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Effect of resonant microwave power on a PIG ion source. Revision (open access)

Effect of resonant microwave power on a PIG ion source. Revision

We have investigated the effect of applying microwave power at the electron cyclotron frequency on the characteristics of the ion beam extracted from a hot-cathode PIG ion source. No change was seen in the ion charge state distribution. A small but significant reduction in the beam noise level was seen, and it is possible that the technique may find application in situations where beam quiescence is important. 32 refs., 2 figs.
Date: August 1, 1984
Creator: Brown, I.G.; Galvin, J.E.; Gavin, B.F. & MacGill, R.A.
System: The UNT Digital Library
Neutron and gamma-ray dose measurements at various distances from the Little Boy replica (open access)

Neutron and gamma-ray dose measurements at various distances from the Little Boy replica

We measured neutron and gamma-ray dose rates at various distances from the Little Boy-Comet Critical Assembly at Los Alamos National Laboratory (LANL) in April of 1983. The Little Boy-Comet Assembly is a replica of the atomic weapon detonated over Hiroshima, designed to be operated at various steady-state power levels. The selected distances for measurement ranged from 107 m to 567 m. Gamma-ray measurements were made with a Reuter-Stokes environmental ionization chamber which has a sensitivity of 1.0 ..mu..R/hour. Neutron measurements were made with a pulsed-source remmeter which has a sensitivity of 0.1 ..mu..rem/hour, designed and built at Lawrence Livermore National Laboratory (LLNL). 12 references, 7 figures, 6 tables.
Date: August 1, 1984
Creator: Huntzinger, C.J. & Hankins, D.E.
System: The UNT Digital Library
O(18) revived (open access)

O(18) revived

We present an O(18) theory which is pertubatively unifiable and which accounts for the absence of right-handed families in the low-energy world. The model gives rise to dramatic predictions for proton decay and for the Z/sup 0/ width.
Date: August 1, 1984
Creator: Bagger, J.; Dimopoulos, S. & Masso, E.
System: The UNT Digital Library
Look at energy compression as an assist for high power rf production (open access)

Look at energy compression as an assist for high power rf production

The desire to construct electron linacs of higher and higher energies, coupled with the realities of available funding and real estate, has forced machine designers to reassess the limitations in both accelerator gradient (MeV/m) and energy. The gradients achieved in current radio-frequency (RF) linacs are sometimes set by electrical breakdown in the accelerating structure, but are in most cases determined by the RF power level available to drive the linac. In this paper we will not discuss RF power sources in general, but rather take a brief look at several energy compression schemes which might be of service in helping to make better use of the sources we employ. We will, however, diverge for a bit and discuss what the RF power requirements are. 12 references, 21 figures, 3 tables.
Date: August 9, 1984
Creator: Birx, D. L.; Farkas, Z. D. & Wilson, P. B.
System: The UNT Digital Library
Taus: a probe of new W and Z couplings (open access)

Taus: a probe of new W and Z couplings

If new heavier W's and/or Z's are discovered at the SSC, only partial information on their couplings to quarks and leptons can be obtained by studying their decays into electrons and muons. In particular, without polarized beams, one cannot distinguish between heavy W's which have left-handed (W/sub L/) or right-handed (W/sub R/) couplings to all fermions. Here, we study the tau decays of W/sub L/ and W/sub R/ and compute the distributions of the tau decay products. The most striking effect is W ..-->.. tau + N followed by tau ..-->.. ..pi.. nu/sub tau/; the pT distribution of the pion can distinguish W/sub L/ from W/sub R/ (without a measurement of the pion electric charge).
Date: August 1, 1984
Creator: Haber, H.E.
System: The UNT Digital Library
Structure of charged-current interactions (open access)

Structure of charged-current interactions

The status of the quark mixing matrix is reviewed. New lower bounds on absolute value of sin delta and on sin ..beta../sin THETA in the Maiani representation follow from a maximum top quark mass of 50 GeV. Recent data relevant to possible S, P, and T couplings are reviewed, and new results on muon decay parameters eta and delta are presented. A new measurement of xiP/sub ..mu../delta/rho by a different technique has confirmed the recently published stringent new limit. Constraints on a possible right-handed W and the effect of various assumptions concerning the associated right-handed neutrino are disucssed. 39 references.
Date: August 1, 1984
Creator: Strovink, M.
System: The UNT Digital Library
Coherent QCD radiation from active and spectator jets at the SSC (open access)

