Neutron-induced capture cross sections for the ground states and first isomeric states of /sup 93/Nb, /sup 94/Nb and /sup 95/Nb were studied from the resolved resonance region to 4 MeV via statistical model calculations. The production of isomers was included. Inelastic scattering cross sections and gamma-ray production spectra were also calculated. The anti GAMMA/ sub ..gamma..//D ratios were derived from gamma-ray strength function systematics. Total capture cross sections on the ground states are found to be within a factor of two of each other. Capture cross sections on the isomeric targets are important as well, not only because of their magnitude but also because of the significant population of these isomeric levels by inelastic scattering. 10 references.

One cannot expect measurements alone to supply all of the neutron-induced activation cross-section data required by the fission reactor, fusion reactor, and nuclear weapons development communities, given the wide ranges of incident neutron energies, the great variety of possible reaction types leading to activation, and targets both stable and unstable. Therefore, the evaluator must look to nuclear model calculations and systematics to aid in fulfilling these cross-section data needs. This review presents some of the recent developments and improvements in the prediction of neutron activation cross sections, with specific emphasis on the use of empirical and semiempirical methods. Since such systematics require much less nuclear informaion as input and much less computational time than do the multistep Hauser-Feshbach codes, they can often provide certain cross-section data at a sufficient level of accuracy within a minimum amount of time. The cross-section information that these systematics can and cannot provide and those cases in which they can be used most reliably are discussed.

The authors present a measurement of the fraction f{sub +} of right-handed W bosons produced in top quark decays, based on a candidate sample of t{bar t} events in the {ell}+jets and dilepton decay channels corresponding to an integrated luminosity of 370 pb{sup -1} collected by the D0 detector at the Fermilab Tevatron p{bar p} Collider at {radical}s = 1.96 TeV. They reconstruct the decay angle {theta}* for each lepton. By comparing the cos{theta}* distribution from the data with those for the expected background and signal for various values of f{sub +}, they find f{sub +} = 0.056 {+-} 0.080(stat) {+-} 0.057(syst). (f{sub +} < 0.23 at 95% C.L.), consistent with the standard model prediction of f{sub +} = 3.6 x 10{sup -4}.

Recent studies indicate LaBr3(Ce) scintillation detectors have desirable attributes, such as room temperature operability, which may make them viable alternatives as primary detectors (PD) in a Compton suppression spectrometer (CSS) used for remote-handled transuranic (RH-TRU) waste assay. A CSS with a LaBr3(Ce) PD has been designed and its expected performance evaluated using Monte Carlo analysis. The unique design of this unit minimizes the amount of "dead" material between the PD and the secondary guard detector. The analysis results indicate that this detector will have a relatively high Compton-suppression capability, with greater suppression ability for large angle-scattered photons in the PD. J. K. Hartwell1, M. E. McIlwain1, R. P. Gardner2, J. Kulisek3 1) Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2114 USA 2) North Carolina State University, Dept of Nuclear Eng., PO Box 7909, Raleigh, NC 27695 USA 3) Ohio State University, Columbus, Ohio 43210 The US Department of Energy’s transuranic (TRU) waste inventory includes about 4,500 m3 of remote-handled TRU (RH-TRU) wastes. The RH-TRU waste stream is composed of a variety of containerized waste forms having a contact surface dose rate that exceeds 2 mSv/hr (200 mrem/hr) containing waste materials with a total TRU concentration greater than 3700 …

Experimental measurements were made of the production cross sections and energy distributions of gamma rays emitted when the stable targets /sup 88/Sr, /sup 89/Y and /sup 90/Zr are exposed to protons in the energy range 3 to 8 MeV. The data are being analyzed using a recent version of the Uhl statistical model code. One conclusion is that while the gamma-ray strength functions employed reproduce the proton capture cross sections, they do not achieve the same degree of hardness observed in the measured spectra. To do so, their lower energy regions must be modified; such changes, however, do not affect the capture cross sections. 7 references.

