Synthesis of Novel Extended Phases of Molecular Solids at High Pressures and Temperatures (open access)

Synthesis of Novel Extended Phases of Molecular Solids at High Pressures and Temperatures

This study is for in-situ investigation of chemical bonding and molecular structure of low z-elements and simple molecular solids at high pressures and temperatures using 3rd-generation synchrotron x-ray diffraction. To understand the contribution of the empty d-electron orbital of Mg in relation to the formation of molecular solids like MgO, which is one of the important Earth lower mantle materials and MgB{sub 2}, which has recently been the focus of intense superconducting material research, we have performed double-sided laser heating experiments using a diamond anvil cell (DAC). Understanding the structural stability and the formation of the above Mg-compounds requires studying Mg itself as well as the relevant compounds. BL10XU at the Spring-8 was used to study phase stability and make accurate equation of state (EOS) determinations of Mg coupled with external heating and the double-sided laser heating technique. Monochromatic x-ray at 30 keV (0.4135 {angstrom}) was focused to about 40 {micro}m at the sample and the diffracted x-ray were recorded using a high-resolution image plate (3000 x 3000 pixels with a 0.1 mm resolution per pixel). EOS parameters for hcp and bcc Mg were determined by fitting to a Birch-Murnaghan equation. An isothermal compression of Mg at 300 K up …
Date: March 30, 2004
Creator: Yoo, C; Evans, W & Cynn, H
Object Type: Report
System: The UNT Digital Library
Effective Operators in the NCSM Formalism (open access)

Effective Operators in the NCSM Formalism

No-core shell model (NCSM) calculations using ab initio effective interactions are very successful in reproducing the experimental nuclear spectra. While a great deal of work has been directed toward computing effective interactions from bare nucleon-nucleon (NN) and three-nucleon forces, less progress has been made in calculating the effective operators. Thus, except for the relative kinetic energy, the proton radius, and the NN pair density, all investigations have used bare operators. We apply the Lee-Suzuki procedure to general two-body operators, investigating the importance of the approximations involved. In particular we concentrate on the limitations of the two-body cluster approximation.
Date: November 30, 2004
Creator: Stetcu, I; Barrett, B R; Navratil, P & Vary, J P
Object Type: Article
System: The UNT Digital Library
Feasibility Study on Using Two Mixer Pumps for Tank 241-AY-102 Waste Mixing (open access)

Feasibility Study on Using Two Mixer Pumps for Tank 241-AY-102 Waste Mixing

The current waste retrieval plan at Hanford calls for using two mixer pumps to mix the waste stored in double-shell Tank 214-AY-102. The objective of this evaluation was to determine whether two rotating 300-hp mixer pumps placed 22 ft (6.7 m) off-center in the tank could adequately mix the AY-102 waste. The tank currently contains high-level waste that is 248 inches (6.3 m) deep, comprising 62 inches (1.58 m) of sludge and 186 inches (4.72 m) of supernatant liquid (Galbraith et al. 2002). Based on the available data, AY-102 waste properties were determined, including the densities of liquid and agglomerated settled solids and crystals, the volume fraction of settled solids, the solid particle size distribution, the liquid and slurry viscosities, and the yield stress in shear (shear strength) of the settled solids layer. To evaluate the likely and bounding cases of AY-102 waste mixing, sludge erosion modeling was performed with a median value of 1,090 Pa (likely condition) and a conservative (more difficult to erode) 97.5 percentile value of 2,230 Pa for shear strength. According to model predictions, the two rotating mixer pumps would erode 89% of the sludge with shear strength of 1,090 Pa. They would erode sludge up …
Date: August 30, 2004
Creator: Onishi, Yasuo & Wells, Beric E.
Object Type: Report
System: The UNT Digital Library
Fabrication of Mo/Cu Multilayer and Bilayer Transition Edge Sensors (open access)

Fabrication of Mo/Cu Multilayer and Bilayer Transition Edge Sensors

We are developing cryogenic high-resolution x-ray, {gamma}-ray and neutron spectrometers based on superconducting Mo/Cu transition edge sensors. Here we discuss the sensor design for different applications, present the photolithographic fabrication techniques, and outline future detector development to increase spectrometer sensitivity.
Date: September 30, 2004
Creator: Ali, Z. A.; Drury, O. B.; Cunningham, M. F.; Chesser, J. M.; Barbee, T. W., Jr. & Friedrich, S.
Object Type: Article
System: The UNT Digital Library
Comparison of Ramsauer and Optical Model Neutron Angular Distributions (open access)

