Within the last few years, there have also appeared in the Heavy-Ion Fusion literature several studies of targets which have outer tampers. One-dimensional simulations indicate higher target gains with a judicious amount of tamping. But for these targets, a full investigation has not been carried through in regards to conservative criteria for fluid instabilities as well as reasonable imperfections in target fabrication and illumination symmetry which all affect target ignition and burn. Comparisons of these results with the gain survey of Part I would have to be performed with care. These calculations suggest that experiments relating to high temperature disk heating, as well as beam deposition, focusing and transport can be performed within the context of current design proposals for accelerator test-facilities. Since the test-facilities have lower ion kinetic energy and beam pulse power as compared to reactor drivers, we achieve high-beam intensities at the focal spot by using short focal distance and properly designed beam optics.

A history of the early use of the Monte Carlo method is presented.

Article discussing the temporal complexity of the order parameter at the phase transition.

The authors present Sigma, a Web-rich application which provides user-friendly access in processing and plotting of the evaluated and experimental nuclear reaction data stored in the ENDF-6 and EXFOR formats. The main interface includes browsing using a periodic table and a directory tree, basic and advanced search capabilities, interactive plots of cross sections, angular distributions and spectra, comparisons between evaluated and experimental data, computations between different cross section sets. Interactive energy-angle, neutron cross section uncertainties plots and visualization of covariance matrices are under development. Sigma is publicly available at the National Nuclear Data Center website at www.nndc.bnl.gov/sigma.

We report on design studies for a seeded FEL light source that is responsive to the scientific needs of the future. The FEL process increases radiation flux by several orders of magnitude above existing incoherent sources, and offers the additional enhancements attainable by optical manipulations of the electron beam: control of the temporal duration and bandwidth of the coherent output, reduced gain length in the FEL, utilization of harmonics to attain shorter wavelengths, and precise synchronization of the x-ray pulse with seed laser systems. We describe an FEL facility concept based on a high repetition rate RF photocathode gun, that would allow simultaneous operation of multiple independent FEL's, each producing high average brightness, tunable over the VUV-soft x-ray range, and each with individual performance characteristics determined by the configuration of the FEL. SASE, enhanced-SASE (ESASE), seeded, harmonic generation, and other configurations making use of optical manipulations of the electron beam may be employed, providing a wide range of photon beam properties to meet varied user demands.

This article examines the impact of retail electricity rate design on the economic value of grid-connected photovoltaic (PV) systems, focusing on commercial customers in California. Using 15-min interval building load and PV production data from a sample of 24 actual commercial PV installations, we compare the value of the bill savings across 20 commercial-customer retail electricity rates currently offered in the state. Across all combinations of customers and rates, we find that the annual bill savings from PV, per kWh generated, ranges from $0.05 to $0.24/kWh. This sizable range in rate-reduction value reflects differences in rate structures, revenue requirements, the size of the PV system relative to building load, and customer load shape. The most significant rate design issue for the value of commercial PV is found to be the percentage of total utility bills recovered through demand charges, though a variety of other factors are also found to be of importance. The value of net metering is found to be substantial, but only when energy from commercial PV systems represents a sizable portion of annual customer load. Though the analysis presented here is specific to California, our general results demonstrate the fundamental importance of retail rate design for the …

Distinct maxima and minima in the neutron total cross section uncertainties were observed in our large scale covariance calculations using a spherical optical potential. In this contribution we investigate the physical origin of this oscillating structure. Specifically, we analyze the case of neutron reactions on {sup 56}Fe, for which total cross section uncertainties are characterized by the presence of five distinct minima at 0.1, 1.1, 5, 25, and 70 MeV. To investigate their origin, we calculated total cross sections by perturbing the real volume depth V{sub v} by its expected uncertainty {+-}{Delta}V{sub v}. Inspecting the effect of this perturbation on the partial wave cross sections we found that the first minimum (at 0.1 MeV) is exclusively due to the contribution of the s-wave. On the other hand, the same analysis at 1.1 MeV showed that the minimum is the result of the interplay between s-, p-, and d-waves; namely the change in the s-wave happens to be counterbalanced by changes in the p- and d-waves. Similar considerations can be extended for the third minimum, although it can be also explained in terms of the Ramsauer effect as well as the other ones (at 25 and 70 MeV). We discuss the …