The Booster synchrotron at Brookhaven National Laboratory has been incorporated into the accelerator chain at the Alternating Gradient Synchrotron (AGS) complex. After a successful first commissioning effort in the spring of 1991, the Booster has been part of this year`s silicon, gold and proton physics runs. After a brief review of the Booster design goals, and of the early commissioning, this paper will summarize this year`s activities.

Hydrous Metal Oxides (HMOs) are chemically synthesized materials which contain a homogeneous distribution of ion exchangeable alkali cations that provide charge compensation to the metal-oxygen framework. Both the presence of these alkali cations and the resulting high cation exchange capacities (4-5 meq/g) clearly set these HMO materials apart from conventional precipitated hydrous oxides. For catalyst applications, the HMO material serves as an ion exchangeable support which facilitates the uniform incorporation of catalyst precursor species. Following catalyst precursor incorporation, an activation step is required to convert the catalyst precursor to the desired active phase. Considerable process development activities at Sandia National Laboratories related to HMO materials have resulted in bulk silica-doped hydrous titanium oxide (HTO:Si)-supported NiMo catalysts that are more active in model compound reactions than commercial NiMo catalysts. These reactions, e.g. pyrene hydrogenation, simulate direct coal liquefaction. However, extension of this process to produce NiMo/HTO:Si catalyst coatings on commercial supports is of interest for liquefaction applications since overall catalyst cost can be reduced and bulk HTO:Si mechanical limitations can be circumvented. In the present effort, NiMo/HTO:Si has been evaluated for hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) of coal derived liquids. NiMo/HTO:Si catalysts have been evaluated in both bulk (unsupported) form and …

The Department of Energy, under a government-to-government program, hosted the first visit with the Russian Federation to exchange information and technologies for special nuclear material control, accounting, and physical protection at a plutonium storage facility. The Russian specialists toured a storage facility at the Hanford Site near Richland, Washington, and were shown the physical protection and materials control systems that DOE employs to protect excess nuclear materials. Technical discussions included topics associated with protective forces and their operation, perimeter and interior intrusion detection and assessment equipment/systems, vulnerability assessment demonstrations, and the vault monitoring and materials control systems. In October, the Russian Federation hosted a reciprocal visit to the Mayak Enterprise civil plutonium storage facility, previously known as Chelyabinsk-65. The US specialists participated in technical discussions on the protection and control of plutonium and supported an evaluation of safeguards and security at the Mayak storage facility.

The working group discussed several topics related to charm production that can provide important input for our understanding of QCD. It was recognized that studies of both open and hidden charm in a high-statistics experiment will be essential in order to understand the production mechanisms. Nuclear effects were also discussed and a connection was made to similar effects observed in other reactions.

Measurements have been made of the total back-scattered D/sup -/ yields from Cs, Rb, K, Na and Li surfaces bombarded with D/sub 2//sup +/ and D/sub 3//sup +/ in the energy range 0.05 to 3.5 keV/nucleon. All measurements were made at a background pressure less than 10/sup -9/ Torr and the alkali-metal surfaces were evaporated onto a substrate in situ to assure uncontaminated surfaces. For each target, the D/sup -/ yield is at a maximum (as high as 12% per incident deuteron for Cs) between 150 and 300 eV/nucleon, and at any measured energy, the D/sup -/ yield decreases from Cs to Li in the order given above.

A technique for modeling quasiparticle excitation energies and rotational parameters in odd-odd deformed nuclei has been applied to actinide species where new experimental data have been obtained by use of neutron-capture gamma-ray spectroscopy. The input parameters required for the calculation were derived from empirical data on single-particle excitations in neighboring odd-mass nuclei. Calculated configuration-specific values for the Gallagher-Moszkowski splittings were used. Calculated and experimental level structures for /sup 238/Np, /sup 244/Am, and /sup 250/Bk are compared, as well as those for several nuclei in the rare-earth region. The agreement for the actinide species is excellent, with bandhead energies deviating 22 keV and rotational parameters 5%, on the average. Corresponding average deviations for five rare-earth nuclei are 47 keV and 7%. Several applications of this modeling technique are discussed. 18 refs., 5 figs., 4 tabs.

