically or as a result of high redshift. Sensitivity in the X-ray band also benefits from the large number of photons of the X-ray afterglow. To fill that role we describe a telescope that is a lobster-eye optic in one dimension and a coded aperture in the other. It has larger area and bandwidth than a two-dimensional lobster-eye optic but is subject to more background. A permanent site that can accommodate a complete set of instruments that covers the entire energy range from soft X-ray to gamma ray would be preferable to the current practice of launching new spacecraft periodically with instruments that cover only part of the range. Astronomers generally favor free space, over the Moon as an observatory site. However, the architecture of a gamma ray burst observatory is more compatible with a lunar base than is the typical observatory. The instruments can be delivered gradually and perhaps at lower cost to the astrophysics budget through an Earth-Moon transportation system that is supported by the Exploration program.

We present an innovative X-ray telescope design for diffraction-limited imaging on the mas scale. The long focal distance scheme is based on dispersion-corrected Fresnel lenses made of Li and Be. Annular apertures with an outer diameter of 3.5 m permit simultaneously focused X-rays in two energy bands around 5 and 10 keV. Concentrated to focal spot sizes of ~ 1 mm, a photon throughput of ~ 1400 cm² keV is achieved in the soft and hard band as well. With its partial spectroscopic capability, the device might be preferably suited for measurements of hardness ratios in X-ray emitting coronae of nearby stars and even disc-to-jet conversion mechanisms within AGN.

We have been performing design and optimization of the optics for the Wide Field Spectrometer (WFS): one of the core instruments of the EDGE mission whose science targets are the studies of formation and evolution of large scale structures in the universe. WFS mirrors are based on a conical approximation of the Wolter-I design fabrication technique already applied for ASCA and SUZAKU satellites. In order to give both a large effective area and grasp with small TES detector we use a very short focal length with 1.2 m and 4 reflections system for the outer diameter. The effective area and grasp including the detector efficiency and the filter transmission are 1163 cm² and 405 cm²deg² at 0.6 keV respectively.

A two-reflection optical design for nested X-ray telescopes is described in which the two grazing incidence angles are equal for each ray collected by each mirror, so that the total reflectivity is maximized. A specific design is discussed and its optical performances are compared to a reference type I Wolter optics. In the selected design scenario, a 16% reduction in the number of mirror shells and a 6% increase of the effective area between 1 keV and 10 keV is achieved, along with a small 2.6% decrease of the angular resolution over 12 armin field of view.

Simbol-X, an hard X-ray mission proposed by a consortium of European laboratories, will operate on a broad energy range (0.570 keV) providing a large collecting area ( ~ 1500 cm² at 1.5 keV and ~ 450 cm² at 30 keV) and a good imaging capability over the entire energy range. Relying on two spacecrafts in a formation flight configuration, Simbol-X will use, for the first time, a 20 meters focal length X-ray concentrator with multilayers coated mirrors that efficiently focalize photons above 10 keV and enhance the sensitivity up to 70 keV. Thanks to a ray-tracing code, we simulated the Simbol-X optics performance and investigated the contamination at the focal plane caused by stray−light from diffuse cosmic X-ray background. A dedicated X-ray baffle is mandatory to minimize this contamination that otherwise, would strongly affect the telescope sensitivity. In this paper we investigate different X-ray baffle designs and show their efficiency in reducing the stray−light.

Details of a hard-x-ray science enhancement package for the Constellation-X mission are presented. A scientific case is made for the inclusion of such an instrument on the planned mission and a detailed design is presented that will satisfy science requirements yet fall within the ground rules for enhancement packages: a cost of less than $100M and a mass of no more than 100 kg.

The thermal modeling of the SIMBOL-X X-ray telescope has shown that thermal shielding of both the telescope ends is one possibility to ensure temperature uniformity of the mirror and to reduce the required heating power. The design of the thermal shielding must minimize the thermal exchange in a trade off between transparency of the shields to soft X-rays and mechanical robustness. We discuss two possible designs of the thermal shielding of the mirror module and show transmission curves at X-ray wavelengths.

