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Atopic dermatitis (AD) is a chronic relapsing skin disease, associated with impaired skin barrier function and characterized by poorly defined pruritic, erythematous lesions. In this study, the efficacy of a new topical cream (IALUSET VITAL®), containing hyaluronic acid and the extract of Salvia haenkei, in reducing symptoms of moderate AD in adults was investigated. This study was a randomized, double blind, vehicle-controlled clinical study. Treatment efficacy was evaluated considering both objective parameters (Scoring Atopic Dermatitis, SCORAD) and subjective pa-rameters (Patient Oriented Eczema Measure, POEM, and an itching sensation) and through non-invasive bioengineering techniques to measure skin moisturization and Trans Epidermal Water Loss (TEWL). Under the experimental conditions of the study, IALUSET VITAL® significantly reduced AD severity, as shown by the SCORAD index, and was revealed to be effective in alleviating the most common signs and symptoms of moderate AD, suppressing itch and improving skin moisturization, and to have a good safety profile, being well-tolerated by patients. However, statistically significant differences between active and vehicle group were not found in the other parameters analyzed, likely because the basic formulation of IALUSET VITAL® guarantees good emollient properties and the addition of hyaluronic acid and extract of Salvia haenkei as active ingredients results in a great increase in effectiveness.

Purpose The primary aim of this study was to evaluate the performance of the study product, in terms of volumizing activity as well as the duration of the effect, in women with age-related midfacial volume defects. In addition, the study allowed the evaluation of the tolerability of the product by both volunteers and investigators. Patients and methods Twenty-two female volunteers, aged 42-60 years, participated in this study, which was performed under dermatological control in a single center. After an initial visit at baseline to verify adherence to the protocol criteria, volunteers received an injection of Aliaxin® SV (IBSA Farmaceutici Italia Srl), followed 3-4 weeks later by a second touch-up treatment to treat eventual asymmetries. Four subsequent visits, the last performed 9 months from the first injection, were performed to evaluate clinically and instrumentally the efficacy of the treatment. Results Clinical and statistically significant improvement in cheek volume was recorded after the first postinjection visit, and the effect was maintained until the end of the study period. A clinically measurable amelioration of wrinkle severity was also observed. By 3D picture recording and subsequent quantitative analysis, it was possible to determine the efficacy in terms of increased facial volume, which was already appreciable at the first visit, was further increased at the second and third visits and was maintained at the fourth and last visits. The injections were very well tolerated by the volunteers, as determined by their self-evaluation questionnaires. Conclusion The results of the study confirm the esthetic performance of the study product on age-related midfacial volume defects. The very strong high-volumizing activity of the study product was not only properly determined by the investigators but also confirmed by self-evaluation by the volunteers. These effects were obtained with no appreciable undesired effects.

The Beam Expander Testing X-ray facility (BEaTriX) is a unique X-ray apparatus now operated at the Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Brera (OAB), in Merate, Italy. It has been specifically designed to measure the point spread function (PSF) and the effective area (EA) of the X-ray mirror modules (MMs) of the Advanced Telescope for High-ENergy Astrophysics (ATHENA), based on silicon pore optics (SPO) technology, for verification before integration into the mirror assembly. To this end, BEaTriX generates a broad, uniform, monochromatic, and collimated X-ray beam at 4.51 keV. [...] In BEaTriX, a micro-focus X-ray source with a titanium anode is placed in the focus of a paraboloidal mirror, which generates a parallel beam. A crystal monochromator selects the 4.51 keV line, which is expanded to the final size by a crystal asymmetrically cut with respect to the crystalline planes. [...] After characterization, the BEaTriX beam has the nominal dimensions of 170 mm x 60 mm, with a vertical divergence of 1.65 arcsec and a horizontal divergence varying between 2.7 and 3.45 arcsec, depending on the monochromator setting: either high collimation or high intensity. The flux per area unit varies from 10 to 50 photons/s/cm2 from one configuration to the other. The BEaTriX beam performance was tested using an SPO MM, whose entrance pupil was fully illuminated by the expanded beam, and its focus was directly imaged onto the camera. The first light test returned a PSF and an EA in full agreement with expectations. As of today, the 4.51 keV beamline of BEaTriX is operational and can characterize modular X-ray optics, measuring their PSF and EA with a typical exposure of 30 minutes. [...] We expect BEaTriX to be a crucial facility for the functional test of modular X-ray optics, such as the SPO MMs for ATHENA., Accepted on 29 June 2022 for publication in Astronomy & Astrophysics, Sect. 13, Astronomical instrumentation of Astronomy and Astrophysics. Version after language correction

