A gas pressure and flow regulation system has been designed and constructed to service a wide variety of gas-filled detectors which operate at pressures of approx.2 to 1000 Torr and flow rate of approx.5 to 200 standard cubic centimeters per minute (sccm). Pressure regulation is done at the detector input by a pressure transducer linked to a solenoid leak valve via an electronic control system. Gas flow is controlled via a mechanical leak valve at the detector output. Interchangeable transducers, flowmeters, and leak valves allow for different pressure and flow ranges. The differential pressure transducer and control system provide automatic let-up of vacuum chambers to atmospheric pressure while maintaining a controlled overpressure in the detector. The gas system is constructed on a standard 19'' rack-mounted panel from commercially available parts. Five of these systems have been built and are routinely used for both ionization chambers and position-sensitive avalanche detectors.

A new type of time-of-flight recoil spectrometer designed to measure the masses of neutron-rich light nuclei has recently been completed at LAMPF. The spectrometer relies on an isochronous design that directly correlates an ion's time-of-flight through the spectrometer with it's mass-to-charge ratio. Additional measurements of the ion's velocity and energy enable the charge state of the recoil to be uniquely defined and thus permit precision mass measurements given sufficient statistics. The performance of the spectrometer has been investigated in both off-line (using alpha sources) and on-line tests. The design resolution of ..delta..m/M = 1/2000 (FWHM) has been achieved. Initial performance results of the spectrometer are described with emphasis placed on the techniques used to achieve the overall high mass resolution and large solid angle/momentum acceptance.

Naive applications of Spitzer's theory to very dense plasmas can lead to negative diffusion coefficients. The interdiffusion coefficients in Binary Ionic Mixtures (two species of point ions in a uniform neutralizing background) have been calculated recently using molecular dynamics techniques. These calculations can provide useful benchmarks for theoretical evaluations of the diffusion coefficient in dense plasma mixtures. This paper gives a brief description of a kinetic theoretic approximation to the diffusion coefficient which generalizes Spitzer to high density and is in excellent agreement with the computer simulations. 15 refs., 1 fig., 2 tabs.

A quad delay gate generator has been designed and packaged in a single-width NIM module. Both delay times and gate widths may be set continuously from 25 ns to 120 ..mu..sec. In normal operation, the gate follows the delay time unless a ''stop'' pulse cuts it short. Alternatively, the module may be operated in a bipolar mode, where the delay time is set by the input ''start'' pulse and reset by the input ''stop'' pulse. Modes and coarse time ranges are set via an octal DIP switch on the front panel. Fine adjustments of the delay and gate width are made via two twenty-turn potentiometers. Stability over a several day period was measured at approx. 250 ps on the 120 ns full scale range. LEDs gives a visual indication of both the input rate and the dead time.

Complex fragment emission has been certified as a compound nucleus process at low energies. An extension of the measurements to heavy ion reactions up to 50 MeV/u shows that most complex fragments are emitted by highly excited compound nuclei formed in incomplete fusion reactions. 12 refs., 26 figs.

A recently developed mechanical properties microprobe (MPM) has been used to investigate strength and elastic modulus changes in ion-irradiated metals. The indenter load and its displacement are simultaneously monitored while the indentation is being made and also during unloading. Microindentation hardness measurements have been performed on ion-irradiated copper and Cu-0.15% Zr (AMZIRC). The depth dependence of the ion damage has been investigated in selected specimens which were prepared using a cross-section technique. This procedure allows a direct comparison to be made of hardness data from different irradiation depths while the indent size is held constant. The displacement damage associated with ion irradiation caused either hardening or softening, depending on the irradiation conditions and the material.

The correlation technique at a pulsed neutron spallation source using a mechanical pseudo-random chopper is found to be technically feasible and can be accomplished with relatively minor changes to a conventional chopper spectrometer. The strong variation of resolution with incident energy is a serious disadvantage for some applications. There may be specific instances in which the method is advantageous to the conventional chopper at such a source, but these remain to be identified. 8 refs., 5 figs.

