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Radioactive ion beam research at Lawrence Livermore National Laboratory
Several modifications and additions have been made to improve the radioactive beam facility at Livermore with the main aim of measuring the cross section for /sup 7/Be(p,..gamma..)/sup 8/B (which is important in determining the solar neutrino flux) and other reactions of astrophysical interest. The quadrupole sextuplet spectrometer has been upgraded by inserting an electrostatic deflection element near the midpoint and by installing a movable beam stop near the /sup 7/Be production target. These changes have allowed an improvement in the purity, and a large increase in the intensity, of the /sup 7/Be beam. Six large NaI(Tl) detectors and the gas cell from the OSU system along with its active and passive shielding have been incorporated into the Lawrence Livermore facility. True events are to be identified by a multiple coincidence. The first requirement is the detection of a ..gamma..-ray from the proton capture /sup 7/Be(p,..gamma..)/sup 8/B. After the candidate capture gamma is observed the /sup 8/B decay signature is required. This signature is a positron (from /sup 8/B ..-->.. /sup 8/Be* + e/sup +/ + ..nu..) along with the two ..cap alpha..'s from /sup 8/Be ..-->.. ..cap alpha.. + ..cap alpha.. observed in a CaF/sub 2/ detector into which the …
Date:
September 1, 1986
Creator:
Sale, K. E.; Bauer, R. W.; Boyd, R. N.; Mathews, G. J.; Haight, R. C. & Corn, P. B.
System:
The UNT Digital Library
Use of time averaged precipitation for wet removal in a regional air pollution assessment model
Results are presented of the test of a regional scale assessment model using four modes of precipitation hourly, 6 hourly, average turned on and off with the natural frequency and average precipitation. The test cases were carried out for a release of SO/sub 2/ with transformation to SO/sub 4/ at three different sites in the United States for July 1974. The results indicated that the use of average precipitation turned on and off with the natural frequency could be used instead of hourly precipitation for long-term assessments.
Date:
September 1, 1979
Creator:
Davis, W. E. & Eadie, W. J.
System:
The UNT Digital Library
Compact Fusion Advanced Rankine (CFARII) power cycle---Operating regimes
Performance (cost/kWe and efficiency) of generic Compact Fusion Advanced Rankine (CFARII) power conversion is investigated for various working fluids, operating temperatures and pressures, and thermal power levels. A general conclusion is that good CFARII performance is found for a remarkably broad range of materials, temperatures, pressures and power levels, which gives considerable flexibility to future design studies which may apply CFARII energy conversion to specific fusion energy sources such as ICF, MICF, and Mini-PACER. 5 refs, 7 figs., 2 tabs.
Date:
September 30, 1991
Creator:
Logan, B. G.
System:
The UNT Digital Library
Proceedings of the heavy ion fusion workshop
Separate abstracts were prepared for 35 of the included papers. Abstracts for 9 of the remaining papers appeared earlier in ERA. Two of the included papers were title listed only. (MOW)
Date:
September 1, 1980
Creator:
Herrmannsfeldt, W.B. (ed.)
System:
The UNT Digital Library
Requested information regarding remote analytical capabilities
This document describes a new method for analysis of cyanide in radioactive waste samples from the Hanford Site. The new assay is designed to increase throughput of samples, reduce waste volumes and decrease radiation exposure to analysts. The system is based on the Lachat Micro-Dist{sup TM} microdistillation system. This document contains the reference and methods manual for this kit, and also the specific PNL lab procedures for using this kit. 6 refs., 20 figs. (MHB)
Date:
September 1, 1991
Creator:
Steel, R.T.
System:
The UNT Digital Library
Two-photon results from SPEAR
Results obtained by two experiments at SPEAR on the two-photon production of lepton pairs and resonances are reported. Both experiments find agreement of lepton production with QED expectations, and observe an enhancement of the ..pi pi.. mass spectrum in the 1250 MeV/c/sup 2/ region. The Mark II finds this enhancement not consistent with the decay of the f(1270 MeV/c/sup 2/) alone. The ..gamma gamma.. partial width of the eta' has also been measured by the Mark II.
Date:
September 1, 1980
Creator:
Roussarie, A.
