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in subjects: "Wavelengths"

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Spectra in the 60 )angstrom) to 345 )angstrom) wavelength region of elements injected into the PLT tokamak

High resolution spectra of the elements Fe, Ni, Zn, Ge, Se, and Mo injected into the PLT tokamak were recorded by the 2-meter Schwob-Fraenkel soft X-ray multichannel spectrometer (SOXMOS). Spectra were recorded every 50 ms during the time before and after injection. The spectral lines of the injected element were very strong in the spectrum recorded immedately after injection, and the transition in the injected element were easily distinguished from the transitions in te intrinsic elements (C, … more

Date: March 1, 1988

Creator: Wouters, A.; Schwob, J.L.; Suckewer, S.; Seely, J.F.; Feldman, U. & Dave, J.H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Design study of a 7 kW, visible wavelength FEL

The MIT Lincoln Laboratory is investigating the possibility of building a free electron laser (FEL) operating at an average power of about 7 kW at wavelengths of 500--600 nm. Additional specifications for the FEL include a bandwidth of less than 0.1 cm{sup {minus}1} and a micropulse separation of less than 10 ns. The design study has investigated the basic design parameters of the FEL including an analysis of the electron accelerator, beam line, wiggler and optical cavity. A nonlinear model of … more

Date: January 1, 1990

Creator: Chen, S.C.; Danly, B.G.; Temkin, R.J.; Wurtele, J. & Yang, B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Analysis of polarization properties of shallow metallic gratings by an extended Rayleigh-Fano Theory

Rayleigh-Fano theory has been extended for the purpose of calculating the polarization anomaly of a grating having shallow grooves and finite conductivity. Simple analytic formulas are derived for predicting the position and the appearance of the anomalies. Phenomenological explanations are given to the origin of the anomalies. The validity of our analysis is examined by comparing computed degree of polarization with experimental data obtained in the visible region for Al-, Ag-, and Au-coated b… more

Date: June 1, 1991

Creator: Koike, Masato (Lawrence Berkeley Lab., CA (United States)) & Namioka, Takeshi (Tohoku Univ., Sendai (Japan). Research Inst. for Scientific Measurements)

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Measurements of 2s-2p transition energies in helium-like and lithium-like nickel

The wavelength of the fine structure transition 1s2s /sup 3/S/sub 1/ - 1s2p /sup 3/P/sub 2/ in Ni XXVII has been measured using fast-ion spectroscopy. The transition energy is sensitive to relativistic and Lamb shift corrections in this high-Z two-electron system. Comparison is made with measurements in other high-Z ions and with recent theoretical calculations. A preliminary measurement of the 1s/sup 2/2s /sup 2/S/sub 1/2/ - 1s/sup 2/2p /sup 2/P/sub 1/2/ find structure transition in Ni XXVI is… more

Date: January 1, 1987

Creator: Zacarias, A.S.; Livingston, A.E.; Lu, Y.N.; Ward, R.F.; Berry, H.G. & Dunford, R.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Scattering of elastic waves by small surface-breaking or subsurface cracks in three dimensions

The long-wavelength limit of elastic wave scattering by surface cracks in 3d is considered. It is shown that, if the crack is normal to the surface, the scattering can be described by two real parameters, one of which may be taken to be the crack size. The other therefore depends on shape, orientation, and burial depth. Many computed illustrations are given. It is concluded that the amount of information about cracks obtainable by low frequency elastic wave scattering is very limited.