Comparison of Ramsauer and Optical Model Neutron Angular Distributions

The nuclear Ramsauer model is a semi-classical, analytic approximation to nucleon-nucleus scattering that reproduces total cross section data at the 1% level for A > 40, E{sub n} = 5-60 MeV with 7-10 parameters. A quick overview of the model is given, demonstrating the model's utility in nuclear data evaluation. The Ramsauer model predictions for reaction cross section, elastic cross section, and elastic scattering angular distributions are considered. In a recent paper it has been shown that the nuclear Ramsauer model does not do well in predicting details of the angular distribution of neutron elastic scattering for incident energies of less than 60 MeV for {sup 208}Pb. However, in this contribution it is demonstrated that the default angular bin dispersion most widely used in Monte Carlo transport codes is such that the observed differences in angular shapes are on too fine a scale to affect transport calculations. Simple studies indicate that 512-2048 bins are necessary to achieve the dispersion required for calculations to be sensitive to the observed discrepancies in angular distributions.
Date: September 30, 2004
Creator: McNabb, D. P.; Anderson, J. D.; Bauer, R. W.; Dietrich, F. S.; Grimes, S. M. & Hagmann, C. A.
Object Type: Article
System: The UNT Digital Library
Global Security Rule Sets An Analysis of the Current Global Security Environment and Rule Sets Governing Nuclear Weapons Release (open access)

Global Security Rule Sets An Analysis of the Current Global Security Environment and Rule Sets Governing Nuclear Weapons Release

America is in a unique position in its history. In maintaining its position as the world's only superpower, the US consistently finds itself taking on the role of a global cop, chief exporter of hard and soft power, and primary impetus for globalization. A view of the current global situation shows an America that can benefit greatly from the effects of globalization and soft power. Similarly, America's power can be reduced significantly if globalization and its soft power are not handled properly. At the same time, America has slowly come to realize that its next major adversary is not a near peer competitor but terrorism and disconnected nations that seek nuclear capabilities. In dealing with this new threat, America needs to come to terms with its own nuclear arsenal and build a security rule set that will establish for the world explicitly what actions will cause the US to consider nuclear weapons release. This rule set; however, needs to be established with sensitivity to the US's international interests in globalization and soft power. The US must find a way to establish its doctrine governing nuclear weapons release without threatening other peaceful nations in the process.
Date: September 30, 2004
Creator: Mollahan, K & Nattrass, L
Object Type: Report
System: The UNT Digital Library
A 10 kHz Short-Stroke Rotary Fast Tool Servo (open access)

A 10 kHz Short-Stroke Rotary Fast Tool Servo

None
Date: August 30, 2004
Creator: Montesanti, R C & Trumper, D L
Object Type: Article
System: The UNT Digital Library
PROPOSAL FOR A SILICON VERTEX TRACKER (VTX) FOR THE PHENIX EXPERIMENT. (open access)

PROPOSAL FOR A SILICON VERTEX TRACKER (VTX) FOR THE PHENIX EXPERIMENT.

We propose the construction of a Silicon Vertex Tracker (VTX) for the PHENIX experiment at RHIC. The VTX will substantially enhance the physics capabilities of the PHENIX central arm spectrometers. Our prime motivation is to provide precision measurements of heavy-quark production (charm and beauty) in A+A, p(d)+A, and polarized p+p collisions. These are key measurements for the future RHIC program, both for the heavy ion program as it moves from the discovery phase towards detailed investigation of the properties of the dense nuclear medium created in heavy ion collisions, and for the exploration of the nucleon spin-structure functions. In addition, the VTX will also considerably improve other measurements with PHENIX. The main physics topics addressed by the VTX are: (1) Hot and dense strongly interacting matter--Potential enhancement of charm production; Open beauty production; Flavor dependence of jet quenching and QCD energy loss; Accurate charm reference for quarkonium; Thermal dilepton radiation; High p{sub T} phenomena with light flavors above 10-15 GeV/c in p{sub T}; and Upsilon spectroscopy in the e{sup +}e{sup -} decay channel. (2) Gluon spin structure of the nucleon--{Delta}G/G with charm; {Delta}G/G with beauty; and x dependence of {Delta}G/G with {gamma}-jet correlations. (3) Nucleon structure in nuclei--Gluon shadowing over …
Date: March 30, 2004
Creator: AKIBA,Y.
Object Type: Report
System: The UNT Digital Library
Sealed Combustion System With Diagnostic Self-Tuning. (open access)

Sealed Combustion System With Diagnostic Self-Tuning.

