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0. 4 mm Interferometer System Using Dielectric Waveguide

Description: A 0.4 mm submillimeter-wave, phase-modulated polarimeter/interferometer is used for simultaneous time-dependent measurement of line-averaged electron density and poloidal field-induced Faraday rotation along chords of the plasma column in ISX-B tokamak. Heterodyna detection and hollow dielectric waveguide are utilized to achieve the high sensitivity required for the multichord equipment.
Date: January 1, 1982
Creator: Hutchinson, D. P.; Ma, C. H.; Staats, P. A. & Vander Sluis, K. L.
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A 0. 5 to 3. 0 MeV monoenergetic positron beam

Description: An adjustable, 0.5--3 MeV monoenergetic positron beam has been constructed at Brookhaven. Currently a /sup 22/Na source with a W(100) foil transmission moderator produces a 1.1 mm FWHN beam with an intensity of 3/times/10/sup 5/ e/sup +//sec at a target located downstream from the accelerator. The divergence of the beam is less than 0.1/degree/ at 2.2 MeV energy. A SOA gun with 2 lens transport system brings the beam to a focus at the entrance of an electrostatic 3 MeV Dynamitron accelerator. The post acceleration beam transport system comprises 3 focusing solenolds, 4 sets of steering magnets and a 90/degree/ double focusing bending magnet. The beam energy spread at the target is <1 keV FWHN deduced from the beam size. Below we describe the positron extraction optics and acceleration, the construction of the beamline and the beam diagnostic devices. The salient beam parameters are listed at the end of this paper. 2 refs., 3 figs., 1 tab.
Date: 1988~
Creator: Huomo, H.; AsokaKumar, P.; Henderson, S. D.; Phlips, B. F.; Mayer, R.; McDonough, J. et al.
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0. 9 a Gev /sup 238/U on /sup 238/U collisions in the LBL streamer chamber. Appendix A

Description: Charged particle exclusive data for high multiplicity U on U events are reported. Analyses are based on comparison with Cugnon's intranuclear cascade model, and the explosion-evaporation simulation of Fai and Randrup. The azimuthal structure of the observed events shows evidence of collective flow. The widely used flow angle methodology proves to be relatively insensitive to collective effects under the conditions of the present experiment. An isotropic pattern of ejectile emission is not reached at maximum multiplicity. 18 refs., 4 figs.
Date: January 1, 1984
Creator: Fung, S.Y.; Beavis, D.; Gorn, W.; Keane, D.; Liu, Y.M.; Poe, R.T. et al.
open access

0-D study of the compression of low temperature spheromaks

Description: Compression of low temperature spheromak plasmas has been studied with the aid of a O-D two-fluid computer code. It is found that in a plasma which is radiation dominated, the electron temperature can be increased by up to a factor of seven for a compression of a factor of two, provided the temperature is above some critical value (approx.25eV) and the electron density particle confinement time product n/sub e/tau/sub p/ greater than or equal to 1 x 10/sup 9/s/cm/sup 3/. If the energy balance is dominated by particle confinement losses rather than radiation losses, the effect of compression is to raise the temperature as T/sub e/ approx.C/sup 6/5/, for constant tau/sub p/.
Date: September 1, 1985
Creator: Meyerhofer, D.D.; Hulse, R.A. & Zweibel, E.G.
open access

0/sup -/ to 0/sup +/ beta decay in A = 16

Description: Techniques and results of the measurement of the beta-decay rate of the first excited state of /sup 16/N to the ground state of /sup 16/O are reported. Energy levels involved in the decay are shown, and the /sup 16/N 0/sup -/ beta decay branching ration is given. (WHK)
Date: January 1, 1982
Creator: Gagliardi, C.; Garvey, G.T.; Wrobel, J.R. & Freedman, S.J.
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1-2 GeV synchrotron radiation facility at Lawrence Berkeley Laboratory

Description: The Advanced Light Source (ALS), a dedicated synchrotron radiation facility optimized to generate soft x-ray and vacuum ultraviole (XUV) light using magnetic insertion devices, was proposed by the Lawrence Berkeley Laboratory in 1982. It consists of a 1.3-GeV injection system, an electron storage ring optimized at 1.3 GeV (with the capability of 1.9-GeV operation), and a number of photon beamlines emanating from twelve 6-meter-long straight sections, as shown in Fig. 1. In addition, 24 bending-magnet ports will be avialable for development. The ALS was conceived as a research tool whose range and power would stimulate fundamentally new research in fields from biology to materials science (1-4). The conceptual design and associated cost estimate for the ALS have been completed and reviewed by the US Department of Energy (DOE), but preliminary design activities have not yet begun. The focus in this paper is on the history of the ALS as an example of how a technical construction project was conceived, designed, proposed, and validated within the framwork of a national laboratory funded largely by the DOE.
Date: October 1, 1985
Creator: Berkner, K.H.
open access

