Advances in inherently conducting polymers (open access)

Advances in inherently conducting polymers

The discovery of polyacetylene as the prototype material led to extensive research on its synythesis and characterization. The techniques that emerged as the most important and promising ones are those that dealt with molecular orientation and that resulted in conductivities almost as high as that of copper. The study of dozens of other materials followed. Interest in conducting polymers stems from their nonclassical optical and electronic properties as well as their potential technological applications. However, some of the factors currently limiting their use are the lack of long-term stability and the need to develop conventional low-cost techniques for easy processing. Therefore, research was extended toward solving these problems, and progress has been recently made in that direction. The synthesis of new materials such as stable and easily processable alkylthiophenes, water-soluble polymers, and multicomponent systems, including copolymers and composites, constitutes an important step forward in the area of synthetic metals. However, a full understanding of materials chemistry and properties requires more work in the years to come. Although, few small-scale applications have proven to be successful, long-term stability and applicability tests are needed before their commercial use becomes reality.
Date: September 1, 1987
Creator: Aldissi, M.
System: The UNT Digital Library
Analysis of exposure due to work on activated components (open access)

Analysis of exposure due to work on activated components

In this brief note the author summarized analysis of the exposure incurred in various maintenance jobs involving activated accelerator and beam line components at Fermilab. A tabulation was made of parameters associated with each job. Included are rather terse descriptions of the various tasks. The author presented various plots of the quantities in the table. All exposure rates are mR/hr while all exposures accumulated are mR. The exposure rates were generally measured at the Fermilab standard one foot distance from the activated component. Accumulated exposures are taken from the self-reading pocket dosimeter records maintained by the radiation control technicians.
Date: September 1, 1987
Creator: Cossairt, J.D.
System: The UNT Digital Library
Analysis of the orbit errors in the CERN accelerators using model simulation (open access)

Analysis of the orbit errors in the CERN accelerators using model simulation

This paper will describe the use of the PLUS program to find various types of machine and beam errors such as, quadrupole strength, dipole strength, beam position monitors (BPMs), energy profile, and beam launch. We refer to this procedure as the GOLD (Generic Orbit and Lattice Debugger) Method which is a general technique that can be applied to analysis of errors in storage rings and transport lines. One useful feature of the Method is that it analyzes segments of a machine at a time so that the application and efficiency is independent of the size of the overall machine. Because the techniques are the same for all the types of problems it solves, the user need learn only how to find one type of error in order to use the program.
Date: September 1, 1987
Creator: Lee, M.; Kleban, S.; Clearwater, S.; Scandale, W.; Pettersson, T.; Kugler, H. et al.
System: The UNT Digital Library
Application of Radio Frequency Superconductivity to Recirculating Linacs. (open access)

Application of Radio Frequency Superconductivity to Recirculating Linacs.

The recirculating linear accelerators discussed in this paper are continuous wave devices used to accelerate electrons. Recirculation through the RF accelerating structures is used because it reduces both capital and operating (electric power) costs. Such accelerators are used, at present, for two purposes: nuclear physics and free electron laser drivers.
Date: September 1, 1987
Creator: Sundelin, Ronald
System: The UNT Digital Library
Application of state-multipole Heisenberg equations to Raman excitation dynamics (open access)

Application of state-multipole Heisenberg equations to Raman excitation dynamics

Description of detailed temporal excitation dyanmics for coherent excitation, such as is produced by idealized laser radiation, contrasts with evaluation of rate coefficients by means of generalized Golden Rule procedures; it requires an appropriate time-dependent Schroedinger equation. When the atom undergoing excitation is also affected by incoherent processes, such as collisions, this equation no longer suffices. The Heisenberg equations, or equivalent density-matrix equations, permit treatment in which coherence and incoherence play comparable roles in the excitation dynamics. Unlike rate equations, such equations must incorporate complexities that originate in the orientation degeneracy expressed by magnetic quantum numbers. In simple cases of coherent excitation, both for single-photon and multiphoton excitation, the sublevels merely require an average of 2J+1 independent Schroedinger equations. Relaxation couples the independent equations. It has been known for some time that appropriate state-multipole operators can simplify the description of many phenomena connected with optical pumping. This memo discusses application of these multipole operators to the description of Raman (or more general multiphoton) coherent excitation. In some simple limiting cases the equations simplify, but in general one has a hierarchy of coupled multipole polarizations and coherences in place of the populations and coherences that occur as variables in nondegenerate systems. …
Date: September 10, 1987
Creator: Shore, B. W.; Sacks, R. & Dixit, S. N.
System: The UNT Digital Library
Atmospheric and climatic consequences of a major nuclear war: Results of recent research (open access)

