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SLAC pulsed x-ray facility
The Stanford Linear Accelerator Center (SLAC) operates a high energy (up to 33 GeV) linear accelerator delivering pulses up to a few microseconds wide. The pulsed nature of the electron beam creates problems in the detection and measurement of radiation both from the accelerator beam and the klystrons that provide the rf power for the accelerator. Hence, a pulsed x-ray facility has been built at SLAC mainly for the purpose of testing the response of different radiation detection instruments to pulsed radiation fields. The x-ray tube consists of an electron gun with a control grid. This provides a stream of pulsed electrons that can be accelerated towards a confined target-window. The window is made up of aluminium 0.051 cm (20 mils) thick, plated on the vacuum side with a layer of gold 0.0006 cm (1/4 mil) thick. The frequency of electron pulses can be varied by an internal pulser from 60 to 360 pulses per second with pulse widths of 360 ns to 5 ..mu..s. The pulse amplitude can be varied over a wide range of currents. An external pulser can be used to obtain other frequencies or special pulse shapes. The voltage across the gun can be varied from …
Date:
May 1, 1986
Creator:
Ipe, N.E.; McCall, R.C. & Baker, E.D.
Object Type:
Article
System:
The UNT Digital Library
Tritium processing using metal hydrides
E.I. duPont de Nemours and Company is commissioned by the US Department of Energy to operate the Savannah River Plant and Laboratory. The primary purpose of the plant is to produce radioactive materials for national defense. In keeping with current technology, new processes for the production of tritium are being developed. Three main objectives of this new technology are to ease the processing of, ease the storage of, and to reduce the operating costs of the tritium production facility. Research has indicated that the use of metal hydrides offers a viable solution towards satisfying these objectives. The Hydrogen and Fuels Technology Division has the responsibility to conduct research in support of the tritium production process. Metal hydride technology and its use in the storage and transportation of hydrogen will be reviewed.
Date:
May 1, 1986
Creator:
Mallett, M.W.
Object Type:
Report
System:
The UNT Digital Library
Inertial fusion power for space applications
More than thirty-seven design concepts have been proposed for terrestrial ICF power plants. The design space is large because of the many allowable driver and reaction chamber combinations. These design studies have illustrated advantages of ICF power plants over other sources in lower impact on the environment, high safety, and almost no dependence on consumables like fuel. The fact that, once built, a 1000 MW/sub e/ ICF power plant would require only 240 kg of deuterium and from 770 to 9260 kg of lithium to run for five years (at 70% capacity factor) makes it potentially attractive for space power also. However, the designs proposed to date have emphasized features that would make the plant attractive for terrestrial applications, where economics, efficiency, and environmental considerations dominate. The resulting plants are large and contain many very heavy components that would not be at attractive for space applications. In this paper, we evaluate alternative ICF driver and reactor technologies using space application criteria and also discuss how some of those technologies can be altered to produce smaller, lighter fusion power sources for space.
Date:
May 19, 1986
Creator:
Meier, W. R.; Hogan, W. J.; Hoffman, N. J.; Murray, K. A. & Olson, R. E.
Object Type:
Article
System:
The UNT Digital Library
Recent developments of the LBL ECR ion source
The performance of the LBL ECR has improved significantly since January 85 when the last ECR Ion Source Workshop was held in Berkeley. The 88-Inch Cyclotron began regular operation with the ECR source just prior to the workshop. Since then about 80% of the cyclotron operating schedule has been with the ECR source. The light-ion filament source is used only for runs two or more shifts in length using proton, /sup 3/He, or alpha beams. Occasionally the polarized ion source is used. The heavy-ion PIG sources are not longer used. The operating experience with the Cyclotron+ECR has been highly successful in terms of reliability, stability, production of high charge state currents, and in the range of ions which can be produced. For example, a 32.5 MeV/u /sup 16/O/sup 8 +/ beam was developed and successfully used for a nuclear structure experiment. The 60 nA beam available from the cyclotron was more intense than the experiment could use. A 1.08 GeV /sup 36/Ar/sup 18 +/ beam was used to test the response of various scintillator materials to intermediate energy heavy ions. Three aspects of the LBL ECR source development are discussed. First, the installation of a new first stage cavity has …
Date:
May 1, 1986
Creator:
Lyneis, C.M.