1/2 Sintering of Mullite-Containing Materials: I. Effect of Composition

Description: Sintering behavior of mullite-containing powders was studied over a range of chemical compositions (Al{sub 2}O{sub 3}/SiO{sub 2} ratio). Densification measurements were made for both liquid phase-containing and solid state systems. Small amounts of liquid phase were observed to have a significant effect on densification rate. A linear relationship was obtained between the percent of theoretical density and the logarithm of time for compositions in the range 73-75 wt% Al{sub 2}O{sub 3}. Currently available models for intermediate stage sintering kinetics were considered to be inadequate for these systems. Grain boundary transport 0r diffusion appeared to be the primary mechanism of densification.
Date: December 1, 1981
Creator: Sacks, Michael D. & Pask, Joseph A.
open access

1,4-diphenylbutadiyne as a potential tritium getter, 1980, October 1

Description: Research on the acetylene compound 1,4-diphenylbutadiyne is an effort to develop an air-operative tritium gas scavenger. T/sub 2/ adds to the acetylene bond of the organic in the presence of a metal catalyst. The catalyst also stimulates the oxidation reaction as well. The butadiyne compound has shown good reaction efficiency at 300 ppM T/sub 2/ in static dry air. At this concentration 75% of the scavenged tritium was in the organic. This work has expanded to the investigation of liquid acetylenes, metal acetylene complexes, organometallics and acetylene based alcohols. The best of these compounds has gettered 100% of 10 to 500 ppM T/sub 2/ for both static and dynamic air flow conditions.
Date: October 1, 1980
Creator: Miller, H. H.; Bissell, E. E.; Tsugawa, R. T. & Souers, P. C.
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1. 8K conditioning (non-quench training) of a model SSC dipole

Description: The accepted hypothesis is that training quenches are caused by heat generation when conductors move under Lorentz force. Afterwards no conductor motion will occur until a higher field and greater Lorentz force acts. If superior heat transfer and/or greater temperature margin is provided by operating at lower bath temperature, one might expect that the heat generated by conductor motion will not cause a runaway temperature increase, or quench. To test this hypothesis, the central dipole field in SSC model magnets was ramped at 1.8 K to 7.1 tesla without the magnets' quenching. The bath was then raised to 4.4 K and the magnets quenched at their short sample limits of 6.6 tesla or higher. Comparison with similar magnets trained in He I at 4.4 K is made and the significance of the non-quench training on system operation is discussed.
Date: September 1, 1986
Creator: Gilbert, W. S. & Hassenzahl, W. V.
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1-D closure models for slender 3-D viscoelastic free jets: von Karman flow geometry and elliptical cross section

Description: In this paper we derive one space dimensional, reduced systems of equations (1-D closure models) for viscoelastic free jets. We begin with the three-dimensional system of conservation laws and a Maxwell-Jeffreys constitutive law for an incompressible viscoelastic fluid. First, we exhibit exact truncations to a finite, closed system of 1-D equations based on classical velocity assumptions of von Karman. Next, we demonstrate that the 3-D free surface boundary conditions overconstrain these truncated systems, so that only a very limited class of solutions exist. We then proceed to derive approximate 1-D closure theories through a slender jet asymptotic scaling, combined with appropriate definitions of velocity, pressure and stress unknowns. Our nonaxisymmetric 1-D slender jet models incorporate the physical effects of inertia, viscoelasticity (viscosity, relaxation and retardation), gravity, surface tension, and properties of the ambient fluid, and include shear stresses and time dependence. Previous special 1-D slender jet models correspond to the lowest order equations in the present asymptotic theory by an a posteriori suppression to leading order of some of these effects, and a reduction to axisymmetry. Solutions of the lowest order system of equations in this asymptotic analysis are presented: For the special cases of elliptical inviscid and Newtonian free jets, subject to the effects of surface tension and gravity, our model predicts oscillation of the major axis of the free surface elliptical cross section between perpendicular directions with distance down the jet, and drawdown of the cross section, in agreement with observed behavior. 15 refs.
Date: January 1, 1988
Creator: Bechtel, S. E.; Forest, M. G.; Holm, D. D. & Lin, K. J.
open access

