146 Matching Results

Search Results

Results: 1 - 24 next
open access

Control of indoor radon and radon progeny concentrations

Description: There are three general categories of techniques for the control of radon and radon progeny concentrations in indoor air - restriction of radon entry, reduction of indoor radon concentrations by ventilation or air cleaning, and removal of airborne radon progeny. The predominant radon entry process in most residences appears to be pressure driven flow of soil gas through cracks or other openings in the basement, slab, or subfloor. Sealing these openings or ventilation of the subslab or subfloor … more
Date: May 1, 1985
Creator: Sextro, R.G.
Partner: UNT Libraries Government Documents Department
open access

New rf power system for SuperHILAC

Description: The upgraded rf system for the SuperHILAC is now operational using 9 new tetrode amplifiers. Each amplifier can produce in excess of 1MW of 70 Mhz pulsed rf power. Ferrite is used to decouple the screen grid circuit and to absorb parasitic oscillations. This results in a very stable amplifier with reasonable gain. This system uses a common 8 MW anode power supply and crowbar system. Overall system efficiency has been increased significantly. We project a 3 year payback on the equipment cost, re… more
Date: May 1, 1985
Creator: Fugitt, J.; Lancaster, H. & Sorensen, R.
Partner: UNT Libraries Government Documents Department
open access

High current beam transport with multiple beam arrays

Description: Highlights of recent experimental and theoretical research progress on the high current beam transport of single and multiple beams by the Heavy Ion Fusion Accelerator Research (HIFAR) group at the Lawrence Berkeley Laboratory (LBL) are presented. In the single beam transport experiment (SBTE), stability boundaries and the emittance growth of a space charge dominated beam in a long quadrupole transport channel were measured and compared with theory and computer simulations. Also, a multiple bea… more
Date: May 1, 1985
Creator: Kim, C.H.
Partner: UNT Libraries Government Documents Department
open access

Lattice and bypass design for a coherent xuv facility

Description: The design of a magnet lattice and bypass for a coherent radiation facility is discussed. The lattice is the missing magnet FODO structure first proposed by Vignola for a 6 GeV light source. This has been adapted for a 750-1300 MeV electron storage ring for use with both conventional insertion devices and a high gain FEL optimized for output at 400 A. The latter device requires that the electron bunch be deflected into a small aperture bypass, then reinjected into the ring where the perturbing … more
Date: May 1, 1985
Creator: Jackson, A.; Garren, A.A. & Vignola, G.
Partner: UNT Libraries Government Documents Department
open access

Metal vapor vacuum arc (MEVVA) high current ion source

Description: An ion source is described in which a metal vapor vacuum arc is used to create the plasma from which the ions are extracted. Beams of a variety of ions have been produced, ranging from lithium up to uranium. At an extraction voltage of 25 kV we've measured an ion beam current of over 1 Ampere, with over 550 ema of the beam in an emittance of 0.07..pi.. cm. mradians (normalized). The ion charge state distribution varies with cathode material and with arc power; for uranium a typical distribution… more
Date: May 1, 1985
Creator: Brown, I.G.
Partner: UNT Libraries Government Documents Department
open access

Difficulties with inferring neutron cross sections from charged-particle reactions

Description: We have investigated problems associated with inferring cross sections for neutron reactions on unstable nuclei in the mass-90 region from charged-particle reactions on nearby stable targets. We conclude that effects due to precompound evaporation, isospin, and multiple reaction paths severely limit the circumstances under which charged-particle studies may be directly and easily converted to neutron cross sections of useful accuracy. 4 refs., 2 figs.
Date: May 7, 1985
Creator: Gardner, D. G. & Gardner, M. A.
Partner: UNT Libraries Government Documents Department
open access

Compact heavy ion RFQ preaccelerator for use at the CERN Linac I

Description: This paper describes the LBL contribution to a project designed to provide fully-stripped oxygen beams for acceleration in the CERN PS complex. A preaccelerator for Linac I, consisting of an ECR ion source, an RFQ linac, and rf matching cavities, is being assembled as part of a collaborative arrangement among LBL, GSI, and CERN. The RFQ, designed and built at LBL, will accept analyzed oxygen +6 beam from the ECR at 5.6 keV/amu, and accelerate it to 139.5 keV/amu, the injection energy required f… more
Date: May 1, 1985
Creator: Gough, R.A.; Staples, J.; Caylor, R.; Howard, D.; MacGill, R. & Tanabe, J.
Partner: UNT Libraries Government Documents Department
open access

LBL neutralized beam focusing experiment

Description: An intense neutralized Cs/sup +1/ beam has been focused by an electrostatic polarization field induced by a solenoidal magnetic field of 10-25 gauss. This report describes the experiment and compares the results with the predictions of an analytic linearized fluid model and a particle-in-cell simulation which treats the motion of the warm electrons in detail.
Date: May 1, 1985
Creator: Krafft, G. A.; Kim, C. H. & Smith, L.
Partner: UNT Libraries Government Documents Department
open access

