Charlotte Feldman

Bio: Charlotte Feldman is an academic researcher from University of Leicester. The author has contributed to research in topics: Telescope & Adaptive optics. The author has an hindex of 9, co-authored 29 publications receiving 185 citations.

Active x-ray optics for the next generation of x-ray telescopes

Abstract: The immediate future for X-ray astronomy is the need for high sensitivity, requiring large apertures and collecting areas, the newly combined NASA, ESA and JAXA mission IXO (International X-ray Observatory) is specifically designed to meet this need. However, looking beyond the next decade, there have been calls for an X-ray space telescope that can not only achieve this high sensitivity, but could also boast an angular resolution of 0.1 arc-seconds, a factor of five improvement on the Chandra X-ray Observatory. NASA's proposed Generation-X mission is designed to meet this demand; it has been suggested that the X-ray optics must be active in nature in order to achieve this desired resolution. The Smart X-ray Optics (SXO) project is a UK based consortium looking at the application of active/adaptive optics to both large and small scale devices, intended for astronomical and medical purposes respectively. With Generation-X in mind, an active elliptical prototype has been designed by the SXO consortium to perform point-to-point X-ray focussing, while simultaneously manipulating its optical surface to improve its initial resolution. Following the completion of the large scale SXO prototype, presented is an overview of the production and operation of the prototype, with emphasis on the X-ray environment and preliminary results.

Toward Active X-ray Telescopes II

Abstract: In the half century since the initial discovery of an astronomical (non-solar) x-ray source, the sensitivity for detection of cosmic x-ray sources has improved by ten orders of magnitude Largely responsible for this dramatic progress has been the refinement of the (grazing-incidence) focusing x-ray telescope The future of x-ray astronomy relies upon the development of x-ray telescopes with larger aperture areas (greater than 1 m2) and finer angular resolution (less than 1) Combined with the special requirements of grazing-incidence optics, the mass and envelope constraints of space-borne telescopes render such advances technologically challengingrequiring precision fabrication, alignment, and assembly of large areas (greater than 100 m2) of lightweight (approximately 1 kg m2 areal density) mirrors Achieving precise and stable alignment and figure control may entail active (in-space adjustable) x-ray optics This paper discusses relevant programmatic and technological issues and summarizes progress toward active x-ray telescopes

Additive manufactured x-ray optics for astronomy

Abstract: Additive manufacturing, more commonly known as 3D printing, has become a commercially established technology for rapid prototyping and the fabrication of bespoke intricate parts. Optical components, such as mirrors and lenses, are now being fabricated via additive manufacturing, where the printed substrate is polished in a post-processing step. One application of additively manufactured optics could be within the astronomical X-ray community, where there is a growing need to demonstrate thin, lightweight, high precision optics for a beyond Chandra style mission. This paper will follow a proof-of-concept investigation, sponsored by the UK Space Agency’s National Space Technology Programme, into the feasibility of applying additive manufacturing in the production of thin, lightweight, precision X-ray optics for astronomy. One of the benefits of additive manufacturing is the ability to construct intricate lightweighting, which can be optimised to minimise weight while ensuring rigidity. This concept of optimised lightweighting will be applied to a series of polished additively manufactured test samples and experimental data from these samples, including an assessment of the optical quality and the magnitude of any print-through, will be presented. In addition, the finite element analysis optimisations of the lightweighting development will be discussed.

Testing and modelling of the SVOM MXT narrow field lobster-eye telescope

Abstract: This research used the SPECTRE High Performance Computing Facility at the University of Leicester.

First results from the testing of the thin shell adaptive optic prototype for high angular resolution x-ray telescopes

Abstract: The Smart X-ray Optics project is a UK based consortium of six institutions investigating active/adaptive X-ray optics for both large and small scale applications. The large scale application is aimed towards future high angular resolution, large X-ray telescopes for X-ray astronomy. The work presented here includes the modelling and the testing of the large scale prototype optic. The prototype incorporates piezoelectric devices to a standard X-ray shell to enable the surface to be actively deformed, aiming to achieve an angular resolution better than that currently available (e.g. Chandra 0.5"). The initial design is based on a thin nickel ellipsoid segment on the back of which a series of piezoelectric actuators have been bonded. Results from the initial testing of this prototype in the X-ray beam line at the University of Leicester are presented and simulation of the X-ray performance, the effect of the actuated piezoelectric devices on the detected image and further models are discussed.

