64 Matching Results

Results open in a new window/tab.

New collider scheme at LBL (open access)

New collider scheme at LBL

This paper presents current ideas from Berkeley concerning a possible new facility for studying the phase transition from hadronic matter to quark matter. The physics ideas have evolved over a period of more than five years, the VENUS concept for a 25 GeV/nucleon colliding beam facility having been presented in 1979. The concept for the Minicollider has been, like that of VENUS, the work of Hermann Grunder and Christoph Leemann.
Date: July 1, 1984
Creator: Pugh, Howel G.
System: The UNT Digital Library
First- and second-order charged particle optics (open access)

First- and second-order charged particle optics

Since the invention of the alternating gradient principle there has been a rapid evolution of the mathematics and physics techniques applicable to charged particle optics. In this publication we derive a differential equation and a matrix algebra formalism valid to second-order to present the basic principles governing the design of charged particle beam transport systems. A notation first introduced by John Streib is used to convey the essential principles dictating the design of such beam transport systems. For example the momentum dispersion, the momentum resolution, and all second-order aberrations are expressed as simple integrals of the first-order trajectories (matrix elements) and of the magnetic field parameters (multipole components) characterizing the system. 16 references, 30 figures.
Date: July 1, 1984
Creator: Brown, K.L. & Servranckx, R.V.
System: The UNT Digital Library
Workshop on geophysical modeling of the Long Valley caldera: proceedings (open access)

Workshop on geophysical modeling of the Long Valley caldera: proceedings

Rapporteur's summary reports are given the following workshop sessions: geological background and overview of the Long Valley hydrothermal-magnetic system and processes, concepts and models based on seismological data, electrical and electromagnetic models, and deformation and gravity. 31 references, 36 figures. (MHR)
Date: July 1, 1984
Creator: Goldstein, N.E. (ed.)
System: The UNT Digital Library
Nonrelativistic theory of heavy-ion collisions (open access)

Nonrelativistic theory of heavy-ion collisions

A wide range of phenomena is observed in heavy-ion collisions, calling for a comprehensive theory based on fundamental principles of many-particle quantum mechanics. At low energies, the nuclear dynamics is controlled by the mean field, as we know from spectroscopic nuclear physics. We therefore expect the comprehensive theory of collisions to contain mean-field theory at low energies. The mean-field theory is the subject of the first lectures in this chapter. This theory can be studied quantum mechanically, in which form it is called TDHF (time-dependent Hartree-Fock), or classically, where the equation is called the Vlasov equation. 25 references, 14 figures.
Date: July 17, 1984
Creator: Bertsch, G.
System: The UNT Digital Library
Atom location by electron channeling analysis (open access)

Atom location by electron channeling analysis

For many years the orientation dependence of the characteristic x-ray emission close to a Bragg reflection has been regarded as a hindrance to accurate microanalysis, and a random incident beam direction has always been recommended for accurate composition analysis. However, this orientation dependence can be put to use to extract information on the lattice location of foreign atoms within the crystalline matrix. Here a generalization of the technique is described which is applicable to any crystal structure including monatomic crystals, and can quantitatively determine substitutional fractions of impurities. The technique was referred to as electron channeling analysis, by analogy with the closely related and widely used bulk technique of ion channeling analysis, and was developed for lattice location studies of dopants in semiconductors at high spatial resolution. Only two spectra are required for each channeling analysis, one in each of the channeling conditions described above. If the matrix and dopant x-ray yields vary identically between the two orientations then the dopant necessarily lies within the reflecting matrix planes. If the dopant x-ray yield does not vary the dopant atoms are randomly located with respect to the matrix planes. 10 references, 2 figures.
Date: July 1, 1984
Creator: Pennycook, S.J.
System: The UNT Digital Library
High-bandwidth multichannel fiber optic system for measuring gamma rays (open access)

High-bandwidth multichannel fiber optic system for measuring gamma rays

We describe an analog fiber optic gamma-ray diagnostic system that can transmit signals through fiber cables 600 to 700 m long with a system bandwidth exceeding 1 GHz and measure the relative timing between signals to within 0.3 ns. Gamma rays are converted to visible light via the Cerenkov process in a short length of a radiation-resistant optical fiber. A graded-index optical fiber transmits this pulse to a recording station where the broadened pulse is compensated for material dispersion and recorded using a streak camera. The streak camera can simultaneously record 20 to 30 data channels on a single piece of film. The system has been calibrated using electron linear accelerators and fielded on two experiments.
Date: July 1, 1984
Creator: Roeske, F.; Smith, D. E.; Pruett, B. L. & Reedy, R. P.
System: The UNT Digital Library
TREAT light water reactor source term experiments program (open access)

