Required values of thermonuclear energy-gain, inertial confinement, laser-pulse energy and power for both electric power production by laser-fusion and for plutonium breeding by laser fusion-fission are obtained from simple considerations, and are tabulated for purposes of comparison. It is found that breeder requirements are very significantly less demanding, suggesting that plutonium breeding is a much more feasible near-term goal of laser fusion.

Using a pressure tuned narrowband pulsed dye laser we have investigated hyperfine effects in several ground state transitions in /sup 235/U I using the multistep laser photoionization method on an atomic beam. The instrumental linewidth was 300 to 400 MHz corresponding to a calculated residual Doppler width of approximately 300 MHz and a laser width of about 100 MHz. The technique also provides very accurate values (less than 100 MHz) for the isotope shifts for the investigated transitions.

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.

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 nature of compression and subsequent burn. Results from target experiments on the LLL ARGUS laser facility are present.

A small man-portable neutron detector was constructed using 18 /sup 3/He proportional counters arranged in three layers within a polyethylene moderator. Each counter is 25 mm in diameter by 340 mm long (sensitive length) and is filled with highly-purified /sup 3/He to a pressure of 400 kPa (4 atm). Efficiency measurements were made using a /sup 252/Cf neutron source. Detailed calculations of the detector efficiency were done using the TART Monte Carlo transport code. Calculations and measurements were compared for several source/detector configurations.

In analyzing CaF/sub 2/:Dy (TLD-200) data from the environmental monitoring program at the Lawrence Livermore Laboratory, a quantity of significance is the dose to the thermoluminescence dosimeters during shielded storage. This paper describes a method for determining this shield dose, which can then be related to the dose from cosmic radiation. Data, based on quarterly TLD exposure periods, show a range of 43-56 ..mu..rads per day in a 75 mm thick lead shield. Observed variations in the shield dose have led to studies of prolonged exposure of TLDs to elevated and reduced temperatures typical of those in the Livermore Valley.

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.

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 energy carried by particles and low energy x-rays resulting from irradiation of targets with .5 to 1 TW, 1.06 ..mu..m lasers has been measured. The energy distributions were obtained from measurements at discrete locations using calorimeters and work is in progress to obtain them over a hemisphere with a thermal imaging system. Azimuthal symmetry and polar distributions for different focusing schemes have been determined. The data have been integrated to obtain the absorbed energy and these values compared to box calorimetry and optical energy balance. The relative emission of low energy x-rays from different Z materials can be obtained by comparing these data to charge collector data. Such comparisons also showed that the effective ion charge can be as low as a factor of two below the completely ionized state. The existence of low charge state ions has since been confirmed with high resolutions spectrometers.

In recent years several techniques have become available to characterize the structure and chemical composition of surfaces of ceramic materials. These techniques utilize electron scattering and scattering of ions from surfaces. Low-energy electron diffraction is used to determine the surface structure, Auger electron spectroscopy and other techniques of electron spectroscopy (ultraviolet and photoelectron spectroscopies) are employed to determine the composition of the surface. In addition the oxidation state of surface atoms may be determined using these techniques. Ion scattering mass spectrometry and secondary ion mass spectrometry are also useful in characterizing surfaces and their reactions. These techniques, their applications and the results of recent studies are discussed. 12 figures, 52 references, 2 tables.

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.

To increase the reliability of the criticality monitoring system in a diagnostic chemistry area and to reduce the number of false alarms, a new monitoring system was built using a fast-neutron detector. This paper outlines the design requirements, describes the plastic scintillation detector system as it was built, and reports on the results of several months of operation. The new monitor has proven much more useful than the gamma-detector system it replaced.

This research demonstrates the feasibility of using homogeneously-generated fission fragments to simulate high-fluence fusion neutron damage in niobium tensile specimens. This technique makes it possible to measure radiation effects on bulk mechanical properties at high damage states, using conveniently short irradiation times. The primary knock-on spectrum for a fusion reactor is very similar to that produced by fission fragments, and nearly the same ratio of gas atoms to displaced atoms is produced in niobium. The damage from fission fragments is compared to that from fusion neutrons and fission reactor neutrons in terms of experimentally measured yield strength increase, transmission electron microscopy (TEM) observations, and calculated damage energies.

The direct conversion to electrical energy of the energy carried by the leakage plasma from a fusion reactor and by the ions that are not converted to neutrals in a neutral-beam injector is discussed. The conversion process is electrostatic deceleration and direct particle collection as distinct from plasma expansion against a time-varying magnetic field or conversion in an EXB duct (both MHD). Relatively simple 1-stage plasma direct converters are discussed which can have efficiencies of about 50 percent. More complex and costly (measured in $/kW) 2-, 3-, 4-, and 22-stage concepts have been tested at efficiencies approaching 90 percent. Beam direct converters have been tested at 15 keV and 2 kW of power at 70 +- 2 percent efficiency, and a test of a 120-keV, 1-MW version is being prepared. Designs for a 120-keV, 4-MW unit are presented. The beam direct converter, besides saving on power supplies and on beam dumps, should raise the efficiency of creating a neutral beam from 40 percent without direct conversion to 70 percent with direct conversion for a 120-keV deuterium beam. The technological limits determining power handling and lifetime such as space-charge effects, heat removal, electrode material, sputtering, blistering, voltage holding, and insulation design, …