Object Type:
Article
System:
The UNT Digital Library
Delta, iota and other meson spectroscopies
This talk is given from the point of view of an experimentalist. Meson spectroscopy in the 1 to 3 GeV region is interesting because experiments exploring this region, in particular radiative psi decay, have found a rich structure of resonances too complicated to unravel with any one experiment, and not easily interpreted with any one theoretical model. None of the theoretical calculations predicting all kinds of interesting and exotic objects in this region is very convincing or reliable. Additional input from anti pp annihilation can be very useful in helping to find the answers to the following open questions: what exactly is this spectrum, what are the masses and quantum numbers of the resonances, as determined from analysis of data without theoretical prejudices; how is this spectrum described by QCD, is there evidence for new kinds of states like glue-balls, hybrids, axions, Higgses or multiquark exotics, and is there any evidence for new physics beyond QCD. 20 refs.
Date:
May 1, 1986
Creator:
Lipkin, Harry J.
Object Type:
Article
System:
The UNT Digital Library
Charged particle detectors made from thin layers of amorphous silicon
A series of experiments was conducted to determine the feasibility of using hydrogenated amorphous silicon (..cap alpha..-Si:H) as solid state thin film charged particle detectors. /sup 241/Am alphas were successfully detected with ..cap alpha..-Si:H devices. The measurements and results of these experiments are presented. The problems encountered and changes in the fabrication of the detectors that may improve the performance are discussed.
Date:
May 1, 1986
Creator:
Morel, J.R.
Object Type:
Report
System:
The UNT Digital Library
Unified formulation for linear accelerator design
Expressions for peak and average powers required to produce a given average gradient in an accelerator section are given. They are valid for both lossy and lossless (superconducting) sections, for both traveling wave and standing wave sections, and for pulsed or continuous wave rf input. The expressions are given in terms of structure parameters that are equally applicable to traveling wave or standing wave. These parameters delineate the effect of wall losses and energy required to build up the field. For both traveling wave and standing wave sections it is possible to make the rf pulse length short enough to make the wall losses negligible at the expense of increased peak power requirement. Therefore the expressions will include the effects of pulse compression. 6 refs., 7 figs.
Date:
May 1, 1986
Creator:
Farkas, Z. D.
Object Type:
Article
System:
The UNT Digital Library
Environmental assessment: Deaf Smith County site, Texas, Volume I
In February 1983, the US Department of Energy (DOE) identified a location in Deaf Smith County, Texas, as one of nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. To determine their suitability, the Deaf Smith County site and the eight other potentially sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. The Deaf Smith County site is in the Permian Basin, which is one of five distinct geohydrologic settings considered for the first repository. On the basis of the evaluations reported in this EA, the DOE has found that the Deaf Smith County site is not disqualified under the guidelines. On the basis of these findings, the DOE is nominating the Deaf Smith County site as one of the five sites suitable for characterization. 591 refs., 147 figs., 173 tabs.
Date:
May 1986
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Spin observables in proton-neutron scattering at intermediate energy
A summary of np elastic scattering spin measurements at intermediate energy is given. Preliminary results from a LAMPF experiment to measure free neutron-proton elastic scattering spin-spin correlation parameters are presented. A longitudinally polarized proton target was used. These measurements are part of a program to determine the neutron-proton amplitudes in a model independent fashion at 500, 650, and 800 MeV. Some new proton-proton total cross sections in pure helicity states (..delta..sigma/sub L/(pp)) near 3 GeV/c are also given. 37 refs., 2 figs.
Date:
May 1, 1986
Creator:
Spinka, H.
