A model for a windowed, high-temperature cavity receiver of the heated-air type is developed and used to evaluate the greenhouse effect as a method for obtaining high receiver operating efficiencies. The effects on receiver efficiency of varying the window cutoff wavelength, the amount of absorption in the window pass-band, the cavity operating temperature, and the number of windows are determined. Single windowed cavities are found to offer theoretical efficiencies comparable to windowless ones, while multiple windowed units are found to suffer from low operating efficiencies due to losses resulting from reflections at each window/air interface. A ''first order'' examination is made of the feasibility of air cooling the window to assure its survival. This appears possible if a proper combination of cooling technique and window material characteristics is selected.

Numerical codes have been developed for the description of the nonlinear evolution of tearing modes in tokamaks. The m = 1 mode is observed to continue rapid growth in the nonlinear regime, producing significant changes on a time scale consistent with the experimentally observed minor disruption. The double tearing mode associated with a hollow current profile also continues rapid growth in the nonlinear regime, and thus may play a significant role in the anomalous current penetration during the early stages of a tokamak discharge. Single magnetic islands with m greater than or equal to 2, on the other hand, cease exponential growth upon entering the nonlinear regime and saturate shortly thereafter. A model for the saturation processes is presented. Modifications due to thermal transport are discussed.

A system model of the mirror hybrid reactor has been developed. The major components of the model include (1) the reactor description, (2) a capital cost analysis, (3) various fuel management schemes, and (4) an economic analysis that includes the hybrid plus its associated fission burner reactors. The results presented describe the optimization of the mirror hybrid reactor, the objective being to minimize the cost of electricity from the hybrid fission-burner reactor complex. We have examined hybrid reactors with two types of blankets, one containing natural uranium, the other thorium. The major difference between the two optimized reactors is that the uranium hybrid is a significant net electrical power producer, whereas the thorium hybrid just about breaks even on electrical power. Our projected costs for fissile fuel production are approximately 50 $/g for /sup 239/Pu and approximately 125 $/g for /sup 233/U.

Advances in electrochemical engineering are reviewed and the methodology of analysis of electrochemical systems outlined. Examples illustrative of current research concern simultaneous reactions for flow-through porous electrodes and the more fundamental system of a rotating-disk electrode. Here the undesirable side reaction is the formation of dissolved hydrogen, and the main reaction is the deposition of copper from sulfuric acid solutions. Distributions of reaction rate, concentration, and potential describe the detailed system behavior. The side reaction is responsible for the poorly defined limiting-current plateau on the disk electrode and provides a limit for the maximum flow rate at which good recovery can be achieved with the porous electrode. 16 figures.

The fuel temperature attained in laser initiated fusion of DT filled targets is determined from the line width of the neutron energy spectrum. Spectral measurements are made using a 45-meter neutron time-of-flight spectrometer at the ARGUS laser irradiation facility. The large fluor-photomultiplier package used as the neutron detector has a 4.5 nsec FWHM response to a burst of neutrons and a 3.5 nsec response to a single neutron event. Appropriate unfolding of the measured data enables us to determine line widths above 100 keV with a resolution of 40 keV or equivalently, plasma temperatures of approximately 1 keV and above.

An extensive data acquisition and analysis system has been implemented for experiments on the ARGUS laser. The system is based upon a PDP-11/40 minicomputer and CAMAC interfaces. Highspeed transient digitizers, calorimeter digitizing modules and time integrated data are interfaced through CAMAC over a fiber optic serial highway. The system allows for dynamic definition of the experimental environment by an operator, automatic data acquisition during a shot. Two interactive graphics terminals allow experimenters real-time access to target shot data.

Separate abstracts were prepared for 22 papers that discuss methods for the external measurement of transuranium elements deposited in personnel.

Instrumentation has been developed at the Lawrence Livermore Laboratory for measuring subkilovolt x-rays from laser-produced plasmas. This information is needed to do a complete energy balance on laser fusion experiments. The instruments must have thin windows and yet discriminate against the severe environment of other intense target emissions such as ions, electrons, and scattered laser light. Low energy x-ray measurements down to 0.1 keV will be presented using these absolutely calibrated detectors on laser target shots with the LLL Terawatt laser facility, Cyclops. Precautions in using these detectors in a laser fusion target chamber will be enumerated from our experience in using these instruments on hundreds of laser shots.