We study the evolution and saturation of the gluondistribution function in the quark-gluon plasma as probed by apropagating parton and its effect on the computation of jet quenching ortransport parameter $\hat q $. For thermal partons, the saturation scale$Q2_s$ is found to be proportional to the Debye screening mass $\mu_D2$.For hard probes, evolution at small $x=Q2_s/6ET$ leads to jet energydependence of hat q. We study this dependence for both a conformal gaugetheory in weak and strong coupling limit and for (pure gluon) QCD. Theenergy dependence can be used to extract the shear viscosity $\eta$ ofthe medium since $\eta$ can be related to the transport parameter forthermal partons in a transport description. We also derive upper boundson the transport parameter for both energetic and thermal partons. Thelater leads to a lower bound on shear viscosity-to-entropy density ratiowhich is consistent with the conjectured lower bound $\eta/s\geq 1/4\pi$.Implications on the study of jet quenching at RHIC and LHC and the bulkproperties of the dense matter are discussed.

In the 'Atlas of Neutron Resonances', special care was expended to ensure that the resonance parameter information reproduces the various measured thermal cross sections, as well as the infinite dilute resonance integrals for Z = 1-100. In contrast, the uncertainties of the recommended quantities do not match those generated from the uncertainties of the resonance parameters. To address this problem, the present study was initiated to achieve consistency for 15 actinides and 21 structural and coolant moderator materials. This is realized by assigning uncertainties to the parameters of the negative-energy resonances and changing, if necessary, significantly the uncertainties of the low-lying positive-energy resonances. The influence of correlations between parameters on the derived uncertainties is examined and discussed.

The nuclear reaction code EMPIRE has been extended to provide evaluation capabilities for neutron cross section covariances in the thermal, resolved resonance, unresolved resonance and fast neutron regions. The Atlas of Neutron Resonances by Mughabghab is used as a primary source of information on uncertainties at low energies. Care is taken to ensure consistency among the resonance parameter uncertainties and those for thermal cross sections. The resulting resonance parameter covariances are formatted in the ENDF-6 File 32. In the fast neutron range our methodology is based on model calculations with the code EMPIRE combined with experimental data through several available approaches. The model-based covariances can be obtained using deterministic (Kalman) or stochastic (Monte Carlo) propagation of model parameter uncertainties. We show that these two procedures yield comparable results. The Kalman filter and/or the generalized least square fitting procedures are employed to incorporate experimental information. We compare the two approaches analyzing results for the major reaction channels on {sup 89}Y. We also discuss a long-standing issue of unreasonably low uncertainties and link it to the rigidity of the model.

Design and testing of the United States Navy’s next generation air particle detector (NGAPD) is presently underway. The NGAPD is intended for use in nuclear applications for the United States Navy and is being designed to detect airborne Co-60 with a reduction in false alarms and improved ease of use. Features being developed include gamma compensation, low maintenance, commercial off-the-shelf electronics, and spectrum simulation for quality assurance and functional testing applications. By supplying a spectrum simulator, the radon stripping algorithm can be running when a simulated anthropogenic source spectrum (e.g., from Co-60 or transuranics) is superimposed on the radon progeny spectrum. This will allow alarm levels to be tested when the air flow is running and the radon stripping algorithm is providing the instrument response output. Modern units evaluate source spectra with the air flow off and the radon spectrum absent thereby not testing the true system performance which comes out of the radon stripping algorithm. Testing results of the preliminary prototype show promise along with computer simulations of source spectra. Primary testing results taken to date include gamma compensation, thermal insults, vibration and spectrum simulation.