Object Type:
Report
System:
The UNT Digital Library
Minority and Poor Households: Patterns of Travel and Transportation Fuel Use
This report documents the travel behavior and transportation fuel use of minority and poor households in the US, using information from numerous national-level sources. The resulting data base reveals distinctive patterns of household vehicle availability and use, travel, and fuel use and enables us to relate observed differences between population groups to differences in their demographic characteristics and in the attributes of their household vehicles. When income and residence location are controlled, black (and to a lesser extent, Hispanic and poor) households have fewer vehicles regularly available than do comparable white or nonpoor households; moreover, these vehicles are older and larger and thus have significantly lower fuel economy. The net result is that average black, Hispanic, and poor households travel fewer miles per year but use more fuel than do average white and nonpoor households. Certain other findings - notably, that of significant racial differences in vehicle availability and use by low-income households - challenge the conventional wisdom that such racial variations arise solely because of differences in income and residence location. Results of the study suggest important differences - primarily in the yearly fluctuation of income - between black and white low-income households even when residence location is controlled. …
Date:
May 1, 1986
Creator:
Millar, M.; Morrison, R. & Vyas, A.
Object Type:
Report
System:
The UNT Digital Library
High-gain free electron lasers as generators of short wavelength coherent radiation
The development of coherent radiation in high-gain free electron lasers, either from initial noise or from low-power input radiation, is analyzed in terms of three-dimensional Maxwell-Klimontovich equations. Exponential growth and saturation, transverse radiation profiles, transverse coherence and spectral features are discussed. Two possible systems of high-gain free electron lasers, one based on a storage ring and by-pass, another based on a linac and damping rings, are considered for the generation of 400 A radiation.
Date:
May 1, 1986
Creator:
Kim, K. J. & Pellegrini, C.
Object Type:
Report
System:
The UNT Digital Library
Caldera processes and magma-hydrothermal systems continental scientific drilling program: thermal regimes, Valles caldera research, scientific and management plan
Long-range core-drilling operations and initial scientific investigations are described for four sites in the Valles caldera, New Mexico. The plan concentrates on the period 1986 to 1993 and has six primary objectives: (1) study the origin, evolution, physical/chemical dynamics of the vapor-dominated portion of the Valles geothermal system; (2) investigate the characteristics of caldera fill and mechanisms of caldera collapse and resurgence; (3) determine the physical/chemical conditions in the heat transfer zone between crystallizing plutons and the hydrothermal system; (4) study the mechanism of ore deposition in the caldera environment; (5) develop and test high-temperature drilling techniques and logging tools; and (6) evaluate the geothermal resource within a large silicic caldera. Core holes VC-2a (500 m) and VC-2b (2000 m) are planned in the Sulphur Springs area; these core holes will probe the vapor-dominated zone, the underlying hot-water-dominated zone, the boiling interface and probable ore deposition between the two zones, and the deep structure and stratigraphy along the western part of the Valles caldera fracture zone and resurgent dome. Core hole VC-3 will involve reopening existing well Baca number12 and deepening it from 3.2 km (present total depth) to 5.5 km, this core hole will penetrate the deep-crystallized silicic pluton, …
Date:
May 1, 1986
Creator:
Goff, F. & Nielson, D.L. (eds.)
Object Type:
Report
System:
The UNT Digital Library
Ohm's law for mean magnetic fields
The magnetic fields associated with plasmas frequently exhibit small amplitude MHD fluctuations. It is useful to have equations for the magnetic field averaged over these fluctuations, the so-called mean field equations. Under very general assumptions it is shown that the effect of MHD fluctuations on a force-free plasma can be represented by one parameter in Ohm's law, which is effectively the coefficient of electric current viscosity.
Date:
May 1, 1986
Creator:
Boozer, A. H.
Object Type:
Report
System:
The UNT Digital Library
Deflection by the image current and charges of a beam scraper
Scrapers are often used in storage rings and accelerators to clean the transverse profile of the beam. When the beam is not exactly midway between the jaws of the scraper the transverse electric and magnetic fields produced by the image charges and currents are asymmetric. For a relativistic beam traveling through a longitudinally uniform tube with infinitely conducting walls the transverse force from the electric field is canceled by the transverse force from the magnetic field. When an off-center particle bunch passes by a longitudinal discontinuity in the beam tube the transverse force from the electric field are no longer cancelled by the transverse force from the magnetic field and particles in the bunch experience a transverse momentum kick which is independent of energy. It is shown that scrapers that pass close by high peak current beams can significantly degrade the beam emittance. A circular scraper was chosen for computer simulation. (LEW)
Date:
May 1, 1986
Creator:
Bane, K. L. F. & Morton, P. L.
