Combined Heat and Power for Saving Energy and Carbon inResidential Buildings (open access)

Combined Heat and Power for Saving Energy and Carbon inResidential Buildings

This report is the description of saving carbon in residences using the microCHP.
Date: April 15, 2000
Creator: Kaarsberg, Tina; Fiskum, Ronald; Deppe, Andreas; Kumar, Satish; Rosenfeld, Arthur; Romm, Joseph et al.
System: The UNT Digital Library
Structural aspects of the fivefold quasicrystalline Al-Cu-Fe surface from STM and dynamical LEED Studies (open access)

Structural aspects of the fivefold quasicrystalline Al-Cu-Fe surface from STM and dynamical LEED Studies

We investigate the atomic structure of the fivefold surface of an icosahedral Al-Cu-Fe alloy, using scanning tunneling microscopy (STM) imaging and a special dynamical low energy-electron diffraction (LEED) method. STM indicates that the step heights adopt (primarily) two values in the ratio of tau, but the spatial distribution of these two values does not follow a Fibonacci sequence, thus breaking the ideal bulk-like quasicrystalline layer stacking order perpendicular to the surface. The appearance of screw dislocations in the STM images is another indication of imperfect quasicrystallinity. On the other hand, the LEED analysis, which was successfully applied to Al-Pd-Mn in a previous study, is equally successful for Al-Cu-Fe. Similar structural features are found for both materials, in particular for interlayer relaxations and surface terminations. Although there is no structural periodicity, there are clear atomic planes in the bulk of the quasicrystal, some of which can be grouped in recurring patterns. The surface tends to form between these grouped layers in both alloys. For Al-Cu-Fe, the step heights measured by STM are consistent with the thicknesses of the grouped layers favored in LEED. These results suggest that the fivefold Al-Cu-Fe surface exhibits a quasicrystalline layering structure, but with stacking defects.
Date: April 15, 2001
Creator: Cai, T.; Shi, F.; Shen, Z.; Gierer, M.; Goldman, A. I.; Kramer, M. J. et al.
System: The UNT Digital Library
Advances in Low-Defect Multilayers for EUVL Mask Blanks (open access)

Advances in Low-Defect Multilayers for EUVL Mask Blanks

Low-defect multilayer coatings are required to fabricate mask blanks for Extreme Ultraviolet Lithography (EUVL). The mask blanks consist of high reflectance E W multilayers on low thermal expansion substrates. A defect density of 0.0025 printable defects/cm{sup 2} for both the mask substrate and the multilayer is required to provide a mask blank yield of 60%. Current low defect multilayer coating technology allows repeated coating-added defect levels of 0.05/cm{sup 2} for defects greater than 90 nm polystyrene latex sphere (PSL) equivalent size for lots of 20 substrates. Extended clean operation of the coating system at levels below 0.08/cm{sup 2} for 3 months of operation has also been achieved. Two substrates with zero added defects in the quality area have been fabricated, providing an existence proof that ultra low defect coatings are possible. Increasing the ion source-to-target distance from 410 to 560 mm to reduce undesired coating of the ion source caused the defect density to increase to 0.2/cm{sup 2}. Deposition and etching diagnostic witness substrates and deposition pinhole cameras showed a much higher level of ion beam spillover (ions missing the sputter target) than expected. Future work will quantify beam spillover, and test designs to reduce spillover, if it is confirmed …
Date: April 15, 2002
Creator: Folta, J. A.; Davidson, J. C.; Larson, C. C.; Walton, C. C. & Kearney, P. A.
System: The UNT Digital Library
Design, operational experiences and beam results obtained with the SNS H- ion source and LEBT at Berkeley Lab (open access)

Design, operational experiences and beam results obtained with the SNS H- ion source and LEBT at Berkeley Lab