Suzaku, the fifth in a series of Japanese X-ray astronomy satellites following the highly successful Hakucho, Tenma, Ginga and ASCA satellites, was launched on July 10th, 2005. The X-ray telescope (XRT-I0 through I3) together with the focal plane detector XIS (XIS 0 through 3 corresponding with the number of XRT-I) has features of low background and large effective area covering an energy range from 0.2 to 12 keV. The XRTs were manufactured mostly by a hand, so that their response function is well known very complex. In order to improve the accuracy of the function, we have been developing a Monte-Carlo technique that simulates the X-ray event reflected at the XRT with one photon by one photon (ray-tracing). The imaging capability, the point spread function (PSF) or the encircled energy function (EEF), is the most complex in the response function, that varies from telescope to telescope and ranges from 1.′8 to 2.′3 in half power diameters (HPD). We found that their variations are primarily due to the difference of their focal length. We then tuned the focal length and found that the PSF or EEF was better reproduced when the variations of -50 −+50 mm are given to the focal length of 4750 mm.

We are exploiting the Swift X-ray Telescope (XRT) deepest GRB follow-up observations to study the cosmic X-Ray Background (XRB) population in the 0.2-10 keV energy band. We present some preliminary results of a serendipitous survey performed on 221 fields observed with exposure longer than 10 ks. We show that the XRT is a profitable instrument for surveys and that it is particularly suitable for the search and observation of extended objects like clusters of galaxies. We used the brightest serendipitous sources and the longest observations to test the XRT optics performance and the background characteristics all over the field of view, in different energy bands during the first 2.5 years of fully operational mission.

Future X-ray telescopes like SIMBOL-X will operate in a wide band of the X-ray spectrum (from 0.1 to 80 keV); these telescopes will extend the optical performances of the existing soft X-ray telescopes to the hard X-ray band, and in particular they will be characterized by a angular resolution (conveniently expressed in terms of HEW, Half-Energy- Width) less than 20 arcsec. However, it is well known that the microroughness of the reflecting surfaces of the optics causes the scattering of X-rays. As a consequence, the imaging quality can be severely degraded. Moreover, the X-ray scattering can be the dominant problem in hard X-rays because its relevance is an increasing function of the photon energy. In this work we consistently apply a numerical method and an analytical one to evaluate the X-ray scattering impact on the HEW of an X-ray optic, as a function of the photon energy: both methods can also include the effects of figure errors in determining the final HEW. A comparison of the results obtained with the two methods for the particular case of the SIMBOL-X X-ray telescope will be presented.

Treating protons as de Broglie waves shows that up to a few MeV energies protons experience total external reflection using the index of refraction concept for the target earlier applied to electrons. Angular distributions can be explained by random surface scattering as known for X-rays. Applied ot the Chandra and XMM-Newton X-ray telescopes the calculated reflection efficiencies can explain the observed degradation of the X-ray CCDs for both missions. Some discussion about the possibility of realizing imaging sub-MeV proton optics is presented.

Simbol-X is a hard X-ray telescope being developed by France and Italy, with the participation of Germany, that will operate in the 0.5-80 keV. Simbol-X will allow, in the key 10-40 keV band, a two order of magnitude leap both in sensitivity and angular resolution, by means of a hybrid focal plane coupled with a 20m focal length multi-layer coated X-ray mirrors. The novel telescope architecture and its three-decade extended energy band translate however into technical issues never addressed before for what concerns the on-ground calibrations. In fact, at least in the full-illumination geometry, the unprecedented focal length causes, due to the calibration source finite distance, two main problems: (a) a non-negligible increase of the fraction of incident photons undergoing only one reflection (in the parabola); (b) a variation of the reflectivity curve between parabola and hyperbola, due to a corresponding variation of the incidence angle of incoming photons. In this work, the issue of calibrating a 20m X-ray focussing telescope is addressed in details, and technical solutions are envisaged and proposed to tackle and minimized the above mentioned problems.

