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SHIVA is a powerful (10-kJ 25 TW) neodymium glass laser system to be used (in 1977) for target irradiation in fusion research. SHIVA is also a development project in that it is pushing the state of the art in laser and optical technology. The present design calls for 20 parallel laser amplification chains whose light output is pointed and focused at a small (100 $mu$) target within a chamber from semi-equally spaced three-dimensional directions. It is probable that SHIVA will be upgraded to as many as 42 chains in the next few years. Each chain of SHIVA contains 7 high energy laser amplifiers and perhaps 20 other major optical components, many of which send and receive control and measurement information. Again future expansion may add additional elements. Each chain has also associated 10 gimbal or translation motions for beam assignment from the oscillator onto the target. (auth)

Experimental and theoretical values for the Lamb shift in hydrogen and in hydrogenic atoms are presented. 3 tables, 32 references. (GHT)

The SHIVA laser system, which is being built at LLL, consists of a 1.06 $mu$m master oscillator whose 100 picosecond output pulse is beam split into 20 laser amplifier chains, each outputting 1 terawatt for a total of 20 TW with optical aberration of $sup 1$/$sub 2$ wave. Before firing, the beams are automatically aimed at the target within 5 microradians and focused within 7 $mu$m. Computer calculations predict significant thermonuclear burn will be achieved with this system. (MOW)

The accurate measurement of transuranic elements deposited in the lung is a complex task. One of the problems is measuring uranium-L x-rays associated with plutonium passing through the chest of an accidentally exposed subject. Because the normal human chest-wall thickness varies from about 1 to 4.5 cm, it is important that an accurate determination be made for every person counted for plutonium or for other heavy elements with similar emissions. An ultrasonic B-scanning system (brightness modulated time-base) was developed for defining the structure within the body. Computer programs were written to determine the distance between the lung and chest-wall interface and the outer surface of the chest wall at several points on each scan. These points are exponentially averaged to obtain an average chest-wall thickness that is used, with other information, to derive a calibration factor for plutonium in the subject. It is also combined with the counting data to obtain the plutonium lung burden. Since photon transmission characteristics differ in fat and soft tissue, assessing the fat content is important and can provide a correction factor for counter sensitivity when viewing various organs. The main advantage of the B-scanning and three-dimensional systems are discussed.

The Fuels and Materials Examination Facility (FMEF) is systematically analyzed from a remote maintenance standpoint using functional analysis methods. From the analysis the remote maintainability of equipment is ascertained, required tooling lists are formed, and maintenance downtimes are established. These techniques identify deficiencies or inefficiencies in the early design stage where changes have a minimum impact on cost. Special tooling and fixture requirements are minimized by standardizing remote maintenance design features.

The coaxial-gun, compact-torus experiments at LLNL and LASNL are believed to be radiation-dominated, in the sense that most or all of the input energy is lost by impurity radiation. This paper presents a simple analytic model of the radiation-dominated decay of a compact torus, and demonstrates that several striking features of the experiment (finite lifetime, linear current decay, insensitivity of the lifetime to density or stored magnetic energy) may also be explained by the hypothesis that impurity radiation dominates the energy loss. The model incorporates the essential features of the more elaborate 1 1/2-D simulations of Shumaker et al., yet is simple enough to be solved exactly. Based on the analytic results, a simple criterion is given for the maximum tolerable impurity density.

The LLNL Nuclear Chemistry Counting Facility (NCCF) is being converted to a modern production facility. A computer network has been designed and built to implement this conversion. The outermost node of the computer network is a dedicated EPROM-based controller. The controller handles the details of driving the attached nuclear instrumentation, providing a standard interface to the remainder of the network. This paper addresses the design and the implementation of the dedicated instrumentation controller.

This paper addresses the stability aspects of several successful dc superconducting magnets such as large bubble chamber magnets, and magnets for the Mirror Fusion Test Facility and MHD Research Facility. Specifically, it will cover Argonne National Laboratory 12-Foot Bubble Chamber magnets, the 15-foot Bubble Chamber magnets at Fermi National Laboratory, the MFTF-B Magnet System at Lawrence Livermore National Laboratory, the U-25B Bypass MHD Magnet, and the CFFF Superconducting MHD magnet built by Argonne National Laboratory. All of these magnets are cooled in pool-boiling mode. Magnet design is briefly reviewed. Discussed in detail are the adopted stability critera, analyses of stability and disturbance, stability simulation, and the final results of magnet performance and the observed coil disturbances.

