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in creator/contributor: "Bajt, S"

open access

Simultaneous imaging of the near- and far-field intensity distributions of the Ni-like Sn X-ray laser

We report on 2D near-field imaging experiments of the 11.9-nm Sn X-ray laser that were performed with a set of novel Mo/Y multilayer mirrors having reflectivities of up to {approx}45% at normal and at 45 incidence. Second-moment analysis of the X-ray laser emission was used to determine values of the X-ray beam propagation factor M{sup 2} for a range of irradiation parameters. The results reveal a reduction of M{sup 2} with increasing prepulse amplitude. The spatial size of the output is a fact… more

Date: July 26, 2004

Creator: Staub, F; Braud, M; Balmer, J E; Nilsen, J & Bajt, S

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Correlated Nitrogen and Carbon Anomalies in an Anhydrous Interplanetary Dust Particle - Implications for Extraterrestrial Organic Matter Accreted by the Prebiotic Earth

Given the ubiquitous presence of H and N isotopic anomalies in interplanetary dust particles (IDPs) and their probable association with carbonaceous material, the lack of similar isotopic anomalies in C has been a major conundrum. We report here the first observation of correlated N and C isotopic anomalies in organic matter within an anhydrous IDP. The {sup 15}N composition of the anomalous region is the highest seen to date in an IDP and is accompanied by a moderate depletion in {sup 13}C. Ou… more

Date: December 17, 2003

Creator: Floss, C; Stadermann, F J; Bradley, J P; Dai, Z; Bajt, S & Graham, G

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Design and Performance of Capping Layers for EUV Multilayer Mirrors

The reflectance stability of multilayer coatings for extreme ultraviolet lithography (EUVL) in a commercial tool environment is of uttermost importance to ensure continuous exposures with minimum maintenance cost. We have made substantial progress in designing the protective capping layer coatings, understanding their performance and estimating their lifetimes based on accelerated electron beam and EUV exposure studies. Our current capping layer coatings have about 40 times longer lifetimes tha… more

Date: March 10, 2003

Creator: Bajt, S.; Chapman, H. N.; Nuygen, N.; Alameda, J.; Robinson, J. C.; Malinowski, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Structural Characterization and Lifetime Stability of Mo/Y Extreme Ultraviolet Multilayer Mirrors

We observe a dramatic dependence of the extreme ultraviolet (EUV) reflectivity of Mo/Y multilayers on the oxygen content of yttrium. This is explained by a change in microstructure, increase in roughness of the Y layers and not by an increase in absorption due to oxygen in Y layers. We find best reflectivity of 38.4% is achieved with an oxygen content of 25%, which reduces to 32.6% and 29.6% for multilayers manufactured from oxygen free yttrium and 39%-oxygen yttrium, respectively. These result… more

Date: May 20, 2004

Creator: Kjornrattanawanich, B & Bajt, S

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

An assesment of yttrium optical constants in the EUV using Mo/Y multilayers designed as linear polarizers

We have produced and characterized Mo/Y multilayers designed as linear-polarizers for use near {lambda} {approx} 8 nm. By depositing these films directly onto silicon photodiodes, we are able to measure both reflectance and transmittance in the EUV using synchrotron radiation. These measurements have been used to access the accuracy of yttrium optical constants in this wavelength range. We describe our experimental results and discuss the prospects for the future development of efficient EUV po… more

Date: September 13, 2004

Creator: Kjornrattanawanich, B; Soufli, R; Bajt, S; Windt, D L & Seely, J F

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Star Formation in High Pressure, High Energy Density Environments: Laboratory Experiments of ISM Dust Analogs

Dust grains control the chemistry and cooling, and thus the gravitational collapse of interstellar clouds. Energetic particles, shocks and ionizing radiation can have a profound influence on the structure, lifetime and chemical reactivity of the dust, and therefore on the star formation efficiency. This would be especially important in forming galaxies, which exhibit powerful starburst (supernovae) and AGN (active galactic nucleus) activity. How dust properties are affected in such environments… more

Date: January 5, 2005

Creator: van Breugel, W; Bajt, S; Bradley, J; Bringa, E; Dai, Z; Felter, T et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

High-efficiency diffractive x-ray optics from sectioned multilayers

We investigate the diffraction properties of sectioned multilayers in Laue (transmission) geometry, at hard x-ray energies (9.5 and 19.5 keV). Two samples are studied, a 200 period W/Si multilayer of 29 nm d-spacing, and a 2020 period Mo/Si multilayer of 7 nm d-spacing, with cross-section depths ranging from 2 to 17 {micro}m. Rocking curves across the Bragg reflections exhibit well-defined interference fringes originating from the depth of the sample. Efficiencies as high as 70% were obtained. … more

Date: December 14, 2004

Creator: Kang, H. C.; Stephenson, G. B.; Liu, C.; Conley, R.; Macrander, A. T.; Maser, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

X-Ray Optics Research for Linac Coherent Light Source: Interaction of Ultra-Short X-Ray Pulses with Matter