X-Rays in Theory and Experiment

Abstract: “X-RAYS in Theory and Experiment” was originally conceived as a second edition of Compton's deservedly celebrated “X-Rays and Electrons”. That book was published just at the time when the great revolution in physical theory, characterised by the new quantum mechanics, was making itself felt, and the changes which this new outlook produced?changes due not in small part to the work of the authors?have caused instead a second book to be written, twice as large, and containing far more than twice the amount of data and interpretation. X-Rays in Theory and Experiment Prof. Arthur H. Compton Prof. Samuel K. Allison. Second edition of ” X-Rays and Electrons” by Arthur H. Compton. Pp. xiv + 828. (New York: D. Van Nostrand Co., Inc.; London: Macmillan and Co., Ltd., 1935.) 31s. 6d. net.

XMM-Newton observatory*: I. The spacecraft and operations. Commentary

Abstract: The XMM-Newton Observatory is a cornerstone mission of the European Space Agency's Horizon 2000 programme, and is the largest scientific satellite it has launched to date. This paper summarises the principal characteristics of the Observatory which are pertinent to scientific operations. The scientific results appearing in this issue have been enabled by the unprecedentedly large effective area of the three mirror modules, which are briefly described. The in-orbit performance and preliminary calibrations of the observatory are briefly summarised. The observations from the XMM-Newton calibration and performance verification phase, which are public and from which most papers in this issue have been derived, are listed. The flow of data from the spacecraft, through the ground segment, to the production of preliminary science products supplied to users is also discussed.

Near-Net-Shaping Methods for Ceramic Elements of (Body) Armor Systems

Abstract: Shape-forming techniques which may be useful in producing components for body armor are reviewed. The techniques are classified in three general categories, dry, wet, and plastic. The different shaping techniques are compared based on key parameters including shape limitations, rate of production, cost, and safety. The techniques are evaluated as to their suitability to be used to produce different body armor components such as breast plates, deltoid, shin and knee protection, and helmets. Dry-pressing is the current standard for producing “relatively flat” components such as breast plates, but performance is limited by the inherent problem associated with dry-pressing, namely, the difficulty in producing homogeneous green bodies because of agglomerates in the powder. Plastic processing has the potential to be useful to produce more reliable “flat” components with improved performance due to high shear mixing breaking up agglomerates. Wet (colloidal) processing techniques such as gelcasting and freeze casting may be useful to produce components with high curvature and more complex shape such as helmets. Tiles or segments may be combined to produce shaped components with increased flexibility.

Raman spectroscopy of piezoelectrics

Abstract: Raman spectroscopy represents an insightful characterization tool in electronics, which comprehensively suits the technological needs for locally and quantitatively assessing crystal structures, domain textures, crystallographic misalignments, and residual stresses in piezoelectric materials and related devices. Recent improvements in data processing and instrumental screening of large sampling areas have provided Raman spectroscopic evaluations with rejuvenating effectiveness and presently give spin to increasingly wider and more sophisticated experimental explorations. However, the physics underlying the Raman effect represents an issue of deep complexity and its applicative development to non-cubic crystallographic structures can yet be considered in its infancy. This review paper revisits some applicative aspects of the physics governing Raman emission from crystalline matter, exploring the possibility of disentangling the convoluted dependences of the Raman spectrum on crystal orientation and mechanical stress. Attention is paid to the technologically important class of piezoelectric materials, for which working algorithms are explicitly worked out in order to quantitatively extract both structural and mechanical information from polarized Raman spectra. Systematic characterizations of piezoelectric materials and devices are successively presented as applications of the developed equations. The Raman response of complex crystal structures, described here according to a unified formalism, is interpreted as a means for assessing both crystallographic textures and stress-related issues in the three-dimensional space (thus preserving their vectorial and tensorial nature, respectively). Statistical descriptions of domain textures based on orientation distribution functions are also developed in order to provide a link between intrinsic single-crystal data and data collected on polycrystalline (partly textured) structures. This paper aims at providing rigorous spectroscopic foundations to Raman approaches dealing with the analyses of functional behavior and structural reliability of piezoelectric devices.

Capped Mo/Si multilayers with improved performance at 30.4 nm for future solar missions

Abstract: Novel capping layer structures have been deposited on periodic Mo/Si multilayers to optimize reflectance at 30.4 nm. Design, deposition and characterization of such coatings are presented. Most of the structures proposed show improved performance with respect to standard Mo/Si multilayers and are stable over time. Reflectance at 121.6 nm and in the visible spectral range have been also tested to explore the applicability of such coatings to the Multi Element Telescope for Imaging and Spectroscopy (METIS) instrument, a coronagraph being developed for the ESA Solar Orbiter platform.