This task grew out of a proposal to develop a ''concept'' oil-fired heating system that would incorporate advanced technologies available and suitable for a residential system. Discussions among the program and project personnel resulted in the identification of a sealed combustion system as of programmatic interest and the objective was to develop an approach to a sealed system with diagnostic self-tuning. The major conclusion with regard to the specific objective for this task is that a measurement of the static pressure in the input pipe can be used to provide a measure of the excess air for a limit control. Its implementation would require a suitable pressure sensor, and a circuit to combine its output signal, at the appropriate time in the operating cycle, to the burner control. The sensor and control combination will also have to be tested successfully under all conceivable contingencies that can cause the airflow to decrease. It could also be implemented, possibly even more reliably, if a mass flow sensor, such as is used in automobile engines and hence may be cheap, could be used. The pressure measurements reported here, both steady and transient, represent only the subset of a much larger set that gave …
Date: September 30, 2004
Creator: Krishna, C. R.
Object Type: Report
System: The UNT Digital Library
Ab Initio No-Core Shell Model Calculations Using Realistic Two- and Three-Body Interactions (open access)

Ab Initio No-Core Shell Model Calculations Using Realistic Two- and Three-Body Interactions

There has been significant progress in the ab initio approaches to the structure of light nuclei. One such method is the ab initio no-core shell model (NCSM). Starting from realistic two- and three-nucleon interactions this method can predict low-lying levels in p-shell nuclei. In this contribution, we present a brief overview of the NCSM with examples of recent applications. We highlight our study of the parity inversion in {sup 11}Be, for which calculations were performed in basis spaces up to 9{Dirac_h}{Omega} (dimensions reaching 7 x 10{sup 8}). We also present our latest results for the p-shell nuclei using the Tucson-Melbourne TM three-nucleon interaction with several proposed parameter sets.
Date: November 30, 2004
Creator: Navratil, P; Ormand, W E; Forssen, C & Caurier, E
Object Type: Article
System: The UNT Digital Library
Turbulence Kinetic Energy in the Oklahoma City Urban Environment (open access)

Turbulence Kinetic Energy in the Oklahoma City Urban Environment

The Joint URBAN 2003 field experiment took place in Oklahoma City, Oklahoma, during July 2003 to explore the effect of an urban canopy on the transport and diffusion of a passive tracer released in an urban area. Over one hundred three-dimensional sonic anemometers were deployed in and around the urban area to monitor wind speed, direction, and turbulence during releases of SF6. Deployment locations include a profile of eight sonic anemometers mounted on a crane located 1 km north (typically downwind) of the central business district, and several surface meteorological towers within an urban canyon.
Date: March 30, 2004
Creator: Lundquist, J K; Leach, M & Gouveia, F
Object Type: Article
System: The UNT Digital Library
Neutron and Charged-Particle Induced Cross Sections for Radiochemistry in the Region of Samarium, Europium, and Gadolinium (open access)

Neutron and Charged-Particle Induced Cross Sections for Radiochemistry in the Region of Samarium, Europium, and Gadolinium

We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron and proton induced nuclear reaction cross sections in the mass region of samarium, europium and gadolinium (62 {le} Z {le} 64, 82 {le} N {le} 96).
Date: November 30, 2004
Creator: Hoffman, R. D.; Kelley, K.; Dietrich, F. S.; Bauer, R. & Mustafa, M.
Object Type: Report
System: The UNT Digital Library
In Search of the Next Micron? (open access)

In Search of the Next Micron?

Lawrence Livermore National Lab's National Ignition Facility (NIF) Project presents numerous measurement challenges and tasks, demanding an extremely high level of precision and accuracy. This paper discusses some of the efforts to optimize, and better understand the results and looks at some of the alignment tools tested to lay hold of this complex task. The methodologies discussed were commonplace in the 'good old days' of land surveying. However, with the introduction of high accuracy equipment many of those practices have fallen by the wayside. This paper looks at the results of a series of in-depth, comparison measurements using three different laser tracker measurement instruments.
Date: June 30, 2004
Creator: Nelson, D C
Object Type: Article
System: The UNT Digital Library
Recharge Data Package for the 2005 Integrated Disposal Facility Performance Assessment (open access)

Recharge Data Package for the 2005 Integrated Disposal Facility Performance Assessment