The favorite solution foreseen for the realization of future very large x-ray mirror modules (diameters above 1 m) is the partition of the optics in azimuthal and radial modules. Even if this approach solves the initial problem of the procurement and the handling of very large substrates, it moves the difficulties in the second phase, when thousands of segments have to be aligned and assembled without degrading their optical performances. The usage of large monolithic shells would provide indubitable advantages with respect to the segmented approach, but poses challenging procurement problems. For example, in the case of Lynx, where superb imaging capabilities are combined with a very large effective area, a mirror module with 3mdiameter is foreseen. One of the three technologies considered by the Study Team for the realization of the mirrors is based on monolithic glass (fused silica) shells, figured with direct polishing technique. The simplicity of the full shell concept is quite attractive: the complete optics module could be composed of few hundreds of parts instead of several thousands of pieces. As a drawback, to be compliant with the mass budget, the shell thickness should be maintained very small even for larger mirror shells. Given that the glass is a brittle material, the procurement of such large raw shells, and of their spares, is considered the major critical issue of the process. In order to overcome the difficulties and the cost related to the assembly of thousands of segments, a straightforward way to realize very large monolithic raw mirrors shells is needed. In this paper we present the first results related to an alternative approach, based on light-weighted metal sheets, which could have an astonishing impact on the full shell concept, providing very large shells at negligible costs. In particular, we focus on spin forming technology, commonly used for the realization of axial-symmetric parts. This process makes use of a rotating machine to deform metal over a pre-shaped mold. As a replica approach, it allows the realization of several back up optics without major impacts on the costs, as it would be the case if the mirror shell realization starts from blanks machining. Aluminium is commonly used in plate turning. Given its low density and good mechanical properties, it may represent an effective and cheap alternative to more exotic low-density materials or to the glass itself. Metal optics, made of Aluminium 6061, are already widely used to fulfil the demands of a-thermal instrument design. Starting from aluminum substrates, diamond turning can be used for figuring the optic. An additional thin layer of electro-less nickel will allow final figuring and polishing. These further figuring processes are nowadays well proven on thick substrates, allowing the realization of optics with cutting-edge performances. Their successful employ on thin shell substrates would open new window on x-ray optics realization.

The Lynx X-ray Observatory, with superb imaging capabilities and with large throughput, is one of the four large strategic missions considered in the Astro2020 decadal survey. The realization of the mirror assembly within the desired tolerances is quite challenging and different mirror module concepts are proposed. The simplest mirror module design corresponds to less than a few hundred monolithic shells made of fused silica. The complete optomechanical design, compliant with the mass budget, foresees that the shell thickness ranges between 2 and 4 mm (for mirror shells between 0.4 and 3 m diameter). A technology development roadmap for this approach is funded in Italy by ASI and pursued out by INAF-OAB. In this paper, we present the advancements obtained in the procurement of new raw glass shells, in the development of the different phases of the process, and in the realization of a new single-reflection shell, representative of the final optical configuration suitable to validate the

The BEaTriX (Beam Expander Testing X-ray) facility, being completed at INAF-Brera Astronomical Observatory, will represent an important step in the acceptance roadmap of Silicon Pore Optics mirror modules, and so ensure the final angular resolution of the ATHENA X-ray telescope. Aiming at establishing the final angular resolution that can be reached and the respective fabrication/positioning tolerances, we have been dealing with a set of comprehensive optical simulations. Simulations based on wave optics were carried out to predict the collimation performances of the paraboloidal mirror, including the effect of surface errors obtained from metrology. Full-ray-tracing routines were subsequently employed to simulate the full beamline. Finally, wavefront propagation simulation allowed us assessing the sensitivity and the response of a wavefront sensor that will be utilized for the qualification of the collimated beam. We report the simulation results and the methodologies we adopted.

BEaTriX (Beam Expander Testing X-ray) is the X-ray facility under construction at the INAF-Osservatorio Astronomico Brera (Merate, Italy) to prove that it is possible to perform the X-ray acceptance tests (PSF and Aeff) of the ATHENA mirror modules at the required rate and with the required accuracy. The unique optical setup makes use of a micro-focus X-ray source with anode in Titanium, a paraboloidal mirror with small radius of curvature, and a set of crystals to monochromate and expand the beam to fully illuminate the entrance pupil of the ATHENA MMs. The quality of the optical components, and their precise alignment, guarantees the production of a parallel beam at 4.51 keV, to be extended in a second phase to 1.49 keV in order to complete the acceptance requirements for the ATHENA MMs. The completion of the facility is expected to occur in July this year, while the commissioning will start in September. In this paper, we present the current status.