Coherent QCD radiation from active and spectator jets at the SSC

A gauge theory model is given which accounts for spectator jet radiation, interference effects between spectator and active jets, and coherence corrections when final state quark and gluon jets overlap. A simple Abelian complex color charge model can be used to mimic the QCD coherence effects.
Date: August 1, 1984
Creator: Brodsky, Stanley J.
System: The UNT Digital Library
Geometric Hamiltonian structures and perturbation theory (open access)

Geometric Hamiltonian structures and perturbation theory

We have been engaged in a program of investigating the Hamiltonian structure of the various perturbation theories used in practice. We describe the geometry of a Hamiltonian structure for non-singular perturbation theory applied to Hamiltonian systems on symplectic manifolds and the connection with singular perturbation techniques based on the method of averaging.
Date: August 1, 1984
Creator: Omohundro, S.
System: The UNT Digital Library
Energy minimization calculations for diamond (111) surface reconstructions (open access)

Energy minimization calculations for diamond (111) surface reconstructions

A remarkable variety of surface reconstructions occur on the (111) surfaces of the tetrahedral elements C, Si and Ge. A possible common denominator may be the occurrence of a similar 2 x 1 reconstruction on all three elemental surfaces. While clear 2 x 1 LEED patterns are observed for Si and Ge (111) surfaces, LEED cannot distinguish between a true 2 x 2 or disordered domains of 2 x 1 for the diamond (111) surface. However, the similarity of the angle-resolved photoemission (ARUPS) results for C, Si, and Ge suggests that a common 2 x 1 structure may be responsible. The 2 x 1 structure disappears upon annealing for Si and Ge but appears upon annealing for C, indicating that it may be thermodynamically stable only for C. Thus the study of the diamond 2 x 2/2 x 1 surface is of particular interest. Here, we report direct energy minimization calculations for these models. A first principles linear combination of atomic orbitals approach has been used to calculate total energies in the pseudopotential and local density (LDA) approximations. 27 refs., 3 figs., 2 tabs.
Date: August 1, 1984
Creator: Vanderbilt, D. & Louie, S.G.
System: The UNT Digital Library
Proceedings of the workshop on polarized targets in storage rings (open access)

Proceedings of the workshop on polarized targets in storage rings

Polarization phenomena have played an increasingly important part in the study of nuclei and nucleons in recent years. Polarization studies have been hampered by the relatively few and rather fragile polarized targets which are presently available. The concept of polarized gas targets in storage rings opens a much wider range of possibilities than is available in the external target geometry. This novel method will represent a considerable advance in nuclear physics and will continue to receive much attention in plans for future facilities. An internal, polarized-target station is being planned for the cooler ring at the Indiana University Cyclotron Facility. Internal targets are compatible with recent designs of electron accelerators proposed by the Massachusetts Institute of Technology and the Southeastern Universities Research Association. The key to nuclear-science programs based on internal targets pivots on recent developments in polarized atomic beam methods, which include the more recent laser-driven polarized targets. The workshop drew together a unique group of physicists in the fields of high-energy, nuclear and atomic physics. The meeting was organized in a manner that stimulated discussion among the 58 participants and focused on developments in polarized target technology and the underlying atomic physics. An impressive array of future possibilities …
Date: August 1, 1984
Creator: Holt, R.J. (ed.)
System: The UNT Digital Library
Z/sup 0/ decay modes - experimental measurements (open access)

Z/sup 0/ decay modes - experimental measurements

This report summarizes three lectures given at the Theoretical Advanced Study Institute at the University of Michigan at Ann Arbor. The lectures begin with an introduction to storage rings and linear colliders with special reference to the parameters of the SLC and LEP. The rigors of the Z/sup 0/ environment are presented along with the requirements for SLC and LEP detectors. The pedagogy needed for testing the Standard Model is developed, and some experimental tests of the Standard Model are discussed. Tests which involve extensions of the Standard Model (charged Higgs particles, more generations) as well as a few examples of how supersymmetry may show up at the Z/sup 0/ are discussed. 25 references, 34 figures. (WHK)
Date: August 1, 1984
Creator: Dorfan, J. M.
System: The UNT Digital Library
Stability in dynamical systems I (open access)