The ion source and Low-Energy Transport (LEBT) system that will provide H{sup -} ion beams to the Spallation Neutron Source (SNS)** Front End and the accelerator chain have been developed into a mature unit that fully satisfies the operational requirements through the commissioning and early operating phases of SNS. Compared to the early R&D version, many features of the ion source have been improved, and reliable operation at 6% duty factor has been achieved producing beam currents in the 35-mA range and above. LEBT operation proved that the purely electrostatic focusing principle is well suited to inject the ion beam into the RFQ accelerator, including the steering and pre-chopping functions. This paper will discuss the latest design features of the ion source and LEBT, give performance data for the integrated system, and report on commissioning results obtained with the SNS RFQ and Medium-Energy Beam Transport (MEBT) system. Prospects for further improvements will be outlined in concluding remarks.
Date: April 15, 2002
Creator: Keller, R.; Thomae, R.; Stockli, M. & Welton, R.
System: The UNT Digital Library
The effect of penetration factor, deposition, and environmental factors on the indoor concentration of PM2.5 sulfate, nitrate, and carbon (open access)

The effect of penetration factor, deposition, and environmental factors on the indoor concentration of PM2.5 sulfate, nitrate, and carbon

Indoor exposure to particles of outdoor origin constitutes an important exposure pathway. We conducted an intensive set of indoor particle measurements in an unoccupied house under differing operating conditions. Real-time measurements were conducted both indoors and outdoors, including PM2.5 nitrate, sulfate, and carbon. Because the time-scale of the fluctuations in outdoor particle concentrations and meteorological conditions are often similar to the time constant for building air exchange, a steady state concentration may never be reached. The time-series experimental data were used to determine the effect of changes in air exchange rate and indoor/outdoor temperature and relative humidity differences on indoor particle concentrations. A multivariate regression was performed to investigate the difference between measured indoor concentrations and results from a simple time-dependent physical model. Environmental conditions had a significant effect on indoor concentrations of all three PM2.5 species, but did not explain all of the model variation.
Date: April 15, 2002
Creator: Thatcher, T. L.; Lunden, M. M.; Sextro, R. G.; Hering, S. & Brown, N. J.
System: The UNT Digital Library
Electrical and optical properties of carbon-doped GaN grown by MBE on MOCVD GaN templates using a CCl4 dopant source (open access)

Electrical and optical properties of carbon-doped GaN grown by MBE on MOCVD GaN templates using a CCl4 dopant source

Carbon-doped GaN was grown by plasma-assisted molecular-beam epitaxy using carbon tetrachloride vapor as the dopant source. For moderate doping mainly acceptors were formed, yielding semi-insulating GaN. However at higher concentrations p-type conductivity was not observed, and heavily doped films (>5 x 10{sup 20} cm{sup -3}) were actually n-type rather than semi-insulating. Photoluminescence measurements showed two broad luminescence bands centered at 2.2 and 2.9 eV. The intensity of both bands increased with carbon content, but the 2.2 eV band dominated in n-type samples. Intense, narrow ({approx}6 meV) donor-bound exciton peaks were observed in the semi-insulating samples.
Date: April 15, 2002
Creator: Armitage, Rob; Yang, Qing; Feick, Henning; Park, Yeonjoon & Weber, Eicke R.
System: The UNT Digital Library
Employing Thin HPGe Detectors for Gamma-Ray Imaging (open access)

Employing Thin HPGe Detectors for Gamma-Ray Imaging

We have evaluated a collimator-less gamma-ray imaging system, which is based on thin layers of double-sided strip HPGe detectors. The position of individual gamma-ray interactions will be deduced by the strip addresses and the Ge layers which fired. Therefore, high bandwidth pulse processing is not required as in thick Ge detectors. While the drawback of such a device is the increased number of electronics channels to be read out and processed, there are several advantages, which are particularly important for remote applications: the operational voltage can be greatly reduced to fully deplete the detector and no high bandwidth signal processing electronics is required to determine positions. Only a charge sensitive preamplifier, a slow pulse shaping amplifier, and a fast discriminator are required on a per channel basis in order to determine photon energy and interaction position in three dimensions. Therefore, the power consumption and circuit board real estate can be minimized. More importantly, since the high bandwidth signal shapes are not used to determine the depth position, lower energy signals can be processed. The processing of these lower energy signals increases the efficiency for the recovery of small angle scattering. Currently, we are studying systems consisting of up to ten …
Date: April 15, 2002
Creator: Vetter, K; Mihailescu, L; Ziock, K; Burks, M; Hull, E; Madden, N et al.
System: The UNT Digital Library
Investigations of low amplitude radio frequency pulses at and awayfro m rotary resonance conditions for I = 5/2 nuclei (open access)