The potential waste releases for commercial fusion power plants were estimated by use of standard environmental analysis procedures incorporating a high degree of speculation. The analytical procedure is presented. A description was obtained for each of the ten fusion power plant concepts currently being developed. These concepts were then analyzed to determine the general characteristics and probable waste releases. (MOW)

Experiments with relativistic nuclear beams which will provide new data on nucleus-nucleus collisions at Bevalac energies over the next one or two years are summarized. A brief description of each experiment and its goals are presented. In addition, future improvements to the Bevalac Facility are discussed.

This study describes studies being conducted to quantify dry removal rates of air pollutants by natural surfaces. Processes involved are discussed in a resistance model framework. Values from the literature and results of current field tests relating to rates of dry removal are summarized for selected gases and particles, and the experimental accuracy of particulate sulfur deposition values is discussed.

The complementary techniques of flash x-ray radiography (FXR) and flash x-ray diffraction (FXD) provide access to a unique domain in nondestructive materials testing. FXR is useful in studies of macroscopic properties during extremely short time intervals, and FXD, the newer technique, is used in studies of microscopic properties. Although these techniques are similar in many respects, there are some substantial differences. FXD generally requires low-voltage, line-radiation sources and extremely accurate timing; FXR is usually less demanding. Phenomena which can be profitably studied by FXR often can also be studied by FXD to permit a complete materials characterization.

A more compact ..cap alpha..-particle time-of-flight spectrometer using a permanent field deflection magnet has been developed for laser fusion burn diagnostics. The spectrometer is being used to measure the number and energy distribution of fusion-produced ..cap alpha.. particles emitted from laser implosions of DT gas contained in glass microshells. It is planned to view the target from different angles using several spectrometers simultaneously. Comparison of energy loss and energy broadening vs angle can yield information concerning the symmetry of compression and subsequent burn. Results from target experiments on the LLL ARGUS laser facility are present.

Holographic interferometry at 2660 A has been used to study plasma blowoff from 80 micron diameter laser fusion targets. Scale lengths of 11 microns, measured with 1 micron spatial resolution, are recorded at 7 x 10/sup 20/ e/cc after 800 psec of hydrodynamic expansion. These results suggest much steeper density gradients at peak irradiation intensity. The observed fringe pattern is strongly dependent on interferometric imaging, as expected for strong transverse gradient refractive media. Significant interpretive errors, which might occur in a single image classical interferometer, are avoided with this holographic technique.

The RTNS-II Facility at Livermore was authorized in the FY76 ERDA budget. This facility will house two 4 x 10/sup 13/ n/s sources of 14-MeV neutrons for materials damage experimentation. RTNS-II will be the first of DCTR's dedicated neutron source facilities. Initial operation is currently scheduled for March 1978. Engineering design of buildings and neutron sources started in March 1976 with construction scheduled to begin in August 1976. Design of the 150 mA D/sup +/ accelerators is based upon LLL experience with the MATS-III ion source and with the ICT accelerator of the RTNS-I source. Hardware design for the 50 cm, 5000 rpm tritium-in-titanium targets was guided by computer modeling of the target system now in use on RTNS-I. The final design of neutron sources and building layout will be discussed.

Double differential cross sections have been measured for high energy p,d,t, /sup 3/He, and /sup 4/He particles emitted from uranium targets irradiated with /sup 20/Ne ions at 250, 400, and 2100 MeV/nucleon and /sup 4/He ions at 400 MeV/nucleon. By using the shape and yield of the proton energy spectra, the shape and yield of the d, t, /sup 3/He, and /sup 4/He energy spectra can be deduced at all measured angles for all incident projectile energies assuming that they are formed by coalescence of cascade nucleons. Finally, it is found that the overall features of the proton inclusive spectra are fit without any adjustable parameter by a proposed nuclear fireball model. In this model the nucleons which are mutually swept out from the target and projectile form a hot quasi-equilibrated fireball which decays as an ideal gas.