The aim of the present work was the development of a novel glycosaminoglycan (GAG)-based injectable formulation intended for intra-articular administration that should best mimic the healthy synovial fluid. Hyaluronic acid (HA) was chosen among GAG polymers, since it is the most abundant component of the synovial fluid. A DoE (Design of Experiment) approach was used for the development of a formulation containing two HA (very high (VHMW) and low (LMW) molecular weight) grades. The rationale for this choice is that so far, no commercial product based on a single HA grade or even on binary HA mixture possesses optimal viscoelastic properties in comparison with healthy synovial fluid. A full factorial design was chosen to investigate the influence of concentration and relative fraction of the two polymer grades (retained as factors of the model) on formulation functional (viscosity and viscoelastic) properties, which are considered response variables. Thanks to the DoE approach, the composition of the optimized HA formulation was found. The addition to such formulation of an injectable grade fat-free soy phospholipid, which was rich in phosphatidylcholine (PC), resulted in improved lubrication properties. The final HA + PC formulation, packaged in pre-filled sterile syringes, was stable in long-term and accelerated ICH (International Council for Harmonisation) storage conditions. The overall results pointed out the formulation suitability for further steps of pharmaceutical developments, namely for the passage to pilot scale.

The construction of BEaTriX, the Beam Expander Testing X-ray facility, is underway at INAF-OAB (Osservatorio Astronomico di Brera). This laboratory-based X-ray source was designed to generate a broad (170 mm x 60 mm), uniform, and collimated X-ray beam, with a residual divergence of 1.5 arcsec HEW at either 1.49 keV and 4.51 keV. The main scientific driver for BEaTriX is represented by the opportunity to routinely calibrate the modular elements of the ATHENA (ESA) X-ray telescope, based on the silicon pore optics (SPO) technology. Nevertheless, the application domain of BEaTriX is potentially much wider (e.g., X-ray tomography). BEaTriX comprises a microfocus source of X-rays, followed by an optical chain including a collimating mirror, crystal monochromators, and an asymmetric beam expander. The final beam collimation and homogeneity relies on the optical quality of the optical components (X-ray source dimension, mirror polishing, crystal lattice regularity) and on their mutual alignment. In order to determine the most critical parameters, focus the development efforts, and establish specifications, a set of optical simulations has been built. Our paper describes the simulation tool we developed to this specific aim, and discusses the results achieved in terms of manufacturing and alignment tolerances.

ATHENA Silicon Pore Optics (SPO) Mirror Modules (MM) have to be tested and accepted prior to integration in the full ATHENA Mirror Assembly (MA). X-ray tests of the MMs are currently performed at the PTB laboratory of the BESSY synchrotron facility in pencil beam configuration, but they require a PSF reconstruction. Full illumination X-ray tests could be performed using a broad, low-divergent X-ray beam like the one in use at PANTER (MPE, Neuried, Germany), but the large volume to be evacuated makes it impossible to perform the functional tests at the MMs production rate (3 MM/day). To overcome these limitations, we started in 2012 to design a facility aimed at generating a broad (170 x 60 mm2), uniform and low-divergent (1.5 arcsec HEW) X-ray beam within a small lab (∼ 9 x 18 m2), to characterize the ATHENA MM. BEaTriX (the Beam Expander Testing X-ray facility) makes use of an X-ray microfocus source, a paraboloidal mirror, a crystal monochromation system, and an asymmetrically-cut diffracting crystal for the beam expansion. These optical components, in addition to a modular low-vacuum level (10-3 mbar), enable to match the ATHENA SPO acceptance requirements. The realization of this facility at INAF-OAB in Merate (Italy) is now on going. Once completed, BEaTriX can be used to test the Silicon Pore Optics modules of the ATHENA X-ray observatory, as well as other optics, like the ones of the Arcus mission. In this paper we report the advancement status of the facility.

