Quantitative estimates of charge exchange (CE) losses during acceleration are very important in the design and operation of heavy ion cyclotrons. Such estimates have been made using a vacuum model computer code which was developed to establish vacuum requirements for the MSU superconducting heavy ion cyclotron. This code uses pressure and cross-section data to calculate the radial loss of beam due to charge exchange. Since CE cross sections and radial pressure profiles are not always well known, certain specific measurements have been made using the LBL 88-Inch Cyclotron to provide experimental data needed to test the code. These include measurements of pressure versus radius under vacuum conditions closely approximating those existing during acceleration of /sup 14/N/sup 4 -/ and /sup 40/Ar/sup 8 -/ beams. Beam intensity versus radius data demonstrating transmission losses for three beams are presented. Comparisons with theoretical predictions are given.

The Field Reversed Mirror Reactor is composed of a horizontal linear chain of cells, each of which requires neutral beam injection. Blanket replacement is achieved by lifting one complete cell module from the reactor and replacing it with a preassembled and tested identical module. Ioffe bar connectors eliminate redundant bus bars. Asymmetric cell design simplifies magnet construction and reduces replacement time. A tapered cylindrical coolant distributor simplifies blanket removal. An evacuated housing surrounds the reactor reducing cell-to-cell sealing problems related to maintenance. Remote couplings are used for coolant and accessories. Hot-cell location and design permits immediate reconditioning or storage of replacement cells.

The nuclear design analysis and performance of the blanket for the Pu/sup 239/ producing standard mirror hybrid is discussed. The blanket is based on present day materials and technology. It is designed for peak power density and burnup in the uranium fuel of 500 W/cc and 3 atom percent. The blanket produces 2.0 Mg/yr of Pu-239 (net) from 400 MW fusion (D-T) and depleted uranium and has an average energy multiplication of 11.

A reactor based on this concept that produces 1000 MWe consists of a solenoidal magnet about 50 to 100 m long. A cylindrical blanket is used for energy recovery and tritium breeding. Thus the reactor itself is simple and of low technology. The end plugs, however, are of high technology, having the high magnetic fields needed to confine the high-pressure plasma and the high injection energy (0.6 to 1.2 MeV) needed to achieve good magnetic confinement. A low technology, compact, economical hybrid fusion-fission reactor results from injection in the central cell as well as the ends, provided a means can be found to stabilize the end plugs against microinstabilities, particularly in small sizes (plug radius divided by ion gyroradius less than or equal to 10). The Q value is 1.8 and the power is 500 MWe, with 1000 kG of /sup 233/U produced per year. If, on the other hand, the tandem is operated in the two-component mode (i.e., cold tritium plasma electrostatically contained into which a 100-200 keV D/sup 0/ beam is injected), then the end plugs can be stabilized by the outward flowing tritium plasma. Finally, we show that D-D burning tandem reactors appear feasible in large sizes …

Three models have been developed to estimate the effects of air pollutants on vegetation at the photosynthetic process (PHOTO), plant (GROWl), and community (SILVA) levels of resolution. PHOTO simulates the enhancement of photosynthesis at low H/sub 2/S levels, depression of photosynthesis at high H/sub 2/S levels, and the threshold effects for sulfur pollutants. GROWl simulates the growth and development of a plant during a growing season. GROWl has been used to assess the effects on sugar beets of geothermal energy development in the Imperial Valley, California. SILVA is a community-level model simulating the effects of SO/sub 2/ on growth, species composition, and succession, for the mixed conifer forest types of the Sierra Nevada, California.

A distributed microprocessor control and data acquisition network has been designed for implementation on the Lawrence Livermore National Laboratory 100 MeV electron/positron accelerator (LINAC). The system has been designed to be as transparent to the user as possible by stressing responsiveness, reliability, and relevance of data presented to the user. Implementation of the network will take place in modular fashion in three stages, so as to minimize disruption of normal operations. The first elements to be installed will be the beam transport system controls, beam set-up time. Beam diagnostic equipment is now being position monitors, and accelerator operating status monitors. These units will reduce beam set-up time. Beam diagnostic equipment is now being designed that will be used in a second stage implementation. This stage will concentrate on determining beam parameters and allowing the user to optimize the beam for a given parameter. The final stage will be to install experimenter data acquisition equipment. The equipment will augment the presently existing data acquisition system. The completed network will allow a more efficient operation of the LINAC, resulting in reduced experiment costs, and more controllable beam parameters, both of which are major concerns of experimenters.