One of the most important parameters defining the angular resolution of an X-ray optical module is its Half-Energy Width (HEW) as a function of the photon energy. Future X-ray telescopes with imaging capabilities (SIMBOL-X, Constellation-X, NeXT, EDGE, XEUS,...) should be characterized by a very good angular resolution in soft (< 10 keV) and hard (> 10 keV) X-rays. As a consequence, an important point in the optics development for these telescopes is the simulation of the achievable HEW for a system of X-ray mirrors. This parameter depends on the single mirror profile and nesting accuracy, but also on the mirrors surface microroughness that causes X-ray Scattering (XRS). In particular, owing to its dependence on the photon energy, XRS can dominate the profile errors in hard X-rays: thus, its impact has to be accurately evaluated in every single case, in order to formulate surface finishing requirements for X-ray mirrors. In this work we provide with some simulations of the XRS term of the HEW for some future soft and hard X-ray telescopes.

The hard X-ray telescope-concentrator ART-XC on board the Spectrum-X-Gamma X-ray astrophysical observatory (launching in 2011) is one of the main instruments of the mission. The instrument will be used for an all-sky survey and then for pointed observations which are planned for the first four and the next three years of the Mission, respectively. ART-XC will be sensitive in the 4-30 keV energy range and will have an effective area of several hundred square centimeters at 10 keV. It will have a field of view of about ~28 arcmin, angular resolution better than 1 arcmin and will be an order of magnitude more sensitive than the current generation of collimated instruments and coded mask telescopes in the survey mode and a two or three orders of magnitude more sensitive in the pointing mode. With its high sensitivity in the hard X-ray band and good imaging capabilities, ART-XC will extend the operating energy range of the observatory (complementing the capabilities of the primary science instrument eROSITA), thus significantly enhancing the mission both in the all-sky survey over the energy band 4-10 keV and, especially, in pointed observations over the energy band 4-30 keV. During the 4-year survey, this ART-XC would detect more than ~10⁴ sources over 4-10 keV. For a 10⁵ second pointed observation, the telescope will provide better than 10 microCrab sensitivity in the 4-20 keV energy range.

We report the status of the HAXTEL project, devoted to perform a design study and the development of a Laue lens prototype. After a summary of the major results of the design study, the approach adopted to develop a Demonstration Model of a Laue lens is discussed, the set up described, and some results presented.

The concept of a gamma-ray telescope based on a Laue lens offers the possibility to increase the sensitivity by more than an order of magnitude with respect to existing instruments. Laue lenses have been developed by our collaboration for several years : the main achievement of this R&D program was the CLAIRE lens prototype, which has successfully demonstrated the feasibility of the concept in astrophysical conditions. Since then, the endeavour has been oriented towards the development of efficient diffracting elements (crystal slabs) in order to increase both the effective area and the width of the energy bandpass focused, the aim being to step from a technological Laue lens to a scientifically exploitable lens. The latest mission concept featuring a gamma-ray lens is the European Gamma- Ray Imager (GRI) which intends to make use of the Laue lens to cover energies from 200 keV to 1300 keV. Investigations of two promising materials, low mosaicity copper and gradient concentration silicongermanium are presented in this paper. The measurements have been performed during three runs: 6 + 4 days at the European Synchrotron Radiation Facility (Grenoble, France), on beamline ID15A, using a 500 keV monochromatic beam, and 14 days on the GAMS 4 instrument of the Institute Laue Langevin (Grenoble, France) featuring a highly monochromatic beam of 517 keV. Despite it was not perfectly homogeneous, the presented copper crystal has exhibited peak reflectivity of 25 % in accordance with theoretical predictions, and a mosaicity around 26 arcsec, the ideal range for the realization of a Laue lens such as GRI. Silicon-germanium featuring a constant gradient have been measured for the very first time at 500 keV. Two samples showed a quite homogeneous reflectivity reaching 26%, which is far from the 48 % already observed in experimental crystals but a very encouraging beginning. The measured results have been used to estimate the performance of the GRI Laue lens design.