Free electron lasers operating in the 0.1 to 1.5 nm wavelength range have been proposed for the Stanford Linear Accelerator Center (USA) and DESY (Germany). The unprecedented brightness and associated fluence predicted for pulses <300 fs pose new challenges for optical components. A criterion for optical component design is required, implying an understanding of x-ray - matter interactions at these extreme conditions. In our experimental effort, the extreme conditions are simulated by curren… more

Date: April 16, 2003

Creator: Kuba, J; Wootton, A; Bionta, R M; Shepherd, R; Fill, E E; Dunn, J et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Comparison of Synchrotron X-Ray Fluorescence Mapping and Micro-XANES to Bulk X-Ray Absorption Spectra in Metal-Contaminated Sediments

Synchrotron X-ray absorption spectroscopy (XAS) is one of the few techniques that can supply molecular-scale information for a variety of elements at concentrations relevant to natural systems in non-vacuum conditions. Bulk XAS analysis supplies the dominant chemical bonding mode(s) for a specific element. In complex materials such as natural soils and sediments, however, the dominant mode may not necessarily be the most reactive because changes in speciation at surfaces may results in changes … more

Date: January 16, 2003

Creator: O'Day, P; Carroll, S A & Bajt, S

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

X-Ray Optics Research for the Linac Coherent Light Source: Interaction of Ultra-Short X-Ray Laser Pulses with Optical Materials

Free electron lasers operating in the 0.1 to 1.5 nm wavelength have been proposed for the Stanford Linear Accelerator Center and DESY (Germany). The unprecedented brightness and associated fluence predicted for pulses <300 fs pose new challenges for optical components. A criterion for optical component design is required, implying an understanding of x-ray-matter interactions at these extreme conditions. In our experimental effort, the extreme conditions are simulated by currently available … more

Date: July 24, 2002

Creator: Kuba, J; Wootton, A; Bionta, R M; Shepherd, R; Dunn, J; Smith, R F et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Simultaneous near-field and far-field imaging of the 11.9-nm Ni-like Sn soft x-ray laser

We report on two-dimensional near-field imaging experiments of the 11.9-nm Sn x-ray laser that were performed with a set of Mo/Y multilayer mirrors having reflectivities of up to {approx}45% at normal and at 45{sup o} incidence. Second-moment analysis of the x-ray laser emission was used to determine values of the x-ray beam propagation factor M{sup 2} for a range of irradiation parameters. The results reveal a reduction of M{sup 2} with increasing prepulse amplitude. The spatial size of the ou… more

Date: October 11, 2004

Creator: Staub, F; Braud, M; Balmer, J E; Nilsen, J & Bajt, S

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Synchrotron x-ray study of multilayers in Laue geometry

Zone plates with depth to zone-width ratios as large as 100 are needed for focusing of hard x-rays. Such high aspect ratios are challenging to produce by lithography. We are investigating the fabrication of high-aspect-ratio linear zone plates by multilayer deposition followed by sectioning. As an initial step in this work, we present a synchrotron x-ray study of constant-period multilayers diffracting in Laue (transmission) geometry. Data are presented from two samples: a 200 period W/Si multi… more

Date: July 21, 2004

Creator: Kang, H. C.; Stephenson, G. B.; Liu, C.; Conley, R.; Macrander, A. T.; Maser, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Oxidation Resistance of Ru-Capped EUV Multilayers

Differently prepared Ru-capping layers, deposited on Mo/Si EUV multilayers, have been characterized using a suite of metrologies to establish their baseline structural, optical, and surface properties in as-deposited state. Same capping layer structures were tested for their thermal stability and oxidation resistance. Post-mortem characterization identified changes due to accelerated tests. The best performing Ru-capping layer structure was studied in detail with transmission electron microscop… more

Date: February 23, 2005

Creator: Bajt, S.; Dai, Z.; Nelson, E. J.; Wall, M. A.; Alameda, J.; Nguyen, N. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Aerogel Keystones: Extraction Of Complete Hypervelocity Impact Events From Aerogel Collectors

In January 2006, the Stardust mission will return the first samples from a solid solar-system body since Apollo, and the first samples of contemporary interstellar dust ever collected. Although sophisticated laboratory instruments exist for the analysis of Stardust samples, techniques for the recovery of particles and particle residues from aerogel collectors remain primitive. Here we describe our recent progress in developing techniques for extracting small volumes of aerogel, which we have ca… more

Date: November 7, 2003

Creator: Westphal, A J; Snead, C; Butterworth, A; Graham, G A; Bradley, J; Bajt, S et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Robust Extraction and Multi-Technique Analysis of Micrometeoroids Captured in Low Earth Orbit

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Date: April 16, 2004

Creator: Westphal, A.; Graham, G.; Bench, G.; Brennan, S.; Luening, K.; Pianetta, P. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Carriers of the astronomical 2175 ? extinction feature

The 2175 {angstrom} extinction feature is by far the strongest spectral signature of interstellar dust observed by astronomers. Forty years after its discovery the origin of the feature and the nature of the carrier remain controversial. The feature is enigmatic because although its central wavelength is almost invariant its bandwidth varies strongly from one sightline to another, suggesting multiple carriers or a single carrier with variable properties. Using a monochromated transmission elect… more

