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On the Density Oscillations of a Warm Particle Bunch (open access)

On the Density Oscillations of a Warm Particle Bunch

The density oscillations of warm particle bunches is investigated theoretically. Two different mathematical approaches are employed to derive the basic equation describing density oscillations; one is a fluid approach and the second is a more general Green1s function formulation. The motion is analyzed in first order perturbation theory where it is shown, under the assumption of no degeneracy, that there are only stable oscillations. Second order perturbation theory gives damping of the motion. The perturbation theory is examined and a criterion is exhibited for its proper use. Thus, when the resistivity is small enough (but nonzero) then the motion is stable, but when the resistivity is large then the motion is essentially unstable with a growth rate which is that of an unbunched beam. The criterion is approximately evaluated using a model for a bunched beam.
Date: November 1, 1982
Creator: Channell, P. J.; Sessler, A. M. & Wurtele, J. S.
System: The UNT Digital Library
3 mm Anisotropy Measurement: On the Quadrupole Component in theCosmic Background Radiation (open access)

3 mm Anisotropy Measurement: On the Quadrupole Component in theCosmic Background Radiation

We have mapped the large-scale anisotropy in the cosmic background radiation at 3 mm wavelength using a liquid-helium-cooled balloon-borne radiometer sensitive enough to detect the dipole in one gondola rotation (1 minute). Statistical errors on the dipole and quadrupole components are below 0.1 mK with less than 0.1 m K galactic contribution. We find a dipole consistent with previous measurements but disagree with recent quadrupole reports. The measurement is also useful in searching for spectral distortions.
Date: November 1, 1982
Creator: Lubin, Philip M.; Epstein, Gerald L. & Smoot, George F.
System: The UNT Digital Library
Fast multichannel analog storage system (open access)

Fast multichannel analog storage system

A Multichannel Analog Storage System based on a commercial 32-channel parallel in/serial out (PISO) analog shift register is described. The basic unit is a single width CAMAC module containing 512 analog cells and the associated logic for data storage and subsequent readout. At sampling rates of up to 30 MHz the signals are strobed directly into the PISO. At higher rates signals are strobed into a fast presampling stage and subsequently transferred in block form into an array of PISO's. Sampling rates of 300 MHz have been achieved with the present device and 1000 MHz are possible with improved signal drivers. The system is well suited for simultaneous handling of many signal channels with moderate numbers of samples in each channel. RMS noise over full scale signal has been measured as 1:3000 (approx. = 11 bit). However, nonlinearities in the response and differences in sensitivity of the analog cells require an elaborate calibration system in order to realize 11 bit accuracy for the analog information.
Date: November 1, 1982
Creator: Freytag, D.R.
System: The UNT Digital Library
High-explosive-driven delay line pulse generator (open access)

High-explosive-driven delay line pulse generator

The inclusion of a delay line circuit into the design of a high-explosive-driven generator shortens the time constant of the output pulse. After a brief review of generator concepts and previously described pulse-shortening methods, a geometry is presented which incorporates delay line circuit techcniques into a coil generator. The circuit constants are adjusted to match the velocity of the generated electromagnetic wave to the detonation velocity of the high explosive. The proposed generator can be modeled by adding a variable inductance term to the telegrapher's equation. A particular solution of this equation is useful for exploring the operational parameters of the generator. The duration of the electromagnetic pulse equals the radial expansion time of the high-explosive-driven armature until it strikes the coil. Because the impedance of the generator is a constant, the current multiplication factor is limited only by nonlinear effects such as voltage breakdown, diffusion, and compression at high energies.
Date: November 15, 1982
Creator: Shearer, J.W.
System: The UNT Digital Library
Minimally Extended Elctroweak Gauge Theories in SO(10) and E/sub 6/ (open access)

Minimally Extended Elctroweak Gauge Theories in SO(10) and E/sub 6/

The possibility of minimally extending the standard SU(2)/sub L/xU(1) electroweak theory within the context of SO(10) and E/sub 6/ grand unification by adding U(1) factors is explored. The neutrino neutral-current interactions in these schemes are arranged to coincide with the standard-model predictions. Limits on the masses of the extra Z's generated by these U(1) factors are obtained by considering other parity-violating effects. Additional Z's as light as 2.5 to 3.0 times the standard model Z/sup 0/ mass are allowed.
Date: November 1, 1982
Creator: Robinett, R. W. & Rosner, J. L.
System: The UNT Digital Library
Towards a systematic format for (seismic) equipment qualification standards (open access)

Towards a systematic format for (seismic) equipment qualification standards

As part of technical assistance to the US Nuclear Regulatory Commission (NRC, 1), a systematic format for seismic equipment qualification (EQ) was initiated. This format consists of thirty issues associated with seismic EQ. Each issue was considered as a Category of Possible Seismic EQ Requirements and Criteria. That is, seismic EQ standards might be (but presently are not formulated in terms of requirements and criteria that address each of the thirty issues. Each of the thirty issues was ranked and a minimum set identified. The current requirements in existing NRC and national standards were also evaluated against this common set of issues, and they were estimated to score 60 out of 100 overall. It is believed that the systematic format exhibited in this paper can be of assistance in obtaining a broader and more complete perspective on seismic EQ issues. This format (but especially the technique) may also be of interest in non-seismic EQ since many of the issues are common.
Date: November 9, 1982
Creator: Smith, P.D.
System: The UNT Digital Library
Electronically focused power diffractometers at IPNS-I (open access)

Electronically focused power diffractometers at IPNS-I

Two powder diffractometers have been operated at IPNS-I since August 1981. The diffractometers achieve high resolution with large detector solid angles for scattering angles from +- 12 to 157/sup 0/ by electronically focussing the events from individual detectors in an on-line microprocessor.
Date: November 1, 1982
Creator: Jorgensen, J.D. & Faber, J.
System: The UNT Digital Library
Future directions for high-spin studies (open access)

Future directions for high-spin studies

Some future directions for experimental high-spin studies are discussed, concentrating mainly on the region above I -- 30h, where the ..gamma..-ray spectra are currently unresolvable. The 4..pi.. NaI balls offer a means to exploit the temperature effects recently shown to exist in such spectra. Large arrays of Compton-suppressed Ge detectors, on the other and, lead to higher effective resolution as it becomes possible to study triple and quadruple coincident events.
Date: November 1, 1982
Creator: Stephens, F.S.
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
RFQ development at LBL (open access)

RFQ development at LBL

The radio frequency quadrupole (FRQ) is a structure which can efficiently focus, bunch and accelerate low velocity ion beams. It has many features which make it particularly attractive for applications in the biomedical and nuclear sciences. There are two projects in progress at LBL where the incorporation of heavy ion RFQ technology offers substantial benefits: in the upgrade of the Bevatron local injector, and in the design of a dedicated heavy ion medical accelerator. In order to meet the requirements of these two important applications, a 200 MHz RFQ structure has been designed for ions with charge to mass ratios as low as 0.14, and a low rf power scale model has been built and tested. Construction of the high power model has begun. The status of this project is reviewed and a summary of technical specifications given.
Date: November 1, 1982
Creator: Abbott, S.; Brodzik, D.; Gough, R.A.; Howard, D.; Lancaster, H.; MacGill, R. 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
sigma. /sup +/ and. sigma. /sup -/ production polarizations (open access)

sigma. /sup +/ and. sigma. /sup -/ production polarizations

We report preliminary results from Fermilab experiment E497 on the production polarizations of ..sigma../sup +/ and ..sigma../sup -/ hyperons. Hyperons were produced inclusively at non zero production angles by 400 GeV/c protons incident on a Cu target. The polarization was analyzed by the weak decay asymmetry in the hadronic decay modes ..sigma../sup +/ ..-->.. p..pi../sup 0/ and ..sigma../sup -/ ..-->.. n..pi../sup -/. Based upon samples of 38,000 ..sigma../sup +/ and 317,000 ..sigma../sup -/ decays we observe polarizations as a function of P/sub t/ which average 22% at an X of 0.53 for ..sigma../sup +/ and 40% at X of 0.68 and 0.78 for ..sigma../sup -/. The direction of polarization for both ..sigma../sup +/ and ..sigma../sup -/ is in the direction of K/sub -p/ x K/sub ..sigma../ where the K's are the momentum vectors of the incident proton and produced hyperon respectively. This is opposite to the direction of polarization of inclusively produced lambdas.
Date: November 1, 1982
Creator: Cooper, P.S.; Anderson, E.W. & Ankenbrandt, C.
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
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