A practical model has been developed that is capable of describing the overall Ge(Li) detection efficiency as a function of several known or measurable parameters such as gamma-ray energy, source-to-detector distance, detector dimensions, source extension (area and volume), source composition, and external absorbers. The algorithms of this model permit the evaluation of a large variety of sample shapes, sizes, material compositions, and source strengths with a single initial detector calibration. Sources of small volume generally can be measured to within 1 to 2 percent regardless of energy or source-to-detector distance. Even large volume sources placed at close-in geometries give results within 10 percent of the correct values.

This paper describes the results of digital image analysis and techniques applied to acoustic sounder data and topographic relief in the Geyser's region. The two dimensional fast Fourier transform (2DFFT) represents the spacial variability of a photographic image. The spacial variability of topography in complex terrain can be represented in this way and insight into degree of complexity and dominating spacial wavelengths can be gained. This was performed for a 16 km square digitized topographic map of the Geyser's region with 63.5 m resolution. It was also of interest to compare facsimile recordings of acoustic sounder data to optical turbulence measurements.

The objectives of testing low-temperature hydrothermal wells are to characterize well response to production (injection), determine resource characteristics and project reservoir longevity. Testing procedures and analysis techniques differ in some respects from proven procedures in the oil and gas and ground water fields. Some basic definitions and standard techniques necessary for the evaluation of a fluid resource in an intergranular permeable reservoir are presented. Problems particular to a non-ideal thermal resource are outlined and some analytical techniques are discussed.

A brief review is given of some recent developments in the fields of optical model potentials; level densities; and statistical model, precompound, and direct reaction codes and calculations. Significant developments have occurred in all of these fields since the 1977 Conference on Neutron Cross Sections, which will greatly enhance the ability to calculate high-energy neutron-induced reaction cross sections in the next few years. 11 figures, 3 tables.

TMX experimental data on ambipolar potential control and on the accompanying electrostatic confinement are reported. New results on the radial dependence of the central-cell confining potential are given. Radial and axial particle losses as well as scaling of the central-cell axial confinement are discussed.

The point code TANDEM has been used to survey the range of plasma parameters which can be attained in MFTF-B. The code solves for the electron and ion densities and temperatures in the central cell, yin-yang, barrier, and A-cell regions as well as the plasma potential in each region. In these studies, the A-cell sloshing ion beams were fixed while the neutral beams in the yin-yang and central cell, the gas feed in the central cell, and the applied ECRH power ..beta.., central cell ion density and temperature, and the confining potential are discussed.

The large potentials and potential gradients in tandem mirrors have several effects. Some of these are discussed, together with supporting data from TMX. These include: azimuthal averaging by the E x B rotation, reduction of radial outward drifts (from high order multipoles) by the rapid E x B azimuthal velocity, neoclassical-resonant diffusion, Joule heating of central cell ions due to non-ambipolar transport in the radial electric field, low frequency instabilities, and differences between the details of the electron behavior and theory.

The Axicell MFTF-B magnet system will provide the field environment necessary for tandem mirror plasma physics investigation with thermal barriers. The performance of the device will stimulate DT to achieve energy break-even plasma conditions. Operation will be with deuterium only. There will be 24 superconducting coils consisting of 2 sets of yin-yang pairs, 14 central-cell solenoids, 2 sets of axicell mirror-coil pairs, and 2 transition coils between the axicell mirror coil-pairs and the yin-yang coils. This paper describes the progress in the design and construction of MFTF-B Superconducting-Magnet System.

This paper describes the cooldown and testing of the first yin-yang magnet for the Mirror Fusion Test Facility. The introduction describes the superconducting magnet; the rest of the paper explains the tests prior to and including magnet cooldown and final acceptance testing. The MFTF (originally MX) was proposed in 1976 and the project was funded for construction start in October 1977. Construction of the first large superconducting magnet set was completed in May 1981 and testing started shortly thereafter. The acceptance test procedures were reviewed in May 1981 and the cooldown and final acceptance test were done by the end of February 1982. During this acceptance testing the magnet achieved its full design current and field.

With statistical analysis of global data from one, two and four stellarators, it is possible to draw limited conclusions whether Gyro- Bohm or Bohm scaling prevails. Either scaling may be favored, depending on whether corrections are included for possible {Beta} and v{sub *} corrections and whether all data are taken, or selected cases with low collisionality, or low net toroidal current, or with ECH heating applied, and so on. Monte Carlo-like simulations are used to test reliability of inferences about power-law scaling exponents made from data having substantial statistical variance and collinearity of control parameters. These show that for reliable conclusions, statistical studies should be augmented; more directed experimental studies are needed, with well controlled discharges and radially resolved data - such as those already begun on ATF and W7-AS.