Object Type:
Article
System:
The UNT Digital Library
Radial Fokker-Planck model for plasmas confined by magnetic mirror fields
A time-dependent computer model has been developed for the spatially dependent distribution function f(r,v,t). An orbit averaged Fokker-Planck equation treats Coulomb collisions and various atomic physics processes. The motivation for the present code is to provide an accurate treatment of gyro-radius effects and realistic beam geometries which have been neglected in previous Fokker-Planck codes. Finite width beams may be offset from the plasma center to determine beam injection for build-up studies. The inclusion of a finite gyro-radius is essential for studying radial transport due to both quasilinear fluctuations and charge exchange collisions. Charge exchange with energetic beam atoms and plasma erosion due to charge-exchange collisions with thermal gas are both included. Quasilinear diffusion terms include the effects of turbulent diffusion in the model. The model has been used to study particle and energy confinement times in the 2XIIB experiment and in the mirror plug of the TMX experiment. Calculated values of T/sub e/ decrease from classical Fokker-Planck values (1000 eV for 2XIIB) to the 50 eV to 200 eV range observed in 2XIIB and TMX experiments. Radial density profiles and n tau scaling with plasma radius and magnetic field agree with experimental data.
Date:
May 1, 1986
Creator:
Futch, A.H.
Object Type:
Report
System:
The UNT Digital Library
Environmental assessment, Deaf Smith County site, Texas Volume II
The Nuclear Waste Policy Act of 1982 (42 USC sections 10101-10226) requires the environmental assessment of a proposed site to include a statement of the basis for nominating a site as suitable for characterization. Volume 2 provides a detailed statement evaluating the site suitability of the Deaf Smith County Site under DOE siting guidelines, as well as a comparison of the Deaf Smith County Site to the other sites under consideration. The evaluation of the Deaf Smith County Site is based on the impacts associated with the reference repository design, but the evaluation will not change if based on the Mission Plan repository concept. The second part of this document compares the Deaf Smith County Site to Davis Canyon, Hanford, Richton Dome and Yucca Mountain. This comparison is required under DOE guidelines and is not intended to directly support subsequent recommendation of three sites for characterization as candidate sites. 259 refs., 29 figs., 66 refs. (MHB)
Date:
May 1986
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Physics overview of the Fermilab Low Energy Antiproton Facility Workshop
A physics overview is presented of the Fermilab workshop to consider a possible high flux, low energy antiproton facility that would use cooled antiprotons from the accumulator ring of the Tevatron collider. Two examples illustrate the power of each a facility to produce narrow states at high rates. Physics topics to which such a facility may be applied are reviewed.
Date:
May 1, 1986
Creator:
Chanowitz, Michael S.
Object Type:
Article
System:
The UNT Digital Library
Quantification of neptunium by isotope dilution mass spectrometry
A surface ionization-diffusion-type ionization source that uses a rhenium filament overplated with platinum has been developed and optimized for 0.1-ng neptunium samples. This source is capable of measuring the neptunium content of nuclear-test-debris samples to 0.15% precision at the 95% confidence level. 14 refs., 3 figs., 3 tabs.
Date:
May 1, 1986
Creator:
Efurd, D. W.; Drake, J.; Roensch, F. R.; Cappis, J. H. & Perrin, R. E.