High-resolution, wide-field-of-view hard X-ray telescopes are essential for detecting and studying cosmic sources in the 10-100 keV photon energy band, which are typically inaccessible to conventional Wolter I X-ray telescopes. To focus such high-energy photons, we developed special Lobster-Eye optics consisting of multiple reflective channels with square cross sections, which are formed by intersecting two sets of semiconductor-grade gold-coated flat silicon elements. Reflective channels with square cross sections The presented hard X-ray Lobster-Eye telescope lens designed for the 10-80 keV energy band consists of approximately 100 channels in both the horizontal and the vertical directions, with the angle between the adjacent plates being less than 1'. An array of such lenses, in which the orientation of each lens is independently controlled, can be used as an adaptive X-ray focusing device capable of changing its imaging properties depending on the user-selected mode. In the wide-angle operation, the individual lenses are aligned toward a common center to form a lobster-eye lens with a large (~2°) field of view, which would be suitable for monitoring stellar or galactic X-ray bursts. For observing a specific event, the telescope can be switched to the high-sensitivity mode by aligning the axes of the individual lenses in parallel so that they are all pointing to the region of interest, effectively adding up the effective areas of individual lenses (up to ~1600 cm² at 40 keV). In the paper we will discuss the system performance simulations and the experimental results using initial prototype Lobster-Eye lenses.

The Fourier Analytical Investigation results of the Performance of the Multiple Annuli Coded Aperture (MACA) and Complementary Multiple Annuli Coded Aperture Systems (CMACA) are summarised and the probable application of these systems in Astronomy, High energy radiation Imaging, optical filters, and in the field of metallurgy, are suggested.

We have investigated the stress and roughness in W/B₄C X-ray multilayer films grown by reactive DC magnetron sputtering in a nitrogen-argon gas mixture. We have also studied the properties of single-layer W and B₄C films, in order to understand specifically how the stress, roughness, chemical composition and microstructure in these materials depends on the sputter gas composition. We find that the stress and roughness in both single-layer and multilayer films deposited reactively is reduced substantially; we find a corresponding improvement in X-ray performance in the case of multilayer films designed to operate at X-ray energies for which the incorporation of nitrogen will not adversely affect the optical properties of these coatings. Furthermore, the observed reduction in film stress in these coatings will mitigate stress-driven adhesion failures. In the case of single-layer W films, the observed reduction in stress and roughness is correlated with a change in microstructure: the W film is amorphous when deposited reactively (and contains ~12-25% incorporated N, depending on the sputter gas composition), versus polycrystalline when deposited in pure argon gas. Finally, we find extremely low surface roughness in reactively-sputtered films of amorphous B₄CN_x; thus, in addition to their use in X-ray multilayer reflective coatings, these films can be used as smoothing layers to reduce the surface roughness of X-ray mirror substrates, thereby leading to reduced scattering and higher specular reflectance.

Imaging observations by means of optics is crucially important, not only for its capability of spatially resolving astronomical objects, but also for its sensitivity superior to non-imaging experiments by orders of magnitude. In order to study feasibilities of reflective optics in soft gamma-ray region, we measured Pt/C multilayer and multilayer-supermirror at 200 keV. Angular dispersion is measured at wide range of incidence angle. The results showed that measured reflectivities agree well with model calculation using tabulated optical constants and roughness measured at 8.4, 30 and 60 keV. Possible configuration of soft gamma-ray telescope is discussed.