Stability in dynamical systems I

We have reviewed some of the basic techniques which can be used to analyze stability in nonlinear dynamical systems, particularly in circular particle accelerators. We have concentrated on one-dimensional systems in the examples in order to simply illustrate the general techniques. We began with a review of Hamiltonian dynamics and canonical transformations. We then reviewed linear equations with periodic coefficients using the basic techniques from accelerator theory. To handle nonlinear terms we developed a canonical perturbation theory. From this we calculated invariants and the amplitude dependence of the frequency. This led us to resonances. We studied the cubic resonance in detail by using a rotating coordinate system in phase space. We then considered a general isolated nonlinear resonance. In this case we calculated the width of the resonance and estimated the spacing of resonances in order to use the Chirikov criterion to restrict the validity of the analysis. Finally the resonance equation was reduced to the pendulum equation, and we examined the motion on a separatrix. This brought us to the beginnings of stochastic behavior in the neighborhood of the separatrix. It is this complex behavior in the neighborhood of the separatrix which causes the perturbation theory used here to …
Date: August 1, 1984
Creator: Courant, E. D.; Ruth, R. D. & Weng, W. T.
System: The UNT Digital Library
Workshop on detectors for relativistic nuclear collisions: proceedings (open access)

Workshop on detectors for relativistic nuclear collisions: proceedings

Separate abstracts were prepared for ten papers in this proceedings. Two other papers in the proceedings had been previously indexed for EDB. (LEW)
Date: August 1, 1984
Creator: unknown
System: The UNT Digital Library
Detectors for high energy nucleus-nucleus collisions. [Workshop review] (open access)

Detectors for high energy nucleus-nucleus collisions. [Workshop review]

The Workshop on Detectors for Relativistic Nuclear Collisions, held March 26 to 30, 1984, at the Lawrence Berkeley Laboratory is reviewed. 21 references. (WHK)
Date: August 1, 1984
Creator: Schroeder, L. S.
System: The UNT Digital Library
Facilities for studying radiation damage in nonmetals during irradiation (open access)

Facilities for studying radiation damage in nonmetals during irradiation

Two facilities have been developed for making optical absorption, luminescence and other measurements on a single sample before, during and after irradiation. One facility uses /sup 60/Co gamma rays and the other 0.5 to 3 MeV electrons from an accelerator. Optical relays function as spectrophotometers, luminescenc detectors, etc. All radiation sensitive components are outside of walk-in irradiation chambers; all measurement control and data recording is computerized. Irradiations are made at controlled temperatures between 5K and 900/sup 0/C. The materials studied include glasses, quartz, alkali halides (especially natural rock salt), organic crystals, etc. As determined from color center measurements the damage formation rate in all materials studied at 25/sup 0/C or above is strongly temperature dependent. The defect concentration during irradiation is usually much greater than that measured after irradiation. The fraction of defects annealing after irradiation and the annealing rate usually increases as the irradiation temperature increases. The completed studies demonstrate that, in most cases, the extent of maximum damage and the damage formation and annealing kinetics can be determined only by making measurements during irradiation.
Date: August 1, 1984
Creator: Levy, P.W.
System: The UNT Digital Library
Ab initio calculations of the optical properties of ions in glass (open access)

Ab initio calculations of the optical properties of ions in glass

There is interest in the optical properties of ions in insulating glasses for various applications. This paper addresses the task of predicting optical properties of ions in glass from first principles given only the physics of the constituent atoms. The prospects for developing such ab initio-computation procedures are gleaned from examining the progress made in understanding the properties of dopant ions in crystals. It is probable that in 20 years, there will be reliable procedures for predicting optical properties of ions in crystals, but the development of corresponding procedures for complex glasses is a herculean task. The use of computer simulations is addressed. (DLC)
Date: August 1, 1984
Creator: Weber, M. J.
System: The UNT Digital Library
Total energy calculations and bonding at interfaces (open access)

Total energy calculations and bonding at interfaces

Some of the concepts and theoretical techniques employed in recent ab initio studies of the electronic and structural properties of surfaces and interfaces are discussed. Results of total energy calculations for the 2 x 1 reconstructed diamond (111) surface and for stacking faults in Si are reviewed. 30 refs., 8 figs.
Date: August 1, 1984
Creator: Louie, S.G.
System: The UNT Digital Library
CSNI specialist meeting on leak-before-break in nuclear reactor piping: proceedings (open access)

CSNI specialist meeting on leak-before-break in nuclear reactor piping: proceedings