Irradiation experiments were performed with the two beam Nd:YAG glass laser systems, Janus(approximately less than 40 J/100 psec, approximately 0.4 TW), Cyclops (approximately less than 70 J/100 psec, approximately 0.7 TW), and Argus (approximately less than 70 J, 35 psec, approximately 2 TW). Two classes of targets have been used, glass microshells (approximately 40 to 120 ..mu..m diameter x approximately 0.75 ..mu..m wall thickness) filled with an equimolar DT mixture and disks (approximately 160 to 600 ..mu..m diameter x approximately 10 ..mu..m thick) of several compositions. The targets were supported in vacuum (pressure approximately less than 10/sup -5/ Torr) by thin glass stalks. This paper reports results related to the propagation, absorption and scattering of laser light by both spherical and planar targets. The absorption measurements cannot be explained using only inverse Bremsstrahlung. The scattered light and the plasma energy are polarization dependent, which is evidence of resonance absorption. The x-ray spectra are characterized by a thermal and a suprathermal distribution. The ''temperature'' of the hot x-rays is given by theta/sub H/ approximately equals I./sup 3/-./sup 4/ depending on the target material. Evidence is also presented which indicates that the laser radiation pressure is producing density steepening in the region …

In the Elmo Bumpy Torus Reactor (EBTR) study the feasibility of achieving a fusion power plant based on the EBT confinement concept was evaluated. If the present understanding of the physics can be extrapolated to reactor scale devices the reactor could operate at high beta, high power density, and at steady state. The high aspect ratio of the device eases the accessibility, structural design and remote maintenance problems which are common to low aspect ratio machines. A version of the EBTR reference design described here could be constructed with only minor extrapolations in available technology.

The cross section for the generation of helium in neutron irradiated carbon was found to be 654 mb at 14.4 MeV and 744 mb at 14.9 MeV. Extrapolating to 14.1 MeV (the fusion reactor spectrum) gives 615 mb. The diffusion of helium in dense polycrystalline graphite and in pyrographite was measured and found to be D = 7.2 x 10/sup -7/ m/sup 2/s/sup -1/ exp (-80 kJ/RT). It is assumed that diffusion is primarily in the basal plane direction in crystals of the graphite. In polycrystalline graphite the path length is a factor of ..sqrt..2 longer than the measured distance due to the random orientation mismatch between successive grains. Isochronal anneals (measured helium release as the specimen is steadily heated) were run and maximum release rates were found at 200/sup 0/C in polycrystalline graphite, 1000/sup 0/C in pyrographite, 1350/sup 0/C in boron carbide, and 1350/sup 0/ and 2400/sup 0/C (two peaks) in silicon carbide. It is concluded that in these candidates for curtain materials in fusion reactors the helium releases can probably occur without bubble formation in graphites, may occur in boron carbide, but will probably cause bubble formation in silicon carbide. 7 figures.

The current interest in fast ions has prompted the design of a new time-of-flight ion spectrometer which measures the high energy ions from a laser produced plasma. A magnet was used to separate the ions from the intense background of electrons, x-rays and scattered light. The design of the instrument is wide band so that ions with energies 0.03 to 3000 keV/amu can be measured. Results from target experiments on the LLL ARGUS laser facility will be presented. The fast ion spectrum is dovetailed with the spectrum of the slower ions collected by Faraday cups and thus provides a measurement for the total energy carried by ions. The charge to mass ratio of the ions can be calculated from the spectrometer output.

The targets used for the creation of laser produced plasmas often contain sodium, silicon and other period 3 elements. Temperature and density information can be inferred from detailed study of the characteristic radiation from these elements. The resolution capabilities of crystal spectrographs designed to look at such target radiation are discussed. Data from several types of spectrographs are compared. The fine structure of the hydrogen and helium-like silicon lines are used to illustrate spectrograph resolution. A spectrograph for examining weak characteristic radiation near 1 keV due to plasma which has been compressed with a spherical irradiation system is discussed.

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, scale lengths on the order of one micron are inferred. 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.

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.

There are four known geothermal resource areas in the Imperial Valley that have a combined potential of over 4,000 megawatts of electrical energy for 25 years. The water resources available to support geothermal energy development are imported Colorado River water, agricultural waste waters, Salton Sea water, and ground water. In addition, geothermal power plants can produce their own cooling water in the form of steam condensate. Nevertheless, the relatively high water requirements of geothermal facilities along with a series of real and potential constraints may cause water supply dilemmas involving both the acquisition and use of cooling water. Important constraints are institutional policies, water supply costs, technical problems, and impacts upon the Salton Sea. These constraints and related dilemmas are examined in light of relevant information on the valley's water resources, geothermal resources and energy technologies, cooling water requirements, and water supply options.

Lead-tin plating can be rapidly and uniformly applied to a 0.25 in. square copper conductor. Such plating can be used as solder with a minimum flux requirement. In the range studied, the tin content of the coating can be controlled. It varies directly with the tin content of the bath and amperage and inversely with the temperature.

The incentive for high density operation of a tokamak reactor was discussed. It is found that high density permits ignition in a relatively small, moderately elongated plasma with a moderate magnetic field strength. Under these conditions, neutron wall loadings approximately 4 MW/m/sup 2/ must be tolerated. The sensitivity analysis with respect to impurity effects shows that impurity control will most likely be necessary to achieve the desired plasma conditions. The charge exchange sputtered impurities are found to have an important effect so that maintaining a low neutral density in the plasma is critical. If it is assumed that neutral beams will be used to heat the plasma to ignition, high energy injection is required (approximately 250 keV) when heating is accompished at full density. A scenario is outlined where the ignition temperature is established at low density and then the fueling rate is increased to attain ignition. This approach may permit beams with energies being developed for use in TFTR to be successfully used to heat a high density device of the type described here to ignition.