Depth graded multilayer designs for hard x-ray telescopes in the 10 keV to 70-80 keV energy range have had either W or Pt as the heavy element. These materials have been chosen because of reasonable optical constants, the possibility to grow smooth interfaces with the spacer material, and the stability over time. On the flip side both W and Pt have an absorption edge -- 69.5 keV (W) and 78.4 keV (Pt) -- which is very close to the two ⁴⁴Ti lines at 67.9 keV and 78.4 keV that are produced in the envelope of a super nova explosion. Other materials have better optical constants and no absorption edges in this energy range, for example Ni_0.93V_0.07, but are not used because of high interface roughness. By using a WC/SiC multilayer for the bottom and a Ni_0.93V_0.07/SiC multilayer for the thicker top layers of a depth graded multilayer we have made a reflector that doesn't have a clear absorption edge. This reflector has been measured at energies between 8 keV and 130 keV. At a graze angle of 0.11 degree there is still nearly the same reflectivity below the W absorption edge as for a traditional W based coating, and above the W absorption edge there is still 48% reflection at 80 keV.

In X-ray astronomical telescopes, the focalization of the radiation is achieved by means of grazing incidence Wolter I (parabola + hyperbola) optics in total reflection regime. In general, high density materials (e.g. Au, Pt, Ir, W) are used as reflecting coatings, in order to increase as much as possible the cut-off angles and energies for total reflection. However these materials present an important reduction of the reflectivity between 0.2 and 5 keV, due to the photoabsorption, and this phenomenon is particularly enhanced in correspondence of the M absorption edges (between 2 and 3.5 keV). In general, this determines a strong decrease of the telescope effective area. To overcome the problem we suggested in previous works the coating of the mirror surface by a low-density material such as carbon. Mirror samples with different coatings made by high density materials: Au, Ir, Pt, and W with a carbon overcoating were manufactured and reflectivity data in the soft X-ray band (100-2000 eV), performed both at the XACT facility in Palermo (Italy) and at BSRF synchrotron in Beijing (China), are showed. In this paper we present some of the first results concerning the measurements carried out at the photon energies of 200 eV (i.e. below the carbon K absorption edge) and 1280 eV (i.e. the region just below the heavy material M absorption edge).

Future Astrophysics missions operating in the hard X-ray/Soft Gamma ray range is slated to carry novel focusing telescopes based on the use of depth graded multilayer reflectors. Current design studies show that, at the foreseen focal lengths, it should be feasible to focus X-rays at energies as high as 300 keV. These designs use extrapolations of theoretical and experimentally determined optical constants from below 200 keV. In this paper we report on the first experimental determination of optical constants up to and above 200 keV. We present these first results as obtained at the National Synchrotron Light Source in Brookhaven and compare these to results obtained previously up to 180 keV of some of the same materials at the European Synchrotron Radiation Facility in Grenoble.

The Extreme-Ultraviolet Imaging Spectrometer (EIS) on the Hinode satellite records high-resolution solar spectra in the 170-210 Å and 246-290 Å wavelength ranges. The EIS optics operate at near normal incidence and consist of an off-axis parabolic mirror, a toroidal diffraction grating, two CCD detectors, and two thin aluminum filters. To increase the normal incidence efficiency, high-reflectance multilayer interference coatings were deposited on the mirror and the grating. Prior to launch, each of the optical components was calibrated using synchrotron radiation, and the spectral and spatial resolution of the complete instrument were measured. In this paper, we compare the preflight calibrations with the first-light spectra recorded in space.

We present a spectrometer design based on a novel nanofabricated blazed X-ray transmission grating which is modeled to have superior efficiency. Here we outline a full instrument design proposed for Constellation-X which is expected to give resolving powers ~2000 (HEW). The spectrometer advantages include lower mass budget and smaller diffractor area, as well as order-of-magnitude more relaxed alignment tolerances for crucial degrees of freedom than reflection grating schemes considered in the past¹,²,³. The spectrometer readout is based on conventional CCD technology adapted to operate with very high speed and low power. This instrument will enable high resolution absorption and emission line spectroscopy in the critical band between 0.2 and 1.5 keV.