Date: January 1, 1985

Creator: Visscher, W.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The Los Alamos POP Project: FEL oscillator experiments in the ultraviolet and beyond

The Los Alamos POP Project will include a series of proof-of-principle FEL oscillator experiments in 1992 designed to extend FEL operation into the ultraviolet (UV) and vacuum ultraviolet (VUV). With beam energy extended to 50 MeV, enhanced beam brightness with a photoinjector, and appropriate UV and VUV resonator optics, the Los Alamos FEL oscillator should have sufficient single-pass gain (20--30%) to reach below 200 nm. The first goal will be lasing at 250 nm utilizing a permanent-magnet und… more

Date: January 1, 1992

Creator: Newnam, B. E.; Warren, R. W.; Goldstein, J. C.; Schmitt, M. J.; Bender, S. C.; Carlsten, B. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Measurements of photo-induced changes in conjugated polymers

We have used the highly sensitive technique of Photothermal Deflection Spectroscopy (PDS) to measure changes in the infrared absorption spectra of MEHPPV, P3HT and Polydiacetylene-4BCMU induced by pumping these polymers with light above the {pi}--{pi}* transition energy. In contrast to previous chopped light transmission measurements of these effects, the PDS technique can directly measure the buildup or decay of the absorption coefficient, {alpha}, on the time scale of second to days. In the c… more

Date: January 1, 1991

Creator: Seager, Carleton H.; Sinclair, Michael B.; Mc Branch, D.; Heeger, A. J. & Baker, G. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Operation of a Free-Electron Laser from the Extreme Ultraviolet to the Water Window

We report results on the performance of a free-electron laser operating at a wavelength of 13.7 nm where unprecedented peak and average powers for a coherent extreme-ultraviolet radiation source have been measured. In the saturation regime, the peak energy approached 170 {micro}J for individual pulses, and the average energy per pulse reached 70 {micro}J. The pulse duration was in the region of 10 fs, and peak powers of 10 GW were achieved. At a pulse repetition frequency of 700 pulses per seco… more

Date: December 17, 2007

Creator: Ackermann, W.; Asova, G.; Ayvazyan, V.; Azima, A.; Baboi, N.; Bahr, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Multi-Megajoule NIF: Ushering In a New Era in High Energy Density Science

This paper describes the status of the stadium-sized National Ignition Facility (NIF), the world's largest laser system and first operational multi-megajoule laser. The 192-beam NIF, located at Lawrence Livermore National Laboratory (LLNL), is 96% complete and scheduled for completion in March 2009. The NIF laser will produce nanosecond laser pulses with energies up to approximately 4 MJ in the infrared (laser wavelength = 1.053-{micro}m) and 2MJ in the ultraviolet (laser wavelength = 0.35-{mic… more

Date: April 30, 2008

Creator: Keane, C & Moses, E I

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Electric-dipole 5s - 5p Transitions in Promethiumlike Ions

The 5s-5p electric-dipole resonance transitions in highly ionized promethiumlike ions have been studied applying relativistic multi-reference Moeller-Plesset second-order perturbation theory. The transition wavelengths are determined to within 0.2 {angstrom} in the more highly charged ions, where the level degeneracies are small. For somewhat lighter ions a very large reference space was used in order to account for the many degeneracies. In order to calculate transition probabilities and lifet… more

Date: February 29, 2008

Creator: Vilkas, M J; Ishikawa, Y & Trabert, E

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Damage threshold of inorganic solids under free-electron-laser irradiation at 32.5 nm wavelength

We exposed samples of B4C, amorphous C, chemical-vapor-deposition (CVD)-diamond C, Si, and SiC to single 25 fs-long pulses of 32.5 nm free-electron-laser radiation at fluences of up to 2.2 J/cm{sup 2}. The samples were chosen as candidate materials for x-ray free electron laser (XFEL) optics. We found that the threshold for surface-damage is on the order of the fluence required for thermal melting. For larger fluences, the crater depths correspond to temperatures on the order of the critical te… more

Date: December 3, 2007

Creator: Hau-Riege, S.; London, R. A.; Bionta, R. M.; McKernan, M. A.; Baker, S. L.; Krzywinski, J. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

The Status of the ACRF Millimeter Wave Cloud Radars (MMCRs), the Path Forward for Future MMCR Upgrades, the Concept of 3D Volume Imaging Radar and the UAV Radar

