Journal of X-Ray Science and Technology - Volume 5, issue 1

Authors: Shealy, David L. | Wang, Cheng | Hoover, Richard B.

Article Type: Research Article

Abstract: Promoted by the successful application of multilayer coated optics in soft x-ray imaging experiments in solar physics and projection lithography, several groups have designed, analyzed, fabricated, and are testing Schwarzschild multilayer soft x-ray microscopes. Simulations have indicated that diffraction limited performance of a spherical Schwarzschild microscope operating near 100 Å will be limited to systems with a small numerical aperture of approximately 0.15 and a corresponding resolution, based on the Rayleigh criterion, of 3.3 times the wavelength of the incident radiation. In principle, a two aspherical mirror Head microscope, which satisfies the constant optical path length condition and the Abbé …sine condition, should achieve diffraction limited performance for very large numerical apertures. For a practical soft x-ray microscope, surface contour errors, microroughness, reflectance of multilayer coatings, and variation of the angle of incidence over the multilayer substrates become significant factors in degrading system resolution and must be controlled before an ultra-high resolution, two-mirror microscope will be realized. For a 30x reflecting microscope with a numerical aperture ranging from 0.15 to 0.35, the effects on resolution of surface contour errors, tilts, and misalignments of the optics have been studied. Graded spacing of the multilayer coatings on the mirror substrates are required of a fast, two-mirror microscope. Show more

DOI: 10.3233/XST-1995-5101

Citation: Journal of X-Ray Science and Technology, vol. 5, no. 1, pp. 1-19, 1995

Authors: Durfee, D. S. | Moody, J. W. | Brady, K. D. | Brown, C. | Campbell, B. | Durfee, M. K. | Early, D. | Hansen, E. | Madsen, D. W. | Morey, D. B. | Roming, P. W. A. | Savage, M. B. | Eastman, P. F. | Jensen, V.

Article Type: Research Article

Abstract: The Goldhelox Project is the construction and use of a near-normal incidence soft x-ray robotic solar telescope by undergraduate students at Brigham Young University. Once it is completed and tested, it will be deployed from a Get-Away-Special (GAS) canister in the bay of a space shuttle. It will image the sun at a wavelength of 171-181Å with a time resolution of 1 sec and a spatial resolution of 2.5 arcsec. The observational bandpass was chosen to image x-rays from highly ionized coronal Fe lines. The data will be an aid in better understanding the beginning phases of solar flares and …how flaring relates to the physics of the corona-chromosphere transition region. Goldhelox is tentatively scheduled to fly on a space shuttle sometime in 1995 or 1996. This paper outlines the project goals, basic instrument design, and the unique aspects of making this an undergraduate endeavor. Show more

DOI: 10.3233/XST-1995-5102

Citation: Journal of X-Ray Science and Technology, vol. 5, no. 1, pp. 20-28, 1995

Authors: Gluskin, E. | Randall, K. J. | Mcnulty, I. | Yun, W. | Khounsary, A. M. | Lai, B.

Article Type: Research Article

Abstract: Knowledge of the intermediate energy range from 0.5-4 keV, bridging the “soft” and “hard” x-ray regions, is relatively underdeveloped. However, recent developments in the techniques of microscopy and magnetic circular dichroism have emphasized the need to operate in this energy range for microelectronic, biological, and materials science related experiments. The strong dipole-allowed 3d to 4f transitions in rare-earth magnetic materials fall in this region, as do the K-shells of many of the second and third row elements of the periodic table. Two beamlines to be constructed at the Advanced Photon Source (APS) have been designed to cover this energy region. …The proposed undulator source, the beamline layout, and the experimental programs for these beamlines are described. Show more

DOI: 10.3233/XST-1995-5103

Citation: Journal of X-Ray Science and Technology, vol. 5, no. 1, pp. 29-42, 1995

Authors: Peterson, B. G. | Ivanova, E. P. | Spencer, R. L. | Hart, G. W. | Lin, J. | Stark, T. T. | Panin, A. M. | Knight, L. V.

Article Type: Research Article

Abstract: This paper describes a combined theoretical and experimental approach to understanding the capillary spark discharge with specific application to use as a soft x-ray or extreme ultraviolet laser source. Atomic physics calculations have identified several potential laser lines in a collisionally pumped neon-like or nickel-like plasma, and magnetohydrodynamic (MHD) modeling has shown that a capillary discharge device should be capable of producing the correct plasma conditions to achieve a population inversion in some of these lines. An experiment is constructed to evaluate the accuracy of the MHD model and investigate the potential of observing inversion in a neon-like argon or …a nickel-like krypton plasma. Show more

DOI: 10.3233/XST-1995-5104

Citation: Journal of X-Ray Science and Technology, vol. 5, no. 1, pp. 43-51, 1995

Authors: Stead, A. D. | Cotton, R. A. | Duckett, J. G. | Goode, J. A. | Page, A. M. | Ford, T. W.

Article Type: Research Article

Abstract: Imaging biological specimens with soft x rays offers several potential benefits over electron microscopy, and these are briefly reviewed. The disadvantages, most notably radiation-induced structural changes, have been investigated and images of irradiated algal cells (Chlorella) are presented. In soft x-ray contact microscopy the image is recorded rapidly to avoid both natural and radiation-induced movement and this technique has been used to study the ultrastructural effects of electron microscopy fixatives. In the epidermal hairs of tomato plants there are numerous strands of cytoplasm which, by light microscopy, appear to traverse the vacuole but are rarely seen by electron microscopy. However, …by soft x-ray contact microscopy these strands and the organelles within them can be successfully imaged. Moreover, examination by soft x-ray contact microscopy of the cytoplasm in a fixed material shows that these strands are not present in chemically fixed material. This paper also reports the use of soft x-ray contact microscopy to examine the abscission cells found within the protonema of a moss (Bryum tenuisetum) and compares the images to those obtained by light and electron microscopy. Show more

DOI: 10.3233/XST-1995-5105

Citation: Journal of X-Ray Science and Technology, vol. 5, no. 1, pp. 52-64, 1995

Authors: Chernov, V. A. | Chkhalo, N. I. | Fedorchenko, M. V. | Kruglyakov, E. P. | Mytnichenko, S. V. | Nikitenko, S. G.

