25,168 Matching Results

Search Results

Results: 1 - 24 next
open access

Particle identification in ultrarelativistic nuclear collisions

Description: The role of particle identification (PID) in both fixed-target and colliding-beam studies of ultrarelativistic nuclear (URN) collisions is examined. The demands placed on the PID systems by peculiarities of URN collisions, such as large multiplicities and the need for simultaneous measurement of a number of observables, are discussed. A variety of PID techniques are reviewed, with emphasis on their applicability and efficiency in the environment of such collisions. Two examples of PID as incorp… more
Date: April 1, 1986
Creator: DiGiacomo, N.J.
Partner: UNT Libraries Government Documents Department
open access

Prospects for physics at e/sup +/e/sup -/ linear colliders

Description: The present thinking on high-energy e/sup /plus//e/sup /minus// linear colliders is reviewed, stressing those points that have consequences for detector design and physics analyses. Detector requirements are discussed. Experimental aspects of the physics that can be done at these colliders are discussed: first the general physics environment, then a standard process, W/sup /plus// W/sup /minus// detection, and finally four examples of the discovery potential of these colliders /emdash/ heavy qu… more
Date: March 1, 1988
Creator: Feldman, G. J.
Partner: UNT Libraries Government Documents Department
open access

Rigid muffin-tin approximation for the electron-phonon interaction in transition metals

Description: Progress in calculating the electron-phonon parameters of transition metals has been based on either the rigid muffin-tin approximation (RMTA) or the fitted modified tight-binding approximation (FMTBA). The RMTA has been shown to be remarkably accurate for average electron-phonon properties, but there are indications that RMTA matrix elements may be too small at low momentum transfer. An attempt is made to demonstrate these assertions concerning the accuracy of RMTA and the numerous electron-ph… more
Date: January 1, 1980
Creator: Butler, W. H.
Partner: UNT Libraries Government Documents Department
open access

Nuclear safety guide TID-7016 Revision 2

Description: The present revision of TID-7016 Nuclear Safety Guide is discussed. This Guide differs significantly from its predecessor in that the latter was intentionally conservative in its recommendations. Firmly based on experimental evidence of criticality, the original Guide and the first revision were considered to be of most value to organizations whose activities with fissionable materials were not extensive and, secondarily, that it would serve as a point of departure for members of established nu… more
Date: January 1, 1980
Creator: Thomas, J T
Partner: UNT Libraries Government Documents Department
open access

Assessment of light water reactor fuel damage during a reactivity initiated accident

Description: This paper presents an assessment of LWR fuel damage during a reactivity initiated accident and comments on the adequacy of the present USNRC design requirements. Results from early SPERT tests are reviewed and compared with results from recent computer simulations and PBF tests. A progression of fuel rod and cladding damage events is presented. High strain rate deformation of relatively cool irradiated cladding early in the transient may result in fracture at a radial average peak fuel enthalp… more
Date: January 1, 1980
Creator: MacDonald, P. E.; Seiffert, S. L.; Martinson, Z. R.; McCardell, R. K.; Owen, D. E. & Fukuda, S. K.
Partner: UNT Libraries Government Documents Department
open access

Recovery of deformed and hydrogen-charge palladium

Description: Positron lifetime and Doppler-broadening studies made at 300 K have been used to investigate the interaction between interstitial hydrogen and lattice defects in deformed Pd. Specimens were charged with hydrogen at 300 K to levels up to 0.1%. The presence of hydrogen was found to have no effect on the recovery curves of Pd upon annealing to 400/sup 0/C. By 400/sup 0/C the values for both lifetime and Doppler-broadening for both cold worked and cold worked plus hydrogen were below the values obt… more
Date: January 1, 1982
Creator: Snead, C. L. Jr.; Lynn, K. G. & Lynch, J. F.
Partner: UNT Libraries Government Documents Department
open access

INSPECT: a package of computer programs for planning and evaluating safeguards inspections

Description: As part of the US Program of Technical Assistance to IAEA Safeguards, PNL has developed a package of computer programs, called INSPECT, that can be used in planning and evaluating safeguards inspections of various types of nuclear facilities. The programs are based on the statistical methods described in Part F of the IAEA Safeguards Technical Manual and can be used to calculate the variance components of the MUF (Material Unaccounted For) statistic, the variance components of the D (difference… more
Date: January 1, 1980
Creator: Mullen, M.F.
Partner: UNT Libraries Government Documents Department
open access

Bag model, the hyperspherical formalism and the heavy baryons

Description: The bag model framework is used to discuss the heavy baryons, triple flavored objects like ccc, cbb, etc. A nonrelativistic picture seems justified. It is insisted that the long-range interaction consist of a genuine three-body force. Once the potential energy of the three quarks is determined, the three-body Schroedinger equation is solved by the method of hyperspherical expansion. 1 table. (RWR)
Date: January 1, 1980
Creator: Richard, J. M.
Partner: UNT Libraries Government Documents Department
open access

Excitation of giant resonances via direct reactions

Description: Experimental measurements of electric giant multipole resonances are discussed. The parameters of the giant quadrupole resonance are now firmly established by an extensive set of measurements. The GQR is providing a significant influence in other areas of nuclear physics. The monopole resonance has now been established and its observation has provided the first direct measure of the nuclear compressibility. A strong case for the existence of a giant octupole resonance is now being made through … more
Date: January 1, 1982
Creator: Bertrand, F.E.
Partner: UNT Libraries Government Documents Department
open access

Picotron 100 streak tubes as a 150-channel photometer

Description: The characterization of a streak camera based upon Picotron 100 tube types is given. Both a large (30 cm 1 x 10 cm dia.) and a small (18 cm 1 x 5 cm dia.) version of this design has been tested. Over 150 channels of information are simultaneously time resolved with system S.N.R. of 3 at 100 picosecond time resolution without post intensification. Absolute photometric evaluation is given in the dynamic mode, i.e. while operating in the picosecond time domain. Such quantitative data has been lack… more
Date: January 1, 1982
Creator: Majumdar, S.; Weiss, P.B. & Black, J.P.
Partner: UNT Libraries Government Documents Department
open access

Recent experimental results on the beam-beam effects in storage rings and an attempt of their interpretation

Description: The latest available experimental results on the luminosity, the space charge parameters, and the beam blowup as functions of particle energy and beam current are reviewed. The comparison with the phenomenological diffusion theory is done and useful scaling laws are derived. Some implications for anti p p storage rings are discussed.
Date: June 1, 1980
Creator: Kheifets, S.
Partner: UNT Libraries Government Documents Department
open access

Impulsive ion acceleration in earth's outer magnetosphere

Description: Considerable observational evidence is found that ions are accelerated to high energies in the outer magnetosphere during geomagnetic disturbances. The acceleration often appears to be quite impulsive causing temporally brief (10's of seconds), very intense bursts of ions in the distant plasma sheet as well as in the near-tail region. These ion bursts extend in energy from 10's of keV to over 1 MeV and are closely associated with substorm expansive phase onsets. Although the very energetic ions… more
Date: January 1, 1985
Creator: Baker, D.N. & Belian, R.D.
Partner: UNT Libraries Government Documents Department
open access

Proceedings of the LAMPF workshop on physics with polarized nuclear targets

Description: Topics of discussion included static and dynamic methods for polarizing nuclei, proton and pion nucleus scattering experiments, and possible future experiments at LAMPF. Separate abstracts were prepared for 11 papers in this report. (DWL)
Date: August 1, 1986
Creator: Burleson, G.; Gibbs, W.; Hoffmann, G.; Jarmer, J. J. & Tanaka, N. (eds.)
Partner: UNT Libraries Government Documents Department
open access

Relativistic effects in the atomic and nuclear few-body problems

Description: Relativistic effects in the atomic and nuclear few-body systems are classified and discussed with the emphasis on electromagnetic transitions. The size of relativistic corrections, calculational techniques and ambiguities, and comparison of theory and experiment are considered. 8 figures.
Date: January 1, 1980
Creator: Friar, J.L.
Partner: UNT Libraries Government Documents Department
open access

De-entrainment on vertical elements in air droplet cross flow. [PWR]

Description: De-entrainment phenomena on vertical elements in air-water droplet cross flow are generated using a horizontal array of water spray nozzles and a draft-induced wind tunnel. These conditions are used to obtain experimental values of the de-entrainment efficiency of isolated elements (25.4-, 63.5-, and 101.6-mm-diam cylinders and a 76.2-mm-square tube), and of an array of 101.6-mm-diam cylinders. A flow model is developed that extrapolates the de-entrainment efficiency of isolated elements throug… more
Date: January 1, 1980
Creator: Dallman, J.C. & Kirchner, W.L.
Partner: UNT Libraries Government Documents Department
open access

Fifth high-energy heavy-ion study

Description: This was the fifth of a continuing series of summer studies held at LBL to discuss high energy heavy ion collisions. Recently, a similar meeting has been held on alternate years at GSI (Darmstadt); and, in 1979, we held a meeting at LBL exclusively devoted to ultra-relativistic nuclear collisions. Two new features distinguish this study from earlier meetings in the series. First, the energy range for discussion was broadened by including collisions from about 20 MeV/nucleon to the highest avail… more
Date: October 1, 1981
Partner: UNT Libraries Government Documents Department
open access

Laser-plasma interaction experiments at laser wavelengths of 1. 064. mu. m, 0. 532. mu. m, and 0. 355. mu. m

Description: The effect of laser wavelength on laser-plasma coupling is one of the critical issues facing the laser driven inertial confinement community. The advantages of using lasers with output wavelength less than 1 ..mu..m, such as enhanced absorption and hydrodynamic efficiency, reduction in parametric instabilities and corresponding suprathermal electron generation, have long been predicted theoretically.
Date: January 1, 1982
Creator: Campbell, E. M.; Mead, W. C. & Turner, R. E.
Partner: UNT Libraries Government Documents Department
open access

Stark broadening of isolated lines from high-Z emitters in dense plasmas

Description: The joint distribution of the electric microfield and its longitudinal derivative is required for the calculation of line profiles for the He-like ions in very dense plasmas. We used a molecular dynamics code to compute exact distributions in single- and multi-component plasmas, and then we investigated various analytical approximations to these results. We found that a simplified, two-nearest-neighbor scheme leads to surprisingly accurate distribution functions. Our results are illustrated by … more
Date: September 1, 1980
Creator: Weisheit, J.C. & Pollock, E.L.
Partner: UNT Libraries Government Documents Department
open access

Growth regulation by macrophages

Description: The evidence reviewed here indicates that macrophages, either acting alone or in concert with other cells, influence the proliferation of multiple types of cells. Most of the data indicate that these effects are mediated by soluble macrophage-elaborated products (probably proteins) although the role of direct cell-to-cell contacts cannot be ruled out in all cases. A degree of success has been achieved on the biochemical characterization of these factors, due mainly to their low specific activit… more
Date: January 1, 1982
Creator: Wharton, W.; Walker, E. & Stewart, C.C.
Partner: UNT Libraries Government Documents Department
open access

Diskless LSI-11 systems

Description: Programs for dedicated LSI-11 based systems can easily be stored in ROM instead of floppy disks, yet execute the same as disk-stored programs. Two sample systems are described.
Date: January 1, 1982
Creator: Ford, W. & Shirk, D. G.
Partner: UNT Libraries Government Documents Department
open access

Severe accident core heatup transients in modular high temperature gas-cooled reactors without operating Reactor Cavity Cooling Systems

Description: The ultimate decay heat removal system for the current Modular High Temperature Gas-Cooled reactors is a completely passive natural convection air cooling loop. This paper considers an extremely remote accident scenario, where even this passive system fails, and heat rejection is only via a layer of thermal insulation to the reactor silo structure and the surrounding soil. The results show that even in this case the peak fuel temperatures remain well within safe limits. However, vessel and conc… more
Date: January 1, 1988
Creator: Kroeger, P. G.
Partner: UNT Libraries Government Documents Department
open access

Surprising patterns of CMOS susceptibility to ESD and implications on long-term reliability

Description: CMOS electrostatic discharge (ESD) failures in a product where, by design, the device input terminals are not accessible to ESD led to this study of device susceptibility and an analysis of the long-term reliability of devices in assemblies from that production line. Some surprising patterns of device susceptibility are established and it is shown that the probability of long-term failure in devices whose electrical characteristics have been degraded by electrostatic discharge is small.
Date: January 1, 1980
Creator: Schwank, J.R.; Baker, R.P. & Armendariz, M.G.
Partner: UNT Libraries Government Documents Department
open access

Damage nucleation in Si during ion irradiation

Description: Damage nucleation in single crystals of silicon during ion irradiation is investigated. Experimental results and mechanisms for damage nucleation during both room and liquid nitrogen temperature irradiation with different mass ions are discussed. It is shown that the accumulation of damage during room temperature irradiation depends on the rate of implantation. These dose rate effects are found to decrease in magnitude as the mass of the ions is increased. The significance of dose rate effects … more
Date: January 1, 1984
Creator: Holland, O.W.; Fathy, D. & Narayan, J.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen