Resource Type

Month

40 Matching Results

Results open in a new window/tab.

Production of antihyperons in the central region at the ISR. The axial field spectrometer collaboration (open access)

Production of antihyperons in the central region at the ISR. The axial field spectrometer collaboration

We present measurements of the relative production cross-sections of anti p, anti ..lambda.., anti ..xi.., and anti ..cap omega.. at y approx. 0 for 1 less than or equal to p/sub T/ less than or equal to 2 GeV/c in pp collisions at ..sqrt..s = 63 GeV. The results are compared with previous measurements of antibaryon production in hadronic and e/sup +/e/sup -/ collisions.
Date: July 1, 1983
Creator: Akesson, T.; Albrow, M.C.; Almehed, S.; Batley, R.; Benary, O.; Boggild, H. et al.
System: The UNT Digital Library
Properties of jets in high-E/sub T/ events produced in pp collisions at. sqrt. s = 63 GeV (open access)

Properties of jets in high-E/sub T/ events produced in pp collisions at. sqrt. s = 63 GeV

The properties of jets in high-E/sub tau/ events produced in pp collisions at ..sqrt..s = 63 GeV have been studied at the CERN Intersecting Storage Rings. The fragmentation of the jets is found to be similar to that of jets produced in e/sup +/e/sup -/ annihilation. The jets are wider than calculated from a constituent scattering model with no hard bremsstrahlung component. The charge correlations of positive and negative particles show differences consistent with expectation from valence-quark scattering. 11 references.
Date: July 1, 1983
Creator: Akesson, T.; Albrow, M.G.; Almehed, S.; Batley, R.; Benary, O.; Boggild, H. et al.
System: The UNT Digital Library
Wake force computation in the time domain for long structures (open access)

Wake force computation in the time domain for long structures

One is often interested in calculating the wake potentials for short bunches in long structures using TBCI. For ultra-relativistic particles it is sufficient to solve for the fields only over a window containing the bunch and moving along with it. This technique reduces both the memory and the running time required by a factor that equals the ratio of the structure length to the window length. For example, for a bunch with sigma/sub z/ of one picosecond traversing a single SLAC cell this improvement factor is 15. It is thus possible to solve for the wakefields in very long structures: for a given problem, increasing the structure length will not change the memory required while only adding linearly to the CPU time needed.
Date: July 1, 1983
Creator: Bane, K. & Weiland, T.
System: The UNT Digital Library
Baryon-antibaryon angular correlations in quark jets (open access)

Baryon-antibaryon angular correlations in quark jets

The azimuthal angular distribution of baryon-antibaryon pairs in a quark jet is calculated and compared with experimental data in e/sup +/e/sup -/ annihilation.
Date: July 1, 1983
Creator: Bartl, A.
System: The UNT Digital Library
Planar Channeling Radiation From Relativistic Positrons and Electrons in LiF (open access)

Planar Channeling Radiation From Relativistic Positrons and Electrons in LiF

Channeling radiation has been measured for planar-channeled 54- and 83-MeV positrons and 17-, 31-, and 54-MeV electrons in the ionic crystal LiF. The results are shown to be in reasonable, but not perfect, agreement with the results of many-beam calculations based upon a model of the crystal as an array of isolated Li/sup +/ and F/sup -/ ions.
Date: July 1, 1983
Creator: Berman, B. L.; Datz, S.; Fearick, R. W.; Swent, R. L.; Pantell, R. H.; Park, H. et al.
System: The UNT Digital Library
Self-pumping impurity by in-situ metal deposition (open access)

Self-pumping impurity by in-situ metal deposition

A system for in-situ removal of helium trapping in freshly deposited metal surface layers of a limiter or divertor has been studied. The system would trap helium on a limiter front surface, or a divertor plate, at low plasma edge temperatures, or in a limiter slot region, at high edge temperatures. Fresh material, introduced to the plasma and/or scrape-off zone, would be added at a rate of about five times the alpha production rate. The material would be reprocessed periodically, e.g. once a year. Possible materials are nickel, vanadium, niobium, and tantalum. Advantages of a self-pumping system are the absence of vacuum ducts and pumps, and the minimization of tritium processing and inventory.
Date: July 1, 1983
Creator: Brooks, J. N. & Mattas, R. F.
System: The UNT Digital Library
Construction and operational experience of the Tandem Mirror Experiment-Upgrade (TMX-U) (open access)

Construction and operational experience of the Tandem Mirror Experiment-Upgrade (TMX-U)