At Lawrence Livermore National Laboratory (LLNL) we have recently developed several techniques for volume visualization of scalar and vector fields, all of which use back-to-front compositing. The first renders volume density clouds by compositing polyhedral volume cells or their faces. The second is a ``splatting`` scheme which composites textures used to reconstruct the scalar or vector fields. One version calculates the necessary texture values in software, and another takes advantage of hardware texture mapping. The next technique renders contour surface polygons using semi-transparent textures, which adjust appropriately when the surfaces deform in a flow, or change topology. The final one renders the ``flow volume`` of smoke or dye tracer swept out by a fluid flowing through a small generating polygon. All of these techniques are applied to a climate model data set, to visualize cloud density and wind velocity.

A two-dimensional fluid code called UEDGE is used to simulate the edge plasma in tokamak divertors and to evaluate methods for reducing the heat load on divertor plates by radiating some of the power before it reaches the plates. UEDGE is a fully-implicit code being developed jointly by us, D. A. Knoll and R. B. Campbell. For these studies, UEDGE uses a banded matrix solver and a fixed-fraction impurity model. Work is presently underway with Knoll and Campbell to include a memory-efficient iterative solver and a model of impurity transport. Simulations of the proposed TPX device show that a few percent nitrogen concentration in the scrape-off layer can radiate up to 80% of the divertor power, thus reducing the peak heat flux and electron temperature at the divertor plate to acceptable values. A comparison of the neutral gas distribution from UEDGE with results from the DEGAS Monte Carlo neutrals code confirms the validity of our fluid neutrals model.

After a number of refinements, the stability and ease of tuning of the LBL AECR ion source are greatly improved. Several nuclear science experiments have now used cyclotron ion beams injected by the AECR ion source and have taken advantage of its good short and long term-stability and high performance. Refinements include installation of a dc filament power supply for the electron gun, improved gas flow control.and temperature stabilization of parts of the microwave transmission network. Measurements of the mean plasma potential and plasma potential difference were made on the AECR and the LBL ECR sources. The absolute. mean potentials of plasmas of oxygen, argon, and argon mixed with oxygen in the AECR have been determined. These plasma potentials are positive with respect to the plasma wall and are on the order of a few tens of volts for microwave power up to 600 W and normal operating gas flow. Electrons injected by an electron gun into the AECR plasma reduce the plasma potentials. Beam energy spreads of oxygen, argon and argon mixed with oxygen have also been measured. Measurement of the plasma potential difference between the first and the second stage of the LBL ECR ion source shows that …

I review the current determinations of {alpha}{sub s}. Attention is given to the theoretical uncertainties inherent in most determinations. all current determinations are consistent with an average of {alpha}{sub s}(M{sub Z}) = 0.119{plus_minus}0.005. Prospects for reduction of the errors in the future are discussed.

A variety of elemental foils have been activated by neutron fluence from TFTR under conditions with the DT neutron yield per shot ranging from 10{sup 12} to over 10{sup 18}, and with the DT/(DD+DT) neutron ratio varying from 0.5% (from triton burnup) to unity. Linear response over this large dynamic range is obtained by reducing the mass of the foils and increasing the cooling time, all while accepting greatly improved counting statistics. Effects on background gamma-ray lines from foil-capsule-material contaminants. and the resulting lower limits on activation foil mass, have been determined. DT neutron yields from dosimetry standard reactions on aluminum, chromium, iron, nickel, zirconium, and indium are in agreement within the {plus_minus}9% (one-sigma,) accuracy of the measurements: also agreeing are yields from silicon foils using the ACTL library cross-section. While the ENDF/B-V library has too low a cross-section. Preliminary results from a variety of other threshold reactions are presented. Use of the {sup 115}In(n,n) {sup 115m}In reaction (0.42 times as sensitive to DT neutrons as DD neutrons) in conjunction with pure-DT reactions allows a determination of the DT/(DD+DT) ratio in trace tritium or low-power tritium beam experiments.

This article describes the measurement of collision-induced interaction cross sections for 1-7 MeV diatomic boron molecular ions incident on a nitrogen gas target by using a differentially pumped gas cell.

This paper describes the design, development and performance of a lightweight precision gimbal with dual-axis slew capability to be used in a closed-loop optical tracking system at Lawrence Livermore National Laboratory-LLNL. The motivation for the development of this gimbal originates from the need to acquire and accurately localize warm objects (T{approximately}500 K) in a cluttered background. The design of the gimbal is centered around meeting the following performance requirements: pointing accuracy with control < 35 {mu}rad-(1-{omega}); slew capability > 0.2 rad/sec; mechanical weight < 5 kg. These performance requirements are derived by attempting to track a single target from multiple satellites in low Earth orbit using a mid-wave infrared camera. Key components in the gimbal hardware that are essential to meeting the performance objectives include a nickel plated beryllium mirro, an accurate lightweight capacitive pickoff device for angular measurement about the elevation axis, a 16-bit coarse/fine resolver for angular measurement about the azimuth axis, a toroidally wound motor with low hysteresis for providing torque about the azimuth axis, and the selection of beryllium parts to insure high stiffness to weight ratios and more efficient thermal conductivity. Each of these elements are discussed in detail to illustrate the design trades performed …

