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X-ray photoemission spectroscopy (XPS) study of uranium, neptunium and plutonium oxides in silicate-based glasses (open access)

X-ray photoemission spectroscopy (XPS) study of uranium, neptunium and plutonium oxides in silicate-based glasses

Using XPS as the principal investigative tool, we are in the process of examining the bonding properties of selected metal oxides added to silicate glass. In this paper, we present results of XPS studies of uranium, neptunium, and plutonium in binary and multicomponent silicate-based glasses. Models are proposed to account for the very diverse bonding properties of 6+ and 4+ actinide ions in the glasses.
Date: November 1, 1982
Creator: Lam, D.J.; Veal, B.W. & Paulikas, A.P.
System: The UNT Digital Library
Quark-antiquark bound-state spectroscopy and QCD (open access)

Quark-antiquark bound-state spectroscopy and QCD

The discussion covers quarks as we know them, the classification of ordinary mesons in terms of constituent quarks, hidden charm states and charmed mesons, bottom quarks, positronium as a model for quarti q, quantum chromodynamics and its foundation in experiment, the charmonium model, the mass of states, fine structure and hyperfine structure, classification, widths of states, rate and multipolarity of gamma transitions, questions about bottom, leptonic widths and the determination of Q/sub b/, the mass splitting of the n/sup 3/S/sub 1/ states, the center of gravity of the masses of the n/sup 3/P; states, n/sup 3/ P; fine structure and classification, branching ratios for upsilon' ..-->.. tau chi/sub 6j/ and the tau cascade reactions, hyperfine splitting, and top. (GHT)
Date: November 1, 1982
Creator: Bloom, E.D.
System: The UNT Digital Library
Contribution of twist-4 to the Q/sup 2/ evolution of F/sub 2/ and xF/sub 3/: an experimental review (open access)

Contribution of twist-4 to the Q/sup 2/ evolution of F/sub 2/ and xF/sub 3/: an experimental review

The status of the theoretical and experimental study of higher twist contributions to the nucleon structure functions is reviewed. After noting the dangers of combining experiments with widely different <Q/sup 2/> and targets, emphasis is placed on those results coming from a single experiment. The values of ..lambda.., the twist-2 scale factor, and h/sub 4/, the coefficient of x/Q/sup 2/(1-x), are restricted by: ..lambda.. <0.44 GeV and -0.2 <h/sub 4/<0.5 GeV/sup 2/.
Date: November 1, 1982
Creator: Morfin, J.G.
System: The UNT Digital Library
Damage and in-situ annealing during ion implantation (open access)

Damage and in-situ annealing during ion implantation

Formation of amorphous (..cap alpha..) layers in Si during ion implantation in the energy range 100 keV-11 MeV and temperature range liquid nitrogen (LN)-100/sup 0/C has been investigated. Cross-sectional transmission electron microscopy (XTEM) shows that buried amorphous layers can be created for both room temperature (RT) and LN temperature implants, with a wider 100 percent amorphous region for the LN cooled case. The relative narrowing of the ..cap alpha.. layer during RT implantation is attributed to in-situ annealing. Implantation to the same fluence at temperatures above 100/sup 0/C does not produce ..cap alpha.. layers. To further investigate in situ annealing effects, specimens already containing buried ..cap alpha.. layers were further irradiated with ion beams in the temperature range RT-400/sup 0/C. It was found that isolated small ..cap alpha.. zones (less than or equal to 50 diameter) embedded in the crystalline matrix near the two ..cap alpha../c interfaces dissolved into the crystal but the thickness of the 100 percent ..cap alpha.. layer was not appreciably affected by further implantation at 200/sup 0/C. A model for in situ annealing during implantation is presented.
Date: November 1, 1982
Creator: Sadana, D. K.; Washburn, J.; Byrne, P. F. & Cheung, N. W.
System: The UNT Digital Library
Spectator-velocity pions from heavy ions (open access)

