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New method for positron production at SLAC

Description: The focusing system for the positron beam at SLAC makes use of an adiabatically tapered solenoid whose transverse acceptance remains high over a broad energy band. From the computed distribution in energy of the accepted positrons, one can estimate that approximately one-half of the total number of positrons lies within the energy band from 2 - 4 MeV. Due to the debunching effect over the drift space following the target, only the high energy part (from 4.5 MeV to 10 MeV or more) of the accepte… more
Date: September 1, 1979
Creator: Aune, B. & Miller, R. H.
Partner: UNT Libraries Government Documents Department
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High Angle Grain Boundaries as Sources or Sinks for Point Defects

Description: A secondary grain boundary dislocation climb model for high angle grain boundaries as sources/sinks for point defects is described in the light of recent advances in our knowledge of grain boundary structure. Experimental results are reviewed and are then compared with the expected behavior of the proposed model. Reasonably good consistency is found at the level of our present understanding of the subject. However, several gaps in our present knowledge still exist, and these are identified and … more
Date: September 1, 1979
Creator: Balluffi, R.W.
Partner: UNT Libraries Government Documents Department
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Impact of higher twist terms on the analysis of scaling violation

Description: A critical discussion is given of analyses of scaling violation in deep-inelastic scattering in the context of QCD. Several possible approaches are examined. Higher twist contributions are defined, and it is shown that they can have a crucial impact on tests of QCD. Higher twist terms can dramatically affect R = sigma/sub L//sigma/sub T/. QCD may be harder to test than previously realized. 17 references.
Date: September 1, 1979
Creator: Barnett, R. Michael
Partner: UNT Libraries Government Documents Department
open access

Organohalogen production from chlorination of natural waters under simulated biofouling control conditions

Description: In order to develop information concerning the range of organohalogen products to be expected from low-level chlorination practices, such as those used for biofouling control in electricity generating plants, the organic chlorination chemistry of natural waters have been investigated at 10 locations in the continental United States. The specific objective of our investigations was to document the formation of organohalogen material which by virtue of acutely toxic properties or bioaccumulation … more
Date: September 1, 1979
Creator: Bean, R. M.; Mann, D. C.; Wilson, B. W.; Riley, R. G.; Lusty, E. W. & Thatcher, T. O.
Partner: UNT Libraries Government Documents Department
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Case studies in perturbative quantum chromodynamics

Description: A few aspects of QCD are discussed, beginning with a discussion of the ingredients of QCD and their observational basis. A pedagogical treatment of scaling violations is presented and the argument is presented that while entirely consistent with QCD, the phenomenological situation is clouded by the potentially crucial role of higher twist effects in the theory. Some explicit calculations of higher twist effects are presented.
Date: September 1, 1979
Creator: Berger, E. L.
Partner: UNT Libraries Government Documents Department
open access

Representative-vector method for calculating operator-moments

Description: The utility of operator-moments or traces in the various applications of spectral-distribution theory is well documented. To take full advantage of the powerful entree that spectral distribution theory offers in nuclear physics, it may be generally necessary to have many moments beyond th first two hamiltonian moments <H> and <H/sup 2/>. In order to calculate, for one example, level densities reliably in the excitation-energy regions of physical interest, it may be necessary to have the moments… more
Date: September 1, 1979
Creator: Bloom, S.D. & Hausman, R.F. Jr.
Partner: UNT Libraries Government Documents Department
open access

RF magnetron sputtering of thick film amorphous beryllium

Description: Thick film coatings of beryllium, needed for the low-Z ablator layer in proposed laser fusion targets, have been prepared using high rate magnetron rf sputtering. The requirements for these Be coatings include thicknesses from 5 to 50 ..mu..m, complete freedom from surface defects, and an average surface roughness of 100 nm or less. We have sputtered very smooth, dense, thick Be films with surface roughness less than 100 nm. X-ray diffraction analysis of impurity doped films indicates an amorph… more
Date: September 19, 1979
Creator: Burt, R. J.; Meyer, S. F. & Hsieh, E. J.
Partner: UNT Libraries Government Documents Department
open access

Diagnostic measurements related to laser driven inertial confinement fusion

Description: Scientists at the Lawrence Livermore Laboratory have been conducting laser driven inertial confinement fusion experiments for over five years. The first proof of the thermonuclear burn came at the Janus target irradiation facility in the spring of 1975. Since that time three succeedingly higher energy facilities have been constructed at Livermore, Cyclops, Argus and Shiva, where increased fusion efficiency has been demonstrated. A new facility, called Nova, is now in the construction phase and … more
Date: September 11, 1979
Creator: Campbell, D.E.
Partner: UNT Libraries Government Documents Department
open access

