| Surface Damage Effects Generated by a Fast-Pulse Laser Beam |
06 DEC 94 |
15 pages |
| Authors:
P. G. Burkhalter; J. H. Konnert; E. F. Gabl; NAVAL RESEARCH LAB WASHINGTON DC
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 | A fast-pulse laser was used to induce damage on the surface of a polished silicon wafer. Effects of focused-laser heating at threshold for damage were examined with high-resolution imaging microscopes. The extent and characteristics of various ripple structure were measured with an atomic force microscope. |
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| Soft X-Ray Emission from Alexandrite Laser-Matter-Interaction |
15 JUL 93 |
29 pages |
| Authors:
P. G. Burkhalter; D. J. Harter; E. F. Gabl; P. Bado; D. A. Newman; NAVAL RESEARCH LAB WASHINGTON DC
|
| X-ray spectroscopy was used to quantify the plasma generated by a focused, Alexandrite laser as a potential alternative source in proximity lithography. An x-ray emission efficiency of 2 - 11% was determined by analysis of spectral data (10 - 14A) from transition-metal targets.... X-ray spectroscopy, Proximity, Lithography |
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| X-Ray Emission From Exploded-Wire Array on SATURN |
31 DEC 92 |
38 pages |
| Authors:
P. G. Burkhalter; J. P. Apruzese; J. L. Porter; G. Mehlman; D. A. Newman; NAVAL RESEARCH LAB WASHINGTON DC
|
| X-Ray spectra were collected from sodium imploded-wire emissions employing the 10 MA Saturn pulsed-power accelerator at the Sandia National Laboratories. The spectral profiles of the Na X and XI alpha resonance lines were determined with a high resolution KAP (002) spectrograph while a mica crystal spectrograph was used to acquire the entire sodium K-shell emission. The computer-processed time-integrated intensity data were interpreted by comparing with theoretically-predicted spectra. A static, collisional-radiative ... |
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| Transport in Ultra-Dense Plasmas Produced by a Picosecond Laser Pulse |
06 MAR 92 |
18 pages |
| Authors:
G. Mehlman; P. G. Burkhalter; D. A. Newman; NAVAL RESEARCH LAB WASHINGTON DC
|
| This report presents recent experimental results obtained with the Table Top Terawatt laser at the Ultrafast Science Laboratory (University of Michigan). Interaction of the picosecond laser pulse with an overdense plasma was investigated with spectroscopic observations in the XUV range using a compact 1 m grazing incidence spectrograph. The emission from laser-irradiated targets made of silicon wafers coated with aluminum layers of variable thicknesses (from 100 to 5000A) was recorded ... |
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| Soft X-Ray Emission Spectra from Laser-Irradiated High-Z Targets |
29 JUN 90 |
27 pages |
| Authors:
G. Mehlman; P. G. Burkhalter; D. A. Newman; B. H. Ripin; NAVAL RESEARCH LAB WASHINGTON DC
|
| X-ray data were acquired from mass-limited targets with the Pharos III laser system. Targets, mounted at the tip of thin glass stalks, were microscopic pieces of single or multiple high-Z element composition. The laser irradiance was 4 x 10 to the 14th power W/sq cm with about 300J of focused 1.05 microns wavelength laser beam. A convex KAP crystal spectrograph was used for its capability to collect high resolution spectra ... |
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| Soft X-Ray Emission Spectra from Laser-Irradiated High-Z Targets |
29 JUN 90 |
27 pages |
| Authors:
G. Mehlman; P. G. Burkhalter; D. A. Newman; B. H. Ripin; NAVAL RESEARCH LAB WASHINGTON DC
|
| X-ray data were acquired from mass-limited targets with the Pharos III laser system. Targets, mounted at the tip of thin glass stalks, were microscopic pieces of single or multiple high-Z element composition. The laser irradiance was 4 x 10 to the 14th power w/sg cm with about 300J of focused 1.05 microns wavelength laser beam. A convex KAP crystal spectrograph was used for its capability to collect high resolution spectra ... |
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| X-Ray Performance of Multilayer Diffraction Diagnostics |
13 NOV 89 |
26 pages |
| Authors:
P. G. Burkhalter; R. K. Freitag; J. V. Gilfrich; D. B. Brown; H. B. Rosenstock; NAVAL RESEARCH LAB WASHINGTON DC
|
| X-Ray Spectroscopy is an established diagnostic for the Nuclear Test Program. The high diffraction response of multilayer structures can make important contributions as X-ray diffraction analyzers for UG testing. The soft X-ray performance of a number of commercially deposited multilayers was determined in our laboratory and compared with diffraction theory predictions. |
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| X-Ray Spectra Produced by NaF Implosions |
13 NOV 89 |
19 pages |
| Authors:
G. Mehlman; D. A. Newman; P. G. Burkhalter; NAVAL RESEARCH LAB WASHINGTON DC
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| Spatially-resolved x-ray spectra were collected of imploding sodium plasmas using Naval Research Laboratory Gamble 11 pulsed-power generator. A capillary-discharge was used as the source to inject sodium-fluoride plasmas for the fast Z-pinch implosion experiments. The plasma images recorded by curved- crystal spectrographs correspond to intense emission from a 3.5 cm long plasma column in the 4 cm interelectrode gap. Absolute emissivity values were obtained for the radiation emitted in the ... |