1-D hybrid code for FRM start-up

Description: A one-D hybrid has been developed to study the start-up of the FRM via neutral-beam injection. The code uses a multi-group numerical model originally developed by J. Willenberg to describe fusion product dynamics in a solenoidal plasma. Earlier we described such a model for use in determining self-consistent ion currents and magnetic fields in FRM start-up. However, consideration of electron dynamics during start-up indicate that the electron current will oppose the injected ion current and may even foil the attempt to achieve reversal. For this reason, we have combined the multi-group ion (model) with a fluid treatment for electron dynamics to form the hybrid code FROST (Field Reversed One-dimensional STart-up). The details of this merger, along with sample results of operation of FROST, are given.
Date: January 1, 1982
Creator: Stark, R.A. & Miley, G.H.
open access

A 1-D model for highly sensitive tubular reactors

Description: We consider the steady state operation of wall-cooled, fixed-bed tubular reactors. In these reactors the temperature rise ..delta..T must normally be limited to small fractions of the adiabatic temperature rise ..delta..T/sub ad/, both to avoid runaway and maintain product selectivity. Yet ..delta..T/..delta..T/sub ad/ << 1 can only occur if eta = t/sub dif//t/sub reac/ << 1, where t/sub dif/ is the timescale on which heat escapes the reactor by ''diffusing'' to the cooled walls, and t/sub reac/ is the timescale over which the reaction occurs. So here we use asymptotic methods based on eta << 1 to analyze the 2-d reactor equations, and find the radial concentration and temperature profiles to leading order in eta. We then obtain a 1-d model of the reactor by substituting these asymptotically correct profiles into the reactor equations and averaging over r. This model, the ..cap alpha..-model, is identical to the standard (Beek and Singer) 1-d model, except that the reactor's overall heat transfer coefficient U is a decreasing function of the temperature rise ..delta..T. This occurs because as ..delta..T increases, the reaction becomes increasingly concentrated near r = 0, causing a decreased heat transfer efficiency through the reactor's walls. By comparing it with numerical solutions of the original 2-d reactor equations, we find that the ..cap alpha..-model simulates the 2-d equations very accurately, even for highly sensitive reactors operated near runaway. We also find that a runaway criterion derived from the ..cap alpha..-model predicts the runaway transition of the original 2-d equations accurately, especially for highly sensitive reactors. 19 refs.
Date: January 1, 1987
Creator: Hagan, P. S.; Herskowitz, M. & Pirkle, J. C.
open access


Description: There exist families of field theories with symmetry group SO(N) (or SU(N)) that become simpler as N becomes larger. More precisely, the solutions to these theories possess an expansion in powers of 1/N. This expansion is the subject of these lectures. The 1/N expansion can be used to analyze model field theories. The 1/N expansion is developed for phi/sup 4/ theory and applied to two two-dimensional models with similar combinatoric structures, the Gross-Neveu model and the CP/sup N-1/ model. These models display (in the leading 1/N approximation) such interesting phenomena as asymptotic freedom, dynamical symmetry breaking, dimensional transmutation, and non-perturbative confinement. It is possible that the 1/N expansion, with N the number of colors, might fruitfully be applied to quantum chromodynamics. Unfortunately, it is not possible to make a decisive test of the approximation, because no one knows how to compute even the first term in the expansion in closed form. However, it is possible to argue that this first term, whatever its detailed form, has many properties that are also shared by the real world, and which are otherwise underived from field theory. These include the saturation of scattering amplitudes by an infinite number of narrow resonances, the essential feature of dual-resonance models. (RWR)
Date: March 1, 1980
Creator: Coleman, S.
open access

1-/sup 11/C-D-glucose and related compounds

Description: The novel compounds 1-/sup 11/C-D-glucose, 1-/sup 11/C-D-mannose, 1-/sup 11/C-D-galactose, 2-/sup 11/C-D-glucose, 2-/sup 11/C-D-mannose and 2-/sup 11/C-D-galactose which can be used in nuclear medicine to monitor the metabolism of glucose and galactose can be rapidly prepared by reaction of the appropriate aldose substrate with an alkali metal /sup 11/C-labeled cyanide followed by reduction with a Raney alloy in formic acid.
Date: January 26, 1982
Creator: Shiue, Chyng-Yann & Wolf, Alfred P.
open access