Using the Berkeley polarized-proton target, we have measured the polarization parameter P({theta}) for proton-proton (p-p) scattering. The measurements were obtained at beam kinetic energies of 0.330, 0.680, and 0.740 GeV at the 184-in. synchrocyclotron and 1.70, 2.85, 3.50, 4.00, 5.05, and 6.15 GeV at the Bevatron. The angular regions measured were from 20 to 100 degrees center of mass; the square of the four-momentum transfer ranged from 0.1 to 0.8 (GeV/c){sup 2}.

We completed estimates of neutron cross section covariances for {sup 55}Mn and {sup 90}Zr, from keV range to 25 MeV, considering the most important reaction channels, total, elastic, inelastic, capture, and (n,2n). The nuclear reaction model code EMPIRE was used to calculate sensitivity to model parameters by perturbation of parameters that define the optical model potential, nuclear level densities and strength of the pre-equilibrium emission. The sensitivity analysis was performed with the set of parameters which reproduces the ENDF/B-VII.0 cross sections. The experimental data were analyzed and both statistical and systematic uncertainties were extracted from almost 30 selected experiments. Then, the Bayesian code KALMAN was used to combine the sensitivity analysis and the experiments to obtain the evaluated covariance matrices.

I review recent progress in finite temperature lattice calculations, including the determination of the transition temperature, equation of state, screening of static quarks and meson spectral functions.

A large exchange splitting of the conduction band in ultrathin films of the ferromagnetic semiconductor EuO was determined quantitatively, by using EuO as a tunnel barrier and fitting the current-voltage characteristics and temperature dependence to tunneling theory. This exchange splitting leads to different tunnel barrier heights for spin-up and spin-down electrons, and is large enough to produce a near fully spin-polarized current. Moreover, the magnetic properties of these ultrathin films (<6 nm) show a reduction in Curie temperature with decreasing thickness, in agreement with theoretical calculation [R. Schiller et al., Phys. Rev. Lett. 86, 3847 (2001)].

We present an auto-tuning approach to optimize application performance on emerging multicore architectures. The methodology extends the idea of search-based performance optimizations, popular in linear algebra and FFT libraries, to application-specific computational kernels. Our work applies this strategy to Sparse Matrix Vector Multiplication (SpMV), the explicit heat equation PDE on a regular grid (Stencil), and a lattice Boltzmann application (LBMHD). We explore one of the broadest sets of multicore architectures in the HPC literature, including the Intel Xeon Clovertown, AMD Opteron Barcelona, Sun Victoria Falls, and the Sony-Toshiba-IBM (STI) Cell. Rather than hand-tuning each kernel for each system, we develop a code generator for each kernel that allows us to identify a highly optimized version for each platform, while amortizing the human programming effort. Results show that our auto-tuned kernel applications often achieve a better than 4X improvement compared with the original code. Additionally, we analyze a Roofline performance model for each platform to reveal hardware bottlenecks and software challenges for future multicore systems and applications.

We present the rational synthesis of colloidal copper(I) sulfide nanocrystals and demonstrate their application as an active light absorbing component in combination with CdS nanorods to make a solution-processed solar cell with 1.6percent power conversion efficiency on both conventional glass substrates and flexible plastic substrates with stability over a 4 month testing period.