The Tandem Mirror Experiment-Upgrade (TMX-U) incorporates two new features at Lawrence Livermore National Laboratory (LLNL) tandem mirror program, thermal barriers in the end plugs and injection of the neutral beams at several oblique angles. The thermal barriers isolate the electrons in the end plugs from those in the central cell, making it possible to heat them independently with microwaves. In addition, this innovation produces a large potential gradient in the end plugs with lower magnetic fields and lower neutral-beam energies than would be possible in a conventional tandem mirror device. The TMX-U is also designed to test neutral-beam-injection angles as an experimental parameter. We use angles other than 90/sup 0/ to produce a plasma with improved microstability.
Date: July 1, 1983
Creator: Chargin, A. K.; Calderon, M. O. & Moore, T. L.
System: The UNT Digital Library
Determination of subsurface geological structure with borehole gravimetry (open access)

Determination of subsurface geological structure with borehole gravimetry

Conventional gamma-gamma and gravimetric density measurements are routinely gathered for most holes used for underground nuclear tests. The logs serve to determine the subsurface structural geology near the borehole. The gamma-gamma density log measures density of the rock within about 15 cm of the borehole wall. The difference in gravity measured at two depths in a borehole can be interpreted in terms of the density of an infinite, homogeneous, horizontal bed between those depths. When the gravimetric density matches the gamma-gamma density over a given interval it is assumed that the bed actualy exists, and that rocks far from the hole must be the same as those encountered adjacent to the borehole. Conversely, when the gravimetric density differs from the gamma-gamma density it is apparent that the gravimeter is being influenced by a rock mass of different density than that at the hole wall. This mismatch can be a powerful tool to deduce the local structural geology. The geology deduced from gravity mesurements in emplacement hole, U4al, and the associated exploratory hole, UE4al, is an excellent example of the power of the method.
Date: July 1, 1983
Creator: Clark, S. R. & Hearst, J. R.
System: The UNT Digital Library
Lethal, potentially lethal lesion model (open access)

Lethal, potentially lethal lesion model

A theoretical framework to describe the formation of lethal mutations by radiation is presented. Lesions that are repaired (and misrepaired) in each type of experiment described (delayed plating and split dose) are assumed to be the same. In this model the same (potentially lethal) lesions cause both sublethal and potentially lethal damage. Potentially lethal damage is defined as damage which may be modified by alterations in postirradiation conditions. Sublethal damage is cellular damage whose accumulation may lead to lethality. A crucial consideration in the expression of the damage is the kind of medium in which the cells are placed during the repair period. Fresh or growth medium (F-medium) is assumed to cause fixation of damage after about 3 hours, while no fixation (only misrepair) occurs in conditioned medium (C-medium).
Date: July 1, 1983
Creator: Curtis, S.B.
System: The UNT Digital Library
New particles and interactions (open access)

New particles and interactions

It is intended to indicate how multiparticle dynamics might serve as a valuable means of advancing our knowledge down the more fundamental line of elementary particle physics. The point of view is taken that the Standard SU(3) x SU(2) x U(1) Model is well established, and is now ripe to be used as a tool for analyzing physics beyond the Standard Model. The tool kit should include reliable and efficient ways of distinguishing gluon jets from quark jets, and of discriminating between t,b,c and light quark jets. What the author considers to be the most topical physics issues arising from the recent confirmation of the Standard Model are reviewed. These include the need for dynamical principles which go beyond the gauge princple, and in particular a satisfactory mechanism for gauge symmetry breaking. Some of the ideas proposed for solving these problems, such as technicolor and supersymmetry (SUSY), are reviewed, together with some of the experimental tests that can be performed. SUSY is examined in detail, and some ways of looking for sparticles in e/sup +/e/sup -/ and anti pp collisions are discussed. The author tries to emphasize the crucial role to be played by the multiparticle jet tools in resolving …
Date: July 1, 1983
Creator: Ellis, J.
System: The UNT Digital Library
Design of the SLC damping ring to linac transport lines (open access)

Design of the SLC damping ring to linac transport lines

The first and second order optics for the damping ring to linac transport line are designed to preserve the damped transverse emittance while simultaneously compressing the bunch length of the beam to that length required for reinjection into the linac. This design, including provisions for future control of beam polarization, is described.
Date: July 1, 1983
Creator: Fieguth, T. H. & Murray, J. J.
System: The UNT Digital Library
Hugoniot Measurements in Vanadium Using the LNL Two-Stage Light-Gas Gun (open access)