We present a method for the manufacturing of thin shells of glass, which appears promising for the development of active optics for future space telescopes. The method exploits the synergy of different mature technologies, while leveraging the commercial availability of large, high-quality sheets of glass, with thickness up to few millimeters. The first step of the method foresees the pre-shaping of flat substrates of glass by replicating the accurate shape of a mold via hot slumping technology. The replication concept is advantageous for making large optics composed of many identical or similar segments. After the hot slumping, the shape error residual on the optical surface is addressed by applying a deterministic sub-aperture technology as computer-controlled bonnet polishing and/or ion beam figuring. Here we focus on the bonnet polishing case, during which the thin, deformable substrate of glass is temporary stiffened by a removable holder. In this paper, we report on the results so far achieved on a 130 mm glass shell case study., This is a pre-print of an article published in CEAS Space Journal. The final authenticated version is available online at: http://link.springer.com/article/10.1007/s12567-019-00259-7

The BEaTriX (Beam Expander Testing X-ray) facility is now under construction at INAF-Brera Astronomical Observatory with the support of ESA. We aim to use it as a pathfinder to demonstrate the feasibility of the acceptance tests of the ATHENA’s Silicon pore optics Mirror Modules (MM), i.e., point spread function and effective area measurements at two energies for all MMs. A microfocus X-ray source placed in the focus of a paraboloid mirror will provide a collimated X-ray beam to the next stages featuring the facility, i.e., the monochromator and the beam expansion units, which will finally enable the full illumination of the mirror modules under test. The collimating mirror has to satisfy severe surface specifications to allow the divergence of the X-ray beam reaching the requirements. Simulations, based on physical optics, have shown that the optical quality of the mirror surface has to reach 0.5 arcsec Half-Energy Width (HEW) at 4.51 keV. We procured a ground and lapped mirror substrate in HOQ 310 fused quartz material. The first step of the process is based on the bonnet polishing technology with our CNC IRP1200 Zeeko machine, and it is guided by the analysis of the metrological data obtained by the optical profilometer present at Media Lario S.r.l. laboratories. The spatial frequency errors not correctable by bonnet polishing can be then removed by smoothing and superpolishing processes, followed by ion beam figuring to correct the remaining errors in the low frequency range. In this paper, we report on the analysis performed to correlate the requirement on beam divergence to the manufacturing tolerances on the surface. We present the manufacturing process and the results so far achieved.

We consider an array working in receiving mode at the frequency of 175 MHz. An Unmanned Aerial Vehicle (UAV) equipped with a continuous wave transmitter is exploited in order to perform a near eld scan. While UAV ies in the near eld of the array, voltages at each antenna element are acquired by means of digital system. The aim of this work is to retrieve the phase information. This is not trivial because the RF transmitter on the UAV is not phase-locked to the receiver on the ground. This work will enable us to perform a near eld to far eld transformation in order to compute the radiation pattern of the whole array.

We present a method for the manufacturing of thin shells of glass, which appears promising for the production of lightweight mirrors for future space telescopes. The method exploits the synergy of different mature technologies, while it takes advantage of the commercial availability of large, high-quality sheets of glass, with thickness up to few millimeters. The first step of the method foresees the pre-shaping of flat substrates of glass by replicating the accurate shape of a mold via hot slumping technology. The replication concept can be strongly beneficial for making large optics composed of many identical or similar segments. After the hot slumping, the shape error residual on the optical surface is addressed by applying a deterministic sub-aperture technology as computer-controlled bonnet polishing and/or ion beam figuring. Here we focus on the bonnet polishing case, during which the thin, deformable substrate of glass is temporary stiffened by a removable holder. In this paper, we report on the latest results achieved on a 130 mm glass shell case study.

Lynx is an X-ray mission concept with superb imaging capabilities (< 1arcsec Half Energy Width, HEW) and large throughput (2 m2 effective area @1keV). Several approaches are being considered to meet the challenging technological task of the mirror fabrication. Thin and light substrates are necessary to meet mass constraints. Monolithic fused silica shells are a possible solution if their thickness can be maintained to below 4 mm for mirror shells up to 3 m diameter. In this paper we present the opto-mechanical design of the mirror assembly, the technological processes, and the results achieved so far on a prototypal shells under development. In particular, emphasis is placed on the figuring process that is based on direct polishing and on ion beam figuring and on a temporary stiffening structure designed to support the shell during the figuring and polishing operations and to manage the handling of the shell through all phases up to integration into the telescope supporting structure.