Investigations of low amplitude radio frequency pulses at and awayfro m rotary resonance conditions for I = 5/2 nuclei

Additional experimental evidence of rotary resonance effects for multiple-quantum coherence conversion in a spin-5/2 system is presented. Two dimensional plots of the relative efficiency of MQ excitation and conversion are given as a function of radio frequency (rf) amplitude and pulse width. Data are presented for the excitation of five-quantum coherence (5QC), as well as for 5QC to three-quantum coherence (3QC) conversion, 5QC to 1QC (the central transition coherence) conversion, and 3QC to 1QC conversion. A two-fold increase in the signal-to-noise ratio is achieved by substituting low amplitude rf pulses in place of hard rf pulses for 5QC excitation and 5QC to 3QC conversion in a mixed multiple-quantum MAS (MMQMAS) experiment. The anisotropic line shape for the low amplitude rf pulse version of the MMQMAS experiment was observed to be distorted from the MAS line shape. The cause and implications of the distortion are discussed.
Date: April 15, 2002
Creator: Logan, John W.; Urban, Jeffry T.; Walls, Jamie D.; Lim, Kwang Hun; Jerschow, Alexej & Pines, Alexander
System: The UNT Digital Library
The Snowmass points and slopes : benchmarks for SUSY searches. (open access)

The Snowmass points and slopes : benchmarks for SUSY searches.

The ''Snowmass Points and Slopes'' (SPS) are a set of benchmark points and parameter lines in the MSSM parameter space corresponding to different scenarios in the search for Supersymmetry at present and future experiments. This set of benchmarks was agreed upon at the 2001 ''Snowmass Workshop on the Future of Particle Physics'' as a consensus based on different existing proposals.
Date: April 15, 2002
Creator: Allanach, B. C.; Battaglia, M.; Blair, G. A.; Carena, M.; De Roeck, A. & Wagner, C. E. M.
System: The UNT Digital Library
Suggestions for benchmark scenarios for MSSM Higgs Boson searches at hadron colliders. (open access)

Suggestions for benchmark scenarios for MSSM Higgs Boson searches at hadron colliders.

The Higgs boson search has shifted from LEP2 to the Tevatron and will subsequently move to the LHC. Due to the different initial states, the Higgs production and decay channels relevant for Higgs boson searches were different at LEP2 to what they are at hadron colliders. They suggest new benchmark scenarios for the MSSM Higgs boson search at hadron colliders that exemplify the phenomenology of different parts of the MSSM parameter space. Besides the m{sub h}{sup max} scenario and the no-mixing scenario used in the LEP2 Higgs boson searches, they propose two new scenarios. In one the main production channel at the LHC, gg {yields} h, is suppressed. In the other, important Higgs decay channels at the Tevatron and at the LCH, h {yields} b{bar b} and h {yields} {tau}{sup +}{tau}{sup -}, are suppressed. All scenarios evade the LEP2 constraints for nearly the whole M{sub A}-tan {beta}-plane.
Date: April 15, 2002
Creator: Carena, M.; Heinemeyer, S.; Wagner, C.E.M. & Weiglein, G.
System: The UNT Digital Library
SUSY dark matter and non-universal gaugino masses (open access)

SUSY dark matter and non-universal gaugino masses

In this talk the authors investigate the dark matter prospects for supersymmetric models with non-universal gaugino masses. They motivate the use of non-universal gaugino masses from several directions, including problems, with the current favorite scenario, the cMSSM. They then display new corridors of parameter space that allow an acceptable dark matter relic density once gaugino mass universality is relaxed. They finish with a specific string-derived model that allows this universality relaxation and then use the dark matter constraint to make specific statements about the hidden sector of the model.
Date: April 15, 2002
Creator: Birkedal-Hansen, Andreas
System: The UNT Digital Library
Uniaxial creep behavior of V-4Cr-4Ti alloy. (open access)

Uniaxial creep behavior of V-4Cr-4Ti alloy.