Atmospheric and climatic consequences of a major nuclear war: Results of recent research

During the last several years, comprehensive three-dimensional atmospheric circulation models, including detailed parametric formulations of a wide range of climatologically significant processes, have been applied to study the potential consequences of a major nuclear war involving the injection of smoke which could result from the large-scale fires ignited by such an exchange. For plausible smoke injections during the warm season of the year, all model calculations suggest that a significant climatic perturbation would result. In the lower range of smoke injection scenarios (producing of order 10 Tg of highly carbonaceous smoke), smoke would act primarily to inhibit convection and rainfall, especially over land areas, including possibly some disruption of the summer monsoon. The upper range of smoke scenarios (of order 100 Tg of highly carbonaceous smoke) would cause not only rapid and sharp decreases in land temperature and precipitation (a mid-latitude average land-temperature drop of the order of 20/sup 0/C, up to perhaps twice this amount in continental interiors), but also seems likely to leave enough smoke in the atmosphere to persist into the following warm season, inducing a cooling of several degrees.
Date: September 1, 1987
Creator: Golitsyn, G.S. & MacCracken, M.C.
System: The UNT Digital Library
Beam dynamics issues for linear colliders (open access)

Beam dynamics issues for linear colliders

In this paper we discuss various beam dynamics issues for linear colliders. The emphasis is to explore beam dynamics effects which lead to an effective dilution of the emittance of the beam and thus to a loss of luminosity. These considerations lead to various tolerances which are evaluated for a particular parameter set.
Date: September 1, 1987
Creator: Ruth, R. D.
System: The UNT Digital Library
Beta-delayed two-proton emission as a nuclear probe (open access)

Beta-delayed two-proton emission as a nuclear probe

A brief history of beta-delayed two-proton emission is given. Speculations about future experiments which would enhance our knowledge about both nuclear spectroscopy and this relatively unique decay mode are presented. 16 refs., 7 figs.
Date: September 1, 1987
Creator: Moltz, D. M.; Reiff, J. E.; Robertson, J. D.; Lang, T. F. & Cerny, J.
System: The UNT Digital Library
Bottom and Top Physics (open access)

Bottom and Top Physics

The production of bottom quarks at the SSC and the formalism and phenomenology of observing CP violation in B meson decays is discussed. The production of a heavy t quark which decays into a real W boson, and what we might learn from its decays is examined.
Date: September 1, 1987
Creator: Foley, K. J.; Fridman, A.; Gilman, F. J.; Herten, G.; Hinchliffe, I.; Jawahery, A. et al.
System: The UNT Digital Library
Calculation of radial and vertical forces on the CIT 1. 75 m vacuum vessel for several TSC disruption scenarios (open access)

Calculation of radial and vertical forces on the CIT 1. 75 m vacuum vessel for several TSC disruption scenarios

The report consists of viewgraphs. (WRF)
Date: September 15, 1987
Creator: Sayer, R.O.
System: The UNT Digital Library
Cermet fuel reactors (open access)

Cermet fuel reactors

Cermet fueled nuclear reactors are attractive candidates for high performance space power systems. The cermet fuel consists of tungsten-urania hexagonal fuel blocks characterized by high strength at elevated temperatures, a high thermal conductivity and resultant high thermal shock resistance. Key features of the cermet fueled reactor design are (1) the ability to achieve very high coolant exit temperatures, and (2) thermal shock resistance during rapid power changes, and (3) two barriers to fission product release - the cermet matrix and the fuel element cladding. Additionally, thre is a potential for achieving a long operating life because of (1) the neutronic insensitivity of the fast-spectrum core to the buildup of fission products and (2) the utilization of a high strength refractory metal matrix and structural materials. These materials also provide resistance against compression forces that potentially might compact and/or reconfigure the core. In addition, the neutronic properties of the refractory materials assure that the reactor remains substantially subcritical under conditions of water immersion. It is concluded that cermet fueled reactors can be utilized to meet the power requirements for a broad range of advanced space applications. 4 refs., 4 figs., 3 tabs.
Date: September 1, 1987
Creator: Cowan, C. L.; Palmer, R. S.; Van Hoomissen, J. E.; Bhattacharyya, S. K. & Barner, J. O.
System: The UNT Digital Library
Channeling and dechanneling at high energy (open access)