Pacific Northwest National Laboratory assisted CH2M Hill Hanford Group, Inc., (CHG) by providing estimates of recharge rates for current conditions and long-term scenarios involving disposal in the Integrated Disposal Facility (IDF). The IDF will be located in the 200 East Area at the Hanford Site and will receive several types of waste including immobilized low-activity waste. The recharge estimates for each scenario were derived from lysimeter and tracer data collected by the IDF PA Project and from modeling studies conducted for the project. Recharge estimates were provided for three specific site features (the surface barrier; possible barrier side slopes; and the surrounding soil) and four specific time periods (pre-Hanford; Hanford operations; surface barrier design life; post-barrier design life). CHG plans to conduct a performance assessment of the latest IDF design and call it the IDF 2005 PA; this recharge data package supports the upcoming IDF 2005 PA.
Date: June 30, 2004
Creator: Fayer, Michael J. & Szecsody, Jim E.
Object Type: Report
System: The UNT Digital Library
Ray tracing through a hexahedral mesh in HADES (open access)

Ray tracing through a hexahedral mesh in HADES

In this paper we describe a new ray tracing method targeted for inclusion in HADES. The algorithm tracks rays through three-dimensional tetrakis hexahedral mesh objects, like those used by the ARES code to model inertial confinement experiments.
Date: November 30, 2004
Creator: Henderson, G L & Aufderheide, M B
Object Type: Article
System: The UNT Digital Library
Neutron and Charged-Particle Induced Cross Sections for Radiochemistry for Isotopes of Scandium, Titanium, Vanadium, Chromium, Manganese, and Iron (open access)

Neutron and Charged-Particle Induced Cross Sections for Radiochemistry for Isotopes of Scandium, Titanium, Vanadium, Chromium, Manganese, and Iron

We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Local systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron and proton induced nuclear reaction cross sections in the mass region of scandium, titanium, vanadium, chromium, manganese, and iron (21 {le} Z {le} 26, 20 {le} N {le} 32).
Date: November 30, 2004
Creator: Kelley, K.; Hoffman, R. D.; Dietrich, F. S.; Bauer, R. & Mustafa, M.
Object Type: Report
System: The UNT Digital Library
Structural and Functional Studies of the Protamine 2-Zinc Complex from Syrian Gold Hamster (Mesocricetus Auratus) Spermatids and Sperm (open access)

Structural and Functional Studies of the Protamine 2-Zinc Complex from Syrian Gold Hamster (Mesocricetus Auratus) Spermatids and Sperm

The research described in this dissertation consists of four major areas: (1) sequence analysis of protamine 2 from Muroid rodents to identify potential zinc-binding domain(s) of protamine 2; (2) structural studies of the protamine 2-zinc complex from Syrian Gold hamster sperm and spermatids to elucidate the role of zinc during spermiogenesis; (3) structural studies of an unique protamine 2-zinc complex from chinchilla sperm; and (4) Nuclear Magnetic Resonance (NMR) studies of soluble complexes of hairpin oligonucleotides with synthetic arginine-rich peptides or protamine 1 isolated from bull sperm. First, zinc was quantitated in spermatids and sperm by Proton-Induced X-ray Emission (PIXE) to determine whether zinc is present in the early stages of spermiogenesis. The PIXE results revealed the zinc content varies proportionately with the amount of protamine 2 in both spermatid and sperm nuclei. An exception was chinchilla sperm containing twice the amount of protamine 2 than zinc. Further analyses by PIXE and X-ray Absorption Spectroscopy (XAS) of zinc bound to protamines isolated from hamster sperm confirmed the majority of the zinc is bound to protamine and identified the zinc ligands of protamine 2 in hamster spermatids and sperm in vivo. These studies established that zinc is bound to the protamine …
Date: August 30, 2004
Creator: Dolan, C E
Object Type: Thesis or Dissertation
System: The UNT Digital Library
ASSESSMENT OF RADIONUCLIDE RELEASE FROM INTACT STRUCTURES BACKFILLED WITH CONTAMINATED CONCRETE AT THE YANKEE NUCLEAR POWER STATION. (open access)

ASSESSMENT OF RADIONUCLIDE RELEASE FROM INTACT STRUCTURES BACKFILLED WITH CONTAMINATED CONCRETE AT THE YANKEE NUCLEAR POWER STATION.