The combination of the hot slumping and the Ion Beam Figuring (IBF) technologies can be a very competitive solution for the realization of x-ray optics with excellent imaging capabilities and high throughput. While very thin mirrors segments can be realized by slumping with residual figure errors below few hundreds of nanometres, a non-contact and deterministic process (dependent on dwell time), like IBF, is a very effective post facto correction, as it avoids all the problems due to the handling and the supporting system. In the last years, the two processes were proven compatible with very thin sheet of Eagle XG glasses (0.4 mm thickness). Nevertheless, the fast convergence of the process is a key factor to limit the cost of the mirror plate production. A deeper characterization of removal function stability showed that its repeatability between each run has to be improved for a real enhancement of the process convergence factor. A new algorithm based on de-convolution has been implemented and tested, with important advantages in terms of calculation speed, minimum material removal and optimization possibilities. By analysing the metrological data of test slumped glasses, we showed how the IBF is effective in the correction of figure errors on scales above 8 - 10 mm. An overall figuring time of few hours is required with surface error around 100 nm rms. Thanks to the thickness measurement data, which are performed in transmission mode with an interferometric set-up, we demonstrated that it is possible to disentangle the effective amount of the material removed and the deformations introduced during the process.

The use of 3MTM TrizactTM diamond tiled abrasive pads was proven as a cost-effective pre-polishing technique. Thanks to the low subsurface damages introduced it allows to speed up the polishing phases, reducing the amount of material to be removed. Nowadays, different kind of abrasive pads are available on the market and some of these are dedicated to the last phases of the surface finishing. In this paper, we present the results obtained with 3MTM TrizactTM HookitTM Film Disc 268XA as last step of the polishing phases. The test activity has been carried out on fused silica samples prepared with initial Rq around 50 - 70 nm. In particular, we focused on the wear rate of the pads, the material removal rate and the micro-roughness evolution, in dependence of several parameters as the amount of water, pH, velocity and pressure. The removal rate depends on the status of the abrasive pad and on the polishing conditions, while the micro-roughness of the surface can be decreased well below 1nm rms on millimetre scale. Moreover, a combined process of bonnet pre-polishing followed by 3MTM TrizactTM polishing has been proven as a cost-effective solution to realize super-polished optical surfaces.

Future space X-ray mission concepts like STAR-X, AXIS and Lynx foresee optics with both high angular resolutions (HEW ~ 0.5 to 5 arcsec) and large collecting areas (~0.2-2.0 m2). These optics are very challenging to be produced and their manufacturing is under study. The Ion Beam Figuring (IBF) is one of the few techniques that is capable of correcting the residual manufacturing errors of the mirror shells and obtain the desired final optical figure. INAF-OABrera has two IBF facilities and is investigating the use of IBF on thin foils made by different materials, namely Silicon and Fused Silica. In this paper we describe the results obtained in a preliminary study on Silicon shells.

We present a manufacturing process based on the deterministic polishing and figuring of thin glass substrates (shells), with thickness ranging from 0.5 up to a few millimeters, in “stand-alone” configuration or as part of a composite sandwich structure with low-density core. The methods will be well suited for a broad range of applications in astronomy like, e.g., the production of thin substrates for adaptive optics, the realization of sandwiched lightweight segments for the mirrors of future ground-based and space telescopes, and the realization of low-cost mirrors for amateur astronomy telescopes. The method foresees the pre-shaping of thin glass substrates via hot slumping technology followed by highprecision form correction of the optical surfaces via computer-controlled bonnet and ion beam figuring technologies. During the phase of bonnet polishing of a shell in stand-alone configuration, a removable holder stiffens it temporarily. This paper describes the main steps of the process under study and reports on the realization of the first prototypes.

To significantly improve the performances of the current X-ray observatories, the next generation of X-ray telescopes has to be characterized by a large effective area (Aeff { 2 m2 at 1 keV) and angular resolution better than 5 arcsec. The large dimension implied by these requirements forces the use of a modular approach, splitting the optics into segments. Moreover, lightweight materials, such as glass, have to be selected for the segmented optics in order to maintain a manageable weight for the optics. Since 2009 we are developing a direct hot slumping technique assisted by pressure, in which the glass optical surface is in contact with the mould and a pressure is applied in order to force the glass to copy the mould shape. A cold slumping step is used then to integrate the mirror segments into the final Wolter-I configuration. We present the state of the art of our hot slumping technology, comparing the results obtained with different glass types and mould materials. We also provide an overview of the possibilities of this technology also in view of future developments.