1 to 2 GeV/c beam line for hypernuclear and kaon research

Description: A kaon beam line operating in the range from 1.0 to 2.0 GeV/c is proposed. The line is meant for kaon and pion research in a region hitherto inaccessible to experimenters. Topics in hypernuclear and kaon physics of high current interest include the investigation of doubly strange nuclear systems with the K/sup -/,K/sup +/ reaction, searching for dibaryon resonances, hyperon-nucleon interactions, hypernuclear ..gamma.. rays, and associated production of excited hypernuclei. The beam line would provide separated beams of momentum analyzed kaons at intensities greater than 10/sup 6/ particles per spill with a momentum determined to one part in a thousand. This intensity is an order of magnitude greater than that currently available. 63 references.
Date: February 15, 1985
Creator: Chrien, R. E.
open access

2-1/2-dimensional numerical solution for the electromagnetic scattering using a hybrid technique

Description: The use of the electromagnetic method for geothermal reservoir exploration and delineation was studied. A number of techniques were developed to provide high quality field data. The remaining problem of interpreting these data in regions of complex geologic structure was overcome by the development of a numerical solution based on the hybrid technique, making use of both the finite element and the integral equation techniques. The major improvement is in the computing speed. (ACR)
Date: March 1, 1983
Creator: Lee, K. H. & Morrison, H. F.
open access

2. 5 MeV neutron source for fission cross section measurement

Description: A 2.5 MeV neutron source has been established on the beamline of a 100 kV, 0.5 ma ion accelerator. The ion accelerator provides a 100 kV deuteron beam of about 200 ..mu..a into a 3 mm beam spot at the target position. The neutron source is produced by the D(d,n)/sup 3/He reaction with a yield of about 10/sup 7/ n/sec. The time-correlated associated particle method (TCAP) is utilized for the neutron fluence determination and for neutron background elimination. The /sup 3/He associated particles are detected at 90 degrees behind a thin aluminum foil and the corresponding neutrons are emitted at 73.5 degrees with an energy near 2.5 MeV. Also, the protons from the competing D(d,p)T reaction are monitored at 135 degrees for normalization and diagnostic purposes. A fission chamber containing six uranium tetrafluoride deposits has been designed for use in the /sup 235/U(n,f) cross section measurement at 2.5 MeV. The 5 cm diameter deposits range in thickness from 230--300 ..mu..g/cm/sup 2/ and are expected to have good uniformity. A description of the 2.5 MeV neutron source facility is presented along with details of the associated particle detection and neutron beam characteristics. Preparations for the fission cross section measurement are discussed. 6 refs., 4 figs.
Date: January 1, 1988
Creator: Duvall, K. C.; Wasson, O. A. & Ma, Honchang
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2. 6/sup 0/K refrigeration system for CBA magnet testing

Description: The superconducting magnets for the accelerator's rings will be cooled by a forced flow supercritical helium system from a central refrigeration plant. The design temperature for these magnets varies from 2.6 to 3.8/sup 0/K depending on a magnet's location in the ring. This paper describes the forced flow cooling system for testing a prototype magnet near 2.6/sup 0/K; this lowest temperature being of special interest to evaluate magnet quench protection. The test forced flow cooling system uses a three-stage approach, including an ejector pumped bath, similar to a cycle described previously. The coolant exists at 3.8/sup 0/K from these first stages and is then cooled further in a 64 cm diameter by 3 m high shielded liquid helium dewar. The supercritical helium gas passes through a submerged copper coil in this bath which is pumped to a pressure of 65 mm absolute by a screw compressor system. Temperatures are measured by thermistors located in the gas stream, and also embedded in the magnet coil.
Date: January 1, 1982
Creator: Bamberger, Joseph A.
open access

2-D ACAR measurements of Ni/sub 3/A1

Description: In connection with a detailed study of the electronic structure and stability of the aluminides (Ni,Fe)/sub 3/Al, 2-D ACAR positron annihilation measurements were made on a Ni/sub 3/Al single crystal to study the Fermi surface. The results for Ni/sub 3/Al have been compared with results for pure Ni. Strong similarities were found for the electronic structures of these materials. Theoretical calculations of the Fermi surface for Ni/sub 3/Al are in good agreement with the experimental results. The GAMMA/sub 16/ sheet, not previously observed in any experiment, has now been observed for the first time in Ni/sub 3/Al. 14 refs., 10 figs.
Date: July 1987
Creator: Smedskjaer, L. C.; DasGupta, A.; Legnini, D. G. & Stahulak, M. D.
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