We consider in detail the effects of local mass anomalies in Eoetvoes-like experiments. It is shown that in the presence of an intermediate-range non-gravitational force, the dominant contributions to both the sign and magnitude of the Eoetvoes anomaly may come from nearby masses and not from the earth as a whole. This observation has important implications in the design and interpretation of future experiments, and in the formulation of unified theories incorporating new intermediate-range forces.

A new glove-box system that was designed around a high-pressure tritium pump is described. The system incorporates new containment ideas such as ''burpler'' passive pressure controls, valves that can be turned from outside the box, inflatable door seals, ferro-fluidic motor-shaft seals, and rapid box-to-hood conversion during cryostaging. Currently under construction, the system will contain nine separate sections with automatic pressure-balancing and venting systems. 3 refs., 5 figs.

Experiment 791 at Fermilab`s Tagged Photon Laboratory has just accumulated a high statistics charm sample by recording 20 billion events on 24000 8mm tapes. A 500 GeV/c {pi}{sup {minus}} beam was used with a fixed target and a magnetic spectrometer which now includes 23 silicon microstrip planes for vertex reconstruction. A new data acquisition system read out 9000 events/sec during the part of the Tevatron cycle that delivered beam. Digitization and readout took 50 {mu}S per event. Data was buffered in eight large FIFO memories to allow continuous event building and continuous tape writing to a wall of 42 Exabytes at 9.6 MB/sec. The 50 terabytes of data buffered to tape is now being filtered on RISC CPUs. Preliminary results show D{sup 0} {yields} K{sup {minus}}{pi}{sup +} and D{sup +} {yields} K{sup {minus}}{pi}{pi}{sup +} decays. Rarer decays will be pursued.

Experiment 791 at Fermilab's Tagged Photon Laboratory has just accumulated a high statistics charm sample by recording 20 billion events on 24000 8mm tapes. A 500 GeV/c [pi][sup [minus]] beam was used with a fixed target and a magnetic spectrometer which now includes 23 silicon microstrip planes for vertex reconstruction. A new data acquisition system read out 9000 events/sec during the part of the Tevatron cycle that delivered beam. Digitization and readout took 50 [mu]S per event. Data was buffered in eight large FIFO memories to allow continuous event building and continuous tape writing to a wall of 42 Exabytes at 9.6 MB/sec. The 50 terabytes of data buffered to tape is now being filtered on RISC CPUs. Preliminary results show D[sup 0] [yields] K[sup [minus]][pi][sup +] and D[sup +] [yields] K[sup [minus]][pi][pi][sup +] decays. Rarer decays will be pursued.

The need for normal incidence mirrors maintaining reflectivity greater than 60% for an industrially competitive Extreme Ultraviolet Lithography (EUV) system has been well documented. The Molybdenum/Silicon system has emerged as the de-facto standard, where researchers are now routinely fabricating mirrors demonstrating 63% reflectivity near 130 Angstroms. However, multilayer mirrors using beryllium as the low atomic number (low-Z) spacer could potentially show similar or better reflectivity, and operate at wavelengths down to the beryllium K-edge at 111 Angstroms. Besides offering potentially greater reflectivity, the shorter wavelength light offers increased dissolution depth in photoresists, and offers potentially better resolution and depth of focus. We will report our latest results from beryllium based multilayers. The mirrors were fabricated at the Lawrence Livermore National Laboratory (LLNL) and tested at the Center for X-Ray Optics at Lawrence Berkeley Laboratory (CXRO/LBL).

This paper reports on the measurement of the polarization in the decay B{sup o} {yields} J/{psi}K{sup *o} using data collected at the collider Detector at Fermilab in {bar p}p collisions at {radical}s = 1.8 TeV. B{sup O} mesons were reconstructed through the decay chain B{sup o} {yields} J/{psi}K{sup *o}, J/{psi} {yields} {mu}{sup +}{mu}{sup {minus}}, K{sup *o} {yields} K{sup +}{pi}{sup {minus}}. A sample of 50 {plus_minus} 11 events was used in the measurement, yielding the result {Gamma}{sub L}/{Gamma} = 0.66 {plus_minus} 0.10 (stat) {sub {minus}}0.10 {sup +0.08} (sys).

A cost-effective, 320-MJ power-conditioning system has been completed for the proposed National Ignition Facility (NIF). The design features include metallized dielectric capacitors, a simple topology, and large (1.6-MJ) module size. Experimental results address the technical risks associated with the design.