The high-quality surface characteristics, both in terms of figure error and of micro-roughness, required on the mirrors of a high angular resolution x-ray telescope are challenging, but in principle well suited with a deterministic and non-contact process like the ion beam figuring. This process has been recently proven to be compatible even with very thin (thickness around 0.4mm) sheet of glasses (like D263 and Eagle). In the last decade, these types of glass have been investigated as substrates for hot slumping, with residual figure errors of hundreds of nanometres. In this view, the mirrors segments fabrication could be envisaged as a simple two phases process: a first replica step based on hot slumping (direct/indirect) followed by an ion beam figuring which can be considered as a post-fabrication correction method. The first ion beam figuring trials, realized on flat samples, showed that the micro-roughness is not damaged but a deeper analysis is necessary to characterize and eventually control/compensate the glass shape variations. In this paper, we present the advancements in the process definition, both on flat and slumped glass samples.

The implementation of an X-ray mission with high imaging capabilities, similar to those achieved with Chandra (< 1 arc second Half Energy Width, HEW), but with a much larger throughput (2.5 m2 effective area @1 keV), represents a compelling request by the scientific community. To this end the Lynx/XRS mission is being studied in USA, with the participation of international partners. In order to figure out the challenging technological task of the mirror fabrication, different approaches are considered, based on monolithic and segmented shells. Starting from the experience done on the glass prototypal shell realized in the past years, the direct polishing of thin (2 mm thick) fused silica monolithic shells is being investigated as a possible solution. A temporary stiffening structure is designed to support the shell during the figuring and polishing operations and to manage the handling up to its integration in the telescope structure. After the grinding and the polishing phases, in order to achieve the required surface accuracy, a final ion beam figuring correction is foreseen. In this paper, we present the technological process and the results achieved so far on a prototypal shell under development.

In order to look beyond Chandra, the Lynx/XRS mission has been proposed in USA and is currently studied by NASA. The optic will have an effective area of 2.5 m2 and an angular resolution of 0.5 arcsec HEW at 1 keV. In order to fulfill these requirements different technologies are considered, with the approaches of both full and segmented shells (that, possibly, can be also combined together). Concerning the production of segmented mirrors, a variety of thin substrates (glass, metal, silicon) are envisaged, that can be produced using both direct polishing or replication methods. Innovative post-fabrication correction methods (such as piezoelectric or magneto-restrictive film actuators on the back surface, differential deposition, ion implantation) are being also considered in order to reach the final tolerances. In this paper we are presenting a technology development based on fused silica (SiO2) segmented substrates, owing the low coefficient of thermal expansion of Fused Silica and its high chemical stability compared to other glasses. Thin SiO2 segmented substrates (typically 2 mm thick) are figured by direct polishing combined with final profile ion figuring correction, while the roughness reduction is reached with pitch tools. For the profile and roughness correction, the segments are glued to a substrate. In this paper we present the current status of this technology.

The Slumping Glass Optics technology for the fabrication of astronomical X-ray mirrors has been developed in recent years in USA and Europe. The process has been used for making the mirrors of the Nustar, mission. The process starts with very thin glass foils hot formed to copy the profile of replication moulds. At INAF - Osservatorio Astronomico di Brera a process based on cold shaping is being developed, based on an integration method involving the use of interconnecting ribs for making stacks. Each glass foil in the stack is shaped onto a very precise integration mould and the correct shape is frozen by means of glued ribs that act as spacers between one layer and the next one (the first layers being attached to a thick substrate). Therefore, the increasing availability of flexible glass foils with a thickness of a few tens of microns (driven by electronic market for ultra-thin displays) opens new possibilities for the fabrication of X-ray mirrors. This solution appears interesting especially for the fabrication of mirrors for hard X-rays (with energy > 10 keV) based on multilayer coatings, taking advantage from the intrinsic low roughness of the glass foils that should grant a low scattering level. The stress frozen on the glass due to the cold shaping is not negligible, but it is kept into account in the errors of the X-ray optics design. As an exercise, we have considered the requirements and specs of the FORCE hard Xray mission concept (being studied by JAXA) and we have designed the mirror modules assuming the cold slumping as a fabrication method. In the meantime, a prototype (representative of the FORCE mirror modules) is being design and integrated in order to demonstrate the feasibility and the capacity to reach good angular resolution.