Spectator-velocity pions from heavy ions

The discussion centers on pions in the velocity regions of target and projectile, where strong spectral features appear. The topics covered include stopped-pion studies, and convoy pions in the projectile frame. (GHT)
Date: November 1, 1982
Creator: Rasmussen, J.; Ridout, J.; Murphy, D. & Radi, H.M.A.
System: The UNT Digital Library
Summary talk for the Brookhaven spin physics conference, 1982 (open access)

Summary talk for the Brookhaven spin physics conference, 1982

I review the following highlights of this conference: polarized hyperon production, magnetic moments, symmetries, polarized ep physics, hadronic processes and QCD, and future prospects at colliders.
Date: November 1, 1982
Creator: Prescott, C.
System: The UNT Digital Library
Design of a 10-T superconducting dipole magnet using niobium-tin conductor (open access)

Design of a 10-T superconducting dipole magnet using niobium-tin conductor

In order to minimize the size and cost of conventional facilities - land, tunneling, shielding, cryogenic and vacuum system - the dipole magnets for the next generation of particle accelerators must produce as strong a magnetic field as possible. Ten tesla seems to be a reasonable goal, and can be attained by using either niobium-tin conductor at 4.2 K or niobium-titanium at 1.8 K. The beam diameter in a multi-TeV accelerator, can in principle, be quite small, say 20 mm, depending on the design of the injection and extraction systems, and on beam-cooling technology. Magnet cost is strongly dependent on bore diameter, so there is a strong incentive to minimize that. We believe that a 40-mm bore diameter - about 60-mm winding inside diameter is feasible and is a reasonable goal for initial research and development. For such a high field and small bore, there is an incentive to achieve a high overall current density in order to minimize the amount of superconductor. Our design is based on an overall current density of 400 A/sq mm. LBL has undertaken the development of a magnet using niobium-tin conductor intended to meet the above specifications. The conductor is a Rutherford-type cable consisting …
Date: November 1, 1982
Creator: Taylor, C.; Meuser, R.; Caspi, S.; Gilbert, W.; Hassenzahl, W.; Peters, C. et al.
System: The UNT Digital Library
Tritium effects on germ cells and fertility (open access)

Tritium effects on germ cells and fertility

Primordial oocytes in juvenile mice show acute gamma-ray LD/sub 50/ as low as 6 rad. This provides opportunities for determining dose-response relations at low doses and chronic exposure in the intact animal - conditions of particular interest for hazard evaluation. Examined in this way, /sup 3/HOH in body water is found to kill murine oocytes exponentially with dose, the LD/sub 50/ level for chronic exposure being only 2..mu..Ci/ml (delivering 0.4 rad/day). At very low doses and dose rates, where comparisons between tritium and other radiations are of special significance for radiological protection, the RBE of tritium compared with /sup 60/Co gamma radiation reaches approximately 3. Effects on murine fertility from tritium-induced oocyte loss have been quantified by reproductive capacity measurements. Chronic low-level exposure has been examined also in three primate species - squirrel, rhesus, and bonnet monkeys. In squirrel monkeys the ovarian germ-cell supply is 99% destroyed by the time of birth from prenatal exposure to body-water levels of /sup 3/HOH (administered in maternal drinking water) of only 3 ..mu..Ci/ml, the LD/sub 50/ level being 0.5 ..mu..Ci/ml (giving 0.1 rad/day), one fourth that in mice. Though not completely ruled out, similar high sensitivity of female germ cells has not been …
Date: November 19, 1982
Creator: Dobson, R.L.; Kwan, T.C. & Straume, T.
System: The UNT Digital Library
Introduction to FASTBUS (open access)

Introduction to FASTBUS

FASTBUS is a standardized modular 32-bit data-bus system for performing data acquisition, data processing, and control in high energy physics and other applications. It has been developed by the Fast System Design Group of the U.S. NIM Committee. Presented here is an overview of the FASTBUS hardware specification, the operation of the FASTBUS protocol, the implications that the use of FASTBUS has for software systems, and some of the computer to FASTBUS interfaces developed to date.
Date: November 1, 1982
Creator: Logg, C.A.
System: The UNT Digital Library
Massive lepton pair production: what has QCD done to the classical Drell-Yan model (open access)