System:
The UNT Digital Library
Recirculating induction accelerator as a low-cost driver for heavy ion fusion
As a fusion driver, a heavy ion accelerator offers the advantages of efficient target coupling, high reliability, and long stand-off focusing. While the projected cost of conventional heavy ion fusion (HIF) drivers based on multiple beam induction linacs are quite competitive with other inertial driver options, a driver solution which reduces the cost by a factor of two or more will make the case for HIF truly compelling. The recirculating induction accelerator has the potential of large cost reductions. For this reason, an intensive study of the recirculator concept was performed by a team from LLNL and LBL over the past year. We have constructed a concrete point design example of a 4 MJ driver with a projected efficiency of 35% and projected cost of less than 500 million dollars. A detailed report of our findings during this year of intensive studies has been recently completed. 3 refs., 2 figs., 2 tabs.
Date:
September 1, 1991
Creator:
Barnard, J. J.; Newton, M. A.; Reginato, L. L.; Sharp, W. M.; Shay, H. D. & Yu, S. S.
System:
The UNT Digital Library
Properties of epitaxial YBa sub 2 Cu sub 3 O sub 7-. delta. -based superconducting superlattices
Epitaxial YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} superconducting superlattices have been fabricated using pulsed laser deposition in which c-axis oriented YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} layers as thin as one unit cell thick are separated by relatively thick PrBa{sub 2}Cu{sub 3}O{sub 7-{delta}} based barrier layers. The superlattice {Tc} (R=0) decreases rapidly with increasing barrier layer thickness, but then saturates at a finite {Tc} for YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} layers as thin as a single c-axis unit cell. The superconducting properties of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}-based superlattices are shown to depend strongly on the electronic properties of the barrier layers. The resistive transition width decreases significantly as the hole carrier density in the barrier layers is increased. However, {Tc} (onset) does not change, contrary to predictions of hole filling models. Theoretical analyses suggest that the broadening of the resistive transition for the thinnest YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} layers is most likely due to a crossover to 2D resistive behavior involving thermally-generated vortices. Scanning tunneling microscopy reveals that epitaxial YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} thin films grow unit cell-by-unit cell, by a terraced-island growth mode. This terraced microstructure explains the steps found in ultrathin YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} layers in these superlattices. These steps may act …
Date:
September 1, 1991
Creator:
Norton, D.P.; Lowndes, D.H.; Zheng, Z. Y.; Feenstra, R. (Oak Ridge National Lab., TN (United States)) & Zhu, Shen (Tennessee Univ., Knoxville, TN (United States). Dept. of Physics and Astronomy)
System:
The UNT Digital Library
Workshop on radiobiological effectiveness of neutrons
The radiobiological effectiveness (RBE) of neutrons has become the subject of some heated discussions in both scientific and radiation-protection oriented communities. This has become especially so since the realization that neutron exposures of A-bomb survivors in Hiroshima were considerably lower than previously assumed, thus ''devaluating'' the importance of what we thought was a solid human data base. At the same time, more recent data from radiobiological research appeared to indicate that, at least for some biological endpoints, the RBE of neutrons at low doses and low dose rates was increased dramatically compared to the RBE at higher dose and dose rates. As a consequence, the protection of health against neutrons became a subject of some urgency. The objective of this workshop was to evaluate the existing data base in order to determine the need for additional research in this field. 22 refs., 3 figs., 6 tabs.
Date:
September 1, 1985
Creator:
Stapleton, G. E.; Thomas, R. G. & Thiessen, J. W.
System:
The UNT Digital Library
Poloidal field coil design for a fusion--fission breeder reactor
The magnetic, structural, and thermal design of superconducting poloidal field coils for a tokamak fusion-fission breeder reactor are described. The design requirements and considerations, with the resulting parameters, are presented.
Date:
September 30, 1977
Creator:
Howland, H. R.; Kelly, J .L. & Chi, J. W. H.