We are undertaking a systematic study at Argonne National Laboratory to evaluate the uniaxial creep behavior of V-Cr-Ti alloys in a vacuum environment as a function of temperature in the range of 650-800 C and at applied stress levels of 75-380 MPa. Creep strain in the specimens is measured by a linear-variable-differential transducer, which is attached between the fixed and movable pull rods of the creep assembly. Strain is measured at sufficiently frequent intervals during testing to define the creep strain/time curve. A linear least-squares analysis function is used to ensure consistent extraction of minimum creep rate, onset of tertiary creep, and creep strain at the onset of tertiary creep. Creep test data, obtained at 650, 700, 725, and 800 C, showed power-law creep behavior. Extensive analysis of the tested specimens is conducted to establish hardness profiles, oxygen content, and microstructural characteristics. The data are also quantified by the Larson-Miller approach, and correlations are developed to relate time to rupture, onset of tertiary creep, times for 1 and 2% strain, exposure temperature, and applied stress.
Date: April 15, 2002
Creator: Natesan, K.; Soppet, W.K. & Purohit, A.
System: The UNT Digital Library
Flow Instabilities During Injection of CO2 into SalineAquifers (open access)

Flow Instabilities During Injection of CO2 into SalineAquifers

Injection of carbon dioxide (CO{sub 2}) into saline aquifers has been proposed as a means to reduce greenhouse gas emissions (geological carbon sequestration). The injection process can be classified as immiscible displacement of an aqueous phase by a less dense and less viscous gas phase. Under disposal conditions (supercritical CO{sub 2}) the viscosity of carbon dioxide can be less than the viscosity of the aqueous phase by a factor of 15. Because of the lower viscosity, the CO{sub 2} displacement front will have a tendency towards instability so that waves or rounded lobes of saturation may appear and grow into fingers that lead to enhanced dissolution, bypassing, and possibly poor sweep efficiency. This paper presents an analysis, through high-resolution numerical simulations, of the onset of instabilities (viscous fingering) during injection of CO{sub 2} into saline aquifers. We explore the influence of viscosity ratio, relative permeability functions, and capillary pressure on finger growth and spacing. In addition, we address the issues of finger triggering, convergence under grid refinement and boundary condition effects. Simulations were carried out on scalar machines, and on an IBM RS/6000 SP (a distributed-memory parallel computer with 6080 processors) with a parallelized version of TOUGH2.
Date: April 15, 2003
Creator: Garcia, Julio E. & Pruess, Karsten
System: The UNT Digital Library
Observation of THz emission from a laser-plasma accelerated electron bunch crossing a plasma-vacuum boundary (open access)

Observation of THz emission from a laser-plasma accelerated electron bunch crossing a plasma-vacuum boundary

Coherent radiation in the 0.3 - 3 THz range has been generated from femto second electron bunches at a plasma-vacuum boundary via transition radiation. The bunches produced by a laser-plasma accelerator contained 1.5 nC of charge. The THz energy per pulse within a limited 30 mrad collection angle was 3.5 nJ and scaled quadratically with bunch charge, consistent with coherent emission. Modeling indicates that this broadband source produces about 0.3 muJ per pulse within a 100 mrad angle, and that increasing the transverse plasma size and electron beam energy could provide more than 100 muj/pulse.
Date: April 15, 2003
Creator: Leemans, W. P.; Geddes, C. G. R.; Faure, J.; Toth, Cs.; van Tilborg, J.; Schroeder, C. B. et al.
System: The UNT Digital Library
Specimen charging on thin films with one conducting layer:Discussion of physical principles (open access)

Specimen charging on thin films with one conducting layer:Discussion of physical principles