Date: July 20, 2004

Creator: Bradley, J.; Dai, Z.; Ernie, R.; Browning, N.; Graham, G.; Weber, P. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

High-precision reflectometry of multilayer coatings for extreme ultraviolet lithography

Synchrotron-based reflectometry is an important technique for the precise determination of optical properties of reflective multilayer coatings for Extreme Ultraviolet Lithography (EUVL). Multilayer coatings enable normal incidence reflectances of more than 65% in the wavelength range between 11 and 15 nm. In order to achieve high resolution and throughput of EUVL systems, stringent requirements not only apply to their mechanical and optical layout, but also apply to the optical properties of t… more

Date: December 29, 1999

Creator: Wedowski, M; Underwood, J H; Gullikson, E M; Bajt, S; Folta, J A; Kearney, P A et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Study of Combustion Originated Ash Particles

We are engaged in a study of the ash produced by combustion of lignite in a 750-MW power station. The aim is to follow the transport of elements with Z> 16 from the mine, through: (a) the combustion process, (b) emission to the atmosphere or (c) deposition in a land fill, (d) transport in the environment and (e) subsequent uptake by animals and humans. The resulting data will be used to estimate potential adverse impact on human health caused by operation of the power station.

Date: December 31, 1993

Creator: Toeroek, S.; Faigel, G.; Osan, J.; Toeroek, B.; Jones, K. W.; Rivers, M. L. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Multilayers are enabling new science with x-ray free electron lasers

Newly developed multilayer-based mirrors and optical elements enable the imaging of high-resolution structure and ultrafast dynamics of samples with the soft X-ray free electron laser, FLASH, at DESY in Hamburg. The FLASH free-electron laser (FEL) produces intense ultrashort soft X-ray pulses with more than 10{sup 8} times higher peak brightness as compared with the most advanced synchrotron radiation sources. This allows time-resolved X-ray imaging and holography of nanostructures with a tempo… more

Date: July 17, 2007

Creator: Bajt, S & Chapman, H N

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Properites of ultrathin films appropriate for optics capping layers in extreme ultraviolet lithography (EUVL)

The contamination of optical surfaces by irradiation shortens optics lifetime and is one of the main concerns for optics used in conjunction with intense light sources, such as high power lasers, 3rd and 4th generation synchrotron sources or plasma sources used in extreme ultraviolet lithography (EUVL) tools. This paper focuses on properties and surface chemistry of different materials, which as thin layers, could be used as capping layers to protect and extend EUVL optics lifetime. The most pr… more

Date: June 25, 2007

Creator: Bajt, S; Edwards, N V & Madey, T E

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Single Particle Difraction at FLASH

Single-pulse coherent diffraction patterns have been collected from randomly injected single particles with a soft X-ray free-electron laser (FEL). The intense focused FEL pulse gives a high-resolution low-noise coherent diffraction pattern of the object before that object turns into a plasma and explodes. A diffraction pattern of a single particle will only be recorded when the particle arrival into the FEL interaction region coincides with FEL pulse arrival and detector integration. The prope… more

Date: June 11, 2010

Creator: Bogan, M.; Boutet, S.; Starodub, Dmitri; Decorwin-Martin, Philippe; /SLAC; Chapman, H. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A Camera for Coherent Diffractive Imaging and Holography With a Soft-X-Ray Free Electron Laser

We describe a camera to record coherent scattering patterns with a soft-X-ray free-electron laser. The camera consists of a laterally-graded multilayer mirror which reflects the diffraction pattern onto a CCD detector. The mirror acts as a bandpass filter both for wavelength and angle, which isolates the desired scattering pattern from non-sample scattering or incoherent emission from the sample. The mirror also solves the particular problem of the extreme intensity of the FEL pulses, which are… more

Date: September 24, 2007

Creator: Bajt, S.; Chapman, H. N.; Spiller, E.; Alameda, J.; Woods, B.; Frank, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

LCLS soft x-ray imager mirrors and their performance

Soft X-ray imager mirrors have been designed, calibrated and fabricated at Lawrence Livermore National Laboratory and characterized at the Advanced Light Source for their performance between 200 and 1300 eV. The mirrors are coated with a multilayer coating consisting of 70 bilayers of W/ SiC. The mirrors are to reflect at 22.5 deg from grazing angle at 1.50 nm wavelength and the width of the reflectivity peak should be at least 1.3%. Also, the mirrors should be non-reflective elsewhere. Our mul… more

Date: October 19, 2007

Creator: Bajt, S

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Applied Focused Ion Beam Techniques for Sample Preparation of Astromaterials for Integrated Nano-Analysis

Sample preparation is always a critical step in study of micrometer sized astromaterials available for study in the laboratory, whether their subsequent analysis is by electron microscopy or secondary ion mass spectrometry. A focused beam of gallium ions has been used to prepare electron transparent sections from an interplanetary dust particle, as part of an integrated analysis protocol to maximize the mineralogical, elemental, isotopic and spectroscopic information extracted from one individu… more

Date: February 20, 2007

Creator: Graham, G A; Teslich, N E; Kearsley, A T; Stadermann, F J; Stroud, R M; Dai, Z R et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department