The grain size and strain dependence of work hardening in Type 304L stainless steel were analyzed between 200 and 250 K where hydrogen damage is greatest. Tensile data were obtained for specimens of several grain sizes, both with and without prior exposure to hydrogen gas at 69 MPa pressure. The analysis suggests that hydrogen has little influence on lattice friction stress but has a large effect on dislocation interaction and the back stress of dislocation pileups. This report discusses this study.

Hydrogen solubility was directly measured in specimens of Types 304L, 21-6-9, and modified A-286 austenitic stainless steels saturated with hydrogen at 69 MPa pressure at 470 K. Nitrogen in Type 21-6-9 stainless steel and precipitate morphology in the modified Type A-286 stainless steel altered the hydrogen solubility. Cold work and surface treatment had only minor effects on hydrogen solubility in the three stainless steels. This reports discusses this study.

A direct method for surface-structure determination from normal emission photoelectron diffraction (NPD) data is presented. Fourier transforms of the calculated NPD intensities yield peaks at adsorbate-substrate normal interlayer distances. Applications are demonstrated using theoretical NPD curves for the Se/Ni system calculated by dynamical theory. These results show that interplanar spacings between the overlayer and as many as four substrate layers could be determined with an accuracy of better than 3%.

A thermal shock test has been designed which permits the thermal fracture resistance and the mechanical strength of brittle materials to be quantitatively correlated. Thermal shock·results for two materials, Al{sub 2}O{sub 3} and SiC, have been accurately predicted from biaxial strength measurements and a transient thermal stress analysis (performed using a finite element method). General implications for the prediction of thermal shock resistance, with special reference to ceramic components, are discussed.

Both the magnitude and alignment of the transferred angular momentum in the reaction {sup 165}Ho + {sup 165}Ho have been measured as a function of Q-value via continuum {gamma}-ray multiplicity and anisotropy techniques. The spin transfer and the continuum {gamma}-ray anisotropy increase throughout the quasielastic region. The spin transfer as a function of Q-value saturates at ~35{bar h}/fragment, the anisotropy peaks at a value of ~2 and then decreases to near unity for the largest Q-values. The observed anisotropies are in good agreement with predictions from an equilibrium statistical model in which thermal excitation of angular-momentum-bearing collective modes and neutron evaporation give rise to in-plane components of the angular momentum.

A new type of reciprocating solar engine utilizing small particles to absorb concentrated sunlight directly within the cylinders is described. The engine operates by drawing an air particle mixture into the cylinder, compressing the mixture, opening an optical valve to allow concentrated sunlight to enter through a window in the top of the cylinder head, absorbing the solar flux with the particles, and converting the heat trapped by the air-particle mixture into mechanical energy with the downward stroke of piston. It differs from other gas driven heat engines using solar energy in three main respects. First, the radiant flux is deposited directly in the working fluid inside the cylinder; second, the heat is directed to the appropriate cylinder by controlling the solar flux by an optical system; third, the gas is heated during a significant portion of the compression stroke. The thermodynamic efficiency of the engine is calculated using an analytical model and is compared to several other engine cycles of interest.

Olive-green crystals of the title compound, [({underline n}-C{sub 3}H{sub 7}){sub 2}NH{sub 2}{sup +}]{sub 2} [UO(({underline n}-C{sub 3}H{sub 7}){sub 2}NCOS){sub 2}(S{sub 2}){sup -2}, are orthorhombic, space group Pcan, with {underline a}= 15.326(6) {Angstrom}, {underline b} = 17.474(6) {Angstrom}, {underline C} = 14.728(6) {Angstrom}, and Z = 4, (d{sub X} = 1.45 g/cm{sup 3}). For 1833 data, I >{sigma}, R = 0.052, and R{sub w} = 0.069. The structure was revealed by single-crystal x-ray diffraction studies to consist of [(n-C{sub 3}H{sub 7}){sub 2}NH{sub 2}]+ cations and [UO{sub 2}(({underline n|-C{sub 3}H{sub 7}){sub 2}NCOS){sub 2}(S{sub 2}){sup -2} anions with the uranium atom at the center of an irregular hexagonal bipyramid. The uranyl oxygen atoms occupy the axial positions. The equatorial coordination plane contains the disulfide (S{sub 2}{sup -2}) group bonded in a "side-on" fashion, and two oxygen and two sulfur donor atoms from the monothiocarbamate ligands. Interatomic distances are S-S = 2.05(1) {Angstrom}, U-S= 2.714(3) {Angstrom} (disulfide); U-S= 2.871(3) {Angstrom} and U-O = 2.46(1) {Angstrom} (thiocarbamate); U-O = 1.81(1) {Angstrom} (uranyl), The nitrogen atom in the dipropylammonium cation is hydrogen bonded to the uranyl oxgyen atoms,

Samarium clusters exhibit mixed-valence behavior which is sensitive to particle size. XPS and UPS data show samarium to be primarily divalent (4f{sup 6} ) at small particle size. The trivalent state (4f{sup 5} ) becomes progressively more abundant with increasing s1ze, becoming the dominant state for the bulk metal. These results are interpreted using a model in which band narrowing, due to reduced surface coordination, is more dominant than surface tension effects in establishing the valence of small samarium clusters.