TREAT light water reactor source term experiments program

Pre-test calculations indicate that, for the STEP-1 (Source Term Experimental Program) test, cladding temperatures in excess of 4200/sup 0/F can be reached on a heatup transient similar to that of the AD accident sequence in a 20-min test duration. This is well above the Zircaloy melting point of approx. 3350/sup 0/F and should provide a degree of cladding disruption sufficient to allow a singificant release of products from the fuel into the flowing steam. The same temperature range can be reached in a 60-min-duration run to simulate the TQUW sequence for the STEP-2 test. The complete paper will present initial experimental results from these two tests and perhaps from the two TMLB' simulations run without and with control rod material in STEP-3 and STEP-4, respectively.
Date: July 1, 1984
Creator: Herceg, J. E.
System: The UNT Digital Library
Theoretical studies in tandem mirror physics (open access)

Theoretical studies in tandem mirror physics

Recent developments in six areas of tandem-mirror theory are explored. Specifically, FLR terms (including electric-field drift) have been added to our 3-D paraxial MHD equilibrium code. Our low-frequency MHD stability analysis with FLR, which previously included only m/sub theta/ = 1 rigid perturbations, has been extended to incorporate moderate m/sub theta/, rotational drive, finite-beta effects on wall stabilization, and the well-digging effect of energetic electrons by using three computational techniques. In addition, we have examined the microstability of relativistic electrons with a loss-cone distribution, emphasizing the whistler and cyclotron-maser instabilities. We have also studied techniques for controlling radial transport, including the floating of segmented end plates and the tuning of transition-region coils, and have quantified the residual transport in a tandem mirror with axisymmetric throttle coils. Earlier work on the effect of ECRH on potentials in thermal-barrier cells has been extended. The transition between the weak- and strong-heating regimes has been examined using Fokker-Planck and Monte Carlo codes; an analytic model for the potentials relative to the end wall has been developed. Finally, our investigation of drift-frequency pumping of thermal-barrier ions has demonstrated that pumping is optimized when the magnetic fluctuation is perpendicular to both the unperturbed field and the …
Date: July 17, 1984
Creator: Cohen, R. H.; Auerbach, S. P.; Baldwin, D. E.; Byers, J. A.; Chen, Y. J.; Cohen, B. I. et al.
System: The UNT Digital Library
Large linear colliders (open access)

Large linear colliders

This lecture is a status report on work we have been doing at SLAC on studies of large linear colliders (LLC) with energies far beyond those attainable with either the SLC or LEP.
Date: July 1, 1984
Creator: Richter, Burton
System: The UNT Digital Library
Parity nonconservation in proton-proton and proton-water scattering at 1. 5 GeV/c (open access)

Parity nonconservation in proton-proton and proton-water scattering at 1. 5 GeV/c

Experiments searching for parity nonconservation in the scattering of 1.5 GeV/c (800 MeV) polarized protons from an unpolarized water target and a liquid hydrogen target are described. The intensity of the incident proton beam was measured upstream and downstream of the target by a pair of ionization detectors. The beam helicity was reversed at a 30-Hz rate. Auxiliary detectors monitored beam properties that could give rise to false effects. The result for the longitudinal asymmetry from the water is A/sub L/ = (1.7 +- 3.3 +- 1.4) x 10/sup -7/, where the first error is statistical and the second is an estimate of systematic effects. The hydrogen data yield a preliminary result of A/sub L/ = (1.0 +- 1.6) x 10/sup -7/. The systematic errors for p-p are expected to be < 1 x 10/sup -7/.
Date: July 1, 1984
Creator: Mischke, R. E.; Bowman, J. D.; Carlini, R.; MacArthur, D.; Nagle, D. E.; Frauenfelder, H. et al.
System: The UNT Digital Library
Activated barrier for protection of special nuclear materials in vital areas (open access)

Activated barrier for protection of special nuclear materials in vital areas

The Argonne National Laboratory and Sandia National Laboratory have recently installed an activated barrier, the Access Denial System (ADS) for the upgrade of safeguards of special nuclear materials. The technology of this system was developed in the late 70's by Sandia National Laboratory-Albuquerque. The installation was the first for the Department of Energy. Subsequently, two additional installations have been completed. The Access Denial System, combined with physical restraints, provide the system delay. The principal advantages of the activated barrier are: (1) it provides an order of magnitude improvement in delay over that of a fixed barrier, (2) it can be added to existing vital areas with a minimum of renovations, (3) existing operations are minimally impacted, and (4) health and safety risks are virtually nonexistent. Hardening of the vital areas using the ADS was accomplished in a cost-effective manner. 3 references, 1 figure, 1 table.
Date: July 15, 1984
Creator: Timm, R. E.; Miranda, J. E.; Reigle, D. L. & Valente, A. D.
System: The UNT Digital Library
Neutron spectra as a function of angle at two meters from the Little Boy assembly (open access)