Massive lepton pair production: what has QCD done to the classical Drell-Yan model

A report is presented of recent experimental and theoretical progress in studies of the production of massive lepton pairs in hadronic collisions. Among the topics discussed are deviations from scaling, the status of the proofs of factorization in the parton model, higher-order terms in the QCD expansion, the discrepancy between measured and predicted yields (K factor), high-twist terms, soft gluon effects, and transverse momentum distributions.
Date: November 1, 1982
Creator: Berger, E. L.
System: The UNT Digital Library
Fire and the related effects of nuclear explosions. 1982 Asilomar Conference (open access)

Fire and the related effects of nuclear explosions. 1982 Asilomar Conference

This report summarizes the proceedings of a Federal Emergency Management Agency-sponsored Conference on fire and the related effects of nuclear explosions (with passing attention to earthquakes and other nonnuclear mishaps). This conference, the fifth of an annual series (formally called Blast/Fire Interaction Conferences), was held during the week of April 25, 1982, again at Asilomar, California.
Date: November 1, 1982
Creator: Martin, S.B. & Alger, R.S. (eds.)
System: The UNT Digital Library
Four-layer, two-inch bore, superconducting dipole magnet (open access)

Four-layer, two-inch bore, superconducting dipole magnet

Superconductors provide the accelerator designer with a unique opportunity to construct machines that can achieve high particle energies and yet have low operating costs. This paper describes the design, fabrication and testing of a 4 layer, 50 mm bore superconducting dipole magnet, D-9A. The magnet reached short sample, 5.8 T at 4.4 K and 8.0 T and 1.8 K, with little training, and exhibited low losses and low ramp rate sensitivity.
Date: November 1, 1982
Creator: Hassenzahl, W.V.; Peters, C.; Gilbert, W.; Taylor, C. & Meuser, R.
System: The UNT Digital Library
Manufacture and evaluation of Nb/sub 3/Sn conductors fabricated by the MJR method (open access)

Manufacture and evaluation of Nb/sub 3/Sn conductors fabricated by the MJR method

The bronze matrix/niobium filament process has become established as a commercially viable method for producing multifilamentary Nb/sub 3/Sn superconductors. This paper describes a new method, the Modified Jelly-Roll (MJR) approach, which can produce a structure similar to that in a conventionally fabricated multifilamentary Nb/sub 3/Sn conductor. This approach utilizes alternate sheets of niobium expanded metal and bronze, which are rolled into a jelly-roll configuration and then extruded. During extrusion and subsequent drawing, the junctures in the niobium are elongated and the material develops a filamentary structure. This method may offer significant advantages in terms of reduced fabrication time and cost over the conventional approach. Results of a manufacturing development program will be presented in which two lengths of conductor were made to High-Field Test Facility conductor specifications. In addition, critical current and transition temperature measurements of the sub-elements used to construct the HFTF-type lengths will be reported.
Date: November 23, 1982
Creator: McDonald, W. K.; Curtis, C. W.; Scanlan, R. M.; Larbalestier, D. C.; Marken, K. & Smathers, D. B.
System: The UNT Digital Library
Charge collection in silicon strip detectors (open access)

Charge collection in silicon strip detectors

The use of position sensitive silicon detectors as very high resolution tracking devices in high energy physics experiments has been a subject of intense development over the past few years. Typical applications call for the detection of minimum ionizing particles with position measurement accuracy of 10 ..mu..m in each detector plane. The most straightforward detector geometry is that in which one of the collecting electrodes is subdivided into closely spaced strips, giving a high degree of segmentation in one coordinate. Each strip may be read out as a separate detection element, or, alternatively, resistive and/or capacitive coupling between adjacent strips may be exploited to interpolate the position via charge division measrurements. With readout techniques that couple several strips, the numer of readout channels can, in principle, be reduced by large factors without sacrificing the intrinsic position accuracy. The testing of individual strip properties and charge division between strips has been carried out with minimum ionizing particles or beams for the most part except in one case which used alphs particless scans. This paper describes the use of a highly collimated MeV proton beam for studies of the position sensing properties of representative one dimensional strip detectors.
Date: November 1, 1982
Creator: Kraner, H. W.; Beuttenmuller, R.; Ludlam, T.; Hanson, A. L.; Jones, K. W.; Radeka, V. et al.
System: The UNT Digital Library
Acceleration of magnetized plasma rings (open access)

