Bubbles are concentrations of electromagnetic energy in the region of the critical density that force out the plasma to form a void. Since the critical density surface is cratered, absorption may be greater than a smooth surface since a larger area will be available for absorption and the reflected light will have a large probability of restriking the critical density. The distance between bubbles is several wavelengths and consequently they may encourage Rayleigh--Taylor instabilities. The threshold, magnetic field generation, and possible experimental evidence for bubbles are discussed. Also, the competition between sidescatter and self focusing in an entirely underdense plasma is studied and it is found that sidescatter dominates for polarization out of the simulation plane.

An attempt was made to develop a thesaurus of terminology associated with geothermal energy for use in the information storage and retrieval system of LBL's Geothermal Information Group. The development of the thesaurus is discussed, beginning with an outline of its subject scope, sources, and methods used in compiling the list of terms. The tendency was to include, rather than exclude, terms of unknown usefulness, and to provide paths through the thesaurus to make these terms accessible. The thesaurus structure and links to other vocabularies are described. The thesaurus processing software developed at LBL is briefly mentioned.

ARGUS is a two-beam Nd: glass laser system built for laser fusion irradiation experiments. It is the first glass laser system planned and built with the understanding that small-scale beam break-up is the dominant performance limiting factor in obtaining high output power. Accordingly, five vacuum spatial filters are located at strategic intervals along each chain to eliminate the accumulated small-scale filamentation. This strategy permits cascading of amplifiers to obtain a focusable output of more than one terawatt per arm in a spatially clean beam of 20 centimeter diameter. Beam diagnostics which characterize each shot include the time-integrated spatial profile and the time resolved intensity/power at the target. Demonstrated performance to date includes: (1) Peak power in excess of 2 TW at the target is achieved with regularity. (2) Maximum system brightness is in excess of 10/sup 17/ watts/cm/sup 2/ ster. (3) Shot-to-shot pointing stability within 50 ..mu.. radians is achieved over periods of days. (4) Successful target experiments have been performed with pulses of from 30 to 500 ps duration.

The neutral-beam energy required for adequate penetration of tokamak plasmas of high opacity can be reduced by a large factor if the beam is injected vertically into a region of large TF (toroidal-field) ripple. Energetic ions are trapped in local magnetic wells and drift vertically toward the midplane (z = 0). If the ripple is made very small on the opposite side of the midplane, drifting ions are detrapped and thermalized in the central plasma region. This paper discusses design considerations for establishing the required vertically asymmetric ripple. Examples are given of special TF-coil configurations, and of the use of auxiliary coil windings to create the prescribed ripple profiles.

The plateout distribution of gamma-emitting nuclides in the primary circuit of the Peach Bottom HTGR at end-of-life has been determined by in situ gamma scanning. The specific activity was mapped by scanning the accessible ducting at 12 locations with a Ge(Li) detector and by axially traversing 79 steam generator tubes with travelling CdTe detectors from the water side. Following destructive removal of trepan samples, a travelling intrinsic germanium detector was inserted sequentially into two vertical ducts and the plateout mapped along 6-m runs of ducting. Calibration measurements on mockups allowed reduction of the spectra to specific activity. The measured plateout profiles were in excellent agreement with those predicted with the PAD code. The dominant gamma emitters were Cs-137 and Cs-134; their relative distributions were similar. Little local structure to the plateout in the ducts was observed, only a gradual decrease in specific activity in the direction of coolant flow. In the steam generator, a significant entrance effect was observed in the superheater section; the activity was highest where the inlet jet impinged and lowest at the ends of the bundle despite the presence of a flow baffle. The effect damped out with penetration into the bundle, and the axial profile …

A Digital Equipment Corporation PDP-14 Industrial Programmable Controller was employed to provide automatic, closed-loop control for an explosive pellet manufacturing system at Mound Laboratory. Programmable controllers allow the application of sophisticated and flexible control, through programming. Advantages of the PDP-14 controller are ease of installation and maintenance, capability for modular expansion, and immunity to electrical noise. Safety requirements were met by using new techniques for adapting electrical equipment to a hazardous environment and by locating the PDP-14 remotely outside the explosive area. Another advantage of the new explosion proofing (EP) methods/equipment was that they produced a minimum of clutter on the controlled explosive pellet manufacturing system.

Various waste management systems were examined in order to determine what the environmental impacts might be and to rank the relative importance of those impacts. This examination determined that radiation dose to man was the most significant, and probably overriding, impact. This report describes methods of providing an objective function for dose to man. The search for an objective function began with a reading of Federal Regulations and the output of various standard setting councils and committees. Ample guidance was found on maximum allowable doses to individuals but no guidance on dose to large populations or criteria by which systems could be compared or optimized. Several other ways were postulated by which waste management systems could be evaluated besides maximum allowable dose to individuals. 0.1 man-rem per MW(e)-year was selected as the measure of system performance. This unit compares a rational estimate of population dose commitment with the concurrent benefit.