Performance of laser fusion targets depends critically on the characteristics of the incident beam. The spatial distribution and temporal behavior of the light incident on the target varies significantly with power, with choice of beam spatial profile and with location of spatial filters. On each ARGUS shot we photograph planes in the incident beams which are equivalent to the target plane. Array cameras record the time integrated energy distributions and streak cameras record the temporal behavior. Computer reduction of the photographic data provides detailed spatial energy distributions, and instantaneous power on target vs. time. Target performance correlates with the observed beam characteristics.

Experimental evidence is presented of a steepened electron density profile near critical density obtained from studying the time-integrated scattered light from targets illuminated by linearly polarized, 1.06 ..mu.. light. Both 10 ..mu.. thick disks and DT-filled glass microshells were irradiated by light focused by f/1 or f/2.5 lenses in one and two-beam experiments, respectively. From the dependence of the asymmetry of the scattered light about the beam axis upon the scattering angle, we infer scale lengths on the order of one micron. Scale lengths have also been deduced from measurements on the polarization state of the reflected light. Both analytic and numerical results are presented to show how the polarization state varies with the incidence angle and the scale length.

The review of baryon spectroscopy includes a number of new generation experiments with greatly improved statistics which have emerged and are enhancing experimental knowledge of baryon resonances. The future research directions are pointed out, and some problems and deficiencies which can be resolved with contemporary techniques are mentioned. (JFP)

The laser and fluorescence output of KrCl and ArF were measured and the effect of the gas mixture on the laser output was determined. Possible mechanisms for the effects observed are suggested. (JSR)

The fast-rabbit facilities of the ORRR were used to irradiate 1- to 10-..mu..g samples of /sup 235/U for 1, 10, and 100 s. Released power is observed using nuclear spectroscopy to permit separate observations of emitted ..beta.. and ..gamma.. spectra in successive time intervals. The spectra were integrated over energy to obtain total decay heat and the ..beta..- and ..gamma..-ray results are summed together. 10 fig, 2 tables. (DLC)

Polarized x-radiation is shown to be a superior and practical excitation source for measuring trace elements by energy dispersive x-ray fluorescence. In this study, polarization was obtained by scattering the primary beam at 90/sup 0/ from boron carbide. The losses inherent in the geometric requirements and the polarizer efficiency can be more than compensated for by using a close-coupled system and a standard, high-power x-ray tube. With the system described here, which uses a molybdenum anode x-ray tube, detection limits for the elements from K to Sr in NBS Standard Orchard Leaves are approximately 2 to 4.5 times lower using polarized excitation as compared to direct excitation, and about 1 to 3 times lower as compared to secondary excitation.

TREAT F-series tests are being conducted to provide data on fuel motion at accident power levels from one to about ten times design for use in development of fuel motion models. Test F2 was conducted to evaluate motion of high power fuel in a hypothetical LMFBR unprotected TUC (transient undercooling) accident. Fuel and fuel-boundary conditions following coolant boiling and dryout under TUC conditions are achieved in each F-series test with a single fuel element surrounded by a nuclear heated wall in a dry test capsule. Test F2 was conducted with a low burnup but restructured fuel element to investigate the effect of fuel vapor pressure on fuel motion. Results are presented and discussed.

The presence of hydrodynamic fluid instability at the ablation surface puts constraints on the kinds of targets, surface finish, and energy sources that one can use for thermonuclear micro-implosions. If Taylor-like modes grow at near the classical value, one is limited to low aspect ratio shells and surface finishes of 10-100 A. These surface finish requirements can be reduced by 1 to 2 orders of magnitude by exploiting density gradient modification techniques to obtain a shallow density gradient at the ablation surface. For laser driven targets, the gradient is achieved by utilizing suprathermal electrons with a high energy ''get lost'' region to eliminate severe preheat problems. For charged particle sources, the reduction is achieved by introducing an energy spread on the driving source.