In situ chemical oxidation is a developing class of remediation technologies in which organic contaminants are degraded in place by powerful oxidants. Successful implementation of this technology requires an effective means for dispersing the oxidant to contaminated regions in the subsurface. An oxidant delivery technique has been developed wherein the treatment solution is made by adding an oxidant to extracted groundwater. The oxidant-laden groundwater is then injected and recirculated into a contaminated aquifer through multiple horizontal and/or vertical wells. This technique, referred to as in situ chemical oxidation through recirculation (ISCOR), can be applied to saturated and hydraulically conductive formations and used with relatively stable oxidants such as potassium permanganate (KMnO{sub 4}). A field-scale test of ISCOR was conducted at a site (Portsmouth Gaseous Diffusion Plant) where groundwater in a 5-ft thick silty gravel aquifer is contaminated with trichloroethylene (TCE) at levels that indicate the presence of residual dense non-aqueous phase liquids (DNAPLs). The field test was implemented using a pair of parallel horizontal wells with 200-ft screened sections. For approximately one month, groundwater was extracted from one horizontal well, dosed with crystalline KMnO{sub 4}, and re-injected into the other horizontal well 90 ft away. Post-treatment characterization showed that ISCOR …

An efficient, scalable, parallel algorithm for treating material surface contacts in solid mechanics finite element programs has been implemented in a modular way for MIMD parallel computers. The serial contact detection algorithm that was developed previously for the transient dynamics finite element code PRONTO3D has been extended for use in parallel computation by devising a dynamic (adaptive) processor load balancing scheme.

The development of hydrothermal energy for direct heat applications is being aided by twenty-two demonstration projects that are funded on a cost-sharing basis by the US Department of Energy, Division of Geothermal Energy. These projects are designed to demonstrate the technical and economic feasibility of the direct use of geothermal heat in the United States. Twelve of these projects are administered by the DOE-Idaho Operations Office with technical support from EG and G Idaho, Inc. Engineering and economic data for these projects are summarized in this paper. The data and experience being generated by these projects will be an important basis for future geothermal direct use projects.

The RELAP5-3D (version bt) computer program was used to assess a GE level swell experiment. The primary goal of the new assessment models was to faithfully represent the experimental facility and instrumentation. In developing the new models, a non-physical representation of the vessel heads in a previous assessment was found. This distortion resulted in predictions that closely matched the experimental data, but were in error. The new assessment also highlighted an instability in the calculation of interfacial drag. To explore this issue, analyses were performed using three different interfacial drag correlations appropriate for large diameter pipes and/or vessels. The results of this study show that the Kataoka-Ishii correlation, which is currently used in RELAP5-3D, compares most favorably with the experimental data. Additionally, a numerical instability was uncovered with the analysis performed using the Gardner correlation and was traced to the calculation of bubble diameter in the bubbly flow regime.

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For application in plasma heating, fueling, and current drive of magnetic fusion devices, high current negative deuterium ion sources for intense neutral beam injectors are being developed using efficient production of negative hydrogen isotope ions on low work function metal surfaces imbedded in hydrogen plasmas. In order to investigate the correlation between work function and negative hydrogen ion production, photoelectron emission from a cesiated metal surface, which is immersed in a hydrogen plasma with an electron density less than 5 x 10/sup 10//cc, was measured in the photon energy range of 1.3 to 4.1 eV. The work function determination was based on Fowler's analysis, and at the optimum coverage a work function of less than 1.5 eV was observed for a Cs-Cu surface. Measured values of work functions for different Cs coverages were compared to the negative hydrogen currents produced at the metal surface in the discharge; the surface production of negative hydrogen ion current is monotonically increasing with decreasing work function.