Article Type: Research Article

Abstract: In the present work we have used the EXAFS and SAXS methods to study the inner structure of “classical” Co/C and Ni/C multilayers. This enabled us to study in detail the structure of a multilayer as a function of the thickness of a metal layer within the multilayer. On the basis of these data a model for multilayer growth produced with pulsed laser evaporation technology is proposed.

DOI: 10.3233/XST-1995-5106

Citation: Journal of X-Ray Science and Technology, vol. 5, no. 1, pp. 65-72, 1995

Authors: Yaakobi, B. | Marshall, F. J. | Su, Q. | Epstein, R.

Article Type: Research Article

Abstract: The case of an x-ray radiographed (backlit) image of a CH-shell laser-fusion target to be imploded by the Omega Upgrade laser system is studied. The goal is to obtain information on the conditions at peak compression, where the experimental constraints due to target self-emission and required spatial resolution are maximal. Particular attention is devoted to the problem of discriminating against the target self-emission. It is shown that a way to selectively image the target with radiation from a backlight source is to obtain a monochromatic image at a single spectral line emitted by the backlighter. Two experimental configurations are discussed: …(a) an x-ray microscope with a flat crystal monochromator, and (b) pinhole imaging in conjunction with a curved crystal monochromator. Useful images are obtained with simple CH-shell targets and without the need for a short-pulse backlighter beam. Show more

DOI: 10.3233/XST-1995-5107

Citation: Journal of X-Ray Science and Technology, vol. 5, no. 1, pp. 73-87, 1995

Authors: Ridgeley, A. | Goodman, D. | Hall, T. A.

Article Type: Research Article

Abstract: Using an x-ray spectrometer with an elliptically curved crystal it is possible to study absorption spectra from a target placed at one focus of the ellipse using a backlighting source placed at the other focus. This principle has been used to develop a spectrometer for EXAFS studies of laser compressed materials. The backlighting source is placed at one focus of the ellipse and the laser compressed EXAFS sample at the other. Using this technique a small area of the EXAFS target can be probed, thereby minimizing any spatial variations in the compressed plasma due to nonuniformities in the laser beams. …Also, the dispersive nature of the crystal ensures that it acts as a bandpass filter, so that the EXAFS sample is not probed by other x-ray wavelengths which may cause unwanted heating. Another advantage is that compressed and uncompressed EXAFS spectra can be compared on a single shot. The optical properties of the spectrometer are discussed analytically and using a computer ray-tracing program. The development and alignment of the elliptical spectrometer are discussed, and its performance using both x-ray film and a CCD detector is evaluated. The use of the elliptical spectrometer as a high-resolution x-ray instrument is presented. Show more

DOI: 10.3233/XST-1995-5108

Citation: Journal of X-Ray Science and Technology, vol. 5, no. 1, pp. 88-104, 1995

Authors: Daido, H. | Schulz, M. S. | Murai, K. | Kodama, R. | Yuan, G. | Goto, J. | Tanaka, K. A. | Kato, Y. | Nakai, S. | Shinohara, K. | Honda, T. | Kodama, I. | Iwasaki, H. | Yoshinobu, T. | Tsukamoto, M. | Niibe, M. | Fukuda, Y. | Neely, D. | Macphee, A. | Slark, G.

Article Type: Research Article

Abstract: Near- and far-field characteristics of a germanium soft x-ray laser at the wavelengths of 23.2–23.6 nm (J = 2-1 transitions) and 19.6 nm (J = 0-1 transition) are given for quantitative evaluation of the germanium laser for holographic applications. In-line Gabor holography of simple structured objects, such as thin opaque fibers and a standard electron microscope test specimen, is demonstrated. The holograms were recorded on PMMA (polymethyl methacrylate) photoresists and llford Q-plates. The holograms recorded on PMMA were retrieved with an atomic force microscope. The object image was reconstructed by numerical reconstruction with phase retrieval algorithm, resulting in a clear, …ghost-free image with sharp edges which infer sub-μm resolution. Future directions for x-ray laser holography are briefly discussed. Show more

DOI: 10.3233/XST-1995-5109

Citation: Journal of X-Ray Science and Technology, vol. 5, no. 1, pp. 105-120, 1995

Authors: Diehl, P. E. | Pew, Hans K. | Madsen, D. W. | Leavitt, John A. | Smith, David J.

Article Type: Research Article

Abstract: Single layer and multilayer films of titanium and Inconel 600 (76 at.% Ni, 16 at.% Cr, 8 at.% Fe) have been prepared by sputtering in argon/nitrogen atmospheres, with nitrogen partial pressures ranging from 0% to 40%. The microstructure and chemistry of the sputtered films were characterized using transmission/high-resolution electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, secondary ion mass spectroscopy, electron probe microanalysis, and ion beam analysis with MeV helium beams. The microstructure depended on deposition power and individual layer thickness, as well as the sputtering atmosphere composition. Metal nitrides were formed in single layers of both materials whereas, for multilayers, …nitrogen was preferentially incorporated into the titanium layer. Show more

DOI: 10.3233/XST-1995-5110

Citation: Journal of X-Ray Science and Technology, vol. 5, no. 1, pp. 121-158, 1995