This study assumes that commercial-scale production of propylene-based isotactic polymers with metallocene catalyst systems will become a reality. The challenge that must be overcome for commercial success with these propylene polymers is to discover a metallocene system recipe that will give sufficient catalyst activity along with the requisite stereo-selectivity at reasonable cost. Anticipating such a discovery, it is assumed here that the economics are well-represented by a catalyst system that consists in part of a silylene-bridged cyclopentadienyl zirconocene made in a batchwise process having an annual capacity of 15,000 pounds. Activation will be achieved with a cocatalyst such as methylaluminoxane (MAO), coated in conjunction with the catalyst on a support such as silica. The MAO at an estimated $100/lb contributes $1800/lb cost to the finished catalyst with an assumed recipe of 18:1 mass ratio of MAO to zirconocene. Based on a 20% return on investment, the selling price for the supported zirconocene system is estimated to be $2915/lb. The required capital investment to make 735,000 lb/yr of the total supported system is 9 million dollars. These estimates have {plus_minus}50% range of uncertainty. Payback period for this plant in a sold-out condition is three years. The catalyst system cost in ethylene-propylene …

The first structural determination with spin-polarized, energy-dependent photoelectron diffraction using circularly-polarized x-rays is reported for Fe films on Cu(001). Circularly-polarized x-rays produce spin-polarized photoelectrons from the Fe 2p doublet, and intensity asymmetries in the 2p{sup 3/2} level are observed. . Fully spin-specific multiple scattering calculations reproduce the experimentally determined energy and angular dependences. A new analytical procedure which focuses upon intensity variations due to spin-dependent diffraction is introduced.

Successful operation of large-scale high-power lasers, such as those in use and planned at LLNL and elsewhere, require optical elements that can withstand extremely high fluences without suffering damage. Of particular concern are dielectric diffraction gratings used for beam sampling and pulse compression. Laser induced damage to bulk dielectric material originates with coupling of the electric field of the radiation to bound electrons, proceeding through a succession of mechanisms that couple the electron kinetic energy to lattice energy and ultimately to macroscopic structural changes (e.g. melting). The constructive interference that is responsible for the diffractive behavior of a grating or the reflective properties of a multilayer dielectric stack can enhance the electric field above values that would occur in unstructured homogeneous material. Much work has been done to model damage to bulk matter. The presence of nonuniform electric fields, resulting from diffractive coherence, has the potential to affect damage thresholds and requires more elaborate theory. We shall discuss aspects of work directed towards understanding the influence of dielectric structures upon damage, with particular emphasis on computations and interpretation of electric fields within dielectric gratings and multilayer dielectric stacks, noting particularly the interference effects that occur in these structures.

Successful operation of large-scale high-power lasers, such as those in use and planned at LLNL and elsewhere, require optical elements that can withstand extremely high fluences without suffering damage. Of particular concern are gratings used for pulse compression. Laser induced damage to bulk dielectric material originates with coupling of the electric field of the radiation to bound electrons, proceeding through a succession of mechanisms that couple the electron kinetic energy to lattice energy and ultimately to macroscopic structural changes (e.g. fracture, melting, ablation, etc.). The constructive interference that is responsible for the diffractive behavior of a grating or the reflective properties of a multilayer dielectric stack can enhance the electric field above values that would occur in unstructured homogeneous material. The presence of nonuniform electric fields, resulting from diffractive coherence, has the potential to affect damage thresholds We describe aspects of LLNL work directed towards understanding the influence of dielectric structures upon damage, with particular emphasis on electric fields within multilayer dielectric stacks.

Although welding is an established technology used in many industrial settings, it is least understand terms of the phases that actually exist, the variation of their spatial disposition with time, and the rate of transformation from one phase to another at various thermal coordinates in the vicinity of the weld. With the availability of high flux and, more recently, high brightness synchrotron x-radiation sources, a number of diffraction and spectroscopic methods have been developed for structural characterization with improved spatial and temporal resolutions to enable in-situ measurements of phases under extreme temperature, pressure and other processing conditions not readily accessible with conventional sources. This paper describes the application of spatially resolved x-ray diffraction (SRXRD) for in-situ investigations of phase transformations in the heat affected zone (HAZ) of fusion welds. Results are presented for gas tungsten (GTA) welds in commercially pure titanium that show the existence of the high temperature bcc {beta}-phase in a 3.3 {plus_minus} 0.3 mm wide HA band adjacent to the liquid weld pool. Phase concentration profiles derived from the SRXRD data further show the co-existence of both the low temperature hcp ({alpha}-phase and the {beta}-phase in the partially, transformed region of the HA. These results represent the …