System:
The UNT Digital Library
Soil washing results for mixed waste pond soils at Hanford
Soil washing technology was assessed as a means for remediating soil contaminated with mixed wastes primarily composed of heavy metals and radionuclides. The soils at the US Department of Energy's Hanford Site are considered suitable for soil washing because of their relatively low quantities of silt and clay. However, in a limited number of soil washing experiments using soils from different locations in the north pond of the 300 Area, the degree of decontamination achieved for the coarse fraction of the soil varied considerably. Part of this variation appears to be due to the presence of a discrete layer of contaminated sediment found in some of the samples. 7 refs., 2 figs., 4 tabs.
Date:
September 1, 1991
Creator:
Gerber, M. A.
System:
The UNT Digital Library
Theoretical study of a high-extraction efficiency undulator for a free-electron laser oscillator
Theoretical issues in designing a high-extraction efficiency undulator for a free-electron laser oscillator are discussed. Assuming that an undulator system consists of a prebuncher undulator and a main undulator separated by a drift, design criteria of the untapered prebuncher are studied. The main undulator is designed parabolically tapered in wave number from no taper to a 30% taper. A small signal gain is enhanced at the low taper section, and the large signal gain is enhanced at the high taper section. To optimize the operation of this prebuncher system, electron dynamics in phase space from the prebuncher to the main undulator is studied. To demonstrate the advantage of having the prebuncher, comparisons of the extraction efficiency and the gain are performed between the prebuncher system and the system with the prebuncher removed. The optimized prebuncher system is then tested for the sideband instability with more complex one-dimensional FEL codes that assume a finite electron pulse and a finite laser pulse length. The electron beam emittance requirement is studied using a three-dimensional FEL simulation code.
Date:
September 1, 1986
Creator:
Takeda, H.; McVey, B.D. & Goldstein, J.C.
System:
The UNT Digital Library
Dynamics of vitreous and molten zinc chloride
The dynamics of vitreous and molten zinc chloride have been studied with inelastic neutron scattering at the Intense Pulsed Neutron Source. The results are analyzed in terms of the scattering function S(Q,E) and the effective vibrational density of states G(E). The vibrational spectra of both glass and liquid are dominated by broad features centered at 15 and 35 MeV which are identified with F{sub 2} modes of ZnCl{sub 4}{sup 2{minus}} tetrahedra. The other two normal modes are not observed because of inadequate resolution and broadening and overlap resulting from coupling between tetrahedra. The behavior of ZnCl{sub 2} is contrasted with other tetrahedrally coordinated glasses that have been studied with the same technique. 15 refs,. 5 figs., 1 tab.
Date:
September 1, 1991
Creator:
Price, D.L.; Saboungi, M.L.; Susman, S.; Volin, K.J. (Argonne National Lab., IL (United States)) & Wright, A.C. (Reading Univ. (United Kingdom). J.J. Thomson Physical Lab.)
System:
The UNT Digital Library
Fifty megawatt klystron for the Stanford Linear Collider
The proposed Stanford Linear Collider (SLC) has been designed to provide 50 on 50 GeV electron-positron collisions. The performance of the 240 klystrons driving the two-mile long linac must be upgraded to achieve at least 50 Megawatts of peak power output at a pulse of 5 ..mu..sec and a pulse repetition frequency of 180 pulses per second. The operating frequency of the upgraded linac will continue to be 2856 MHz. A klystron amplifier meeting these new requirements has been designed to operate at 315 kV, ..mu..k = 2, with a computed efficiency of slightly greater than 50%. Initial tests indicate the achievement of the basic power objectives; however, observed parasitic instabilities make beam focusing, RF drive frequency and drive level extremely critical. High electric fields in the electron gun, output gap and output window are all potential problems. Steps taken in the design to overcome these problems are discussed and test results are presented.
Date:
September 1, 1983
Creator:
Lee, T. G.; Lebacqz, J. V. & Konrad, G. T.
System:
The UNT Digital Library
Test results from the 500 kW direct contact pilot plant at East Mesa
A 500 kW power plant utilizing direct contact heat exchange (DCHX) between the geothermal brine and the isobutane (IC/sub 4/) working fluid is being operated at the East Mesa test facility. The power plant incorporates a 40-inch-diameter direct-contactor approximately 35 feet tall. The purpose of the pilot plant is to determine the feasibility of large-scale direct-contact heat exchange and power plant operation with the DCHX. The binary cycle offers higher conversion factors (heat energy transformed to electrical energy) than the flashed steam approach for geothermal brines in the 300 to 400/sup 0/F range and preliminary results indicate the DCHX system may have higher performance than the conventional tube-and-shell binary approach. This performance advantage results from the absence of any fouling and the very close pinch temperatures achieved in the DCHX itself. The baseline performance tests for the plant were completed in January 1980. The results of these tests and follow-on testing are covered.