A novel approach for measuring linear X-ray polarization over a broad-band using conventional imaging optics and cameras is described. A new type of high efficiency grating, called the critical angle transmission grating is used to disperse soft X-rays radially from the telescope axis. A set of multilayer-coated paraboloids re-image the dispersed X-rays to rings in the focal plane. The intensity variation around these rings is measured to determine three Stokes parameters: I, Q, and U. By laterally grading the multilayer optics and matching the dispersion of the gratings, one may take advantage of high multilayer reflectivities and achieve modulation factors over 50% over the entire 0.2 to 0.8 keV band. A sample design is shown that could be used with the Constellation-X optics.

The precisely shaped glass sheets and Si wafers are generally considered as the most promising substrates for future large space astronomical X-ray telescopes. Both approaches have demonstrated promising results obtained in the course of last years. In this contribution, we report on continued systematic efforts and analysis in precise shaping of thin glass sheets as well as Si wafers. New results will be briefly presented and discussed. For Si wafers, recent efforts focus also on improving the intrinsic quality of the slices to better meet the high requirements of future space projects.

One of the most important aspects of the Constellation-X x-ray optics development is the fabrication of lightweight mirror segments. Given its multi-faceted requirements, i.e., good angular resolution, light weight, and low production cost, we have adopted a glass slumping or forming technique that takes advantage of the naturally excellent microroughness of thin float glass sheets. In this paper we present measured quantities of formed mirror segments and compare them with requirements to show that the formed mirror segments have met all except the sag requirement. The larger than acceptable sag error may be an artifact of the measurement process. It may also be caused by coating stress or residual thermal stress resulting from the slumping process. Our immediate future task is to identify the source(s) of the sag error and address them accordingly.

Glass micro-pore optics technology, developed over the last years for planetary X-ray imagers, has been used to assemble optical modules in approximation of a Wolter-I configuration. These tandems of glass sectors consist of hundreds of square, millimetre sized, multi-fibres that each contain more than a thousand, 3 μm thin, X-ray mirrors with a surface roughness suitable for application at medium X-ray energies. The performance of the tandems can be traced back to the quality of the individual fibres. Extensive X-ray testing has been done on all constituents, from several fibres up to tandem level, using pencil beam and, for the first time, full beam illumination at PANTER. The results of these campaigns and of reflectometry measurements are discussed in this paper and have been used throughout the technology development program to monitor the X-ray performance. It will be shown that the quality of focussing micro-pore X-ray optics is now high enough to achieve an angular resolution of several arc minutes and that the multi-fibres are as good as 20 arc seconds, demonstrating the potential of this technology. The tandems can be combined and assembled into larger geometries, hence forming a very light and compact X-ray lens of ~200 mm diameter and a focal length of 1 m. This is part of an ESA breadboard program discussed elsewhere in this conference.

Silicon pore X-ray optics enable future astrophysical science missions that require imaging X-ray telescopes with an angular resolution better than 5" and an effective area of several square meters at photon energies of 1 keV. The characteristics of the latest generation of these very light, stiff and modular X-ray optics, termed high-performance pore optics (HPO), are discussed in this paper. HPOs 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. Test plates have been coated to enhance the reflectivity of the optic. Several HPOs have been integrated into modules in Wolter-I configuration, some of them with properly wedged plates. Their performance has been measured during test campaigns at X-ray testing facilities using pencil beam and full beam illumination. Pencil beam measurements at BESSY-II yield information on the production process with high spatial resolution and without the need for image deconvolution. It will be shown in this paper that the full beam results on the figure of the optics can be predicted from the pencil beam data. Full beam illumination at PANTER, besides yielding integrated information on the performance of the optic, delivers also unique data on the large angle scattering properties of the system. Experimental results including reflectometry and surface roughness measurements are presented and discussed in this paper.