Channeling and dechanneling at high energy

The possibility of using channeling as a tool for high energy particle physics has now been extensively investigated. Bent crystals have been used as an accelerator extraction element and for particle deflection. Applications as accelerating devices have been discussed but appear remote. The major advantage in using a bent crystal rather than a magnet is the large deflection that can be achieved in a short length. The major disadvantage is the low transmission. A good understanding of dechanneling is important for applications. 43 refs., 1 fig., 3 tabs.
Date: September 30, 1987
Creator: Carrigan, R. A., Jr.
System: The UNT Digital Library
Chaotic dynamics in dense fluids (open access)

Chaotic dynamics in dense fluids

We present calculations of the full spectra of Lyapunov exponents for 8- and 32-particle systems with periodic boundary conditions and interacting with the repulsive part of a Lennard-Jones potential both in equilibrium and nonequilibrium steady states. Lyapunov characteristic exponents lambda/sub n/ describe the mean exponential rates of divergence and convergence of neighbouring trajectories in phase-space. They are useful in characterizing the stochastic properties of a dynamical system. A new algorithm for their calculation is presented which incorporates ideas from control theory and constraint nonequilibrium molecular dynamics. 4 refs., 1 fig.
Date: September 1, 1987
Creator: Posch, H. A. & Hoover, W. G.
System: The UNT Digital Library
Charge state evolution in an ion trap irradiated by VUV synchrotron radiation (open access)

Charge state evolution in an ion trap irradiated by VUV synchrotron radiation

The energies of photons obtainable from the VUV ring at the National Synchrotron Light Source (NSLS) are ideally suited for high-efficiency ionization of atomic outer-shell electrons. Given the high fluxes of photons available on a wiggler beam line, multiple photoionization in an ion trap can be easily achieved within times short compared to typical ion storage times in the trap. Measurements of the time evolution of ion populations in such a trap can yield ionic photoionization cross sections and charge-exchange interaction rates for ion-atom or ion-ion collisions. The various processes governing this time evolution are discussed and model calculations illustrating the relative importance of these processes under different conditions are presented. 8 refs., 5 figs., 1 tab.
Date: September 1, 1987
Creator: Meron, M.; Johnson, B. M.; Jones, K. W. & Church, D. A.
System: The UNT Digital Library
Charm Hadroproduction Results From Fermilab E-400 (open access)

Charm Hadroproduction Results From Fermilab E-400

Results are presented from Fermilab E-400 on the production of charmed baryons and mesons at a mean energy of 640 GeV. We show evidence for the charm-strange baryon, ..xi../sub c//sup +/, and present our measurements of its mass, width, lifetime, cross section and relative branching fractions, and the A, x/sub f/, p/sub t/, and particle/antiparticle dependence of the state. We show evidence for both the ..sigma../sub c//sup 2 +/ and ..sigma../sub c//sup 0/, and present measurements of three mass differences, ..sigma../sub c//sup 2 +/ - ..sigma../sub c//sup 0/, ..sigma../sub c//sup 0/ - ..lambda../sub c//sup +/, and ..sigma../sub c//sup 2 +/ - ..lambda../sub c//sup +/. Measurements of the A dependence and particle/antiparticle ratios for ..sigma../sub c/ production are also presented. We show preliminary results on the ratio of two decay modes of the D/sup 0/, D/sup 0/ ..-->.. K/sup +/K/sup -/ and D/sup 0/ ..-->.. K/sub 0/anti K/sub 0/. The latter mode has not been previously observed. 8 refs., 10 figs.
Date: September 1, 1987
Creator: Coteus, P.; Binkley, M.; Bossi, F.; Butler, J.; Cumalat, J. P.; DiCorato, M. et al.
System: The UNT Digital Library
Charmless B decays to baryons (open access)