Neutron spectra as a function of angle at two meters from the Little Boy assembly

Measurements of neutron spectra produced by the Los Alamos National Laboratory (LANL) Little Boy replica assembly (Comet) were made with a combined multisphere and liquid scintillator system, that has been widely used at the Lawrence Livermore National Laboratory. The combined system was used for measurements at the side (90/sup 0/) and nose (0/sup 0/) of the assembly; additional measurements were made at 45/sup 0/ using only the liquid scintillator. Data were obtained at two meters from the center of the reactive region of the assembly, with good agreement between the multisphere and scintillator results. Comparison with liquid scintillator measurements performed by experimenters from the Canadian Defence Research Establishment, Ottawa (DREO) and calculations from LANL depended on the specific angle, obtaining the best agreement at 90/sup 0/. 32 references, 11 figures, 4 tables.
Date: July 2, 1984
Creator: Griffith, R.V.; Huntzinger, C.J. & Thorngate, J.H.
System: The UNT Digital Library
Multivent effects in a large scale boiling water reactor pressure suppression system (open access)

Multivent effects in a large scale boiling water reactor pressure suppression system

The steam-driven GKSS pressure suppression test facility, which contains 3 full scale vent pipes, has been used for 5 years to investigate the postulated loss-of-coolant accident in a Mark II and Type 69 boiling water reactor. Using the results from several of these tests, wetwell boundary load data (peak pressures and spectral power) during the chugging stage, have been evaluated for sparse pool response (one and two vents in the three vent pool) and for full pool response (one, two, or three vent operation in pools of constant wetwell pool area per vent). The sparse pool results indicate the pool-system, chug event boundary loads are strongly dependent on wetwell pool area per vent, with the load increasing with decreasing area. The full pool results show a substantial increase in the pool-system, chug event boundary loads upon a change from single cell to double cell operation; only minor change occurs in going from double to triple cell operation.
Date: July 6, 1984
Creator: McCauley, E.W.; Aust, E. & Schwan, H.
System: The UNT Digital Library
X-ray L. beta. /sub 2/ /sub 15/ emission spectrum of Ru in Ru(NH/sub 3/)/sub 6/Cl/sub 3/ (open access)

X-ray L. beta. /sub 2/ /sub 15/ emission spectrum of Ru in Ru(NH/sub 3/)/sub 6/Cl/sub 3/

One of the broader applications of synchrotron radiation has been to EXAFS studies for material structure determination, i.e., for an analysis of x-ray absorption over an extended energy region beyond a core ionization limit. Studies of the near edge structure (XANES) give a different type of information, characteristic of the local symmetry and electronic configuration of the absorbing atom. This type of information is reflected also in the x-ray emission spectra, in particular for transitions involving the valence levels. Examination of the near edge absorption or the emission spectrum does not require an instrument capable of scanning a wide energy range with high counting statistics, as does EXAFS; the needs are rather for good resolution and a reliable calibration of the energy scale. Some of the problems of near edge spectra were particularly evident in our investigation of Ru-L..beta../sub 2/ /sub 15/ emission from Ru(NH/sub 3/)/sub 6/Cl/sub 3/. The Ru-L..beta../sub 2/ /sub 15/ emission was measured with a laboratory Rowland circle x-ray spectrometer with a curved quartz (1010) crystal (radius = 22 inches) in a fixed position appropriate to the energy range, and a position sensitive detector which can be positioned along the Rowland circle. The Ru spectrum was excited …
Date: July 1, 1984
Creator: Perera, R.C.C.; Barth, J.; LaVilla, R.E. & Nordling, C.
System: The UNT Digital Library
Review of trigger and on-line processors at SLAC (open access)