While the most familiar consequences of specimen charging in transmission electron microscopy can be eliminated by evaporating a thin conducting film (such as a carbon film) onto an insulating specimen, or by preparing samples directly on such a conducting film to begin with, a more subtle charging effect still remains. We argue here that specimen charging is in this case likely to produce a dipole sheet rather than a layer of positive charge at the surface of the specimen. A simple model of the factors that control the kinetics of specimen charging, and its neutralization, is discussed as a guide for experiments that attempt to minimize the amount of specimen charging. Believable estimates of the electrostatic forces and the electron optical disturbances that are likely to occur suggest that specimen bending and warping may have the biggest impact on degrading the image quality at high resolution. Electron optical effects are likely to be negligible except in the case of a specimen that is tilted to high angle. A model is proposed to explain how both the mechanical and electron-optical effects of forming a dipole layer would have much greater impact on the image resolution in a direction perpendicular to the …
Date: April 15, 2003
Creator: Glaeser, Robert M. & Downing, Kenneth H.
System: The UNT Digital Library
Two-dimensional computational fluid dynamics and conduction simulations of heat transfer in window frames with internal cavities - Part 1: Cavities only (open access)

Two-dimensional computational fluid dynamics and conduction simulations of heat transfer in window frames with internal cavities - Part 1: Cavities only

Accurately analyzing heat transfer in window frame cavities is essential for developing and characterizing the performance of highly insulating window products. Window frame thermal performance strongly influences overall product thermal performance because framing materials generally perform much more poorly than glazing materials. This paper uses Computational Fluid Dynamics (CFD) modeling to assess the accuracy of the simplified frame cavity conduction/convection models presented in ISO 15099 and used in software for rating and labeling window products. (We do not address radiation heat-transfer effects.) We examine three representative complex cavity cross-section profiles with varying dimensions and aspect ratios. Our results support the ISO 15099 rule that complex cavities with small throats should be subdivided; however, our data suggest that cavities with throats smaller than seven millimeters (mm) should be subdivided, in contrast to the ISO 15099 rule, which places the break point at five mm. The agreement between CFD modeling results and the results of the simplified models is moderate. The differences in results may be a result of the underlying ISO correlations being based on studies where cavity height/length (H/L) aspect ratios were smaller than 0.5 and greater than five (with linear interpolation assumed in between). The results presented here are …
Date: April 15, 2003
Creator: Gustavsen, Arild; Kohler, Christian; Arasteh, Dariush & Curcija, Dragan
System: The UNT Digital Library
UTILIZATION OF PHOSWICH DETECTORS FOR SIMULTANEOUS, MULTIPLE RADIATION DETECTION (open access)

UTILIZATION OF PHOSWICH DETECTORS FOR SIMULTANEOUS, MULTIPLE RADIATION DETECTION

A phoswich radiation detector is comprised of a phosphor sandwich in which several different phosphors are viewed by a common photomultiplier. By selecting the appropriate phosphors, this system can be used to simultaneously measure multiple radiation types (alpha, beta, gamma and/or neutron) with a single detector. Differentiation between the signals from the different phosphors is accomplished using digital pulse shape discrimination techniques. This method has been shown to result in accurate discrimination with highly reliable and versatile digital systems. This system also requires minimal component count (i.e. only the detector and a computer for signal processing). A variety of detectors of this type have been built and tested including: (1) a triple phoswich system for alpha/beta/gamma swipe counting, (2) two well-type detectors for measuring low levels of low energy photons in the presence of a high energy background, (3) a large area detector for measuring beta contamination in the presence of a photon background, (4) another large area detector for measuring low energy photons from radioactive elements such as uranium in the presence of a photon background. An annular geometry, triple phoswich system optimized for measuring alpha/beta/gamma radiation in liquid waste processing streams is currently being designed.
Date: April 15, 2003
Creator: Miller, William H. & Leon, Manuel Diaz de
System: The UNT Digital Library
Wetting and strength issues at Al/alpha-alumina interfaces (open access)