Our earlier theoretical work on the relative muon capture between heavy and light fission fragments is extended by including 2p{sigma} states as well as 1s{sigma}. We calculate about 0.8% population of the 2p state in the heavy fragment with negligible change from our earlier two-state basis regarding the ls population of light and heavy fragments.

Eighteen papers are included, one of which was previously abstracted for EDB. A separate abstract was prepared for each of the remaining seventeen papers for Energy Research Abstracts (ERA); ten of the papers are included in Energy Abstracts for Policy Analysis (EPA).

Power conditioning systems for high peak and average power, high repetition rate discharge excited lasers involve operation of modulator components in unconventional regimes. Reliable operation of switches and energy storage elements under high voltage and high di/dt conditions is a pacing item for laser development at the present time. To test and evaluate these components a Modulator Component Test Facility (MCTF) was constructed. The MCTF consists of a command charge system, energy storage capacitors, thyratron switch with inverse thyratron protection, and a resistive load. The modulator has initially been operated at voltages up to 60 kV at 600 Hz. Voltage, current, and calorimetric diagnostics are provided for major modulator components. Measurements of thyratron characteristics under high di/dt operation are presented. Commutation energy loss and di/dt have been measured as functions of the tube hydrogen pressure.

The Spin Spectrometer at the Holifield Heavy Ion Research Facility (HHIRF) is a multidetector ..gamma..-ray spectrometer consisting of 72 separate NaI detector elements closely packed in a 4..pi.. geometry. The basic apparatus was constructed at Washington University and has been installed and implemented at the HHIRF at Oak Ridge National Laboratory. The spectrometer was designed especially for the investigation of the mechanisms of heavy-ion induced nuclear reactions and of the structure of nuclei with high angular momentum. The data acquisition system is described. (WHK)

The Workshop on Core and Sample Curation was held to discuss the best means of handling, distributing, and advertising samples and data collected during a Continental Scientific Drilling Program (CSDP) and to establish better communication between sample curators regarding common problems. It was geneerally agreed that CSDP samples should be handled, on a regional basis, by existing data systems and sample repositories judged to have adequate staff and support. Repository design, sample handling procedures, and sample accounting systems were discussed. Across North America, support for curation of geological samples was varied, but it was strongest within states or regions with well-established energy and mineral industries. A well-supported repository pays for itself through the circulation and preservation of samples and stratigraphic information. A national CSDP must have a well-established curatorial policy and system of regional repositories to circulate information and samples throughout the scientific community. Well-curated samples and data are a national resource with considerable benefits for industry and academia. Attendees agreed to form a Society of Geoscience Curators to maintain communication between curators from private, government, and university repositories and core research laboratories.

High-intensity, short-duration x-ray pulses are necessary to diagnose the compression of laser film targets. Present target designs are such that backlighting sources ranging from a few thousand electron volts to 100 keV will be necessary. The desired source durations range from a few tens of picoseconds for flash radiography to several nanoseconds for streaked backlighting, and the source occurrence must be tightly synchronized to that of the target-irradiating laser pulse. For the latter reason, a laser-induced x-ray pulse is preferred. An initial study of the K lines of Ti, Ni, and Zn as possible backlighting sources was conducted. The conversion efficiency of laser light into line radiation was obtained as a function of laser intensity, pulse length, and wavelength. A threshold laser intensity for x-ray line production was identified. Information was obtained on the size and duration of the x-ray emission source, in relation to laser parameters. The experimental results, and their impact on backlighting capability for high-density laser function targets, are discussed.

This paper reviews the state-of-the-art for conducting risk assessment studies, especially known and unknown factors relative to radioinduced cancer or other diseases, sources of scientific and epidemiological data, dose-response models used, and uncertainties which limit precision of estimation of excess radiation risks. These are related to decision making for radiation protection policy. (PSB)

The Fusion Materials Irradiation Test Facility (FMIT) is being built to study neutron radiation effects in candidate fusion reactor materials. The FMIT will yield high fluence data in a fusion-like neutron radiation environment produced by the interaction of a 0.1A, 35 MeV deuteron beam with a flowing lithium target. The design of the facility as a whole is driven by a high availability requirement. The variety of radiation environments in the facility requires the use of diverse and extensive shielding. Shielding design throughout the FMIT must accommodate the need for maintenance and operations access while providing adequate personnel and equipment protection.