Charmless B decays to baryons

We attempt an estimate of vertical bar V/sub ub//V/sub cb/vertical bar from the recent ARGUS observation of B/sup + -/ ..-->.. p anti p..pi../sup + -/ and B/sup 0/ ..-->.. p anti p..pi../sup +/..pi../sup -/ by studying general processes of the type B ..-->.. N anti N + n..pi.. (n greater than or equal to 0). The main ingredients of the analysis are the pion multiplicity distribution and a few models for the isospin structure of the final state. It is concluded quite generally that vertical bar V/sub ub//V/sub cb/vertical bar = 0.25 +- 0.10 and vertical bar V/sub ub//V/sub cb/vertical bar greater than or equal to 0.08. The ratio may become lower only in the event that both the relevant experimental and theoretical quantities obtain the extreme values considered in our study. We also discuss briefly a possible realization of a ..delta..I = 1/2 rule in these processes.
Date: September 1, 1987
Creator: Gronau, M.
System: The UNT Digital Library
Conducting hybrid polymeric systems (open access)

Conducting hybrid polymeric systems

The studies took advantage of the opportunities offered by copolymerization for gaining insight into electrical conduction, morphology, phase separation, polymer-polymer interfaces, and solubility. Copolymerization is technologically important for it allows one to tailor-make products with specifically desired properties. However, the utility of copolymerization involving conjugated, rigid components could be different from that of conventional polymers. This paper is focused on the synthesis and properties of various materials: Rod-coil systems such as polyisoprene/polyacetylene diblock copolymers (resonance raman and small angle neutron scattering studies correlated to conductivity); and alternating copolymers such as poly (arylpyrroles) (electrochemical synthesis and characterization). 8 refs., 4 figs.
Date: September 1, 1987
Creator: Aldissi, M.; White, J.W.; Agnew, S. & Jorgensen, B.S.
System: The UNT Digital Library
Correction of the field in the SSC dipoles using superconductor on the wedges (open access)

Correction of the field in the SSC dipoles using superconductor on the wedges

The SSC colliding beam storage ring requires superconducting magnets capable of producing a magnetic field of 6.6 T which has very high accuracy. For many of the multipoles, that multipole must be reduced (at a radius of 1 centimeter) to the order of 0.2 parts in 10,000. This field accuracy is dictated by the physics of storing very small high-current proton beams at energies ranging from 1 TeV to 20 TeV. Magnetization of the superconductor can cause sextupole field errors of up to 6 parts in 10,000 at an injection field of 0.33 T at a radius of 1 centimeter. Saturation of the magnet iron can induce sextupole field errors of 1 to 2 parts in 10,000 at the full field of 6.6 T. Manufacturing errors can induce other multipole components, both normal and skew. The SSC coil has three wedges separating the superconducting coil blocks on the inner layer of the coil. These wedges must be accurately located. If the wedges have superconductors attached, one can correct all of the magnetic field multipoles (both normal and skew) from N = 1 (dipole) to N = 6 (12 pole). This paper describes this method of correction as it pertains to …
Date: September 1, 1987
Creator: Green, M. A. & Talman, R. M.
System: The UNT Digital Library
Cosmology With Decaying Vacuum Energy (open access)

Cosmology With Decaying Vacuum Energy

Motivated by recent attempts to solve the cosmological constant problem, we examine the observational consequences of a vacuum energy density which decays in time. For all times later than t approx. 1 sec, the ratio of the vacuum to the total energy density of the universe must be small. Although the vacuum cannot provide the ''missing mass'' required to close the universe today, its presence earlier in the history of the universe could have important consequences. We discuss restrictions on the vacuum energy arising from primordial nucleosynthesis, the microwave and gamma ray background spectra, and galaxy formation. A small vacuum component at the era of nucleosynthesis, 0.01 < rho/sub vac//rho/sup rad/ < 0.1, increase the number of allowed neutino species to N/sup nu/ > 5, but in some cases would severely distort the microwave spectrum. 9 refs., 3 figs.
Date: September 1, 1987
Creator: Freese, K.; Adams, F.; Frieman, J. & Mottola, E.
System: The UNT Digital Library
Cross sections for atomic displacements in solids by fast positrons (open access)