Hugoniot Measurements in Vanadium Using the LNL Two-Stage Light-Gas Gun

Hugoniot measurements on vanadium have been made using the LLNL two-stage light-gas gun. The direct collision method with electrical pins and a tantalum flyer accelerated to 6.28 km/s was used. Alt'shuler, et. al., have reported Hugoniot measurements in vanadium using explosives and the impedance match method. They reported a kink in the U/sub s/ - U/sub p/ relationship at 183 GPa, and attribute it to electronic transitions. The upper portion of their curve is based on a single point at 339 GPa. The present work was performed to further investigate the equation-of-state in the high-pressure range.
Date: July 1, 1983
Creator: Gathers, G. R.; Mitchell, A. C. & Holmes, N. C.
System: The UNT Digital Library
Properties of hot expanded liquid aluminum (open access)

Properties of hot expanded liquid aluminum

Measurements of temperature, volume, enthalpy, and electrical resistivity have been made on aluminum expanded isobarically by 50% in volume to temperatures of about 4000/sup 0/K. These measurements are compared with the predictions of liquid-metal pseudopotential theory.
Date: July 1, 1983
Creator: Gathers, G. Roger & Ross, Marvin
System: The UNT Digital Library
ArII - ArXVI produced in slow recoil collisions (open access)

ArII - ArXVI produced in slow recoil collisions

An atom in a gaseous target may be highly ionized in a single collision with a (very fast) very highly ionized projectile. A feature of the kinematics of the collision is that very little kinetic energy is imparted to the target atom. The ion is produced as a slow recoil. Typical recoil energies are 1 eV and change little with the degree of ionization produced in the target. This has several very attractive features as a spectroscopic source. First, the spectra are free from Doppler shifts which depend upon the degree of ionization of the atom, and, second, all of the ionization states produced in the target have the same spatial distribution. This allows reference lines from low ionization states to be reliably used to calibrate the spectra from high ionization states.
Date: July 1, 1983
Creator: Gould, H.
System: The UNT Digital Library
Search for Inclusive Oscillations of Muon Neutrinos in the Mass Range, 20 <. Delta. M/sup 2/ < 900 Ev/sup 2/ (open access)

Search for Inclusive Oscillations of Muon Neutrinos in the Mass Range, 20 <. Delta. M/sup 2/ < 900 Ev/sup 2/

A sensitive search for inclusive neutrino oscillations has been performed using two similar detectors running simultaneously at different locations in the Fermilab dichromatic muon-neutrino beam. The preliminary results show no significant oscillation signal and rule out inclusive oscillations of muon neutrinos into any other type of neutrons for 20 < ..delta..m/sup 2/ < 900 eV/sup 2/ and sin/sup 2/(2 theta) > 0.03 to 0.10.
Date: July 1, 1983
Creator: Haber, C.; Auchincloss, P.; Blair, R.; Ruiz, M.; Sciulli, F.; Shaevitz, M. et al.
System: The UNT Digital Library
Volume generation of negative ions in high density hydrogen discharges (open access)

Volume generation of negative ions in high density hydrogen discharges

A parametric survey is made of a high-density tandem two-chamber hydrogen negative ion system. The optimum extracted negative ion current densities are sensitive to the atom concentration in the discharge and to the system scale length. For scale lengths ranging from 10 cm to 0.1 cm optimum current densities range from of order 1 to 100 mA cm/sup -2/, respectively.
Date: July 1, 1983
Creator: Hiskes, J.R. & Karo, A.M.
System: The UNT Digital Library
Monte Carlo sensitivity in jet studies - what is the physics (open access)

Monte Carlo sensitivity in jet studies - what is the physics

Tests of perturbative QCD in hard processes involving jets have been found to depend on the jet fragmentation model used. We emphasize the need for testing the factorization of hard and soft processes, i.e., the independent fragmentation of jets. A method of analysis is suggested, which allows a model-independent determination of the gluon fragmentation function from e/sup +/e/sup -/ data. We also comment on some simple features expected in anti pp ..-->.. (2 or 3 jets) + X events. 19 references.
Date: July 1, 1983
Creator: Hoyer, P.
System: The UNT Digital Library
Status report on dissolution model development (open access)