On September 1 and 2, 1983, the CSNI subcommittee on primary system integrity held a special meeting in Monterey, California, on the subject of leak-before-break in nuclear reactor piping systems. The purpose of the meeting was to provide an international forum for the exchange of ideas, positions, and research results; to identify areas requiring additional research and development; and to determine the general attitude toward acceptance of the leak-before-break concept. The importance of the leak-before-break issue was evidenced by excellent attendance at the meeting and through active participation by the meeting attendees. Approximately 125 people representing fifteen different nations attended the meeting. The meeting was divided into four technical sessions addressing the following areas: Application of Piping Fracture Mechanics to Leak-Before Break, Leak Rate and Leak Detection, Leak-Before-Break Studies, Methods and Results, Current and Proposed Positions on Leak-Before-Break.
Date: August 1, 1984
Creator: unknown
System: The UNT Digital Library
Radiation field associated with Hiroshima and Nagasaki (open access)

Radiation field associated with Hiroshima and Nagasaki

Accuracy of dosimetric estimates can determine the value of the atomic bomb survivor experience in establishing radiation risks. The status of a major revision of this dosimetry, initiated in 1980, is assessed. 3 references, 6 figures.
Date: August 1, 1984
Creator: Loewe, W.E.
System: The UNT Digital Library
Infrared and neutron scattering studies of ethene adsorbed onto partially exchanged zinc A zeolite (open access)

Infrared and neutron scattering studies of ethene adsorbed onto partially exchanged zinc A zeolite

Infrared and inelastic neutron scattering studies of ethene adsorbed onto ZnNaA zeolite show that the adsorbed molecule occupies a single adsorption site. The C-H streching modes are not observed in the infrared data but are seen as a broad band in the neutron spectrum. Some low frequency adsorbate-adsorbent modes are assigned.
Date: August 1, 1984
Creator: Howard, J.; Nicol, J.M. & Eckert, J.
System: The UNT Digital Library
Hypermultiplet couplings in N = 2 supergravity (open access)

Hypermultiplet couplings in N = 2 supergravity

An arbitrary number of massless spin (0,/sup 1///sub 2/) multiplets are coupled to N = 2 supergravity, and the scalar fields are found to lie on a negatively curved quaternionic manifold. 6 references.
Date: August 1, 1984
Creator: Bagger, J.
System: The UNT Digital Library
Advances in HTGR spent fuel treatment technology (open access)

Advances in HTGR spent fuel treatment technology

GA Technologies, Inc. has been investigating the burning of spent reactor graphite under Department of Energy sponsorship since 1969. Several deep fluidized bed burners have been used at the GA pilot plant to develop graphite burning techniques for both spent fuel recovery and volume reduction for waste disposal. Since 1982 this technology has been extended to include more efficient circulating bed burners. This paper includes updates on high-temperature gas-cooled reactor fuel cycle options and current results of spent fuel treatment testing for fluidized and advanced circulating bed burners.
Date: August 1, 1984
Creator: Holder, N. D. & Lessig, W. S.
System: The UNT Digital Library
Seismic risk assessment as applied to the Zion Nuclear Generating Station (open access)

Seismic risk assessment as applied to the Zion Nuclear Generating Station

To assist the US Nuclear Regulatory Commission (NRC) in its licensing and evaluation role, the NRC funded the Seismic Safety Margins Research Program (SSMRP) at Lawrence Livermore National Laboratory (LLNL) with the goal of developing tools and data bases to evaluate the risk of earthquake caused radioactive release from a commercial nuclear power plant. This paper describes the SSMRP risk assessment methodology and the results generated by applying this methodology to the Zion Nuclear Generating Station. In addition to describing the failure probabilities and risk values, the effects of assumptions about plant configuration, plant operation, and dependence will be given.
Date: August 1, 1984
Creator: Wells, J.
System: The UNT Digital Library
Pulsed rf superconductivity program at SLAC (open access)

Pulsed rf superconductivity program at SLAC

Recent tests performed at SLAC on superconducting TM/sub 010/ caavities using short rf pulses (less than or equal to 2.5 ..mu..s) have established that at the cavity surface magnetic fields can be reached in the vicinity of the theoretical critical fields without an appreciable increase in average losses. Tests on niobium and lead cavities are reported. The pulse method seems to be best suited to study peak field properties of superconductors in the microwave band, without the limitations imposed by defects. The short pulses also seem to be more effective in decreasing the causes of field emission by rf processing. Applications of the pulsed rf superconductivity to high-gradient linear accelerators are also possible.
Date: August 1, 1984
Creator: Campisi, I. E. & Farkas, Z. D.
System: The UNT Digital Library