Review of trigger and on-line processors at SLAC

The role of trigger and on-line processors in reducing data rates to manageable proportions in e/sup +/e/sup -/ physics experiments is defined not by high physics or background rates, but by the large event sizes of the general-purpose detectors employed. The rate of e/sup +/e/sup -/ annihilation is low, and backgrounds are not high; yet the number of physics processes which can be studied is vast and varied. This paper begins by briefly describing the role of trigger processors in the e/sup +/e/sup -/ context. The usual flow of the trigger decision process is illustrated with selected examples of SLAC trigger processing. The features are mentioned of triggering at the SLC and the trigger processing plans of the two SLC detectors: The Mark II and the SLD. The most common on-line processors at SLAC, the BADC, the SLAC Scanner Processor, the SLAC FASTBUS Controller, and the VAX CAMAC Channel, are discussed. Uses of the 168/E, 3081/E, and FASTBUS VAX processors are mentioned. The manner in which these processors are interfaced and the function they serve on line is described. Finally, the accelerator control system for the SLC is outlined. This paper is a survey in nature, and hence, relies heavily …
Date: July 1, 1984
Creator: Lankford, A.J.
System: The UNT Digital Library
Collider Detector (CDF) at FERMILAB: an overview (open access)

Collider Detector (CDF) at FERMILAB: an overview

CDF, the Collider Detector at Fermilab, is a collaboration of almost 150 physicists from ten US universities (University of Chicago, Brandeis University, Harvard University, University of Illinois, University of Pennsylvania, Purdue University, Rockefeller University, Rutgers University, Texas A and M University, and University of Wisconsin), three US DOE supported national laboratories (Fermilab, Argonne National Laboratory, and Lawrence Berkeley Laboratory), Italy (Frascati Laboratory and University of Pisa), and Japan (KEK National Laboratory and Unversity of Tsukuba). The primary physics goal for CDF is to study the general features of proton-antiproton collisions at 2 TeV center-of-mass energy. On general grounds, we expect that parton subenergies in the range 50 to 500 GeV will provide the most interesting physics at this energy. Work at the present CERN Collider has already demonstrated the richness of the 100 GeV scale in parton subenergies.
Date: July 1, 1984
Creator: Theriot, D.
System: The UNT Digital Library
Thermal barrier confinement experiments in the TMX-U tandem mirror (open access)

Thermal barrier confinement experiments in the TMX-U tandem mirror

In our recent experiments on the TMX-U thermal-barrier device, we achieved the end plugging of axial ion losses up to a central cell density of n/sub c/ = 6 x 10/sup 12/ cm/sup -3/. During lower density experiments, we measured the axial potential profile characteristic of a thermal barrier and found an ion-confining potential greater than 1.5 kV and a potential depression of 0.45 kV in the barrier region. The average beta of hot end plug electrons has reached 15% and of hot central cell ions has reached 6%. In addition, we heated deuterium ions in the central cell with ICRF to an average perpendicular energy of 2 keV. During strong end plugging at low density (7 x 10/sup 11/ cm/sup -3/), the axial ion confinement time tau/sub parallel/ reached 50 to 100 ms while the nonambipolar radial ion confinement time tau/sub perpendicular/ was 14 ms - independent of end plugging. Electrically floating end walls increased the radial ion confinement time by a factor of 1.8. At higher densities and lower potentials, tau/sub parallel/ was 6 to 12 ms and tau/sub perpendicular/ exceeded 100 ms.
Date: July 26, 1984
Creator: Simonen, T. C.; Allen, S. L.; Baldwin, D. E.; Casper, T. A.; Clauser, J. F.; Coensgen, F. H. et al.
System: The UNT Digital Library
Elevated Temperature Creep Behavior of Inconel Alloy 625 (open access)

Elevated Temperature Creep Behavior of Inconel Alloy 625

Inconel 625 in the solution-annealed condition has been selected as the clad material for the fuel and control rod housing assemblies of the Upgraded Transient Reactor Test Facility (TREAT Upgrade or TU). The clad is expected to be subjected to temperatures up to about 1100/sup 0/C. Creep behavior for the temperature range of 800/sup 0/C to 1100/sup 0/C of Inconel alloy 625, in four distinct heat treated conditions, was experimentally evaluated.
Date: July 1984
Creator: Purohit, A. & Burke, W. F.
System: The UNT Digital Library
Inertial confinement fusion: present status and future potential (open access)

Inertial confinement fusion: present status and future potential

Power from inertial confinement fusion holds much promise for society. This paper points out many of the benefits relative to combustion of hydrocarbon fuels and fission power. Potential problems are also identified and put in perspective. The progress toward achieving inertial fusion power is described and results of recent work at the Lawrence Livermore National Laboratory are presented. Key phenomenological uncertainties are described and experimental goals for the Nova laser system are given. Several ICF reactor designs are discussed.
Date: July 16, 1984
Creator: Hogan, W.J.
System: The UNT Digital Library
Refrigeration tests of the cryogenic system and solenoid for the Fermilab Collider Detector (open access)