In this paper we study the scattered magnetic field above the surface of the earth due to a buried sheet-like conductor excited by a grounded and oscillating vertical electric dipole (G.V.E.D.) in the earth. The significance of this technique for the detection of water-filled fractures is that there is no magnetic field in the air, assuming that the displacement current is negligible, so long as the G.V.E.D. source is buried in a layered half-space. If any signal is detected it must be due to the presence of a 2-D or 3-D inhomogeneity, such as a sheet-like conductor. Using a numerical modeling approach, we calculated the strength and anomaly shape of the secondary magnetic field from the sheet to determine a G.V.E.D. is a suitable source detecting a major conductive fracture zone.

A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 30/sup 0/ beam-bending achromat and a prototype vernier steering magnet were designed and built. In volume I, the design requirements are stated, the design is summarized and illustrated, and detailed analysis and computations are provided. Also, a summary of materials used, a description of the manufacturing process, and a summary of project funding are provided. (LEW)

The national Neutral Particle Beam (NPB) program has two objectives: to provide the necessary basis for a discriminator/weapon decision by 1992, and to develop the technology in stages that lead ultimately to a neutral particle beam weapon. The ground test accelerator (GTA) is the test bed that permits the advancement of the state-of-the-art under experimental conditions in an integrated automated system mode. An intermediate goal of the GTA program is to support the Integrated Space Experiments, while the ultimate goal is to support the 1992 decision. The GTA system and each of its major subsystems are described, and project schedules and resource requirements are provided. (LEW)

A biological and physical inventory of selected tributaries in the lower Clearwater River basin was conducted to collect information for the development of alternatives and recommendations for the enhancement of the anadromous fish resources in streams on the Nez Perce Reservation. Five streams within the Reservation were selected for study: Bedrock and Cottonwood Creeks were investigated over a two year period (1983 to 1984) and Big Canyon, Jacks and Mission Creeks were studied for one year (1983). Biological information was collected and analyzed on the density, biomass, production and outmigration of juvenile summer steelhead trout. Physical habitat information was collected on available instream cover, stream discharge, stream velocity, water temperature, bottom substrate, embeddedness and stream width and depth. The report focuses on the relationships between physical stream habitat and juvenile steelhead trout abundance.

The initiation and growth of intergranular stress-corrosion cracking (IGSCC) in the heat affected zone (HAZ) of stainless steel reactor piping welds has been a subject of concern to electric utilities for over ten years. This type of crack can be detected with ultrasonic shear waves during normal maintenance periods with a reliability of up to 80%. Often after an inspection indicating cracks, a utility has been allowed to administer a temporary fix to a pipe which is suspected of being cracked. This fix is a weld metal overlay. The repaired pipes often have to be inspected after the overlay has been put on the pipe. The overlay with a complex, elastically anisotropic microstructure, considerably reduces the reliability of the ultrasonic inspection. This paper addresses the problems arising because of the overlay.

None

The project being reported in this document had three components: (1) a research project to carry out cost-benefit analysis of an ethyl alcohol plant at Tuskegee University, (2) seminars to improve the high-technology capabilities of minority persons, and (3) a class in energy management. The report provides a background on the three components listed above. The results from the research on the ethyl alcohol plant, are discussed, along with the seminars, and details of the energy management class.

Thermal place names were compiled from all 1:50,000 topographic quadrangle maps for the Republic of Honduras as of July 1986, from other published maps, and from several sources of unpublished data. Known hot spring sites include those visited by Empresa Nacional de Energia Electrica (Honduras) geologists, sites visited by Los Alamos geologists in 1985, and other sites known to R.C. Finch. The number of known hot spring sites in Honduras with temperatures >30/sup 0/C is 125. In addition, 56 thermal sites are suspected on the basis of thermal place names. The total number of geothermal sites, known and suspected, is 181.