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| X-Ray Spectroscopy of Laser-Produced L-Series Lines |
31 AUG 88 |
29 pages |
| Authors:
P. G. Burkhalter; D. A. Newman; NAVAL RESEARCH LAB WASHINGTON DC
|
| High intensity, frequency-tripled, focused light from a multibeam laser system (OMEGA) was utilized to generate plasma of highly-ionized atoms. This work involves the accurate wavelength measurements of 2p-3d,3s,4d,4s lines in L-series spectra of transition elements. The data were collected with high- resolution x-ray spectrographs. The observed lines were classified based on ab initio, atomic structure calculations using adjusted Slater parameters. The spectral results are presented as isoelectronic sequences of the ... |
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| Spectral Line Shapes from Highly Ionized Sodium Plasmas |
08 MAR 88 |
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| Authors:
G. Mehlman; P. G. Burkhalter; D. A. Newman; NAVAL RESEARCH LAB WASHINGTON DC
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 | Line widths have been measured on spectra from implosions with the Gamble II generator. The K-shell transitions from sodium ions were observed with a curved crystal x-ray spectrograph and imaged with a pinhole camera. The various contributions to spectral line broadening were analyzed. The conclusion is that the line widths were comprised essentially of a source broadening due to the finite plasma size and a plasma broadening due to the ... |
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| Interpretation of X-Ray Spectra from Neon Plasmas Produced by Gas Implosions |
23 MAR 87 |
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| Authors:
G. Mehlman; P. G. Burkhalter; D. A. Newman; SACHS/FREEMAN ASSOCIATES INC LANDOVER MD
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| Spectroscopic measurements of imploded neon plasmas in the energy range 900-1600 eV provide estimates of the plasma thermodynamic properties. Plasma temperatures are found to be in the range 100-140eV. There is experimental evidence for electron densities of several times 10 to the 21st power /cc. Temperature and density gradients are discussed especially for the case of plasmas generated without a fast risetime current driving the implosion, Plasma dynamic properties such ... |
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| X-Ray Spectroscopy with Z-Pinch Neon Plasmas |
31 JUL 86 |
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| Authors:
G. Mehlman; P. G. Burkhalter; D. A. Newman; S. J. Stephanakis; F. C. Young; NAVAL RESEARCH LAB WASHINGTON DC
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| Spatially resolved soft x ray spectra were collected for neon plasmas produced by imploding hollow annular gas puffs with MA level driving currents. the Z pinched imploded plasma were studied for different rise-time currents produced with or without the use of a plasma erosion opening switch (PEOS). Selected spectrograms were processed and analyzed to obtain absolute energies for the radiation emitted in the Neon 1X and Ne X discrete transitions ... |
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| X-Ray Spectroscopy to Determine Line Coincidences |
31 JAN 1983 |
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| Authors:
P. G. Burkhalter; G. Charatis; P. Rockett; NAVAL RESEARCH LAB WASHINGTON DC
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| X-ray spectroscopy in the 12-15 A region of L-shell lines from selected transition elements was performed in a joint Naval Research Laboratory - KMS Fusion, Inc. experiment. The accurate wavelengths determined in this work will be utilized in selecting potential pumping candidates in future X-ray lasing schemes. Specifically, high-resolution X-ray spectra were collected under controlled geometric and target conditions using both red and green light laser excitation in the KMS ... |
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| New Measurement Techniques Using Tracers within Laser-Produced Plasmas |
06 JAN 1983 |
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| Authors:
M. J. Herbst; P. G. Burkhalter; D. Duston; M. Emery; J. Gardner; NAVAL RESEARCH LAB WASHINGTON DC
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| The use of locally embedded tracers within laser-irradiated solid targets has led to a new class of diagnostic methods for laser-produced plasmas. Demonstrated uses of tracers include the first visualizations of hydrodynamic flow of laser-ablated materials and improved spectroscopic measurements of plasma density and temperature profiles; comparisons with a two-dimensional hydrodynamics computer code are shown. Proposed future uses of tracers include the first measurements of fluid velocity profiles and improved ... |
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| Measurements of Laser Coupling and Plasma Profiles in Longer-Scalelength Plasmas |
