The method under development for the production of semiconductor grade silicon is based on the zinc vapor reduction of silicon tetrachloride in a fluidized bed of seed particles. Construction of the PDU was completed during the report period, the fluidized-bed reactor was coated internally with silicon/SiC, and the operation of several systems was checked out. However, problems with the zinc feed system, unrelated to its basic operability, delayed introduction of zinc vapor to the PDU. At the end of the report period, the zinc feed system stood ready for tests of the control of zinc vapor feed rate by regulation of r.f. induction heating directly coupled to the liquid zinc. A study of the zinc distribution in miniplant silicon products containing zinc at the 300 and 3000 ppM levels suggests that the occlusion of zinc is caused by zinc mist entrained from the vaporizer, and it should be possible to drive the level to below 300 ppM by proper equipment design and process control.

The development of stable, efficient, electrochemical photovoltaic cells based on silicon and gallium arsenide in non-aqueous electrolyte systems is being investigated. The effect of surface condition of silicon electrodes on electrochemical and physical characteristics has been studied. An electrode-supporting electrolyte interaction in acetonitrile has been identified which leads to etching of the surface. Improved performance can result, which has practical significance. Gallium arsenide electrodes have been electrochemically characterized in cells containing propylene carbonate with a ferrocene/ferricenium redox additive. Degradation of the ferricenium salt under illumination has been investigated. Other redox couples studied to date have not given promising results. Long-term stability experiments have been deferred while a better understanding of electrode behavior is being obtained.

The evolution of the SLC Final Focus System (FFS) has been discussed in the SLC Red Books and various collider notes. Bulos and Brown and Murray were able to achieve small ..beta..'s with large l/sub 1/'s (the distance between the IP and the effective field boundary of the first quad). However, all current solutions which are compatible with the known constraints of the total path length, aperture and spot size require high gradient, superconducting quads. Such quads cannot be expected to provide very good inherent field quality (i.e., without correction windings) but can be expected to be comparatively expensive to build and operate simply. The purpose of this note is to present a more general solution for the FFS telescope which is compatible with the known constraints of detectors, magnet types, available space and the ingoing and outgoing phase space expectations. While a number of different solutions were found, the ones presented provide comparable performance, simpler operation and lower costs. The gradients are sufficiently low to allow the use of conventional electromagnets, intrinsic or cryostable superconducting or rare earth permanent (REP) magnets or any arbitary combination of all of these magnet types. 8 references, 9 figures, 1 table.

The results of work performed from July 1, 1979 through September 30, 1979 on the Advanced Gas-Cooled Nuclear Reactor Materials Evaluation and Development Program are presented. The objectives of this program are to evaluate candidate alloys for Very High Temperature Reactor (VHTR) Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the effect of simulated reactor primary coolant (helium containing small amounts of various other gases), high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. A second objective is to select and recommend materials for future test facilities and more extensive qualification programs. Work covered in this report includes the activities associated with the status of the simulated reactor helium supply system, testing equipment, and gas chemistry analysis instrumentation and equipment. The status of the data management system is presented. In addition, the progress in the screening test program is described.

This report summarizes the results of titanium-gettering tests performed during August and September of 1983. Several current and voltage schedules were evaluated for possible implementation with TMX-U's computer-controlled getter system. The tests were performed using 1/8-inch wire composed of 85% Ti and 15% Ta. Measurements of wire temperature as a function of getter current were made. We performed glow discharge cleaning (GDC) of the vessel with wires in place to determine if GDC had any adverse effect on wire lifetime.

Many data analysis treatments of positron experiments attempt to resolve two or more positron decay or exist channels which may be open simultaneously. Examples of the need to employ such treatments of the experimental results can be found in the resolution of the constituents of a defect ensemble, or in the analysis of the complex spectra which arise from the interaction of slow positrons at or near the surfaces of solids. Experimental one- and two-dimensional angular correlation of annihilation radiation experiments in Al single crystals have shown that two defect species (mono- and divacancies) can be resolved under suitable conditions. Recent experiments at LLNL indicate that there are a variety of complex exit channels open to positrons interacting at surfaces, and ultimely these decay channels must also be suitably resolved from one another. 6 refs., 4 figs.

Perpendicular electron-cyclotron emission (PECE) is used on TMX-U to diagnose thermal-barrier hot electrons (T/sub H/ approx. 100 to 400 keV); yielding the time history of the temperature of these relativistic electrons. We describe an improved quasi-optical viewing system for these measurements that uses high sensitivity superheterodyne receivers at fixed frequencies of 60, 98, 130, and 196 GHz. The improved viewing and transport system consists of an off-axis ellipsoidal mirror that images the plasma onto a V-band conical collection horn, an overmoded circular waveguide (7/8'' diam) that transports the radiation outside the vacuum vessel where the polarization is selected, and a high absorptivity Macor beam dump to prevent internal wall reflections from entering the viewing system. A relativistic code is used to calculate optically thin PECE signals from relativistic electrons for various energy and pitch angle distributions. 4 refs., 4 figs.