Progress made in developing a ..pi..NN model for describing all NN and ..pi..d reactions up to intermediate energy regions is reported. An accurate ..pi..NN model is the starting point of developing a microscopic description of nuclear phenomena up to the energy region where pion production can occur. The model can be used to carry out many-nucleon calculations, such as the calculations of pion absorption and electroproduction of ..delta.. on nuclei. It reduces to existing nuclear theory in the low energy region. 5 refs., 6 figs.

Orbifold compactifications provide a practical approach to string symmetry breaking. They have the potential to bridge the gap between string theory and the physics of the standard model. 7 refs., 5 figs.

Results of recent beam tests of a physics prototype Cerenkov Ring Imaging Detector (CRID) for the SLD experiment at the SLAC Linear Collider (SLC) are presented. The system includes both liquid (C/sub 6/F/sub 14/) and gas (isobutane) radiators and an 80 cm long Time Projection Chamber (TPC) with a gaseous TMAE (Tetrakis-Dimethylamino-Ethylene) photocathode and charge division readout of proportional wires. Handling of TMAE and development of a gas delivery system are discussed. Design considerations for the construction of the TPC anode planes are presented. Measurements of the multiplicity of detected Cerenkov photons, of Cerenkov angles, and the resolution with both radiators are presented. The particle identification capability of this detector is discussed.

The basic idea of the two-beam accelerator is to have a low-energy beam travel through an undulator magnet and generate microwave radiation by the free electron laser mechanism. The energy of the low-energy beam is repeatedly resupplied by induction units, and the microwave radiation is employed to accelerate the desired particles to very high energies. The two-beam accelerator must incorporate in its free electron laser portion tight control of the rf wave amplitude and phase. With regards to this, the present paper extends many particle simulation to include non-equilibrium conditions and discusses several feedback systems to correct phase errors. A many-particle simulation is used to study the evolution of the radiation phase and amplitude, and results are compared with one-dimensional resonant particle analysis. The electric field evolution is also discussed. (LEW)

The report discusses the difference in conclusions over the cause of the shorting anomaly in the multicouple 16 between the project (DOE,GE,FI) and JPL.

An objective of the Aquatic Species Program is the development of large scale culturing systems for the production of fuels from lipid-rich microalgae. A major constraint to any such culturing system is the provision of sufficient light in the most economical manner possible, which has led to the use of shallow outdoor ponds that are illuminated using natural sunllght.

Diffusion mechanisms of moisture within silica gel particles are investigated. It is found that for microporous silica gel surface diffusion is the dominant mechanism of moisture transport, while for macroporous silica gel both Knudsen and surface diffusion are important.

A description is presented of the conceptual design of the Lawrence Berkeley Laboratory 1-2 GeV Synchrotron Radiation Source, which is designed to produce ultraviolet and soft x-ray radiation. The facility consists of an injection system (linac plus booster synchrotron), a low emittance storage ring optimized at 1.5 GeV, several insertion devices (wigglers and undulators) located in the storage ring straight sections, and beam lines from the insertion devices and bending magnets. Storage ring performance is analyzed in terms of lattice, collective instabilities and beam lifetime. The injection system and its performance are discussed. Spectral characteristics of the radiation are presented.

A large proportion of the dynamic devices used to interact with the charged-particle beams in accelerators or storage rings can be classified as pickups or kickers. These devices act through time-varying electromagnetic fields either to extract information about the particle's motion or to effect a change in that motion. A given configuration of electrodes may be used either as a pickup or as a kicker; that duality will be addressed in this paper. An example of a simple electrode is the loop antenna, which may be made in the shape of an electrical stripline at the side of a beam chamber. This electrode.picks up a signal from the beam current by intercepting time-varying magnetic flux and image charges of the beam. One can also understand that the difference signal from two such striplines placed on opposite sides of the beam will give information on the beam's transverse position. This same electrode, if externally excited as a kicker, can produce transverse forces through its magnetic field acting on moving charges; and its electric fields in the direction of the particle motion produce its effects as a longitudinal kicker. Electrodes for a particular application call for response over a particular range of …