Spectral imaging systems drive the development of remote sensing applications. The possibility to combine integrated multispectral sensors to compact, broadband and wide field optical systems is highly advantageous in terms of reliability, portability, and cost reduction. On the other hand, such optical systems often rely on the feasibility of demanding optical components, as of strongly aspheric optics. The activity of manufacturing and metrological testing of such optics is crucial for the achievement of the whole project. In this paper, we present the design of a compact two-mirror system and the manufacturing of the strongly aspheric primary mirror.

Second-harmonic (SH) reflection and diffraction measurements are performed, at the wavelengths of a Ti:sapphire laser on a GaAs/AlGaAs photonic crystal waveguide patterned with a square lattice, the basis consisting of rings of air in the dielectric matrix. The measured angles of diffracted SH beams agree with those predicted from nonlinear diffraction conditions. Results for reflected and diffracted SH intensities as a function of incidence angle, polarization, and pump wavelength show that, due to the low air fraction of the photonic crystal, the reflected one is dominated by the crystalline symmetry of GaAs, while the diffracted one is related to the photonic crystal structure. The large diffraction-to-reflection ratio points to the importance of nonlinear diffraction in photonic crystals. Preliminary measurements in the 1500nm range reveal explicit features related to photonic modes.

Thin glass modular mirrors are a viable solution to build future X-ray telescopes with high angular resolution and large collecting area. In our laboratories, we shape thin glass foils by hot slumping and we apply pressure to assist the replication of a cylindrical mould figure; this technology is coupled with an integration process able to damp low frequency errors and produces optics in the Wolter I configuration, typical for the X-ray telescopes. From the point of view of the hot slumping process, the efforts were focused in reducing low-, mid- and high- frequency errors of the formed Eagle glass foils. Some of our slumped glass foils were used for the development of active X-ray optics, where piezoelectric actuators are used to correct the slumped glass foil deviations from the ideal shape. In particular, they were used for the Adjustable X-raY optics for astrOnoMy project (AXYOM) developed in Italy, and the X-ray Surveyor mission, as developed at the Smithsonian Astrophysical Observatory / Center for Astrophysics (SAO/CfA) in USA. In this paper we describe the optimisation of the hot slumping process, comparing the results with the requirements of the considered active optics projects. Finally, since the present configuration of the Pennsylvania State University (PSU) coating equipment is limited to 100 x 100 mm2, the slumped glass foils used for the SAO project were cut from 200 x 200 mm2 to 100 x 100 mm2, and a low-frequency change was observed. A characterisation of the profile change upon cutting is presented.

The Slumped Glass Optics technology, developed at INAF/OAB since a few years, is becoming a competitive solution for the realization of the future X-ray telescopes with a very large collecting area, e.g. the approved Athena, with more than 2 m2 effective area at 1 keV and with a high angular resolution (5'' HEW). The developed technique is based on modular elements, named X-ray Optical Units (XOUs), made of several layers of thin foils of glass, previously formed by direct hot slumping in cylindrical configuration and then stacked in a Wolter-I configuration, through interfacing ribs. The latest advancements in the production of thin glass substrates may allow a great simplification of this process, avoiding the preforming step via hot slumping. In fact, the strength and the flexibility of glass foils with thickness lower than 0.1 mm allow their bending up to very small radius of curvature without breaking. In this paper we provide an update of the project development, reporting on the last results achieved. In particular, we present the results obtained on several prototypes that have been assembled with different integration approaches.

An important challenge for the X-ray astronomy of the new millennium is represented by the implementation of an X-ray telescope able to maintain the exquisite angular resolution of Chandra (with a sub-arcsec HEW, on-axis) but, at the same time, being characterized by a much larger throughput and grasp. A mission with similar characteristics is represented by the X-ray Surveyor Mission. The project has been recently proposed in USA and is being currently studied by NASA. It will host an X-ray telescope with an effective area of more than 2 square meters at 1 keV (i.e. 30 times greater than Chandra) and a 15-arcminutes field-of-view, with 1-arcsecond or better half-power diameter (versus the 4 arcmin diameter of Chandra). While the scientific reasons for implementing a similar mission are clear, being related to compelling problems like e.g. the formation and subsequent growth of black hole seeds at very high redshift or the identification of the first galaxy groups and proto-clusters, the realization of a grazing-angle optics system able to fulfil these specs remain highly challenging. Different technologies are being envisaged, like e.g. the use of adjustable segmented mirrors (with use of piezoelectric or magneto-restrictive film actuators on the back surface) or the direct polishing of a variety of thin substrates or the use of innovative correction methods like e.g. differential deposition, ionfiguring or the correction of the profile via controlled stress films. In this paper we present a possible approach based on the direct polishing (with final ion figuring correction of the profile) of thin SiO2 segmented substrates (typically 2 mm thick), discussing different aspects of the technology under implementation and presenting some preliminary results.