A megachannel pulse-height analysis system using a PDP-8/E computer and two moving-head disk memories has been developed. The system has a storage capacity of 220 memory locations, is capable of processing 1100 events/s, and provides on-line sorting and disk storage. An X- or Y-pulse-height spectrum in coincidence with one or several arbitrary pulse-height windows can be assembled in core for scope display and spectral analysis within 2 to 20 seconds. Reconstruction of a complete X- or Y-pulse-height spectrum requires about 3 minutes.

A focusing system which utilizes two f/0.47 doublets in conjunction with ellipsoidal mirrors produces two focusing cones with half angles of 81.5/sup 0/. This system has been used with the LLL Janus laser system to irradiate and implode DT filled glass microshells approximately 80 ..mu..m diameter. The purpose of the system was to provide more uniform heating of the pusher and compression of the fuel than had been obtained with Janus irradiated targets using f/1 lenses. Neutron yields of approximately 10/sup 7/ per event have been obtained and x-ray micrographs indicate tha the heating of the pusher was more uniform. Also the implosions are definitely more spherical than those obtained with the f/1 lenses. Data is also presented which add further confirmation to the importance of absorption by plasma wave resonance for non normal incidence of the laser light with the target.

In a nuclear reactor, tubes are pressurized from interior by coolant, while externally no pressure is applied on them. The pressure that causes any of the tubes to burst is random and has certain distribution. By using the presently available data from stress-strain experiment, mathematical procedure for finding the distribution form of the ultimate stress is made and is justified theoretically and empirically. The distribution function obtained is important in analyzing the problem of loss of coolant in the reactor.

Recent experimental results on narrow states, intermediate between psi and psi', produced by radioactive decays of psi' are discussed. These chi states are examined using the following processes: (1) inclusive photon spectra to search for monoenergetic photon lines, (2) cascade processes, psi' ..-->.. ..gamma../sub 1/chi ..-->.. ..gamma../sub 2/psi ..-->.. e/sup +/e/sup -/ or ..mu../sup +/..mu../sup -/, and (3) hadronic decays of chi states, psi' ..-->.. ..gamma..chi ..-->.. hadrons. Clearly identified states have been produced at masses 3415, 3500, and 3550 MeV with preferred spin-parity assignments of 0/sup +/, 1/sup +/, and 2/sup +/, respectively. (SDF)

Fusion is examined against the yardstick of fission technology with respect to inventories of radioactivity (and associated Biological Hazard Potentials), routine emissions, accident pathways and consequences, radioactive-waste management, and misuse of nuclear materials. Based on conceptual designs of Tokamak fusion reactors with stainless steel structure and tritium inventories of 10 kg per thermal gigawatt, the apparent advantage of fusion is 1 to 2 orders of magnitude in most indices of radiological hazards. Fusion's advantage is 2 to 5 orders of magnitude in comparing damage potential of intentional airborne dispersal of tritium and plutonium, and nonexistent in comparing medium-term radwaste hazard potential (1000 to 100,000 years) and intentional waterborne dispersal of tritium and plutonium. Fusion appears to have some qualitative advantages with respect to accident pathways and safeguards considerations. Fusion has the theoretical potential for improvements of 1 to 2 additional orders of magnitude in short-term BHPs and 3 orders of magnitude and more in radwaste BHPs after 10 years if vanadium-titanium alloy can be used in place of stainless steel in the reactor structure. Other important unresolved questions are how much the inventory of tritium can be reduced by ingenious design, and what fraction of a fusion reactor's activation products …

A 5W argon ion laser that operates CW is used. A broad band rear mirror is tuned to maximum power output. The beam is directed vertically by an adjustable turning prism, through a beam splitter, and then focused with an ordinary microscope objective lens onto the material to be cut. The beam splitter allows a telescope and television camera arranged to view the cutting through the same lens that is focusing the laser. The object to be cut is mounted on a micromanipulator which can move the object in two dimensions in the focal plane of the laser. (MOW)

The chemical reactivity of chars from various ranks of coal with CO/sub 2/ has been studied using the diffusion cell technique which has been previously developed at BNL. Chars from the following coals were used: Montana lignite, Illinois No. 6 bituminous, and Pennsylvania anthracite. The reactivity peaks at a certain temperature and the peaking temperature can be correlated to the ash-melting temperature; this temperature varies widely from the range of 1100 to 1200/sup 0/C to 1500 to 1600/sup 0/C for the three coals. Results on the leached lignite and on the surface area measurements were also obtained and are used to discuss the effect of ash on the reactivity of char.