Acceleration of magnetized plasma rings

One scheme is considered, acceleration of a ring between coaxial electrodes by a B/sub theta/ field as in a coaxial rail-gun. If the electrodes are conical, a ring accelerated towards the apex of the cone undergoes self-similar compression (focussing) during acceleration. Because the allowable acceleration force F/sub a/ = kappa U/sub m//R (kappa < 1) increases as R/sup -2/, the accelerating distance for conical electrodes is considerably shortened over that required for coaxial electrodes. In either case however, since the accelerating flux can expand as the ring moves, most of the accelerating field energy can be converted into kinetic energy of the ring leading to high efficiency.
Date: November 16, 1982
Creator: Hartman, D.; Eddleman, J. & Hammer, J. H.
System: The UNT Digital Library
Charge-exchange products of BEVALAC projectiles (open access)

Charge-exchange products of BEVALAC projectiles

There is a substantial production of fragments of all masses lighter than the projectile, such fragments being centered in a narrow region of velocity space around the beam velocity. The exciting studies about anomalons deal with the curious enhanced reactivity of some of these secondary fragments. I direct attention here to the rather rare fragments of the same mass number as the projectile but differing in charge by one unit. We also keep track, as a frame of reference, of the products that have lost one neutron from the projectile.
Date: November 1, 1982
Creator: Rasmussen, J.
System: The UNT Digital Library
Division of Materials Science (DMS) meeting presentation (open access)

Division of Materials Science (DMS) meeting presentation

Materials preparation techniques are listed. Materials preparation capabilities are discussed for making BeF/sub 2/ glasses and other materials. Materials characterization techniques are listed. (DLC)
Date: November 8, 1982
Creator: Cline, C. F. & Weber, M. J.
System: The UNT Digital Library
Electrodes for stochastic cooling of the FNAL antiproton source (open access)

Electrodes for stochastic cooling of the FNAL antiproton source

AN electrode array for stochastic cooling is being developed for use on the FNAL antiproton source. With minor power handling modifications, the same electrodes can function as pickups or as kickers. When used as pickups, a large array is needed to increase the signal-to-noise ratio. Each electrode is one element of a pair of directional coupler loops that are mounted flush with the upper and lower walls of the beam chamber. The loops, fabricated from flat metal plates, are supported by specially shaped legs.
Date: November 1, 1982
Creator: Voelker, F.
System: The UNT Digital Library
Challenge of ultra-high energies: ultimate limits, possible directions of technology, an approach to collective acceleration (open access)

Challenge of ultra-high energies: ultimate limits, possible directions of technology, an approach to collective acceleration

At the request of Panel Chairman Amaldi, the oral version of this rpeort was largely devoted to a recapitulation and critique of the various methods of collective acceleration, including plasma-laser methods, which had been presented at the meeting.
Date: November 1, 1982
Creator: Keefe, D.
System: The UNT Digital Library
Fast pressure measurements for the TMX-U fusion experiment (open access)

Fast pressure measurements for the TMX-U fusion experiment

The pressure on the boundary of the Lawrence Livermore National Laboratory's (LLNL) tandem mirror (TMX-U) plasma experiment is difficult to trace for several reasons: (1) the TMX-U boundary is in the high vacuum range (10/sup -5/ to 10/sup -6/ Pa) and requires an ionization gauge; (2) the boundary includes high-energy neutral particles and radiation, so the gauge must be optically baffled from the plasma; (3) the gauge must be shielded from the magnetic flux density of 0.03 T; (4) maximum conductance to the gauge must be preserved so that the time response remains about 1 ms; (5) a fast electrical circuit is required to measure the small ion-current changes at a rate consistent with the geometrical and experimental time constant of 1 ms. We have developed solutions to these limitations, including fast ionization gauge (FIG) circuitry for the remote gauge operation and the CAMAC system for recording the pressure-time history in the TMX-U computer data base. We also give some examples of actual fast pressure histories during plasma operation.
Date: November 2, 1982
Creator: Hunt, A.L.; Coffield, F.E. & Pickles, W.L.
System: The UNT Digital Library
Jets: models versus experimental data, I (open access)