With the growing demand for multigroup covariances, the National Nuclear Data Center (NNDC) has been experiencing an upsurge in its covariance data processing activities using the two US codes NJOY-99 (LANL) and PUFF-IV (ORNL). The code NJOY-99 was upgraded by incorporating the new module ERRORJ-2.3, while the NNDC served as the active user and provided feedback. The NNDC has been primarily processing neutron cross section covariances on its 64-bit Linux cluster in support of two DOE programs, the Global Nuclear Energy Partnership (GNEP) and the Nuclear Criticality Safety Program (NCSP). For GNEP, the NNDC used NJOY-99.259 to generate multigroup covariance matrices of {sup 56}Fe, {sup 23}Na, {sup 239}Pu, {sup 235}U and {sup 238}U from the JENDL-3.3 library using the 15-, 33-, and 230-energy group structures. These covariance matrices will be used to test a new collapsing algorithm which will subsequently be employed to calculate uncertainties on integral parameters in different fast neutron-based systems. For NCSP, we used PUFF-IV 1.0.4 to verify the processability of new evaluated covariance data of {sup 55}Mn, {sup 239}Pu, {sup 233}U, {sup 235}U and {sup 238}U generated by a collaboration of ORNL and LANL. For the data end-users at large, the NNDC has made available a …

This article demonstrates the refinement and uniform distribution of the crystalline dendritic phase by friction stir processing of titanium based in situ ductile-phase reinforced metallic glass composite.

A new algorithm for a rigorous collapsing of covariance data is proposed, derived, implemented, and tested. The method is based on a conservation principle that allows preserving at a broad energy group structure the uncertainty calculated in a fine group energy structure for a specific integral parameter, using as weights the associated sensitivity coefficients.

Using Wallace's analysis for steady weak shocks, this paper establishes for Cu, Ur, and 6061T6Al an approximate relations between the shock strength and the maximum deviatoric stress, tau/sub m/, and plastic strain at tau/sub m/. In addition it is shown that the plastic strain rate is very nearly proportional to the total normal strain rate at tau/sub m/. These results and the universal shock strength/strain rate relation of Swegle and Grady are used to draw conclusions about the general plasticity constitutive relation.

Potassium dihydrogen phosphate (KDP) crystals have been used as harmonic converters on the Nova laser at LLNL for over six years. All crystals were coated with a single layer, quarterwave AR coating of porous silica with a refractive index of 1.22. This was prepared by a sol-gel process and was applied from a colloidal suspension by spin coating at room temperature. A few crystals were also coated with a methyl silicone coating prior to the application of the AR coating for environmental protection. The initial optical performance of all crystals was very good but there has been some deterioration over the years because of environmental and laser damage degradation. The deterioration in the silicone samples was, however, much less than the others. We are now in the process of replacing all ten KDP arrays with new crystals and will apply the silicone undercoat to all samples. Recently we have been evaluating a new perfluorinated organic polymer coating which has a refractive index of 1.29. This material is soluble in fluorinated solvents and can be applied by dip coating from solution at room temperature. We hope that this can provide environmental protection when applied to KDP and also act as an …

This paper presents a new formulation of a class of nonlinear optimal control problems in which the system's signals are noisy and some system parameters are changing arbitrarily with time. The methodology is validated with an application to a nonlinear nuclear reactor model. A variational technique based on Pontryagin's Maximum Principle is used to filter the noisy signals, estimate the time-varying parameters, and calculate the optimal controls. The reformulation of the variational technique as an initial value problem allows this microprocessor-based algorithm to perform on-line filtering, parameter tracking, and control.

This paper presents the results of an impact study using the computer program SCANS (Shipping Cask ANalysis System), which was developed by Lawrence Livermore National Laboratory (LLNL) for the US Nuclear Regulatory Commission (NRC) and the Department of Energy (DOE) for structural analysis of transportation packages of radioactive materials. The program operates on IBM PC and compatible microcomputers. It has capabilities for other analysis such as heat transfer, pressure and thermal stress analysis. However, this study uses only the impact analysis capability, which includes a quasi-static and a dynamic analysis option. It is shown that the program produces reasonable results for a wide range of impact conditions. The results are in agreement with existing information on impact analysis and phenomenon. In view of its simplicity in modelling and convenience in usage, the SCANS program can be effectively used for confirmatory analysis, preliminary design study, and quick assessment of the need for detailed impact analysis. 2 refs., 7 figs., 2 tabs.