The Lawrence Livermore Laboratory Solid State Laser System, Arqus, has successfully performed laser implosion experiments at power levels exceeding 2 TW. D-T filled glass microspheres have been imploded to yield thermonuclear reaction products in excess of 5 x 10/sup 8/ per event. Neutron and ..cap alpha.. time-of-flight measurements indicate that D-T ion temperatures of approximately 5-6 keV and a density confinement time product (n tau) of approximately 1 x 10/sup 12/ were obtained in these experiments. Typically two 40J, 40 psec pulses of 1.06 ..mu..m light were focused on targets using 20 cm aperture f/1 lenses, producing intensities at the target in excess of 10/sup 16/ W/cm/sup 2/. An extensive array of diagnostics routinely monitored the laser performance and the laser target interaction process. Measurements of absorption and asymmetry in both the scattered light distribution and the ion blow off is evidence for non-classical absorption mechanisms and density scale heights of the order of 2 ..mu..m or less. The symmetry of the thermonuclear burn region is investigated by monitoring the ..cap alpha..-particle flux in several directions, and an experiment to image the thermonuclear burn region is in process. These experiments significantly extend our data base and our understanding of laser …

Potential advantages of hybrid or fusion/fission systems can be exploited in different ways. With selection of the /sup 238/U--/sup 239/Pu fuel cycle, we show that the system has greatest value as a power producer. Numerical examples of relative revenue from power production vs. /sup 239/Pu production are discussed, and possible plant characteristics described. The analysis tends to show that the hybrid may be more economically attractive than pure fusion systems.

Individual papers were indexed for inclusion in the data base. (LK)

To determine the feasibility of recovering data actively from x-ray imaging instruments used in the Lawrence Livermore Laboratory Laser Fusion Program, a commercial silicon video sensor was used to detect patterns of soft x-rays (1-8 keV). The sensor is a 2-dimensional frame transfer charge coupled device (CCD), modified to allow direct access of x-rays to the sensitive silicon. The x-ray sensitivity, linearity, and dynamic range of the CCD are discussed.

Calculations of damage energy and displacement cross sections using the recommendations of a 1972 IAEA Specialists' Meeting are reviewed. The sensitivity of the results to assumptions about electronic energy losses in cascade development and to different choices respecting the nuclear cross sections is indicated. For many metals, relative uncertainties and sensitivities in these areas are sufficiently small that adoption of standard displacement cross sections for neutron irradiations can be recommended.

As laser capabilities increase, implosions will be performed to achieve high densities. Criteria are discussed for formation of a low-density corona, preheated supersonically, which increases the tolerance of high convergence implosions to non-uniform illumination by utilizing thermal smoothing. We compare optimized double shell target designs without and with atmosphere production. Two significant penalties are incurred with atmosphere production using 1 ..mu..m laser light. First, a large initial shock at the ablation surface limits the pulse shaping flexibility, and degrades implosion performance. Second, the mass and heat capacity of the atmosphere reduce the energy delivered to the ablation surface and the driving pressures obtained for a given input energy. Improvement is possible using 2 ..mu..m light for the initial phase of the implosion. We present results of 2-D simulations which evaluate combined symmetry and stability requirements. At l = 8, the improvement produced in the example is a factor of 10, giving tolerance of 10 percent.

Recent experiments at the LLL 2.0 terawatt laser irradiation facility Argus have been conducted on glass microshells filled with equimolar DT gas. A variety of microshell dimensions and laser pulse widths have been used with the best results producing in excess of 10/sup 8/ fusion reactions. Numerical simulation of selected experiments using the LASNEX computer code confirm the measured performance. Peak DT ion temperatures of about 5 keV and densities of .2 gm/cm/sup 3/ are calculated and are in agreement with that from neutron time-of-flight and alpha particle spectral measurements together with x-ray diagnostics. Laser light absorption is about 20% efficient. General characteristics of ''exploding pusher'' targets will be discussed.

The fabrication steps are examined for a complex glass target which is designated as a Ball-in-Plate or Saturn target. The Ball-in-Plate target consists of a hollow, D-T filled glass sphere mounted in a thin glass plate. The glass plate is coplaner with a diametral plane of the sphere.

A computer code was written to describe the alpha particle energy loss. The problem of a symmetric compression of the DT gas by an exploding microsphere is analyzed. The code calculates the energy spectrum of a Gaussian distribution of alpha particles after passing through the compressed gas and the exploded glass. The calculations are being used to determine design parameters for diagnostic instruments for measuring charged particle energy distributions from laser fusion targets. (MOW)

Using copper (a fast diffusing, multivalent acceptor impurity in Ge) it was shown that hydrogen can form complexes with multivalent acceptors. Hydrogen is incorporated in the Ge single crystal during its growth from a melt in a H/sub 2/ atmosphere. By analogy with the interaction between lithium and multivalent acceptors two acceptor like complexes (Cu-H and Cu-H/sub 2/) were found. Using Photothermal Ionization Spectroscopy and Hall effect the following energy levels are assigned: Cu-H: E/sub V/ + 17.5 meV and E/sub V/ + 170 +- 20 meV and Cu-H/sub 2/: E/sub V/ + 17.0 meV. According to the model the Cu-H/sub 3/ complex is neutral. Consequences for the performance of large volume radiation detectors are discussed.