A design study of 12-T yin-yang coils for a conceptual Tandem Mirror Next Step (TMNS) facility has been recently performed by Lawrence Livermore National Laboratory in conjunction with the Convair Division of General Dynamics. The large magnets have major and minor radii of 3.7 and 1.5 m, 0.70 x 3.75 m/sup 2/ cross section, 46.3 MA turns, and an overall current density of 1765 A/cm/sup 2/, obtained by the use of Nb/sub 3/Sn and Nb-Ti superconductors. Each coil is composed of several subcoils separated by internal strengthening substructure to react the enormous electromagnetic forces. The size of the yin-yang coils, and hence the current density, was reduced by utilizing subcooled, superfluid He-II at 1.8 K for the coolant. This paper reviews the design study, with emphasis on He-II heat transport and conductor stability. Methods are also presented which allow the extension of Gorter-Mellink-channel calculations to encompass multiple, interconnecting coolant channels.

This paper describes the effects of austenitization and tempering treatments on the strength and impact properties of a 12Cr-1Mo-V-W steel. Data are reported for austenitization temperatures covering the range 900 to 1250/sup 0/C and tempering treatments of 600 to 800/sup 0/C. A 50/sup 0/C improvement in the ductile brittle transition temperature is achieved through heat treatment. This is found to result from elimination of delta ferrite and associated carbides at the delta ferrite-matrix interface. 17 figures.

Films of Ta metal on uranium and of Ir metal on tantalum have been irradiated and melted by pulses from Q-switched Ruby and frequency-doubled Nd:YAG lasers to investigate the nature of the resulting mixtures in light of the very different binary-phase diagrams of the two systems. In addition, a two-phase Ir-Ta alloy has been surface-processed with CW CO/sub 2/-laser radiation and with an electron beam in order to study microstructure refinement and test the advantage of using alloys as opposed to film-on-substrate combinations for the development of claddings.

The H/sub 2//sup +/ ions from the volume of a hydrogen discharge will strike the discharge chamber walls with a kinetic energy equivalent to the plasma potential. A three-step process is described in which the H/sub 2//sup +/ ions are neutralized in a two-stage Auger process followed by a third stage wall relaxation collision, with the net result that the incident ions are converted to ground state molecules having a broad vibrational excitation spectrum. For kinetic energies ranging from a few electron volts up to twenty electron volts a substantial fraction, approx. = 2/3, of these ions will reflect as molecules, and of this population a fraction as large as twenty percent will have vibrational excitation of v'' greater than or equal to 6. This large vibrational population will provide a contribution to the total excited level distribution that is comparable to the E-V process. Implications for negative ion generation in an optimized tandem configuration are discussed.

A summary is given of the important characteristics of currently used insulator materials. Figures of merit for materials needed in future systems are identified. A methodology for identifying and evaluating new materials meeting the stringent performance requirements of future fusion laser systems is outlined.

An optimized tandem two-chamber negative-ion source system is discussed. In the first chamber high energy (E > 20 eV) electron collisions provide for H/sub 2/ vibrational excitation, while in the second chamber negative ions are formed by dissociative attachment. The gas density, electron density, and system scale length are varied as independent parameters. The extracted negative ion current density passes through a maximum as electron and gas densities are varied. This maximum scales inversely with system scale length, R. The optimum extracted current densities occur for electron densities near nR = 10/sup 13/ electrons cm/sup -2/ and for gas densities, N/sub 2/R, in the range 10/sup 14/ to 10/sup 15/ molecules cm/sup -2/. The extracted current densities are sensitive to the atomic concentration in the discharge. The atomic concentration is parametrized by the wall recombination coefficient, ..gamma.., and scale length, R. As ..gamma.. ranges from 0.1 to 1.0 and for system scale lengths of one centimeter, extracted current densities range from 8.0 to 80. mA cm/sup -2/.

The use of digital signal techniques for removal of noise components present in plasma diagnostic signals is discussed, particularly with reference to diamagnetic loop signals. These signals contain noise due to power supply ripple in addition to plasma characteristics. The application of noise canceling techniques, such as adaptive noise canceling and model-based estimation, will be discussed. The use of computer codes such as SIG is described. 19 refs., 5 figs.

Low-energy ions trapped in the thermal barrier region of the TMX-U plasma cause a potential reduction which results in increased scattering and less thermal isolation between regions of the plasma. A method of removing these ions using magnetic field perturbations at the ion drift frequency has been developed. The concepts of ''drift pumping'' and hardware development are described in this paper. 5 refs., 7 figs.

A set of 18 separately controlled plates have been added to each end of the Tandem Mirror Experiment Upgrade (TMX-U) vessel to allow measurement of end-wall currents and to provide a means of plasma potential control (PPC). These plates are shaped to form elliptical rings separated into quadrants. Each plate can be individually grounded, float at plasma potentials, or be actively biased to control the plasma. Voltage and current monitoring are provided for each of the plates, and the control and monitoring functions are controlled by the PPC system computer. The details of the field line mapping and the plate shapes are discussed, and the control architecture and performance are presented. 1 ref., 5 figs.