Use of a two-stage concentrator with a fresnel lens primary and a nonimaging dielectric totally internally reflecting secondary, has unique advantages for photovoltaic concentration. Some preliminary ray trace studies have shown that with planar lenses, an increase in angular acceptance for a given geometric concentration to about 2/3 of the maximum theoretical limit can be achieved. To demonstrate this, two preprototype concentrators, each having a geometric concentration of 248:1 for a 0.635cm (0.25 inch) diameter cell, have been designed, built, and tested. Measurements of the angular response show an acceptance of 8[degrees] (full angle) which is drastically better than the 1[degrees]--2[degrees] achievable without a secondary, and is in excellent agreement with the ray trace predictions. For these preprototypes, passive cooling was sufficient to prevent any thermal problems for both the cell and secondary. No problems associated with nouuniform cell illumination were found, as evidenced by the fill factor of 71%--73% measured under concentration. Initial measurements of the system electrical efficiency lie in the range 7.5%--9.9% for a variety of individual cells.

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Jim Mattox, regarding a legal question submitted for clarification: Whether a “ticket” given to a defendant may serve as the complaint in a trial de novo in county court (RQ-1196)

We propose to study the spin-orbit Analyzing Power, A, in p+p + p+p at large P{sub {perpendicular}}{sup 2}. We propose to run at Fermilab around Fall 1987 and scatter a high intensity unpolarized proton beam of 800 to 900 GeV from a Polarized Proton Target; we would measure the difference between the d{sigma}/dt when the target spin is up and when it is down. Our main goal is to see if the unexpected large values of A recently found at the 28 GeV AGS in proton-proton elastic scattering persist to Fermilab energies. The large A value of 24 {+-} 8% at P{sub {perpendicular}}{sup 2} = 6.5 (GeV/c){sup 2} was not only unexpected but also seems difficult to reconcile with the A = 0 prediction of conventional models of strong interactions, such as perturbative QCD. The validity of perturbative QCD is believed to improve with increasing energy and with increasing P{sub {perpendicular}}{sup 2}, and this proposed Fermilab experiment would increase the incident energy by about a factor of 30. The experiment would be done using a Polarized Proton Target (PPT) employing radiation-doped NH{sup 3} beads and a 'local' cooling power of about 130 mW at 1/2{sup o} K. Such a target …

The purpose of this contract is to provide the Coal and Electric Power Analysis Division, EIA, with a revised and fully documented Resource Allocation and Mine Costing (RAMC) model to be used in developing coal supply curves for use in the Mid-range Energy Forecasting System and the National Coal Model. The project is structured in three phases, as follows: establish conceptual underpinnings of revised supply curve methodology; revise mine costing methodology; and revise resource allocation methodology. The first three tasks in Phase I were to review and critique the current RAMC approach, review and critique the NUS deep mine and the Fluor Utah surface mine costing methodologies, and to propose revisions to the current approach. This Interim Report documents our findings under these three tasks. Our review of the current RAMC concludes that the resource allocation methodology is reasonable; however, the mine costing methodology has a number of deficiencies. Hence, Section 5 presents a number of alternative approaches for implementing an improved costing methodology in the RAMC model. Although the resource allocation approach is reasonable, the data used to drive the model need to be improved. The Appendices discuss a number of these data issues, affecting both mine costing and …

Use of a two-stage concentrator with a fresnel lens primary and a nonimaging dielectric totally internally reflecting secondary, has unique advantages for photovoltaic concentration. Some preliminary ray trace studies have shown that with planar lenses, an increase in angular acceptance for a given geometric concentration to about 2/3 of the maximum theoretical limit can be achieved. To demonstrate this, two preprototype concentrators, each having a geometric concentration of 248:1 for a 0.635cm (0.25 inch) diameter cell, have been designed, built, and tested. Measurements of the angular response show an acceptance of 8{degrees} (full angle) which is drastically better than the 1{degrees}--2{degrees} achievable without a secondary, and is in excellent agreement with the ray trace predictions. For these preprototypes, passive cooling was sufficient to prevent any thermal problems for both the cell and secondary. No problems associated with nouuniform cell illumination were found, as evidenced by the fill factor of 71%--73% measured under concentration. Initial measurements of the system electrical efficiency lie in the range 7.5%--9.9% for a variety of individual cells.

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This report describes the Chromatic Correction Scheme for the Antisymmetric RHIC Lattice. The First Approximation.

Newsletter of the Texas Bureau of Disease Control and Epidemiology discussing the news, activities, and events of the organization and other information related to health in Texas.

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"This report summarizes the implementation by the Congress of the policy recommendations made in January 1984 by the National Bipartisan Commission on Central America, the so-called 'Kissinger Commission'" (p. iii).

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