Different hot slumping techniques have been developed in the last decade to shape thin glass plates in Wolter-I configuration for high angular resolution x-ray telescopes. The required high quality surface characteristic, both in terms of figure error and of micro-roughness, is challenging and the best results achieved so far are compatible with an HEW of few arcseconds. In order to push forward the technology enabling x-ray optics with final HEW below 1 arcsec, we investigate the ion beam figuring as a deterministic technology which can correct the low frequency components of the residual error directly on thin glasses. In this paper we present the tests performed so far, giving a first assessment on the deterministic process definition. In particular, we report on the results achieved on flat samples of D263 and Eagle glass, focusing on the removal function characterization, the micro-roughness evolution and the plate shape variation.

The BEaTriX (Beam Expander Testing X-ray facility) project is an X-ray apparatus under construction at INAF/OAB to generate a broad (200 x 60 mm2), uniform and low-divergent X-ray beam within a small lab (6 x 15 m2). BEaTriX will consist of an X-ray source in the focus a grazing incidence paraboloidal mirror to obtain a parallel beam, followed by a crystal monochromation system and by an asymmetrically-cut diffracting crystal to perform the beam expansion to the desired size. Once completed, BEaTriX will be used to directly perform the quality control of focusing modules of large X-ray optics such as those for the ATHENA X-ray observatory, based on either Silicon Pore Optics (baseline) or Slumped Glass Optics (alternative), and will thereby enable a direct quality control of angular resolution and effective area on a number of mirror modules in a short time, in full X-ray illumination and without being affected by the finite distance of the X-ray source. However, since the individual mirror modules for ATHENA will have an optical quality of 3-4 arcsec HEW or better, BEaTriX is required to produce a broad beam with divergence below 1-2 arcsec, and sufficient flux to quickly characterize the PSF of the module without being significantly affected by statistical uncertainties. Therefore, the optical components of BEaTriX have to be selected and/or manufactured with excellent optical properties in order to guarantee the final performance of the system. In this paper we report the final design of the facility and a detailed performance simulation., Comment: Accepted paper, pre-print version. The finally published manuscript can be downloaded from http://dx.doi.org/10.1117/12.2238952

Thin glass mirrors are a viable solution to build future X-ray telescopes with high angular resolution and large collecting area. This approach is very attractive for the optics implementation of future X-ray astronomy projects like the X-ray Surveyor Missions in USA, the XTP mission in China and the FORCE mission in Japan (all this projects could have an European participation). In the case of the X-ray Surveyor Mission, where a sub-arcsec angular resolution is requested, the use of actuators or post correction with sputtering deposition is envisaged. The hot slumping assisted by pressure is an innovative technology developed in our laboratories to replicate a mould figure. Our hot slumping process is based on thin substrates of Eagle XG glass to be thermally formed on Zerodur K20 moulds. This technology is coupled with an integration process able to damp low frequency errors. A continuous improvement in the reduction of the mid-frequency errors led to slumped glass foils with a potential angular resolution evaluated from the metrological data of a few arcsec. High frequency errors have been for a long time a critical point of our technology. In particular, the pressure assistance was leading to a partial replication of the mould micro-roughness, causing a non-negligible contribution to the Point Spread Function (PSF), in the incidence angle and X-ray energy range of operation. Therefore, we developed a new process to further reduce the micro-roughness of slumped glass foils, making now the technology attractive also for telescopes sensitive at higher X-ray energies. This paper provides the latest status of our research.

A 20 MW Lower Hybrid Current Drive system using an antenna based on the Passive-Active Multijunction (PAM) concept is envisaged on ITER. This paper gives an overview of the mechanical analysis, modeling and design carried out on two major elements of the antenna: the grill front face, and the RF feed-through or windows. The front face will have to withstand high heat and fast neutrons fluxes directly from the plasma. It will be actively cooled and present a beryllium coating upon ITER requirement. The RF window being a critical safety importance class component (SIC) because of its tritium confinement function, two of them will be put in series on each line to achieve a double barrier. A design of a water cooled 5 GHz CW RF “pillbox” window capable of sustaining 500 kW of transmitted power is proposed. Both studies allow to move forward, and focus on critical issues, such as manufacturing processes and R&D associated programs including tests of mock-ups.