Magnetic drift pumping on TMX-U involves driving four antennae through high Q-resonant circuits. One of the key elements in the resonant circuit is a variable inductor able to carry the 3500 amperes through the circuit and maintain its shape and inductance. The eight resonant circuits can be combined to feed the four antennae with one or two frequencies on each antenna, or frequency shift keying between two frequencies. Each resonant circuit is fed by two 10 to 30 kHz exciters capable of delivering 80 kW each to the circuit. Each exciter receives its power from its own adjustable 0 to 400 volt power supply. The entire system is controlled by a CAMAC control system over a fiber-optic link. The control system checks interlock status, controls ''On'' and ''Off'' status, calculates and adjusts phasing of the exciters for addition or deletion of the proper beat frequencies, and monitors operation. 3 refs., 5 figs.

The ECRH Control System was installed on the Tandem Mirror Experiment-Upgrade (TMX-U) in 1980. The system provides approximately 1 MW of 28 GHz microwave power to the TMX-U plasma. The subsystems of ECRH that must be controlled include high-voltage charging supplies, series pass tubes, and magnet supplies. In addition to the devices that must be controlled, many interlocks must be continuously monitored. The previous control system used relay logic and analog controls to operate the system. This approach has many drawbacks such as lack of system flexibility and maintainability. In order to address these problems, it was decided to go with a CAMAC and Modicon based system that uses a Hewlett-Packard 9836C personal computer to replace the previous analog controls. 2 figs.

May 1983 marked the beginning of an intensive effort to both improve the operating reliability, and improve the performance of the TMX-U Diagnostic Computer System. At that time, the system was handling (acquiring, storing, processing, plotting, displaying, and archiving) about 3 million bytes (Mb) of data per shot, with a 15-minute cycle time between shots. In addition, the system was fairly fragile, with frequent (about 5 times/day) crashes, requiring re-booting. At the present time, the system reliably handles about 5 Mb of data per shot, with a 7-minute cycle time between shots. This improvement was accomplished by a combination of new hardware, rearranging existing hardware, and new or revised software. Hardware changes were made in two areas. First, the shared disks were rearranged into different domains to make more efficient use of locking features. Second, we purchased and installed a solid-state RAM disk emulator (8 megabytes) to provide extremely fast access to lists and files that must be accessed frequently. In the software area, we made improvements in several areas. Initial effort went into finding bugs and optimizing existing code. We developed a template so that we could produce efficient code from applications that had first been developed on a …

This paper describes control of gyrotron microwave energy output by modulation of gyrotron anode voltage. At present, Electron Cyclotron Resonant Heating (ECRH) uses five gyrotrons on the Tandem Mirror Experiment-Upgrade (TMX-U) for plasma heating. One is in the 10 kG region of each end plug, one at the 5 kG region of each end plug, and one is used for central-cell heating. Also described are the design and operation of the anode modulation system. The operating advantages of gyrotron anode modulation include power balance, independent control of each gyrotron, an ability to modulate microwave output power up to 50 kHz, and gyrotron tuning. The performance results of anode modulation will be discussed. 9 figs.

Ion Cyclotron Resonant Heating (ICRH) is part of the plasma heating system used on the TMX-U experiment. Radio frequency (RF) energy is injected into the TMX-U plasma at a frequency near the fundamental ion resonance (2 to 5 MHz). The RF fields impart high velocities to the ions in a direction perpendicular to the TMX-U magnetic field. Particle collision then converts this perpendicular heating to uniform plasma heating. This paper describes the various aspects of the ICRH system: antennas, power supplies, computer control, and data acquisition. 4 refs., 10 figs.

The Mirror Fusion Test Facility (MFTF-B), under construction at LLNL, requires measurement of the neutral gas density in high magnetic fields near the plasma at several axial regions. This Background Gas Pressure (BGP) diagnostic will help us understand the role of background neutrals in particle and power balance, particularly in the maintenance of the cold halo plasma that shields the hot core plasma from the returning neutrals. It consists of several cold-cathode, magnetron-type gauges stripped of their permanent magnets, and utilizes the MFTF-B ambient B-field in strengths of 5 to 25 kG. Similar gauges have operated in TMX-U in B-fields up to 3 kG. To determine how well the gauges will perform, we assembled a test stand which operated magnetron gauges in an external, uniform magnetic field of up to 30 kG, over a pressure range of 1E-8 T to 1E-5 T, at several cathode voltages. This paper describes the test stand and presents the results of the tests.