Twenty-five papers are included. A separate abstract was prepared for each paper. (MHR)

The relative merits of SiO/sub 2/, MgO and Al/sub 2/O/sub 3/ as insulation for nuclear instrument cables are investigated. Insulation resistance, voltage breakdown phenomena, capacitance, dissipation factors, and spurious voltage and current signals have been investigated on nuclear instrument cables under the combined effects of gamma irradiation (10/sup 5/ R/h) and temperature (to 450/sup 0/C). The SiO/sub 2/, MgO and Al/sub 2/O/sub 3/ cables tested were all fabricated to procedures that controlled insulation and backfill gas impurities. The SiO/sub 2/ cables possessed insulation resistances greater than 10/sup 10/ ..cap omega...ft at 450/sup 0/C and 10/sup 5/ R/h - nearly two decades higher than MgO or Al/sub 2/O/sub 3/ cables. Spontaneously generated currents as high as 250 nA dc were observed on some cables during thermal cycling tests.

A distributed microprocessor control and data acquisition network has been designed for implementation on the Lawrence Livermore National Laboratory 100 MeV electron/positron accelerator (LINAC). The system has been designed to be as transparent to the user as possible by stressing responsiveness, reliability, and relevance of data presented to the user. Implementation of the network will take place in modular fashion in three stages, so as to minimize disruption of normal operations. The first elements to be installed will be the beam transport system controls, beam set-up time. Beam diagnostic equipment is now being position monitors, and accelerator operating status monitors. These units will reduce beam set-up time. Beam diagnostic equipment is now being designed that will be used in a second stage implementation. This stage will concentrate on determining beam parameters and allowing the user to optimize the beam for a given parameter. The final stage will be to install experimenter data acquisition equipment. The equipment will augment the presently existing data acquisition system. The completed network will allow a more efficient operation of the LINAC, resulting in reduced experiment costs, and more controllable beam parameters, both of which are major concerns of experimenters.

Nova is a 200 terawatt, 10-beam High Energy Glass Laser currently under construction at LLNL. This facility, designed to demonstrate the feasibility of laser driven inertial confinement fusion, contains over 5000 elements requiring coordinated control, data acquisition, and analysis functions. The large amounts of data that will be generated must be maintained over the life of the facility. Often the most useful but inaccessible data is that related to time dependent events associated with, for example, operator actions or experiment activity. We have developed an Event Logging System to synchronously record, maintain, and analyze, in part, this data. We see the system as being particularly useful to the physics and engineering staffs of medium and large facilities in that it is entirely separate from experimental apparatus and control devices. The design criteria, implementation, use, and benefits of such a system will be discussed.

This report contains the proceedings of the LAMPF Intermediate-Energy Nuclear Chemistry Workshop held in Los Alamos, New Mexico, June 23-27, 1980. The first two days of the Workshop were devoted to invited review talks highlighting current experimental and theoretical research activities in intermediate-energy nuclear chemistry and physics. Working panels representing major topic areas carried out indepth appraisals of present research and formulated recommendations for future research directions. The major topic areas were Pion-Nucleus Reactions, Nucleon-Nucleus Reactions and Nuclei Far from Stability, Mesonic Atoms, Exotic Interactions, New Theoretical Approaches, and New Experimental Techniques and New Nuclear Chemistry Facilities.

Two-particle (p-p,p-d) coincidence has been measured in p + A collisions. Production mechanism of backscattered proton has been studied by forward-backward coincidence events. Data show the importance of 2N-cluster scattering and/or multiple scattering processes involving a few nucleons. They also show that the nucleon-nucleon quasi-elastic-scattering is not the dominant part of the backscattered proton production.

The present experimental status on single particle inclusive measurements is described. Then, the geometrical aspect of the collision is discussed from the data of total integrated cross sections of nuclear charge or mass. The dynamical aspect of the collision, especially that for the participating region is discussed in connection with proton spectra, composite fragment spectra, pion production, ratios of ..pi../sup -//..pi../sup +/, n/p and t//sup 3/He, and production of strange particles. The spectator physics is described from the data on projectile fragments. (GHT)

Two-photon collisions provide an ideal laboratory for testing many features of quantum chromodynamics, especially the interplay between the vector-meson-dominated and point-like hadronic interactions of the photon. A number of QCD applications are discussed, including: jet and single-particle production at large transverse momentum; the photon structure function and its relationship to the ..gamma.. ..-->.. q anti q wave function; and the possible role of gluonium states in the ..gamma gamma.. ..-->.. rho/sup 0/rho/sup 0/ channel. Evidence that even low momentum transfer photon-hadron interactions are sensitive to the point-like ..gamma.. ..-->.. q anti q coupling is discussed.