The United States (U.S.) Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) operates millimeter wavelength cloud radars (MMCRs) in several climatological regimes. The MMCRs, are the primary observing tool for quantifying the properties of nearly all radiatively important clouds over the ACRF sites. The first MMCR was installed at the ACRF Southern Great Plains (SGP) site nine years ago and its original design can be traced to the early 90s. Since… more

Date: December 30, 2005

Creator: Kollias, P; Miller, MA; Widener, KB; Marchand, RT & Ackerman, TP

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Isothermal Martensitic and Pressure-Induced Delta to Alpha-Prime Phase Transformations in a Pu-Ga Alloy

A well-homogenized Pu-2 at.% Ga alloy can be retained in the metastable face-centered cubic {delta} phase at room temperature. Ultimately, this metastable {delta} phase will decompose via a eutectoid transformation to the thermodynamically stable monoclinic {alpha} phase and the intermetallic compound Pu{sub 3}Ga over a period of approximately 10,000 years [1]. In addition, these low solute-containing {delta}-phase Pu alloys are metastable with respect to an isothermal martensitic phase transfo… more

Date: January 18, 2008

Creator: Schwartz, A J; Wall, M A; Farber, D L; Moore, K T & Blobaum, K M

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Characterization of an AO-OCT system

Adaptive optics (AO) and optical coherence tomography (OCT) are powerful imaging modalities that, when combined, can provide high-volumetric-resolution, images of the retina. The AO-OCT system at UC Davis has been under development for 2 years and has demonstrated the utility of this technology for microscopic, volumetric, in vivo retinal imaging [1]. The current system uses an AOptix bimorph deformable mirror (DM) for low-order, high-stroke correction [2] and a 140-actuator Boston Micromachine… more

Date: July 26, 2007

Creator: Evans, J. W.; Zawadzki, R. J.; Jones, S.; Olivier, S. & Werner, J. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Laser Drilling: Drilling with the Power of Light Phase 1: Feasibility Study

A laser drilling research team was formed from members of academia, industry and national laboratory to explore the feasibility of using modern high-powered lasers to drill and complete oil and gas wells. The one-year Phase 1 study discussed in this report had the goals of quantifying the amount of pulsed infrared laser energy needed to spall and melt rock of varying lithologies and to investigate the possibility of accomplishing the same task in water under atmospheric conditions. Previous wor… more

Date: September 1, 2001

Creator: Gahan, Brian C.; Parker, Richard A.; Graves, Ramona; Batarseh, Samih; Reed, Claude B.; Xu, Zhiyue et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Sub-diffraction-limited multilayer coatings for the 0.3-NA Micro-Exposure Tool for extreme ultraviolet lithography

This manuscript discusses the multilayer coating results for the primary and secondary mirrors of the Micro Exposure Tool (MET): a 0.30-numerical aperture (NA) lithographic imaging system with 200 x 600 {micro}m{sup 2} field of view at the wafer plane, operating in the extreme ultraviolet (EUV) wavelength region. Mo/Si multilayers were deposited by DC-magnetron sputtering on large-area, curved MET camera substrates, and a velocity modulation technique was implemented to consistently achieve mul… more

Date: January 3, 2007

Creator: Soufli, R.; Hudyma, R. M.; Spiller, E.; Gullikson, E. M.; Schmidt, M. A.; Robinson, J. C. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Electron Density Measurements in the National Spherical Torus Experiment Detached Divertor Region Using Stark Broadening of Deuterium Infrared Paschen Emission Lines

Spatially resolved measurements of deuterium Balmer and Paschen line emission have been performed in the divertor region of the National Spherical Torus Experiment using a commercial 0.5 m Czerny-Turner spectrometer. While the Balmer emission lines, Balmer and Paschen continua in the ultraviolet and visible regions have been extensively used for tokamak divertor plasma temperature and density measurements, the diagnostic potential of infrared Paschen lines has been largely overlooked. We analyz… more