Status report on dissolution model development

The computer program PROTOCOL models the dissolution reactions of chemical species in water. It is being developed particularly to study the dissolution of proposed nuclear waste forms and related phases. Experimentally derived leaching rate functions are coupled to thermochemical equilibrium calculations and water flow rates. The program has been developed over a period of years. This report describes improvements that have been done in the past year.
Date: July 1, 1983
Creator: Jackson, D. D.
System: The UNT Digital Library
X-ray streak crystal spectography (open access)

X-ray streak crystal spectography

We have built an x-ray streaked crystal spectrograph for making time-resolved x-ray spectral measurements. This instrument can access Bragg angles from 11/sup 0/ to 38/sup 0/ and x-ray spectra from 200 eV to greater than 10 keV. We have demonstrated resolving powers, E/..delta..E > 200 at 1 keV and time resolution less than 20 psec. A description of the instrument and an example of the data is given.
Date: July 1, 1983
Creator: Kauffman, R.L.; Brown, T. & Medecki, H.
System: The UNT Digital Library
Time-resolved spectral measurements above 80 A (open access)

Time-resolved spectral measurements above 80 A

We have made time-resolved spectral measurements above 80 A from laser-produced plasmas. These are made using a transmission grating spectrograph whose primary components are a cylindrically-curved x-ray mirror for light collection, a transmission grating for spectral dispersions, and an x-ray streak camera for temporal resolution. A description of the instrument and an example of the data are given.
Date: July 1, 1983
Creator: Kauffman, R.L.; Ceglio, N. & Medecki, H.
System: The UNT Digital Library
NCIS - a Nuclear Criticality Information System (overview) (open access)

NCIS - a Nuclear Criticality Information System (overview)

A Nuclear Criticality Information System (NCIS) is being established at the Lawrence Livermore National Laboratory (LLNL) in order to serve personnel responsible for safe storage, transport, and handling of fissile materials and those concerned with the evaluation and analysis of nuclear, critical experiments. Public concern for nuclear safety provides the incentive for improved access to nuclear safety information.
Date: July 1, 1983
Creator: Koponen, B. L. & Hampel, V. E.
System: The UNT Digital Library
Exploration and development of the Cerro Prieto geothermal field (open access)

Exploration and development of the Cerro Prieto geothermal field

A multidisciplinary effort to locate, delineate, and characterize the geothermal system at Cerro Prieto, Baja California, Mexico, began about 25 years ago. It led to the identification of an important high-temperature, liquid-dominated geothermal system which went into production in 1973. Initially, the effort was undertaken principally by the Mexican electric power agency, the Comision Federal de Electricidad (CFE). Starting in 1977 a group of US organizations sponsored by the US Department of Energy, joined CFE in this endeavor. An evaluation of the different studies carried out at Cerro Prieto has shown that: (1) surface electrical resistivity and seismic reflection surveys are useful in defining targets for exploratory drilling; (2) the mineralogical studies of cores and cuttings and the analysis of well logs are important in designing the completion of wells, identifying geological controls on fluid movement, determining thermal effects and inferring the thermal history of the field; (3) geochemical surveys help to define zones of recharge and paths of fluid migration; and (4) reservoir engineering studies are necessary in establishing the characteristics of the reservoir and in predicting its response to fluid production.
Date: July 1, 1983
Creator: Lippmann, M. J.; Goldstein, N. E.; Halfman, S. E. & Witherspoon, P. A.
System: The UNT Digital Library
Intense positron beams and possible experiments (open access)

Intense positron beams and possible experiments

In this paper, we survey some of the ideas that have been proposed regarding the production of intense beams of low energy positrons. Various facilities to produce beams of this type are already under design or construction and other methods beyond those in use have been previously discussed. Moreover, a variety of potential experiments utilizing intense positron beams have been suggested. It is to be hoped that this paper can serve as a useful summary of some of the current ideas, as well as a stimulation for new ideas to be forthcoming at the workshop. 31 references.
Date: July 1, 1983
Creator: Lynn, K.G. & Frieze, W.E.
System: The UNT Digital Library
650 mm long liquid hydrogen target for use in a high intensity electron beam (open access)

650 mm long liquid hydrogen target for use in a high intensity electron beam

This paper describes a 650 mm long liquid hydrogen target constructed for use in the high intensity electron beam at the Stanford Linear Accelerator Center. The main design problem was to construct a target that would permit the heat deposited by the electron beam to be removed rapidly without boiling the hydrogen so as to maintain constant target density for optimum data taking. Design requirements, construction details and operating experience are discussed.
Date: July 1, 1983
Creator: Mark, J.W.
System: The UNT Digital Library