Wetting and strength issues at Al/alpha-alumina interfaces

The wetting behavior and strength at aluminum/alumina interfaces has been an active subject of research. Al/alumina applications include ceramic-metal composites and several applications for electronic industries. In this paper the interface strength and microstructure of Al/alpha-alumina was investigated. We discovered that in a solid-state joining, the strength of the joint increases with increasing joining temperature. In a liquid-state joining, the strength of the joint gradually decreases due to the formation of unbonded areas. The strength, sigma sub b, is expressed by the following equation as a function of unbonded area, A: sigma sub b = 2.22 A + 143 (70 percent {le} A {le} 100 percent). The highest strength reached 400 MPa when the interface was formed at around the melting temperature of aluminum. An aluminum layer close to the interface became a single crystal when it was bonded to a sapphire. The following crystallographic orientation relationship is established: (1{bar 1}1){sub Al}//(001){sub {alpha}}-Al{sub 2} O{sub 3}, (110){sub Al}//<100>{sub {alpha}}-Al{sub 2}O{sub 3}. Amorphous alumina islands were formed at the interface. In the amorphous alumina, gamma-alumina nanocrystals grew from the sapphire, with the same orientation relationship to sapphire as above.
Date: April 15, 2003
Creator: Saiz, Eduardo; Tomsia, Antoni P. & Suganuma, Katsuaki
System: The UNT Digital Library
Accessing High Pressure States Relevant to Core Conditions in the Giant Planets (open access)

Accessing High Pressure States Relevant to Core Conditions in the Giant Planets

We have designed an experimental technique to use on the National Ignition Facility (NIF) laser to achieve very high pressure (P{sub max} &gt; 10 Mbar = 1000 GPa), dense states of matter at moderate temperatures (kT &lt; 0.5 eV = 6000 K), relevant to the core conditions of the giant planets. A discussion of the conditions in the interiors of the giant planets is given, and an experimental design that can approach those conditions is described.
Date: April 15, 2004
Creator: Remington, B. A.; Cavallo, R. M.; Edwards, M. J.; Ho, D. D.; Lorenz, K. T.; Lorenzana, H. E. et al.
System: The UNT Digital Library
Centrality and pseudorapidity dependence of charged hadron production at intermediate p{sub t} in Au+Au collisions at {radical}s{sub NN} = 130 GeV (open access)

Centrality and pseudorapidity dependence of charged hadron production at intermediate p{sub t} in Au+Au collisions at {radical}s{sub NN} = 130 GeV

We present STAR measurements of charged hadron production as a function of centrality in Au + Au collisions at {radical}s{sub NN} = 130 GeV. The measurements cover a phase space region of 0.2 &lt; p{sub T} &lt; 6.0 GeV/c in transverse momentum and 11 &lt; {eta} &lt; 1 in pseudorapidity. Inclusive transverse momentum distributions of charged hadrons in the pseudorapidity region 0.5 &lt; |{eta}| &lt; 1 are reported and compared to our previously published results for |{eta}| &lt; 0.5. No significant difference is seen for inclusive p{sub T} distributions of charged hadrons in these two pseudorapidity bins. We measured dN/d{eta} distributions and truncated mean p{sub T} in a region of p{sub T} &gt; P{sub T}{sup cut}, and studied the results in the framework of participant and binary scaling. No clear evidence is observed for participant scaling of charged hadron yield in the measured pT region. The relative importance of hard scattering process is investigated through binary scaling fraction of particle production.
Date: April 15, 2004
Creator: Adams, J.; Aggarwal, M.M.; Ahammed, Z.; Amonett, J.; Anderson, B. D.; Arkhipkin, D. et al.
System: The UNT Digital Library
Centrality and pseudorapidity dependence of charged hadron production at intermediate p{sub T} in Au+Au collisions at {radical}s{sub NN} = 130 GeV (open access)

Centrality and pseudorapidity dependence of charged hadron production at intermediate p{sub T} in Au+Au collisions at {radical}s{sub NN} = 130 GeV

We present STAR measurements of charged hadron production as a function of centrality in Au + Au collisions at {radical}s{sub NN} = 130 GeV. The measurements cover a phase space region of 0.2 &lt; p{sub T} &lt; 6.0 GeV/c in transverse momentum and -1 &lt; {eta} &lt; 1 in pseudorapidity. Inclusive transverse momentum distributions of charged hadrons in the pseudorapidity region 0.5 &lt; |{eta}| &lt; 1 are reported and compared to our previously published results for |{eta}| &lt; 0.5. No significant difference is seen for inclusive p{sub T} distributions of charged hadrons in these two pseudorapidity bins. We measured dN/d{eta} distributions and truncated mean p{sub T} in a region of p{sub T} &gt; p{sub T}{sup cut}, and studied the results in the framework of participant and binary scaling. No clear evidence is observed for participant scaling of charged hadron yield in the measured p{sub T} region. The relative importance of hard scattering process is investigated through binary scaling fraction of particle production.
Date: April 15, 2004
Creator: Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D.; Arkhipkin, D. et al.
System: The UNT Digital Library
The complete sequence of human chromosome 5 (open access)

The complete sequence of human chromosome 5

Chromosome 5 is one of the largest human chromosomes yet has one of the lowest gene densities. This is partially explained by numerous gene-poor regions that display a remarkable degree of noncoding and syntenic conservation with non-mammalian vertebrates, suggesting they are functionally constrained. In total, we compiled 177.7 million base pairs of highly accurate finished sequence containing 923 manually curated protein-encoding genes including the protocadherin and interleukin gene families and the first complete versions of each of the large chromosome 5 specific internal duplications. These duplications are very recent evolutionary events and play a likely mechanistic role, since deletions of these regions are the cause of debilitating disorders including spinal muscular atrophy (SMA).
Date: April 15, 2004
Creator: Schmutz, Jeremy; Martin, Joel; Terry, Astrid; Couronne, Olivier; Grimwood, Jane; Lowry, State et al.
System: The UNT Digital Library
Convex Crystal X-ray Spectrometer for Laser Plasma Experiments (open access)

Convex Crystal X-ray Spectrometer for Laser Plasma Experiments

Measuring time and space-resolved spectra is important for understanding Hohlraum and Halfraum plasmas. Experiments at the OMEGA laser have used the Nova TSPEC which was not optimized for the OMEGA diagnostic space envelope or for the needed spectroscopic coverage and resolution. An improved multipurpose spectrometer snout, the MSPEC, has been constructed and fielded on OMEGA. The MSPEC provides the maximal internal volume for mounting crystals without any beam interferences at either 2x or 3x magnification. The RAP crystal is in a convex mounting geometry bent to a 20 cm radius of curvature. The spectral resolution, E/dE, is about 200 at 2.5 keV. The spectral coverage is 2 to 4.5 keV. The MSPEC can record four separate spectra on the framing camera at time intervals of up to several ns. The spectrometer design and initial field-test performance will be presented and compared to that of the TSPEC. Work supported by U. S. DoE/UC LLNL contract W-7405-ENG-48
Date: April 15, 2004
Creator: May, M.; Heeter, R. & Emig, J.
System: The UNT Digital Library
Dante Soft X-ray Power Diagnostic for NIF (open access)

Dante Soft X-ray Power Diagnostic for NIF

Soft x-ray power diagnostics are essential for measuring spectrally resolved the total x-ray flux, radiation temperature, conversion efficiency and albedo that are important quantities for the energetics of indirect drive hohlraums. At the Nova or Omega Laser Facilities, these measurements are performed mainly with Dante, but also with DMX and photo-conductive detectors (PCD's). The Dante broadband spectrometer is a collection of absolute calibrated vacuum x-ray diodes, thin filters and x-ray mirrors used to measure the soft x-ray emission for photon energies above 50 eV.
Date: April 15, 2004
Creator: Dewald, E.; Campbell, K.; Turner, R.; Holder, J.; Landen, O.; Glenzer, S. et al.
System: The UNT Digital Library