Studies of isospin quintets and neutron-deficient indium isotopes with the on-line mass analysis system RAMA

Description: The success of the isobaric multiplet mass equation in relating mass excesses of members of light isospin quarters has permitted it to pay a significant role in predicting ground state masses of highly proton-rich 1f2p shell nuclides. An overview is given of an experimental program that was developed to study the most proton-rich members of high-isospin multiplets through radioactive decay. An instrument known as RAMA, for Recoil Atom Mass Analyzer, was constructed and is briefly described. Exp… more
Date: September 1, 1979
Creator: Cerny, J.; Aysto, J.; Cable, M. D.; Haustein, P. E.; Moltz, D. M.; von Dincklage, R. D. et al.
Partner: UNT Libraries Government Documents Department
open access

Influence of nuclear data uncertainties on thorium fusion-fission hybrid blanket nucleonic performance

Description: The fusion-fission hybrid blanket proposed for the Tandem Mirror Hybrid Reactor employs thorium metal as the fertile material. Based on the ENDF/B-IV nuclear data, the /sup 233/U and tritium production rate and blanket energy multiplication averaged over the blanket lifetime of about 9 MW-yr/m/sup 2/ are 0.76 and 1.12 per D-T neutron and 4.8, respectively. At the time of the blanket discharge, the /sup 233/U enrichment in the thorium metal is about 3%. The thorium cross sections given by the EN… more
Date: September 1, 1979
Creator: Cheng, E.T. & Mathews, D.R.
Partner: UNT Libraries Government Documents Department
open access

Recent progress in ion sources and preaccelerators

Description: Recent progress in ion sources is reviewed. The types of sources discussed include positive and negative proton and deuteron sources developed for conventional preaccelerators and for neutral beam applications. Positive heavy ion sources for conventional linacs and for induction linacs are included. Negative heavy ion sources are used for tandem electrostatic accelerators. Positive and negative polarized ion sources for protons and deuterons inject cyclotrons, tandems, and linacs. Some recent p… more
Date: September 1, 1979
Creator: Clark, D. J.
Partner: UNT Libraries Government Documents Department
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Use of time averaged precipitation for wet removal in a regional air pollution assessment model

Description: 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 precip… more
Date: September 1, 1979
Creator: Davis, W. E. & Eadie, W. J.
Partner: UNT Libraries Government Documents Department
open access

Particle acceleration with TE/sub 011/ cavity

Description: Presently, the maximum effective electric field, E/sub a/, in an accelerating structure is limited by the available peak rf power. If the structure is superconducting, the peak power requirements are reduced by several orders of magnitude but E/sub a/ is limited by electron loading caused by surface electric fields. A right circular cylinder TE/sub 011/ cavity has no surface electric fields and therefore, E/sub a/ is not limited by electron loading but can reach a much higher value which is lim… more
Date: September 1, 1979
Creator: Farkas, Z. D.
Partner: UNT Libraries Government Documents Department
open access

Progress in mirror machine research

Description: The Mirror Fusion Program in the US is now focused on two concepts that can obtain high values of the power gain factor Q. These are the tandem mirror and field reversed mirror concepts. A new facility called TMX has been constructed to test the principles of the tandem mirror. A further attempt to create field reversal is being carried out in the 2XIIB facility (renamed Beta II) with neutral beam injection into a reversed-field target plasma to be created by a magnetized coaxial gun. During th… more
Date: September 11, 1979
Creator: Fowler, T. K. & Coensgen, F. H.
Partner: UNT Libraries Government Documents Department
open access

Bioaccumulation and depuration of bromoform in five marine species

Description: Bromoform has been identified as the major halogenated organic compound resulting from the chlorination of seawater. To test the potential for bioconcentration and subsequent return to man, 28-day uptake/28-day depuration studies were conducted with five commercially and recreationally important species (Protothaca staminea, Mercenaria mercenaria, Crassostrea virginica, Penaeus aztecus, Brevoortia tyrannus). The results indicate that for these species, the uptake and depuration is rapid (equili… more
Date: September 1, 1979
Creator: Gibson, C. I.; Tone, F. C.; Schirmer, R. E. & Blaylock, J. W.
Partner: UNT Libraries Government Documents Department
open access