Date:
September 1, 1980
Creator:
Nichols, K.E.; Olander, R.G. & Lobach, J.L.
System:
The UNT Digital Library
A system to deposit boron films (boronization) in the DIII-D tokamak
A system has been added to the D3-D tokamak to coat its plasma facing surfaces with a film of boron using diborane gas. The system includes special health and safety equipment for handling the diborane gas which is toxic and inflammable. The purpose of the boron film is to reduce the levels of impurity atoms in the D3-D plasmas. Experiments following the application of the boron film in D3-D have led to significant reductions in plasma impurity levels and the observation of a new, very high confinement regime. 9 refs., 1 fig.
Date:
September 1, 1991
Creator:
Hodapp, T.R.; Jackson, G.L.; Phillips, J.; Holtrop, K.L.; Petersen, P.I. (General Atomics, San Diego, CA (United States)) & Winter, J. (Forschungszentrum Juelich GmbH (Germany). Inst. fuer Plasmaphysik)
System:
The UNT Digital Library
Technology of mirror machines: LLL facilities for magnetic mirror fusion experiments
Significant progress in plasma confinement and temperature has been achieved in the 2XIIB facility at Livermore. These encouraging results, and their theoretical corroboration, have provided a firm basis for the design of a new generation of magnetic mirror experiments, adding support to the mirror concept of a fusion reactor. Two new mirror experiments have been proposed to succeed the currently operating 2XIIB facility. The first of these called TMX (Tandem Mirror Experiment) has been approved and is currently under construction. TMX is designed to utilize the intrinsic positive plasma potential of two strong, and relatively small, minimum B mirror cells to enhance the confinement of a much larger, magnetically weaker, centrally-located mirror cell. The second facility, MFTF (Mirror Fusion Test Facility), is currently in preliminary design with line item approval anticipated for FY 78. MFTF is designed primarily to exploit the experimental and theoretical results derived from 2XIIB. Beyond that, MFTF will develop the technology for the transition from the present small mirror experiments to large steady-state devices such as the mirror FERF/FTR. The sheer magnitude of the plasma volume, magnetic field, neutral beam power, and vacuum pumping capacity, particularly in the case of MFTF, has placed new and exciting …
Date:
September 15, 1977
Creator:
Batzer, T. H.
System:
The UNT Digital Library
Bending and focusing effects in an FEL oscillator. II. Numerical simulations
Bending and focusing of the optical beam by the electron beam is investigated for an FEL oscillator configuration. Numerical calculations are performed with the simulation code, FELEX.
Date:
September 1, 1986
Creator:
McVey, B.D. & Warren, R.W.
System:
The UNT Digital Library
Intense positron beams: linacs. Preworkshop copy
Beams of monoenergetic positrons with energies of a few eV to many keV have been used in experiments in atomic physics, solid state physics and materials science. The production of positron beams from a new source, an electron linac, is described. Intense, pulsed beams of low-energy positrons have been produced by a high-energy beam from an electron linac. The production efficiency, moderator geometry, beam spot size and other positron beam parameters have been determined for electrons with energies from 60 to 120 MeV. Low-energy positron beams produced with a high-energy electron linac can be of much higher intensity than those beams currently derived from radioactive sources. These higher intensity beams will make possible positron experiments previously infeasible.
Date:
September 1, 1983
Creator:
Howell, R. H.; Alvarez, R. A.; Woodle, K. A.; Dhawan, S.; Egan, P. O.; Hughes, V. W. et al.