Search for new effects in e/sup +/e/sup -/ interactions

Description: Recent measurements of R, the ratio of the total hadron cross section to the lowest order muon pair cross section, are discussed which have systematic overall scale errors on the absolute value of R of 7% or less. Experiments are reviewed that have sought exotic effects in e/sup +/e/sup -/ at the highest available energies. The search for narrow states in the radiative decays of the J/psi and UPSILON are also reviewed. 35 refs., 24 figs. (LEW)
Date: May 1, 1985
Creator: Bloom, E.D.
Partner: UNT Libraries Government Documents Department
open access

Application of a dc SQUID to rf Amplification: NQR

Description: Superconducting QUantum Interference Devices (SQUIDs) have been used for more than a decade for the detection of magnetic resonance. Until recently, these devices had mostly been confined to operation in the audiofrequency range, so that experiments have been restricted to measurements of resonance at low frequencies, or of changes in the static susceptibility of a sample induced by rf irradiation at the resonant frequency. However, the recent extension of the operating range of low noise dc SQ… more
Date: May 1, 1985
Creator: Hilbert, C.; Clarke, J.; Sleator, T. & Hahn, E. L.
Partner: UNT Libraries Government Documents Department
open access

Analytical methods of electrode design for a relativistic electron gun

Description: The standard paraxial ray equation method for the design of electrodes for an electrostatically focused gun is extended to include relativistic effects and the effects of the beam's azimuthal magnetic field. Solutions for parallel and converging beams are obtained and the predicted currents are compared against those measured on the High Brightness Test Stand. 4 refs., 2 figs.
Date: May 9, 1985
Creator: Caporaso, G.J.; Cole, A.G. & Boyd, J.K.
Partner: UNT Libraries Government Documents Department
open access

Nu shifts in betatron oscillations from uniform perturbations in the presence of non-linear magnetic guide fields

Description: Uniform magnetic field perturbations cause a closed orbit distortion in a circular accelerator. If the magnetic guide field is non-linear these perturbations can also cause a Nu shift in the betatron oscillations. Such a shift in radial Nu values has been observed in the Bevalac while studying the low energy resonant extraction system. In the Bevalac, the radial perturbation comes from the quadrants being magnetically about 0.8% longer than 90/sup 0/. The normal effect of this type of perturbat… more
Date: May 1, 1985
Creator: Crebbin, K. C.
Partner: UNT Libraries Government Documents Department
open access

Effect of focusing field nonlinearities in MBE-4 on transverse beam dynamics

Description: A particle simulation code was used to study the effect on transverse beam dynamics of nonlinearities of the focusing field in a linear accelerator transporting a multiple beam array. Nonlinear field strengths for various multiple-beam design geometries were calculated by relaxation codes for use in the simulation calculation. Nonlinearities due to asymmetry of the electrode array with respect to a single beam were found to be negligible. Electrode end effect nonlinearities led to emittance gro… more
Date: May 1, 1985
Creator: Celata, C. M.; Brady, V. O.; Laslett, L. J.; Smith, L. & Haber, I.
Partner: UNT Libraries Government Documents Department
open access

Limits on likesign dilepton production in nu/sub. mu. / interactions

Description: We have searched for the production of likesign dilepton events (nu/sub ..mu../ + Ne ..-->.. ..mu../sup -/ + e/sup -/ + ...) in a wideband neutrino beam at FNAL using the 15' bubble chamber. We observe no signal above the background arising from conventional sources. We set 90% confidence level upper limits for the production rates of (nu/sub ..mu../ + Ne ..-->.. ..mu../sup -/ + e/sup -/ + ...)/(nu/sub ..mu../ + Ne ..-->.. ..mu../sup -/ + ...) less than or equal to 8 * 10/sup -5/ and (nu/sub ..… more
Date: May 21, 1985
Creator: Baker, N. J.; Connolly, P. L.; Kahn, S. A.; Murtagh, M. J.; Palmer, R. B.; Samios, N. P. et al.
Partner: UNT Libraries Government Documents Department
open access

High temperature experiment for accelerator inertial fusion

Description: The High Temperature Experiment (HTE) is intended to produce temperatures of 50 to 100 eV in solid density targets driven by heavy ion beams from a multiple beam induction linac. The fundamental variables (particle species, energy, number of beamlets, current and pulse length) must be fixed to achieve the temperature at minimum cost, subject to criteria of technical feasibility and relevance to the development of a Fusion Driver. The conceptual design begins with an assumed (radiation-limited) … more
Date: May 1, 1985
Creator: Lee, Edward P.
Partner: UNT Libraries Government Documents Department
open access