Following the Fiscal Year (FY) 2010 (Run-10) Relativistic Heavy Ion Collider (RHIC) Au+Au run, RHIC experiment upgrades sought to improve detector capabilities. In turn, accelerator improvements were made to improve the luminosity available to the experiments for this run (Run-11). These improvements included: a redesign of the stochastic cooling systems for improved reliability; a relocation of 'common' RF cavities to alleviate intensity limits due to beam loading; and an improved usage of feedback systems to control orbit, tune and coupling during energy ramps as well as while colliding at top energy. We present an overview of changes to the Collider and review the performance of the collider with respect to instantaneous and integrated luminosity goals. At the conclusion of the FY 2011 polarized proton run, preparations for heavy ion run proceeded on April 18, with Au+Au collisions continuing through June 28. Our standard operations at 100 GeV/nucleon beam energy was bracketed by two shorter periods of collisions at lower energies (9.8 and 13.5 GeV/nucleon), continuing a previously established program of low and medium energy runs. Table 1 summarizes our history of heavy ion operations at RHIC.

The China Spallation Neutron Source (CSNS) is an accelerator based high power project currently under preparation in China. The accelerator complex is based on an H{sup -} linear accelerator and a rapid cycling proton synchrotron. During the past year, the design of most accelerator systems went through major iterations, and initial research and developments were started on the prototyping of several key components. This paper summarizes major activities of the past year.

Lattice for a 3-GeV cooler ring with split functions is presented. The ring consists of two half-rings of different properties: in one half-ring, the phase-slip factor is near-zero; in the other half-ring, the phase-slip factor is large. The near-zero phase slip minimizes the 'bad mixing' between the stochastic-cooling pick-ups and kickers, while the high phase slip maximizes the 'good mixing' between the kickers and the next-turn pick-ups.

Remote-sensing observations of the Sun and inner heliosphere are reviewed to appraise our understanding of the mix of the mechanisms that heat the corona and accelerate the solar wind. An assessment of experimental uncertainties and the basic assumptions needed to translate measurables into physical models, reveals very large fundamental uncertainties in our knowledge of coronal structure near the Sun. We develop a time-dependent, filamentary model of the extended corona that is consistent with a large number of remote sensing observations of the solar atmosphere and the solar wind.

Experimental measurements of the production of H/sup -/ from surfaces bombarded with hydrogen are reviewed. Some measurements of H/sup +/ and H/sup 0/ production from surfaces are also discussed with particular emphasis on work which might be relevant to ion source applications.

The formation of negative ions by hydrogen collisions on cesium-coated surfaces is discussed in the limiting cases where the resident cesium is either in the purely ionic state or in the purely atomic state. The survival fraction for negative ions moving away from a metal surface is calculated using a method employing complex eigenvalues. The fraction of surviving ions is found to be larger than calculated by previous workers. The secondary emission coefficient for negative ion production by incident atoms with energies of ten to one hundred electron volts is estimated to be in the range thirty to fifty percent. The secondary emission coefficient is found to be a sensitive function of the thickness of the alkali adsorbate coating for ion energies in the range below a few hundred electron volts.

As landscape ecology has matured, it has gone beyond description of land-use changes, to examining the functional relationships between spatial patterns of landscapes and ecological processes. Attempts to describe these relationships at larger scales or in complex landscapes have been hampered by the lack of spatially explicit distributed parameter models linked dynamically to geographical information systems (GIS). This paper describes developments we have made to link such models to GIS and to develop visualization methods (a graphical interface) that permits the user to readily manipulate large element files containing model parameters. We then present preliminary results illustrating the effects of pattern (in an agricultural landscape) on water and material flow across a heterogeneous landscape composed of multiple watersheds. These dynamics are driven in large measure by the location, size, and number of forest patches. By use of soil, hydrologic, and vegetation data from a real landscape, the effects of spatial relocation of vegetation on water and sediment dynamics are explored through the model-GIS combination. The spatiotemporal modeling approach described here could be useful in effectively managing ecosystem restoration and rehabilitation at the landscape scale.