System:
The UNT Digital Library
Small-angle neutron scattering from voids in neutron irradiated type 304 stainless steel. [E > 0. 1 MeV]
Preliminary small-angle neutron scattering results designed to investigate the structure of voids in neutron-irradiated polycrystalline annealed type 304 stainless steel were obtained. Specimens were subjected to irradiation at 400/sup 0/C to a fluence of 1.6 x 10/sup 23/ n/cm/sup 2/ (E > 0.1 MeV). Void interference effects were seen for voids having an average diameter of about 290 A. The distribution was ''gas-like''with an exclusion distance of 307 A. 1 figure, 1 table. (RWR)
Date:
September 1, 1977
Creator:
Child, H.R. & Spooner, S.
System:
The UNT Digital Library
Impurity and gas throughput control for TNS
A model of the interaction between an ignited plasma and a wall is utilized to study the impact of impurities and recycled fuel ions and helium ash on the burn time of the plasma. The model indicates that the impurity concentration, n/sub im/, grows exponentially toward a maximum value determined by the confinement time for impurities, tau/sub im/, the sputtering coefficient, S/sub i/, and the isolation coefficient, ..cap alpha... The time for n/sub im/ to reach a critical value and quench the plasma was determined for representative impurities, C, Mo, W, Fe, under various conditions of plasma temperature. Methods for extending the burn time by minimizing the effective sputtering coefficient of the wall and increasing the isolation of the plasma from the wall are reviewed. The carbides, B/sub 4/C and SiC, are found to have encouraging sputtering properties but their thermal, chemical and mechanical properties need to be evaluated before they can be recommended for use as first walls. The magnetic divertor is the preferred isolation scheme. Because the divertor carries impurities and leaked fuel and helium ions to a burial chamber, required pumping speeds are found to be very high for TNS plasmas and supplemental particle trapping systems must …
Date:
September 30, 1977
Creator:
Sucov, E. W.
System:
The UNT Digital Library
Progress in direct heat applications projects
The development of hydrothermal energy for direct heat applications is being aided by twenty-two demonstration projects that are funded on a cost-sharing basis by the US Department of Energy, Division of Geothermal Energy. These projects are designed to demonstrate the technical and economic feasibility of the direct use of geothermal heat in the United States. Twelve of these projects are administered by the DOE-Idaho Operations Office with technical support from EG and G Idaho, Inc. Engineering and economic data for these projects are summarized in this paper. The data and experience being generated by these projects will be an important basis for future geothermal direct use projects.
Date:
September 9, 1980
Creator:
Childs, F. W.; Jones, K. W.; Nelson, L. B.; Strawn, J. A. & Tucker, M. K.
System:
The UNT Digital Library
L-shell photoabsorption spectroscopy for solid metals: Ti, V, Cr, Fe, Ni, Cu
Synchrotron radiation measurements of near-threshold and broad-range (400--1500 eV) absolute photoabsorption cross sections were made for five transition metals with {plus minus}10% overall uncertainties. Fine structure details of 2p-3d autoionizing resonances are shown with better than 1.0 eV resolution for solid metals: Ti, V, Cr, Fe, Ni, and Cu. Fine structure similar to what we measured can be produced using a multi-configuration Dirac Fock (MCDF) model if a statistical distribution is assumed for the initial atomic states. Calculations were performed in intermediate coupling with configuration interactions by Mau H. Chen. The results are compared with other experimental work and theoretical methodologies. 18 refs., 7 figs.
Date:
September 13, 1989
Creator:
Del Grande, N.K. (Lawrence Livermore National Lab., CA (USA))
System:
The UNT Digital Library
Optical design considerations for laser fusion reactors
The plan for the development of commercial inertial confinement fusion (ICF) power plants is discussed, emphasizing the utilization of the unique features of laser fusion to arrive at conceptual designs for reactors and optical systems which minimize the need for advanced materials and techniques requiring expensive test facilities. A conceptual design for a liquid lithium fall reactor is described which successfully deals with the hostile x-ray and neutron environment and promises to last the 30 year plant lifetime. Schemes for protecting the final focusing optics are described which are both compatible with this reactor system and show promise of surviving a full year in order to minimize costly downtime. Damage mechanisms and protection techniques are discussed, and a recommendation is made for a high f-number metal mirror final focusing system.
Date:
September 1, 1977
Creator:
Monsler, M.J. & Maniscalco, J.A.
System:
The UNT Digital Library