Date: April 27, 2007

Creator: Soukhanovskii, V A; Johnson, D W; Kaita, R & Roquemore, A L

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Phase and Amplitude Control of the Radio Frequency Wave in the Two-Beam Accelerator

The sensitivity of the radio frequency (rf) wave generated by the free electron laser portion of a Two-Beam Accelerator (TBA) is analyzed, both analytically and numerically in a 'resonant particle' approximation. It is shown that the phase of the rf wave is strongly dependent upon errors in the wiggler strength and wavelength and upon the electron beam characteristics of energy and current. The resulting phase error is shown to be unacceptable for a TBA, given reasonable errors in various compo… more

Date: July 1, 1985

Creator: Kuenning, R. W. & Sessler, A. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Low-Temperature Aging Kinetics of a 15-Year Old Water-Quenched U-6wt.% Nb Alloy

It is well known that U-6wt.% Nb (U-14at.% Nb) alloy has a microstructure containing martensitic phases supersaturated with Nb that can be obtained by rapid quenching the alloy from {gamma} (bcc)-field solid solution to room temperature. The high cooling rate forces the {gamma}-phase solid solution to transform to variants of the low-temperature {alpha} (orthorhombic) phase in which Nb is forced to retain in the supersaturated solid solution. However, the crystal lattice of supersaturated solut… more

Date: October 30, 2007

Creator: Hsiung, L & Zhou, J

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Free-Electron Lasers: Present Status and Future Prospects

Free-electron lasers as scientific instruments are reviewed. The present status and future prospects are delineated with attention drawn to the size, complexity, availability, and performance capability of this new tool. The Free-Electron Laser (FEL) was proposed by John Madey in 1970 (1), although earlier work, relevant to the concept, had been performed by Motz (2) and by Phillips (3). Experimental demonstration was achieved by Madey, et. al. in 1975 and 1976 (4). Since that time, FELs of div… more

Date: May 1, 1990

Creator: Kim, K. J. & Sessler, Andrew M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

LDRD final report on continuous wave intersubband terahertz sources.

There is a general lack of compact electromagnetic radiation sources between 1 and 10 terahertz (THz). This a challenging spectral region lying between optical devices at high frequencies and electronic devices at low frequencies. While technologically very underdeveloped the THz region has the promise to be of significant technological importance, yet demonstrating its relevance has proven difficult due to the immaturity of the area. While the last decade has seen much experimental work in ult… more

Date: February 1, 2005

Creator: Samora, Sally; Mangan, Michael A.; Foltynowicz, Robert J.; Young, Erik W.; Fuller, Charles T.; Stephenson, Larry L. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Sensitivity study of reliable, high-throughput resolution metricsfor photoresists

The resolution of chemically amplified resists is becoming an increasing concern, especially for lithography in the extreme ultraviolet (EUV) regime. Large-scale screening and performance-based down-selection is currently underway to identify resist platforms that can support shrinking feature sizes. Resist screening efforts, however, are hampered by the absence of reliable resolution metrics that can objectively quantify resist resolution in a high-throughput fashion. Here we examine two high-… more

Date: July 30, 2007

Creator: Anderson, Christopher N. & Naulleau, Patrick P.

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

Phosphor-Free Solid State Light Sources

The objective of this work was to demonstrate a light emitting diode that emitted white light without the aid of a phosphor. The device was based on the combination of a nitride LED and a fluorescing ZnO substrate. The early portion of the work focused on the growth of ZnO in undoped and doped form. The doped ZnO was successfully engineered to emit light at specific wavelengths by incorporating various dopants into the crystalline lattice. Thereafter, the focus of the work shifted to the epitax… more

Date: February 28, 2007

Creator: Nause, Jeff E; Ferguson, Ian & Doolittle, Alan

Item Type: Report

Partner: UNT Libraries Government Documents Department