As part of international agreement between the United States and Russia, a significant amount of plutonium requires disposition. One of the disposition paths is to immobilize it and dispose of it in a geological repository. The two favored immobilization forms are glass and ceramic. The plutonium, as an oxide, would be reacted with the glass or ceramic to form a homogeneousmaterial. The resulting solid product would then be encased in High-Level Waste (1-ILW)glass for the can-in-canister option. The HLW glass gives a radiation barrier to increase proliferation resistance. The glass canister would then be disposed of by geological emplacement. This paper discusses how glass meets two criteria: the condition of significant actinide volubility, and That the PuO{sub 2} feed should be incorporated into the matrix without significant amount of unreacted material.

Using an end-pumped technology developed at LLNL we have demonstrated a Yb:YAG laser capable of delivering up to 434 W of CW power and 280 W of Q-switched power. In addition, we have frequency doubled the output to 515 nm using a dual crystal scheme to produce 76 W at 10 kHz in a 30 ns pulse length.

We have started a search for High Redshift Radio Galaxies (HZRGS) in an area covering 7 sr by selecting a sample of Ultra Steep Spectrum (USS) sources with a low flux density cut-off S1400 > 10 mJy and a steep spectral index cut-off of a < -1.3 (S of about nu-alpha) from the WENSS, NVSS and TEXAS surveys. Our first results for 27 sources show that we are almost twice as effective in finding HZRGs than than surveys of relatively bright radio sources with a spectral index cut-off of a < - 1.0. The redshift distribution is consistent with an extension of the z - a relation to a < -1.3, but a large fraction of our sample (40%) consists of objects which are too faint to observe with 3-4 m class telescopes. Our search is aimed at increasing the number of very high redshift radio galaxies for further detailed studies of the formation and evolution of massive galaxies and their environment.

Negative-parity excitations in the 2.5 MeV region in {sup 112}Cd have been investigated with the (n,n`{gamma}) reaction. Several of these states exhibit enhanced B(E2) values for L decay to the 3{sub 1}{sup -} octupole state, indicative of quadrupole-octupole coupled (2{sup +} {circle_times} 3{sup -}) structures. The B(E1) values observed are typically in the range of 1-5 x 1O{sup -4} W u , irrespective of the final state.

The RELAP5/Mod3.1 computer program has been used to successfully perform thermal-hydraulic analyses to support the Safety Analysis for increasing the MNRC reactor from 1.0 MW to 2.0 MW. The calculation results show the reactor to have operating margin for both the fuel temperature and critical heat flux limits. The calculated maximum fuel temperature of 705 C is well below the 750 C operating limit. The critical heat flux ratio was calculated to be 2.51.

Two instances of research facilities responding to public scrutiny will be discussed. The first concerns emissions from a �tritium labeling facility� operated at Lawrence Berkeley National Laboratory (LBNL); the second deals with releases of plutonium from Lawrence Livermore National Laboratory (LLNL). There are many parallels between these two cases, both of which are still ongoing. In both, the national laboratory is the acknowledged source of low-level (by regulatory standards) radioactive contamination in the community. A major purpose of both investigations is to determine the degree of the contamination and the threat it poses to public health and the environment. The examining panel or committee is similarly constituted in the two cases, including representatives from all four categories of stakeholders: decision makers; scientists and other professionals doing the analysis/assessment; environmental activist or public interest groups; and �ordinary� citizens (nearly everyone else not in one or more of the first three camps). Both involved community participation from the beginning. The levels of outrage over the events triggering the assessment are comparable; though �discovered� or �appreciated� only a few years ago, the release of radiation in both cases occurred or began occurring more than a decade ago. The meetings have been conducted in …

We created three models to represent a comprehensive knowledge model: · Stages of Knowledge Management Model (Forrester) · Expanded Life-Cycle Information Management Model · Organizational Knowledge Management Model. In building a series of models, we started with an attempt to create a graphical model that illustrates the ideas outlined in the Forrester article (Leadership Strategies, Vol. 3, No. 2, November/December 1997). We then expanded and detailed a life-cycle model. Neither of these effectively reflected how to manage the complexities involved in weaving local, enterprise, and global information into an easily navigated resource for end users. We finally began to synthesize these ideas into an Organizational Knowledge Management Model. This model acknowledges the relevance of life-cycle management for different granularities of information collections and places it in the context of the integrating infrastructure needed to assist end users.