The first light of a ultra-lightweight and low-cost micro-pore X-ray optic utilizing MEMS (Micro Electro Mechanical Systems) technologies is reported. Our idea is to use silicon (111) planes appeared after anisotropic wet etching of silicon wafers. As a first step to Wolter type-1 optics, a single-stage optic with a focal length of 750 mm and a diameter of 100 mm was designed for energies below 2 keV. The optic consists of 218 mirror chips for X-ray reflection and an optic mount for packing these chips. Design parameters and required fabrication accuracies were determined with numerical simulations. The fabricated optic satisfied these accuracies and its imaging quality was measured at the ISAS X-ray beam line at Al K_α 1.49 keV. A focused image was successfully obtained. The measured image size of ~4 mm was consistent with the chip sizes. The estimated X-ray reflectivity also could be explained by micro-roughness of less than 3 nm and geometrical occulting effect due to large obstacle structures on the reflection surface.

Winding a plastic foil ribbon into spiral cylinder or spiral cones we can design and build single or multiple reflection X-ray grazing incidence focusing optics with potential applications in Astronomy as well as experimental physics. The use of thin plastic foils from common industrial applications and of a mounting technique which does not require the construction of mandrels make these optics very cost effective. A spiral geometry focusing optic produces an annular image of a point source with the angular size of the annulus depending mainly on the pitch of the winding and the focal length. We use a ray-tracing code to evaluate the performances of cylindrical, and double conical spiral geometry as a function of the design parameters e.g. focal length, diameter, optic length. Some preliminary results are presented on X-ray imaging tests performed on spiral cylindrical optics.

To improve angular resolution of high-throughput X-ray telescope using aluminum foil substrate, a multi-stage closed shell substrate is the key target of the development. For this purpose we have been developing two new fabrication methods to make very thin aluminum substrate. One is to use electron beam welding and the other is to use direct machining with lathe. By means of these methods, test conical mirror substrates were made and it was found that these had enough accurate shape as substrates to be used for epoxy replication.

We are developing a normal incident X-ray telescope with an adaptive optics system in order to achieve an unprecedented high-angular-resolution. The primary mirror with a diameter of 80mm is a spherical shape with a focal length of 2000 mm, which was coated by Mo/Si multilayer. The secondary mirror is a deformable mirror with 55 mm diameter, which was also coated by Mo/Si multilayer. Optical lights from a pin-hole were measured by a wave-front sensor and used as a reference for a correction of the deformable mirror. All the components were installed in a vacuum chamber. A closed loop control with the wave front sensor and the deformable mirror was successfully performed in the telescope and we confirmed the correction of the wave front. The rms-deviation of a performed wave front from a target shape during the control was ~30 nm-rms, whereas it without control was more than ~80 nm-rms. A 13.5 nm X-ray from an electron impact X-ray source was imaged on a backside CCD installed on a focal plane. A mesh made by steel was installed in front of the X-ray source, whose pitch and wire-thickness are 500 micro-m and 50 micro-m. The image of this mesh by optical lights from the X-ray generator is detected by the CCD. The current image quality is ~2.4 arc-sec and this was comparable to a diffraction limit of an optical wave length with our 80mm primary mirror.

We present an overview update of the metrologic approach to be employed for the segmented mirror fabrication for Constellation-X spectroscopy x-ray telescope. We compare results achieved to date with mission requirements. This is discussed in terms of inherent capability versus in-practice capability. We find that all the needed metrics for the mirrors are in hand but that they are currently limited by the mounting of the mirrors themselves.

We present an introduction to the use of a refractive null lens for testing grazing incidence x-ray mirrors for the Constellation-X mission. The singular role of mirror mounting in glass shell mirror metrology is also touched upon. We compare results achieved to date with mission requirements along with some of the unique properties of the null lens. Additionally, uses beyond mirror metrology are briefly discussed.