This calculation determines the release of residual radioactivity (including H-3, C-14, Co-60, Ni-63, Sr-90, and Cs-137), from subsurface structures filled with concrete debris at the Yankee Nuclear Power Station. Analyses were performed to assess the rate of release from the source of contamination and the resulting dose in the groundwater pathway. Two mechanisms were considered, diffusive release from the concrete structures (walls and floors) that remain intact and sorption onto concrete backfill placed within these structures. RESRAD was used to calculate the predicted maximum dose assuming a unit loading of 1 pCi/g on the intact structures. To the extent possible, the same assumptions in the soil DCGL calculations performed for Yankee Atomic were used in the calculation. However, modifications to some input parameter values were needed to represent the geometry of the subsurface facilities, flow through these facilities, and releases from the backfill and intact structures. Input parameters specific to these calculations included the leach rate, disposal geometry, pumping rate, porosity and bulk density. The dose results for a unit loading of 1 pCi/g on intact structures showed that Sr-90 had the highest dose (3.67E-02 mrem/yr).
Date: September 30, 2004
Creator: SULLIVAN, T.
Object Type: Report
System: The UNT Digital Library
Review of the Thermodynamic Properties of Mg(NO3)2(ap), and Their Representation with the Standard and Extended Ion-Interaction (Pitzer) Models at 298.15 K (open access)

Review of the Thermodynamic Properties of Mg(NO3)2(ap), and Their Representation with the Standard and Extended Ion-Interaction (Pitzer) Models at 298.15 K

Published thermodynamic data yielding the osmotic coefficients, relative apparent molar enthalpies, and apparent molar heat capacities of Mg(NO{sub 3}){sub 2}(aq) have been collected, recalculated consistently, and critically assessed. The more reliable of these data have been used to evaluate the parameters of the standard three-parameter form of Pitzer's ion-interaction model to higher molalities than previously available, along with the parameters of Archer's four-parameter, extended ion-interaction model, at 298.15 K. Published experimental thermodynamic data were essentially represented equally well by these two models, provided that the exponential coefficient {alpha}{sub 1} of the standard Pitzer model is fixed at the optimum value of {alpha}{sub 1} = 1.55 kg{sup -1/2} x mol{sup -1/2} rather than the traditional value of {alpha}{sub 1} = 2.0 kg{sup -1/2} x mol{sup -1/2} The use of the standard Pitzer model with this modified {alpha}{sub 1} value is recommended for Mg(NO{sub 3}){sub 2}(aq). In addition, an empirical equation is given for the variation of the water activity of a saturated solution with temperature, from 273.54 to 328.20 K, with Mg(NO{sub 3}){sub 2}(aq) x 6H{sub 2}O(s) as the solid phase.
Date: March 30, 2004
Creator: Rard, J A; Wijesinghe, A M & Wolery, T J
Object Type: Article
System: The UNT Digital Library
Effective Operators Within the Ab Initio No-Core Shell Model (open access)

Effective Operators Within the Ab Initio No-Core Shell Model

We implement an effective operator formalism for general one- and two-body operators, obtaining results consistent with the no-core shell model (NCSM) wave functions. The Argonne V8' nucleon-nucleon potential was used in order to obtain realistic wave functions for {sup 4}He, {sup 6}Li and {sup 12}C. In the NCSM formalism, we compute electromagnetic properties using the two-body cluster approximation for the effective operators and obtain results which are sensitive to the range of the bare operator. To illuminate the dependence on the range, we employ a Gaussian two-body operator of variable range, finding weak renormalization of long range operators (e.g., quadrupole) in a fixed model space. This is understood in terms of the two-body cluster approximation which accounts mainly for short-range correlations. Consequently, short range operators, such as the relative kinetic energy, will be well renormalized in the two-body cluster approximation.
Date: November 30, 2004
Creator: Stetcu, I; Barrett, B R; Navratil, P & Vary, J P
Object Type: Article
System: The UNT Digital Library
Imaging VISAR diagnostic for the National Ignition Facility (NIF) (open access)

Imaging VISAR diagnostic for the National Ignition Facility (NIF)

The National Ignition Facility (NIF) requires diagnostics to analyze high-energy density physics experiments. A VISAR (Velocity Interferometry System for Any Reflector) diagnostic has been designed to measure shock velocities, shock breakout times, and shock emission of targets with sizes from 1 to 5 mm. An 8-inch-diameter fused silica triplet lens collects light at f/3 inside the 30-foot-diameter vacuum chamber. The optical relay sends the image out an equatorial port, through a 2-inch-thick vacuum window, and into two interferometers. A 60-kW VISAR probe laser operates at 659.5 nm with variable pulse width. Special coatings on the mirrors and cutoff filters are used to reject the NIF drive laser wavelengths and to pass a band of wavelengths for VISAR, passive shock breakout light, or thermal imaging light (bypassing the interferometers). The first triplet can be no closer than 500 mm from the target chamber center and is protected from debris by a blast window that is replaced after every event. The front end of the optical relay can be temporarily removed from the equatorial port, allowing other experimenters to use that port. A unique resolution pattern has been designed to validate the VISAR diagnostic before each use. All optical lenses are on …
Date: August 30, 2004
Creator: Malone, R M; Bower, J R; Bradley, D K; Capelle, G A; Celeste, J R; Celliers, P M et al.
Object Type: Article
System: The UNT Digital Library
R and D Experiments at BNL to Address the Associated Issues in the Cascading HGHG Scheme (open access)