Object Type:
Report
System:
The UNT Digital Library
Materials erosion and redeposition studies at the PISCES-facility: net erosion under redeposition
Simultaneous erosion and redeposition of copper and 304 stainless steel under controlled and continuous plasma (D,He,Ar) bombardment has been investigated in the PISCES-facility, which generates typical edge-plasma conditions of magnetic fusion devices. The plasma bombardment conditions are: incident ion flux in the range from 10/sup 17/ to 10/sup 18/ ions/sec/cm/sup 2/, ion bombarding energy of 100 eV, electron temperature in the range from 5 to 15 eV, plasma density in the range from 10/sup 11/ to 10/sup 13/ cm/sup -3/, target temperature in the range from 300 to 900K, and the total ion fluence in the range from 10/sup 20/ to 10/sup 22/ ions/cm/sup 2/. The net erosion yield under redeposition is found to be significantly smaller than the classical sputtering yield data. A first-order modeling is attempted to interpret the erosion and redeposition behavior of materials under plasma bombardment. It is pointed out both theoretically and experimentally that the mean free path for electron impact ionization of the sputtered material is the key parameter to control the overall mechanism of erosion and redeposition. Strongly modified surface morphologies of bombarded targets are observed and indicate a retrapping effect.
Date:
May 1, 1986
Creator:
Hirooka, Y.; Goebel, D. M.; Conn, R. W.; Leung, W. K. & Campbell, G. A.
Object Type:
Article
System:
The UNT Digital Library
Beamstrahlung monitor for SLC final focus using gamma ray energies
Features of the beamstrahlung flux from the SLC interaction point are discussed, and intensity estimates given. A Cherenkov detector intended to monitor the flux is described.
Date:
May 1, 1986
Creator:
Bonvicini, G.; Field, C. & Minten, A.
Object Type:
Article
System:
The UNT Digital Library
Status of the SLC
The goals of the SLAC Linear Collider, SLC, are to develop the techniques of linear colliders and to do physics at and slightly above the energy necessary to produce the Z/sup 0/. A short review is given of the physics goals of the SLC, followed by the status of the SLC and its detectors. Plans for accelerating polarized electrons at SLC are also discussed. 6 figs. (LEW)
Date:
May 1, 1986
Creator:
Moffeit, K.C.
Object Type:
Article
System:
The UNT Digital Library
GENESIS Finite Element Mesh File Format
A new finite element mesh file format which provides a neutral interface from a mesh generation program to a finite element analysis program is described. The file format has been constructed to allow for multiple element types and flexible definition of boundary conditions. It provides for arbitrary element connectivity and attributes, so that continuum and structural elements can easily be accommodated in the same model. Element side boundary conditions as well as nodal point boundary conditions are supported. The file format is applicable to finite element models in any n-dimensional space. Both bandwidth and wavefront optimization schemes can be accommodated with the GENESIS file format. 1 ref.
Date:
May 1, 1986
Creator:
Taylor, L. M.; Flanagan, D. P. & Mills-Curran, W. C.
Object Type:
Report
System:
The UNT Digital Library
Heavy Ion Fusion Accelerator Research (HIFAR) half-year report, October 1, 1985-March 31, 1986
The HIFAR program addresses the generation of high-power, high-brightness beams of heavy ions, the understanding of the scaling laws in this novel physics regime, and the validation of new accelerator strategies, to cut costs. Key elements to be addressed include: (1) beam quality limits set by transverse and longitudinal beam physics; (2) development of induction accelerating modules, and multiple beam hardware, at affordable costs; (3) acceleration of multiple beams with current amplification - both new features in a linac - without significant dilution of the optical quality of the beams; (4) fianl bunching, transport, and accurate focussing on a small target.
Date:
May 1, 1986
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
High time resolution ion temperature profile measurements on PBX
Ion temperature profiles with a time resolution of 2 to 5 ms have been measured on PBX by charge-exchange-recombination spectroscopy (CXRS) and a neutral-particle charge-exchange analyzer (NPA). The sightlines of both diagnostics crossed the trajectory of a near-perpendicular heating beam, which enhanced the local neutral density (proportional to signal strength) and provided spatial resolution. The time resolution of these two independent techniques is sufficient to see sawtooth oscillations and other MHD activity. Effects of these phenomena on the toroidal rotation velocity profile, v/sub phi/(r), are clearly observed by CXRS. For example, a sharp drop in the central v/sub phi/ occurs at the sawtooth crash, followed by a linear rise during the quiescent phase. The NPA results are compared with those from CXRS.
Date:
May 1, 1986
Creator:
Gammel, G.; Kaita, R.; Fonck, R.; Jaehnig, K. & Powell, E.
Object Type:
Report
System:
The UNT Digital Library