This work is primarily concerned with the calculation of neutron capture cross sections and capture gamma-ray spectra, in the framework of the Hauser-Feshbach statistical model and for neutrons from the resonance region up to several MeV. An argument is made that, for applied purposes such as constructing evaluated cross-section libraries, nonstatistical capture mechanisms may be completely neglected at low energies and adequately approximated at high energies in a simple way. The use of gamma-ray strength functions to obtain radiation widths is emphasized. Using the reaction /sup 89/Y + n as an example, the problems encountered in trying to construct a case that could be run equivalently on two different nuclear reaction codes are illustrated, and the effects produced by certain parameter variations are discussed.

This paper describes the development of a long-pulse positive ion source that has been designed to provide high brightness deuterium beams (divergence approx. = 0.25/sup 0/ rms, current density approx. = 0.15 A cm/sup -2/) of 40 to 45 A, at a beam energy of 80 keV, for pulse lengths up to 30 s. The design and construction of the ion source components are described with particular emphasis placed on the long-pulse cathode assembly and ion accelerator.

The control system for the Nova laser must operate reliably in a harsh pulse power environment and satisfy requirements of technical functionality, flexibility, maintainability and operability. It is composed of four fundamental subsystems: Power Conditioning, Alignment, Laser Diagnostics, and Target Diagnostics, together with a fifth, unifying subsystem called Central Controls. The system architecture utilizes a collection of distributed microcomputers, minicomputers, and components interconnected through high speed fiber optic communications systems. The design objectives, development strategy and architecture of the overall control system and each of its four fundamental subsystems are discussed. Specific hardware and software developments in several areas are also covered.

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.

Although there have been many laboratory studies on water movement and contaminant transport, there is a need for more large scale field experiments. Large scale field experiments are necessary to (1) measure hydraulic conductivities on a scale typical of actual shallow land burial facilities and hazardous waste disposal facilities, (2) allow comparisons to be made between full scale and laboratory measurements, (3) verify the applicability of calculational methods for determining unsaturated hydraulic conductivities from water retention curves, and (4) for model validation. Experiments that will provide the information to do this are described in this paper. The results of these experiments will have applications for both the shallow land burial of low level radioactive wastes and the disposal of hazardous chemical wastes. These experiments will provide results that can be used in model verification for system performance. This type of data on experiments done at this scale has not been available, and are necessary for validating unsaturated transport models and other models used to predict long term system performance. Even though these experiments are done on crushed Bandelier Tuff, most models use physical properties of the backfill material such as density, porosity, and water retention curves. For this reason, once …

A mathematical model intended to study the one-dimensional transport of radionuclides in a non-homogeneous soil system under saturated-unsaturated and isothermal conditions is presented. The model is composed of two modules: the first to calculate the pressure distribution enabling one to compute velocities and soil moisture; the second to calculate the migration of species by considering the major processes associated with the transport phenomena of a dissolved substance in porous media, i.e., advection, mechanical dispersion, molecular diffusion, radioactive decay, and sorption, assuming a linear equilibrium isotherm. The numerical method of solving both flow and solute equations used here is the finite-element method based on the weighted residual technique. The flow equation is solved by the Bubnov-Galerkin method. The solute equation is solved by a Petrov-Galerkin type method. The model allows for a variety of boundary conditions; e.g., infiltration, drainage and/or evaporation. A test case involving the movement of a non-reacting ionic species is used to validate the model. Use of the model is illustrated by the analysis of the movement Sr-90 and Cs-137 and H-3 (as water) from a low-level solid-waste disposal trench subject to a steady rate of rainfall.

This document records the proceedings of a symposium on flow and transport processes in partially saturated groundwater systems, conducted at the Battelle Seattle Research Center on March 22-24, 1982. The symposium was sponsored by the US Nuclear Regulatory Commission for the purpose of assessing the state-of-the-art of flow and transport modeling for use in licensing low-level nuclear waste repositories in partially saturated zones. The first day of the symposium centered around research in flow through partially saturated systems. Papers were presented with the opportunity for questions following each presentation. In addition, after all the talks, a formal panel discussion was held during which written questions were addressed to the panel of the days speakers. The second day of the Symposium was devoted to solute and contaminant transport in partially saturated media in an identical format. Individual papers are abstracted.