Refrigeration tests of the cryogenic system and solenoid for the Fermilab Collider Detector

A refrigeration system for the 3 m phi x 5 m superconducting solenoid for the Collider Detector at Fermilab has been installed and operated with a dummy load. The nominal 600-W capacity of the system was achieved in the initial test. The solenoid and integral control dewar were tested in Japan with a 300-W refrigerator. The cooldown time was 7 days and the measured heat load of 35 W agrees well with the estimated value.
Date: July 1, 1984
Creator: Fast, R. W.; Aihara, K.; Dachniwskyj, R. I.; Kephart, R. D.; Kondo, K.; Minemura, H. et al.
System: The UNT Digital Library
Thermal barrier confinement experiments in TMX-U tandem mirror. Revision 1 (open access)

Thermal barrier confinement experiments in TMX-U tandem mirror. Revision 1

In our recent experiments on the TMX-U thermal-barrier device, we achieved the end plugging of axial ion losses up to a central cell density of n/sub c/ = 6 x 10/sup 12/ cm/sup -3/. During lower density experiments, we measured the axial potential profile characteristic of a thermal barrier and found an ion-confining potential greater than 1.5 kV and a potential depression of 0.45 kV in the barrier region. The average beta of hot end plug electrons has reached 15% and of hot central cell ions has reached 6%. In addition, we heated deuterium ions in the central cell with ICRF to an average perpendicular energy of 2 keV. During strong end plugging at low density (7 x 10/sup 11/ cm/sup -3/), the axial ion confinement time tau/sub parallel to/ reached 50 to 100 ms while the nonambiopolar radial ion confinement time tau/sub perpendicular to/ was 14 ms - independent of end plugging. Electrically floating end walls doubled the radial ion confinement time. At higher densities and lower potentials, tau/sub parallel to/ was 6 to 12 ms and tau/sub perpendicular to/ exceeded 100 ms.
Date: July 26, 1984
Creator: Simonen, T. C.; Allen, S. L.; Baldwin, D. E.; Casper, T. A.; Clauser, J. F.; Coensgen, F. H. et al.
System: The UNT Digital Library
K-edge x-ray fluorescence analysis for actinide and heavy elements solution concentration measurements (open access)

K-edge x-ray fluorescence analysis for actinide and heavy elements solution concentration measurements

Advantages of using Co-57 as an exciter for K XRFA include: a compact design that requires no x-ray tubes; the exciter-detector assembly locates remote from support electronics; on-line, at-line, or off-line configurations for monitor/measurements; systems that can be run by semi-skilled technicians, once programmed; and operated via remote terminals with results sent to control rooms; heavy element concentrations that are measurable thru industrial pipes; independent of minor changes in solution matrix or source half life with concentration results reported in near-real-time; a dynamic range of measurable concentrations that is greater than 10/sup 4/; measurement times that are reasonable even at 1 gram/liter; and for nuclear safeguards, it provides the <0.5% accuracy required by DOE for the accountability of U, Pu, or both, once the system is calibrated.
Date: July 1, 1984
Creator: Camp, David C.
System: The UNT Digital Library
Comparison of a center and off-center BWR control rod drop accident (open access)

Comparison of a center and off-center BWR control rod drop accident

A BWR control rod drop accident (RDA) induces a rapid core power transient involving strong neutronic/thermal-hydraulic coupling, which requires a detailed multi-dimensional spatial kinetics analysis. Typical two-dimensional (r,z) RDA calculations require that the dropped rod be a center rod, as a result of geometric limitations, while in three-dimensional (x,y,z) calculations the dropped rod is generally taken to be the center rod in order to allow a quarter-core representation and limit computer running times. However, for typical BWR core loadings, the highest worth rod is not necessarily the center rod and it is not known, a priori, what effect this difference in spatial location has on the RDA dynamics. In order to evaluate the effects of this simplification, three-dimensional RAMONA-3B calculations have been performed for both a center and off-center control rod drop accident.
Date: July 1, 1984
Creator: Cokinos, D.M.; Neogy, P. & Carew, J.F.
System: The UNT Digital Library
Ground Motions and Its Effects in Accelerator Design (open access)

Ground Motions and Its Effects in Accelerator Design

This lecture includes a discussion of types of motion, frequencies of interest, measurements at SLAC, some general comments regarding local sources of ground motion at SLAC, and steps that can be taken to minimize the effects of ground motion on accelerators. (GHT)
Date: July 1984
Creator: Fischer, G. E.
System: The UNT Digital Library