Transient annealing of GaAs by electron and laser beams

Description: Results of pulsed electron beam and ruby laser irradiations of high- and low-dose implanted layers in GaAs were studied. Ruby laser and electron beam irradiations result in peak concentrations higher than can be obtained in furnace annealing. Mobilities after transient annealing are usually lower as compared to conventional annealing. Implantation at doses below the 10/sup 13/ cm/sup -2/ level show poor or no electrical activity after transient annealing. (FS)
Date: September 1, 1979
Creator: Golecki, I.; Nicolet, M. A.; Tandon, J. L.; Ashbeck, P. M.; Sadana, D. K. & Washburn, J.
Partner: UNT Libraries Government Documents Department
open access

Calculation of spin cutoff parameters using moment techniques

Description: Spectral distribution methods are often applied to the calculation of nuclear level densities. If their distribution in spin is required in addition to the total number of levels at each energy, the spin-cutoff parameter and its energy dependence must be known. Recent calculations of the spin-cutoff parameters have shown qualitative agreement with data. Reasons for the remaining discrepancies are discussed, and proecdures for improving agreement between theory and experiment are suggested. 8 fi… more
Date: September 1, 1979
Creator: Grimes, S.M.
Partner: UNT Libraries Government Documents Department
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Limits of thermodynamic models for nuclear level densities. [Review]

Description: The current status of thermodynamic models as applied to nuclear level densities is reviewed. Considerable refinement has taken place during the last fifteen years, with the result that some of the undesirable assumptions originally required by the model are no longer necessary. Some problems remain, however, particularly in calculating level densities for deformed nuclei. Furthermore, some related parameters, such as the positive-parity negative-parity ratio for levels and the spin cutoff para… more
Date: September 1, 1979
Creator: Grimes, S.M.
Partner: UNT Libraries Government Documents Department
open access

Direct imaging of grain boundaries

Description: There are currently two types of microscopes which, in principle, are capable of imaging atom positions at grain boundaries. One, the field ion microscope (FIM), yields a projection of the specimen surface (approximately stereographic) by field ionization of an imaging gas at protruding atom sites, and provides topographic information in high-index pole regions which may be interpreted atom-by-atom. The other, a transmission electron microscope (TEM), yields a projection (approximately linear) … more
Date: September 1, 1979
Creator: Gronsky, R.
Partner: UNT Libraries Government Documents Department
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Preferential acceleration in collisionless supernova shocks

Description: The preferential acceleration and resulting cosmic ray abundance enhancements of heavy elements (relative to protons) are calculated in the collisionless supernova shock acceleration model described by Eichler in earlier work. Rapidly increasing enhancements up to several tens times solar ratios are obtained as a function of atomic weight over charge at the time of acceleration. For material typical of hot phase interstellar medium, good agreement is obtained with the observed abundance enhance… more
Date: September 11, 1979
Creator: Hainebach, K.; Eichler, D. & Schramm, D.
Partner: UNT Libraries Government Documents Department
open access

Defects in germanium: new results and novel methods

Description: Recent results obtained from quenching experiments, electron, gamma-ray, neutron and proton irradiation of germanium are reviewed. Major emphasis is given to the introduction of novel techniques for the study of shallow and deep levels. Explicitly introduced are Photothermal Ionization Spectroscopy (also called Photoelectric Spectroscopy), Deep level Transient Spectroscopy and High-Q Electron Paramagnetic Resonance. Using as examples the recently discovered hydrogen-related centers and the lith… more
Date: September 1, 1979
Creator: Haller, E.E.
Partner: UNT Libraries Government Documents Department
open access

Shielding consideration for a deuteron activated liquid lithium system

Description: A parametric study was conducted to evaluate the potential shielding implication due to the /sup 7/Be plateout on the lithium piping in the FMIT facility. Various parameters such as plateout percentage, hot flush efficiency and /sup 7/Be trapping efficiency were varied to assess the overall shielding requirement relationship. The /sup 7/Be plateout was found to place severe limitations on the hands-on maintenance access. Hot flush and /sup 7/Be traps are effective ways of minimizing the /sup 7/… more
Date: September 1, 1979
Creator: Huang, S. T.; Shapiro, A. M.; Lee, J. B. & Miller, W. C.
Partner: UNT Libraries Government Documents Department
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