The present status of the production of low-energy highly ionized beams by the 4-stage tandem accel-decel method is surveyed, and their use in three atomic physics experiments is summarized. The experiments are: the measurement of the charge state dependence of K-x-ray production in S/sup +q/-Ar collisions at 10 MeV, the impact-parameter dependence of quasimolecular x rays in S/sup +15/-Ar collisions again at 10 MeV, and the determination of charge transfer cross sections in S/sup +q/ + Ar, He collisions. The results of the three experiments give evidence that the 4-stage accel-decel ion production technique is extremely powerful and useful.

This paper summarizes estimates, compiled in a larger report, of the uncertainty associated with models and parameters used to assess the impact on man radionuclide releases to the environment by breeder reactor facilities. These estimates indicate that, for many sites, generic models and representative parameter values may reasonably be used to calculate doses from annual average radionuclide releases when these calculated doses are on the order of one-tenth or less of a relevant dose limit. For short-term, accidental releases, the uncertainty in the dose calculations may be much larger than an order of magnitude. As a result, it may be necessary to incorporate site-specific information into the dose calculation under such circumstances. However, even using site-specific information, inherent natural variability within human receptors, and the uncertainties in the dose conversion factor will likely result in an overall uncertainty of greater than an order of magnitude for predictions of dose following short-term releases.

Analysis of recent conceptual designs reveals that commercial fusion power systems will raise issues of occupational and public health and safety. This paper focuses on radioactive wastes from fusion reactor materials activated by neutrons. The analysis shows that different selections of materials and neutronic designs can make differences in orders-of-magnitude of the kinds and amounts of radioactivity to be expected. By careful and early evaluation of the impacts of the selections on waste management, designers can produce fusion power systems with radiation from waste well below today's limits for occupational and public health and safety.

Recent triply-differential photoelectron spectroscopy experiments designed for the study of correlation effects in atoms and molecules are described. Final-state symmetry of the n=2 state of helium has been determined. The non-Franck-Condon behavior of vibrational branching ratios and large variations of the angular asymmetry parameter has been observed for shape resonances and autoionizing resonances in CO and other molecules. Recent observations of the photoionization of excited sodium atoms are also described.

SEparate abstracts were prepared for 30 of the 39 papers presented. Nine papers wre previously included in the data base. (WHK)

Energetic neutral beams are used for heating and diagnostics in present magnetic fusion experiments. They are also being considered for use in future large experiments. Atomic physics issues are important for both the production of the neutral beams and the interaction of the beams and the plasma. Interest in neutral beams based on negative hydrogen ions is growing, largely based on advances in producing high current ion sources. An extension of the negative ion approach has been the suggestion to use negative ions of Z > 1 elements, such as carbon and oxygen, to form high power neutral beams for plasma heating.

For efficient plasma heating, ion sources of neutral-beam injectors should be capable of producing ion beams with an atomic fraction of 90% or higher. Diagnostic techniques for quantitatively determining source species yield have been developed and evaluated. These include magnetic momentum analysis of the unneutralized ions passing through the neutralizer, energy analysis of the neutral beam by electrostatic separation of ions emanating from a stripping cell, and quantity vs implantation-depth analysis of hydrogen implanted into a crystal by SIMS technique. The operational features and advantages and disadvantages of each technique will be discussed. If the effects of beamlet optics, energy straggling in the accelerator, and neutralizer gas scattering are taken into account, the results of the measurements using the three techniques are shown to be mutually consistent within experimental error.

The APIS ion source is being developed to meet a goal of producing ion beams of less than or equal to 200 keV, 100 A, with 10-30-s pulse lengths. In a continuing effort to advance the state of the art and to produce long pulse ion beams, APIS ion sources with grid dimensions of 10 x 25 cm, 13 x 43 cm, and 16 x 48 cm are being developed. In the past year, the 10- x 25-cm ion source has been operated to produce ion beams in excess of 100 keV for many seconds pulse length. An advanced design concept is being pursued with the primary objectives to improve radiation protection, reduce fabrication costs, and simplify maintenance. The source magnetic sheild will be designed as a vacuum enclosure to house all source components. The electrical insulation requirements of energy recovery are also considered. Because of the frequent maintenance requirements, the electron emitter assembly will be designed with a remote handling capability. A new accelerator design which incorporates the necessary neutron shielding and associated steering gimbal system is also described.

A noncanonical Poisson structure for ideal magnetohydrodynamics is presented and identified with a differential Lie algebra.