Jets: models versus experimental data, I

Present status of jet studies is reviewed with the special empahsis on the merits of various tests of jet models.
Date: November 1, 1982
Creator: Orava, R.
System: The UNT Digital Library
Source, origin, and propagation of quenches measured in superconducting dipole magnets (open access)

Source, origin, and propagation of quenches measured in superconducting dipole magnets

Transitions from the superconducting to normal state at 4.4 and 1.8 K in several model accelerator dipoles were recorded by a fast data-acquisition system. The resistive voltage rise in the conductor during the transitions is used to determine accurately the location of the quench source in the magnets and to estimate the axial and turn-to-turn quench velocities. The quench velocity, temperature evolution and energy deposition in the coil were calculated using the program QUENCH, and are in reasonable agreement with the data. In the two dipole magnets studied, the transitions almost always occurred in the regions of highest field. In one coil the high field region is in the straight section because the field in this region is enhanced by iron support rings. In the other magnet the high field region is at the end, in the innermost turn of the first layer. Some quenches were preceded by large voltage spikes that can be ascribed to conductor motion. Other quenches do not appear to be associated with any large energy release. Acoustic emission (AE) was monitored during the tests and AE bursts were observed simultaneous with the initial voltage spike. An increased AE signal continued as the quench progressed.
Date: November 1, 1982
Creator: Caspi, S. & Hassenzahl, W.V.
System: The UNT Digital Library
Vane coupling rings: a simple technique for stabilizing a four-vane radiofrequency quadrupole structure (open access)

Vane coupling rings: a simple technique for stabilizing a four-vane radiofrequency quadrupole structure

The benefits of stabilized accelerating structures, with regard to the manufacture and operation, have been well documented. The four-vane radiofrequency quadrupoles (RFQ) presently being designed and constructed in many laboratories are not stabilized because of the weak electromagnetic coupling between the quadrant resonators. This paper presents a simple technique developed at the Lawrence Berkeley Laboratory using vane coupling rings (VCR's) which azimuthally stabilize the RFQ structure and greatly enhance its use as a practical accelerator. In particular, the VCR's: completely eliminate the dipole modes in the frequency range of interest; provide adequate quadrant balance with an initial precision mechanical alignment of the vanes; and enhance axial balance and simplify end tuners. Experimental verification tests on a scale model are discussed.
Date: November 1, 1982
Creator: Howard, D. & Lancaster, H.
System: The UNT Digital Library
Betatrons with kiloampere beams (open access)

Betatrons with kiloampere beams

Although the magnetic-induction method of acceleration used in the betatron is inherently capable of accelerating intense particle beams to high energy, many beam-instability questions arise when beams in the kilo-ampere range are considered. The intense electromagnetic fields produced by the beam, and by the image currents and charges induced in the surrounding walls, can produce very disruptive effects. Several unstable modes of collective oscillation are possible; the suppression of any one of them usually involves energy spread for Landau damping and careful design of the electrical character of the vacuum chamber. The various design criteria are often mutually incompatible. Space-charge detuning can be severe unless large beam apertures and high-energy injection are used. In order to have an acceptably low degree of space-charge detuning in the acceleration of a 10-kilo-ampere electron beam, for example, an injection energy on the order of 50 MeV seems necessary, in which case the forces due to nearby wall images can have a larger effect than the internal forces of the beam. A method of image compensation was invented for reducing the net image forces; it serves also to decrease the longitudinal beam impedance and thus helps alleviate the longitudinal instability as well. In order …
Date: November 1, 1982
Creator: Peterson, J. M.
System: The UNT Digital Library