The U.S. Department of Energy, Nevada Operations Office, Underground Test Area Operable Unit (UGTA) is drilling deep (>1500m) monitoring wells that penetrate both unsaturated (vadose) and saturated zones potentially contaminated by sub-surface nuclear weapons testing at the Nevada Test Site, Nye County, Nevada. Drill site radiological monitoring returns data on drilling effluents to make informed management decisions concerning fluid management. Because of rapid turn-around required for on-site monitoring, a representative sample will be analyzed simultaneously for {alpha}, {beta} and {gamma} emitters by instrumentation deployed on-site. For the purposes of field survey, accurate and precise data is returned, in many cases, with minimal sample treatment. A 30% efficient high purity germanium detector and a discriminating liquid scintillation detector are being evaluated for {gamma} and {alpha}/{beta} monitoring respectively. Implementation of these detector systems complements a successful on-site tritium monitoring program. Residual radioactivity associated with underground nuclear tests include tritium, activation products, fission products and actinides. Pulse shape discrimination (PSD) is used in {alpha}/{beta} liquid scintillation counting and is a function of the time distribution of photon emission. In particular, we hope to measure {sup 241}Am produced from {sup 241}Pu by {beta} decay. Because {sup 241}Pu is depleted in fissile bomb fuels, maximum …

The Inertial Confinement Fusion (ICF) program at LLNL is beginning the design of a 1.8 Megajoule, 0.35-{mu}m, laser system called the National Ignition Facility (NIF). In order to reduce cost, and increase performance, high damage threshold optics are essential. As a result of damage initiating defects, only a small percentage of current as-deposited optical coatings can meet the required damage threshold specification. Work has been conducted in the area of understanding the causes of these nodular defects and how they are related to laser damage. While it is not yet possible to produce defect-free coatings, it has been found that the damage threshold of some coatings can be increased by as much as 2 or more times as a result of pre-illumination at incrementally increasing fluences. This process, termed laser conditioning, has been associated with the ejection of the damage-initiating defects. With current damage thresholds, mirrors and polarizers for the NIF will have to be laser conditioned in order to meet the laser requirements for fluence propagation. LLNL has constructed a system dedicated to laser conditioning of meter-sized HfO{sub 2}/SiO{sub 2} multilayer polarizers and mirrors. The optic is moved in a raster pattern through a stationary 10-Hz rep-rated, 1.064 {mu}m …

The design of the National Ignition Facility (NIF) is based on conversion of 1.05 {mu}m wavelength light (1{omega}) into third harmonic light (3{omega}) by passage through KDP frequency conversion crystals. It is important for proper coupling of radiation into the targets that the final beam impinging upon the target should have little 1{omega} or 2{omega} light. It is also desirable to avoid direct line-of sight for neutrons between the target and the KDP crystals, in order to prevent damage. These issues can be overcome by employing diffraction gratings immediately before the final NIF focusing lens to direct the 3{omega} beam to the target. A single grating design is highly dispersive, and may introduce intolerable divergence into the beam. In order to overcome this limitation, we propose to use a grating pair. This will provide transverse offset of the beam and eliminate the dispersion while offering several other advantages.

Chirped pulse amplification is increasingly used to produce intense ultrashort laser pulses. When high-efficiency gratings are the dispersive element, as in the LLNL Petawatt laser, their susceptibility to laser induced damage constitutes a limitation on the peak intensities that can be reached. To obtain robust gratings, it is necessary to understand the causes of short-pulse damage, and to recognize the range of design options for high efficiency gratings. Metal gratings owe their high efficiency to their high conductivity. To avoid the inevitable light absorption that accompanies conductivity, we have developed designs for high efficiency reflection gratings that use only transparent dielectric materials. These combine the reflectivity of a multilayer dielectric stack with a diffraction grating. We report here our present understanding of short-pulse laser induced damage, as it applies to dielectric gratings.

The following report describes the design, construction, and checkout of a high-voltage (HV) impulser built for the heavy ion fusion (HIF) project [1]. The purpose of this impulser is to provide an adjustable diode voltage source of sufficient quality and level to allow the optimization of beam transport and accelerator sections of HIF [2, 3]. An elegant, low-impedance, high-energy storage capacitor circuit has been selected for this application. Circuit parameters of the retrofit to the diode region [4] have been included to provide the controlled rise time. The critical part of this circuit that is common to all candidates is the impedance matching component. The following report provides a description of the implemented circuit, the basic circuit variables for wave shaping, screening techniques revealing the weakest circuit component, and the resulting output of the injector.

The year 2000 is rapidly approaching, and there is a good chance that computer systems that utilize two digit year dates will experience problems in retrieval of date information. The ISA Thermoluminescent Dosimetry Data Processing (TL-DP) software and computer system has been reviewed for Year 2000 compliance issues.