Cuttings from the silicic volcanics in the Bostic 1-A well near Mountain Home, Idaho have been examined petrographically with the assistance of x-ray diffraction and electron microprobe analyses. Results indicate that these rocks have been subjected to much higher temperatures than were observed in the well in 1974, when a static temperature log was run. It is not known to what extent the alternation may be due to greater depth of burial in the past, or whether it resulted from an early hydrothermal system of higher temperature than the one now observed.

The following topics were considered: (1) scaling studies, (2) Chi/sub e/ studies, (3) MHD studies, (4) rotation studies, and (5) analysis techniques. (MOW)

Nuclear theory is used increasingly to supplement and extend the nuclear data base that is available for applied studies. Areas where theoretical calculations are most important include the determination of neutron cross sections for unstable fission products and transactinide nuclei in fission reactor or nuclear waste calculations and for meeting the extensive dosimetry, activation, and neutronic data needs associated with fusion reactor development, especially for neutron energies above 14 MeV. Considerable progress has been made in the use of nuclear models for data evaluation and, particularly, in the methods used to derive physically meaningful parameters for model calculations. Theoretical studies frequently involve use of spherical and deformed optical models, Hauser-Feshbach statistical theory, preequilibrium theory, direct-reaction theory, and often make use of gamma-ray strength function models and phenomenological (or microscopic) level density prescriptions. The development, application, and limitations of nuclear models for data evaluation are discussed, with emphasis on the 0.1 to 50 MeV energy range. (91 references).

The early history of physics at accelerators is reviewed, with emphasis on three experiments which have had a profound influence on our veiw of the structure of matter: The Franck and Hertz experiment opening practical ways of studying nuclear disintegration, and the discovery of the del/sup + +/ isobar of the proton by Fermi and collaborators, revealing structure in the nucleon. Fermi's work is illustrated by pages from his notebooks.

The Fifteenth LAMPF Users Group Meeting was held November 2-3, 1981 at the Clinton P. Anderson Meson Physical Facility. The program of papers scheduled to be presented was amended to include a Report from Washington by Clarence R. Richardson, US Department of Energy. The general meeting ended with a round-table working group discussion concerning the Planning for a Kaon Factory. Individual items from the meeting were prepared separately for the data base.

Systematic scaling experiments aimed at deducing the dependence of laser-plasma interaction phenomena on target plasma material and target irradiation history have been underway in laboratories all over the world in recent years. During 1980 and 1981 the Livermore program undertook to measure the laser light absorption of high and low Z plasmas and the partition of the absorbed energy amongst the thermal and suprathermal electron populations as a function of both laser intensity and wavelength. Simulations suggested that short wavelength laser light would couple more efficiently than longer wavelengths to target plasmas. Shorter wavelength heating of higher electron plasma densities would, it was felt, lead to laser-plasma interactions freer of anomalous absorption processes. The following sections review LLNL experiments designed to test these hypotheses.

The existence of incommensurate structures proves that crystal ordering is not always the most stable one for nonquantum matter. Some properties of structures which are obtained by minimizing a free energy are investigated in the Frenkel Kontorova and related models. It is shown that an incommensurate structure can be either quasi-sinusoidal with a phason mode or built out of a sequence of equidistant defects (discommensurations) which are locked to the lattice by the Peierls force. In that situation the variation of the commensurability ratio with physical parameters forms a complete devil's staircase with interesting physical consequences. Some general results for all structures which minimize a free energy are given. In addition to the known crystal and incommensurate structures, the existence of a new class of structures which have local order at all scale is predicted. Properties of the new class are described in physical terms and possible applications to certain amorphous or nonstoichiometric compounds are discussed.

One consequence of the recently increasing emphasis on energy development is public concern about the adequacy of ancillary natural resources, particularly water. This concern accompanies other water-related issues such as droughts, decling water tables, and increasing urbanization. But as the relatively new user on the water scene, energy attracts a major share of public attention. The physical availabiltiy of water and the role of economics in water demand by energy are reviewed. Also described are the social mechanisms through which the physical availability of water, the historical pattern of water use, and unresolved water issues combine to constrain and channel the energy industry's use of water. These mechanisms include the developing markets for water rights, the legal and administrative structure governing water allocation, the formation of social attidudes about water, and the political process that often implements concensus. The narrow physical interpretation commonly given to the question Is there enough water is broadened to include the social dimension, the most important component of the quenstion.