X-ray mirrors made of slumped glass could be a light-weight solution for large segmented X-ray telescopes. Our goal is the development of a slumping process for high accuracy glass segments with an angular resolution of a few arcseconds. In our studies we try to understand the influence of the process by experimental means. We have recently built a new experimental set-up which allows us to study the sequence of the slumping methods. We report on our laboratory experiments and on the development of metrology methods to measure the figure of the glass segments.

Thin plastic foils are being investigated to build shell optics for X-ray telescopes. Compared to polished glass optics, the advantage is in terms of increased collecting area, light weight and lower cost. Plastic material is also desirable to allow deformation into a complete surface of revolution. We collected plastic materials of common use for industrial applications and also specialty materials developed for the electronic industry. A comparative study was then performed to evaluate the optical quality of the selected plastic films. Surface analysis was carried out with topographic instruments to investigate the microroughness of our samples at different scan lengths. Preliminary results suggest that a facility for the production of high-performance films with adequate microroughness is needed.

Technology associated with x-ray optics for missions such as ESA's XMM-Newton are not compatible with the demanding mass requirements for planetary explorers. Glass micro-pore optics are an enabling technology for future ESA missions to fly remote, planetary, x-ray imagers, by facilitating mass and volume reduction. Activities pursued by ESA have developed manufacturing techniques for micro-channel plates to produce high quality, square fibres, which are used to form glass plates containing square micro-channel pores, with diameters from 10 μm and fill factors around 60%. Matched pairs of plates can be deformed under heat and pressure to form spherical surfaces, such that each plate approximates the radius of one part of the tandem pair of a Wolter I configuration. In such a configuration the tangential walls of the concentric rings of pores are used as the grazing incidence, reflective surfaces that focus x-rays. The monolithic structure of the plates allows dense packing of the rings of x-ray mirrors and simplifies mounting, especially with respect to thermal and mechanical considerations. To improve x-ray reflectivity, processes to coat the channel surfaces with elements such as Ni and Ir have also been investigated. This paper discusses the design of a structure to support the optic segments and assembly of the optics into a structure. Pairs of plates must be aligned into tandems and fixed to form segments of the x-ray optic. Each tandem pair must be aligned into a structure which will support the plates through thermal and mechanical loading. A structure has been designed to allow assembly of the optic within tolerances justified by analysis. Replacement of individual tandems is possible. Thermal and mechanical analyses have been performed to assess the performance and survivability of the optic under loads. An assembly plan has been designed to allow maximisation of the effective area of the optic and ensure its best performance.

We present the concepts behind the current alignment and integration technique for a Constellation-X primary-secondary mirror segment pair prior to an x-ray beam line test. We examine the effects of a passive mount on thin glass x-ray mirror segments, and the issues of mount shape and environment on alignment. We also investigate how bonding and transfer to a permanent housing affects the quality of the final image.

Area and mass requirements for the Constellation-X Spectroscopy X-Ray Telescopes restrict the thickness of the mirror segment to below a mm. Requirement of angular resolution of 15" over the soft x-ray band implies that allowable optic deformation is sub-micrometer for these thin segments. These requirements place stringent constraint on the mounting, alignment and affixing of these mirror segments in both the metrology and integration processes. We present analyses and optimization of the Constellation-X mirrors under relevant mechanical and thermal environments.

We are developing grazing-incidence x-ray optics for astronomy. The optics are full-cylinder mirror shells fabricated using electroformed-nickel replication off super-polished mandrels. For space-based applications where weight is at a premium, very-thin-walled, light-weight mirrors are required. Such shells have been fabricated at MSFC with < 15 arcsec resolution. The challenge, however, is to preserve this resolution during mounting and assembly. We present here a status report on a mounting and alignment system currently under development at Marshall Space Flight Center to meet this challenge.