Cross sections for atomic displacements in solids by fast positrons

The Mott series has been used to calculate the cross section for atomic displacements produced in elastic collisions between relativistic positrons and atomic nuclei. The Kinchin and Pease displacement model was used. Several elements spanning the atomic table were treated using positron energies ranging from threshold to several tens of MeV. The results are compared with previous calculations for relativistic electrons. It is found that for the same energy and atomic number the positron cross sections are always smaller (up to a factor of 5 or more). It is also found that the McKinley-Fesbach formula which is frequently used in radiation damage analysis is even less reliable for positrons than for electrons. 9 refs.
Date: September 1, 1987
Creator: Oen, Ordean S.
System: The UNT Digital Library
Cryogenic instrumentation of an SSC (superconducting super collider) magnet test stand (open access)

Cryogenic instrumentation of an SSC (superconducting super collider) magnet test stand

This paper describes the system used to acquire cryogenic data for the testing of SSC magnets at the Fermilab Magnet Test Facility. An array of pressure transducers, resistance thermometers, vapor pressure thermometers, and signal conditioning circuits are used. Readings with time resolution appropriate for quench recording are obtained with a waveform digitizer and steady-state measurements are obtained with higher accuracy using a digital voltmeter. The waveform digitizer is clocked at a 400 Hz sampling rate and these readings are stored in local ring buffers. The system is modular and can be expanded to add more channels. The software for the acquisition, control, logging, and display of cryogenic data consist of two programs which run as separate tasks. These programs (as well as a third program which acquires quench and magnetic data) communicate and pass data using shared global resources. The acquired data are available for analysis via a nationwide DECnet network.
Date: September 1, 1987
Creator: McGuire, K.; Strait, J.; Kuchnir, M. & McInturff, A.
System: The UNT Digital Library
Density limits and fueling: Prepared for data base assessment, 1985-1987. [Viewgraphs] (open access)

Density limits and fueling: Prepared for data base assessment, 1985-1987. [Viewgraphs]

This paper contains viewgraph material assessing the density limits and fueling limits of different thermonuclear devices. Various density limits are considered with emphasis on the Murakami limit and the Hugill limit. (GSP)
Date: September 21, 1987
Creator: Greenwald, M. & Sheffield, J.
System: The UNT Digital Library
Design, fabrication, and calibration of a cryogenic search-coil array for harmonic analysis of quadrupole magnets (open access)

Design, fabrication, and calibration of a cryogenic search-coil array for harmonic analysis of quadrupole magnets

A cryogenic search-coil array has been fabricated at LBL for harmonic error analysis of SSC model quadrupoles. It consists of three triplets of coils; the center-coil triplet is 10 cm long, and the end coil triplets are 70 cm long. Design objectives are a high bucking ratio for the dipole and quadrupole signals and utility at cryogenic operating currents (approx.6 kA) with sufficient sensitivity for use at room-temperature currents (approx.10 A). the design and fabrication are described. Individual coils are mechanically measured to +-5 ..mu..m, and their magnetic areas measured to 0.05%. A computer program has been developed to predict the quadrupole and dipole bucking ratios from the mechanical and magnetic measurements. The calibration procedure and accuracy of the array are specified. Results of measurements of SSC model quadrupoles are presented. 1 ref., 4 figs.
Date: September 1, 1987
Creator: Green, M. I.; Barale, P. J.; Hassenzahl, W. V.; Nelson, D. H.; O'Neill, J. W.; Schafer, R. V. et al.
System: The UNT Digital Library
Designs of pulsed power cryogenic transformers (open access)

Designs of pulsed power cryogenic transformers

The Westinghouse Electric Corporation has completed designs of three pulsed power cryogenic transformers for the Los Alamos National Laboratory. These transformers will be configured to transfer their stored energy sequentially to an electromagnetic launcher and form a three-stage power supply. The pulse transformers will act as two winding energy storage solenoids which provide a high current and energy pulse compression by transforming a 50 kA power supply into a megamp level power supply more appropriate for the electromagnetic launcher duty. This system differs from more traditional transformer applications in that significant current levels do not exist simultaneously in the two windings of the pulse transformer. This paper describes the designs of the pulsed power cryogenic transformers.
Date: September 1, 1987
Creator: Singh, S. K.; Heyne, C. J.; Hackworth, D. T.; Shestak, E. J.; Eckels, P. W. & Rogers, J. D.
System: The UNT Digital Library