30 SEP 1982 |
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| Authors:
M. J. Herbst; P. G. Burkhalter; J. Grun; S. P. Obenschain; J. A. Stamper; NAVAL RESEARCH LAB WASHINGTON DC
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| Novel configuration of our two-beam laser allows laser-coupling experiments to be performed in longer-scalelength plasmas (Ln approximately 250- 600 micrometer at nc/10), which better simulate reactor-sized pellet plasmas. Preliminary observations show increased backscatter, as expected, but also reveal large reductions in 2 omega 0 and high-energy x-ray emissions. The latter may indicate lessened importance of resonance absorption in longer-scalelength plasmas. Measurements of plasma profiles are at least as important as ... |
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| Laser-Ablative Acceleration of Targets to Near Inertial Fusion Conditions |
30 AUG 1982 |
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| Authors:
B. H. Ripin; S. E. Bodner; P. G. Burkhalter; H. Griem; J. Grun; NAVAL RESEARCH LAB WASHINGTON DC
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| NRL is investigating the physics issues involved in the direct illumination approach to laser fusion. Millimeter diameter planar targets are ablatively accelerated to speeds and conditions near those required of fusion pellet shells using 3-5 ns, 1.05 micrometer light from the PHAROS II laser. At 5 x 10 to the 13th power W/sq cm targets were accelerated to 160 km/sec with a velocity uniformity of + or - 7% through ... |
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| XUV and Xray Spectra from Texas Experimental Tokamak Plasmas |
28 MAY 1982 |
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| Authors:
R. D. Bleach; P. G. Burkhalter; D. J. Nagel; W. Rowan; NAVAL RESEARCH LAB WASHINGTON DC
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| The first XUV and x-ray spectra were recorded from TEXT with a grazing-incidence grating spectrograph and new crystal spectrographs. Time and space-integrated data yielded a qualitative description of the plasma. Line radiation from O, Cr, Fe, and Ni ions were recorded and identified with the aid of ab initio atomic structure calculations. |
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| Spot Spectroscopy: Local Spectroscopic Measurements within Laser- Produced Plasmas |
20 APR 1982 |
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| Authors:
M. J. Herbst; P. G. Burkhalter; J. Grun; R. R. Whitlock; M. Fink; NAVAL RESEARCH LAB WASHINGTON DC
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| Use of a locally embedded tracer in laser-irradiated solid targets yields a localized source of diagnostic x-ray line radiation in the blowoff plasma. This technique potentially eliminates problems of chord-integration over regions of varying density and temperature in an inhomogeneous plasma, and reduces complications due to plasma opacity effects in the interpretation of spectra. Spectra obtained in an experimental test of this new technique are of a quality superior to ... |
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| XUV and Xray Diagnostics of Relativistic Electron Beam Generated Plasmas |
08 FEB 1982 |
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| Authors:
R. D. Bleach; P. G. Burkhalter; D. J. Nagel; NAVAL RESEARCH LAB WASHINGTON DC
|
| XUV and x-ray plasma diagnostics were performed on several relativistic electron beam generators. The data yield information on the spectral, temporal and spatial behavior of radiation in the 40 eV-6 keV range for the elements Al, Ti, Cr, Fe, and Ni as well as the noble gases Ne, Ar, Kr, and Xe. Temperatures, electron densities, and emitting volume of the plasmas were determined by direct measurement and comparison with theoretical ... |
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| XUV Spectra of Mo XIII-XVIII. |
11 MAR 1980 |
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| Authors:
P. G. Burkhalter; Joseph Reader; Robert D. Cowan; NAVAL RESEARCH LAB WASHINGTON DC
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| Spectral lines from intermediate stages of ionization in Mo were measured and identified. The Mo spectra were observed from a laser-produced plasma and vacuum-spark data. The wavelengths of the 3d10 through 3d9(4p), 4f transitions in Mo XV and the 3p6(3d9) through 3p5(3d10) lines in Mo XVI were measured with an estimated accuracy of plus or minus 0.010A. Line classifications were obtained in complex spectral arrays in Mo XIV-XVIII. These were ... |
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| Laser-Produced X-UV Spectra of Ta and W. |
JAN 1977 |
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| Authors:
P. G. Burkhalter; D. J. Nagel; Robert D. Cowan; NAVAL RESEARCH LAB WASHINGTON D C
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| Spectra of tantalum and tungsten in the 15-100 A region were obtained with a focused Nd:glass laser source coupled to a 600 line/mm grazing-incidence grating spectrograph. The spectral lines were identified as transitions to the 4p subshell. |
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