R and D Experiments at BNL to Address the Associated Issues in the Cascading HGHG Scheme

The proof-of-principle HGHG experiment at 5 {mu} [1, 2] and recent HGHG experiment at DUVFEL [3] have generated significant interests in the FEL community. The more relaxed requirement on electron beam current and emittance to generate coherent deep UV output with much narrower bandwidth and high pulse energy stability, as exhibited by the recent experiment, and its potential to be generalized to soft-x-ray FEL, have attracted much attention. Several labs, including BESSY, ELETRRA, LBL, MIT, and SSRF proposed the development of UVFEL based on HGHG principle or soft-x-ray FEL based on the cascaded HGHG principle [4, 5]. Among them SSRF has already started the construction of an FEL system based on the HGHG principle [6]. Hence it would be a contribution to be able to carry out a first proof-of-principle experiment of cascaded HGHG at DUVFEL. In this paper, we discuss this experiment and several associated experiments that can be carried out at BNL before this experiment and may also have important impact on the development of multi-stage cascaded HGHG FELs.
Date: August 30, 2004
Creator: Yu, L. H.
Object Type: Article
System: The UNT Digital Library
Characterization of the Near-Field Transport and Dispersion of Vapors Released from the Headspaces of Hanford Site Underground Storage Tanks (open access)

Characterization of the Near-Field Transport and Dispersion of Vapors Released from the Headspaces of Hanford Site Underground Storage Tanks

A parametric air dispersion analysis has been conducted to define the range of tank vapor concentrations from the Hanford Site underground tanks that can potentially occur in the worker breathing zones from active and passive releases from the waste tanks. The potential influences of tank farm specific release characteristics, ambient meteorological conditions, local farm surface roughness, and topographical influences are considered. The parametric approach allows consideration of the full range venting configurations and potential vapor concentration over the range of meteorological conditions at the Hanford Site. The results indicate that occasional short duration exposures of up to several seconds to relatively undiluted headspace air can be expected in the immediate vicinity of the tank vents. Average concentrations which represent diffusion, as well as spatial averaging, fall off rapidly with distance for the passive vents and to a lesser extent for the forced-air stacks. The addition of the influence of the surface roughness elements on the tank farms will result in a faster decrease of concentrations with downwind distance.
Date: July 30, 2004
Creator: Droppo, James G.
Object Type: Report
System: The UNT Digital Library
Fielding of an Imaging VISAR Diagnostic at the National Ignition Facility (NIF) (open access)

Fielding of an Imaging VISAR Diagnostic at the National Ignition Facility (NIF)

The National Ignition Facility (NIF) requires diagnostics to analyze high-energy density physics experiments. As a core NIF early light diagnostic, this system measures shock velocities, shock breakout times, and shock emission of targets with sizes from 1 to 5 mm. A 659.5 nm VISAR probe laser illuminates the target. An 8-inch-diameter fused silica triplet lens collects light at f/3 inside the 33-foot-diameter vacuum chamber. The optical relay sends the image out an equatorial port, through a 2-inch-thick vacuum window, and into two VISAR (Velocity Interferometer System for Any Reflector) interferometers. Both streak cameras and CCD cameras record the images. Total track is 75 feet. The front end of the optical relay can be temporarily removed from the equatorial port, allowing for other experimenters to use that port. The first triplet can be no closer than 500 mm from the target chamber center and is protected from debris by a blast window that is replaced after every event. Along with special coatings on the mirrors, cutoff filters reject the NIF drive laser wavelengths and pass a band of wavelengths for VISAR, for passive shock breakout light, or for thermal imaging light (bypassing the interferometers). Finite Element Analysis was performed on all …
Date: June 30, 2004
Creator: Malone, R.; Bower, J.; Capelle, G.; Celeste, J.; Celliers, P.; Frogget, B. C. et al.
Object Type: Article
System: The UNT Digital Library