Spin-polarization observables in elastic electron scattering from spin-1/2 nuclei

Description: Using the formalism of nucleon-nucleon scattering as a starting point, electron scattering from spin-1/2 nuclei is examined. It is seen that high-energy electron-nucleon scattering, for example, exhibits a remarkable simplicity when compared with that of nucleon-nucleon scattering. The 6 amplitudes and 36 nucleon-nucleon observables are reduced to 3 and 9, respectively, by the relativistic nature of the electron. The one-photon exchange mechanism finally reduces the number of amplitudes and ind… more
Date: May 1, 1985
Creator: Conzett, H.E.
Partner: UNT Libraries Government Documents Department
open access

Transportable charge in a periodic alternating gradient system

Description: A simple set of formulas is derived which relate emittance, line charge density, matched maximum and average envelope radii, occupancy factors, and the (space charge) depressed and vacuum values of tune. This formulation is an improvement on the smooth limit approximation; deviations from exact (numerically determined) relations are on the order of +-2%, while the smooth limit values are in error by up to +-30%. This transport formalism is used to determine the limits of transportable line char… more
Date: May 1, 1985
Creator: Lee, E.P.; Fessenden, T.J. & Laslett, L.J.
Partner: UNT Libraries Government Documents Department
open access

Measurements of stability limits for a space-charge-dominated ion beam in a long A. G. transport channel

Description: The Single Beam Transport Experiment at LBL consists of 82 electrostatic quadrupole lenses arranged in a FODO lattice. Five further lenses provide a matched beam from a high-current high-brightness cesium source for injection into the FODO channel. We call the transport conditions stable if both the emittance and current remain unchanged between the beginning and end of the channel, and unstable if either the emittance grows or the current decreases because of collective effects. We have explor… more
Date: May 1, 1985
Creator: Tiefenback, M.G. & Keefe, D.
Partner: UNT Libraries Government Documents Department
open access

High-spin properties of some nuclei around A = 160

Description: Two new types of behavior have been observed in /sup 156/Er. The first is a terminating band ending on a 42+ fully aligned state. The second is a strong cross feeding among four negative parity bands, due most likely to a severe reduction or collapse of the neutron pairing. In /sup 158/Er we have found two sequences feeding the 38+ level; one slow and one fast. This suggests that some feeding goes through regions of oblate (or nearly so) shapes, and some does not. Lifetimes have been determined… more
Date: May 1, 1985
Creator: Stephens, F.S.
Partner: UNT Libraries Government Documents Department
open access

Macroscopic quantum effects in the zero voltage state of the current biased Josephson junction

Description: When a weak microwave current is applied to a current-biased Josephson tunnel junction in the thermal limit the escape rate from the zero voltage state is enhanced when the microwave frequency is near the plasma frequency of the junction. The resonance curve is markedly asymmetric because of the anharmonic properties of the potential well: this behavior is well explained by a computer simulation using a resistively shunted junction model. This phenomenon of resonant activation enables one to ma… more
Date: May 1, 1985
Creator: Clarke, J.; Devoret, M. H.; Martinis, J. & Esteve, D.
Partner: UNT Libraries Government Documents Department
open access

Acceleration of compact torus plasma rings in a coaxial rail-gun

Description: We discuss here theoretical studies of magnetic acceleration of Compact Torus plasma rings in a coaxial, rail-gun accelerator. The rings are formed using a magnetized coaxial plasma gun and are accelerated by injection of B/sub theta/ flux from an accelerator bank. After acceleration, the rings enter a focusing cone where the ring is decelerated and reduced in radius. As the ring radius decreases, the ring magnetic energy increases until it equals the entering kinetic energy and the ring stagna… more
Date: May 16, 1985
Creator: Hartman, C. W.; Hammer, J. H. & Eddleman, J.
Partner: UNT Libraries Government Documents Department
open access

LAMPF workshop on Dirac approaches to nuclear physics: proceedings

Description: Separate abstracts were prepared for 20 papers in this proceedings. Two other papers were previously abstracted for EDB. (LEW)
Date: May 1, 1985
Creator: Shepard, J.R.; Cheung, C.Y. & Boudrie, R.L. (eds.)
Partner: UNT Libraries Government Documents Department
open access

Reaction cross-section calculations using new experimental and theoretical level structure data for deformed nuclei

Description: A technique for modeling level structures of odd-odd nuclei has been used to construct sets of discrete states with energies in the range 0 to 1.5 MeV for several nuclei in the rare-earth and actinide regions. The accuracy of the modeling technique was determined by comparison with experimental data. Examination was made of what effect the use of these new, more complete sets of discrete states has on the calculation of level densities, total reaction cross sections, and isomer ratios. 9 refs.
Date: May 1, 1985
Creator: Hoff, R. W.; Gardner, D. G. & Gardner, M. A.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen