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Spectra of negative particles and photons in collisions of p/minus/W and /sup 16/O/minus/W at 200 GeVu

Description: /rho//perpendicular/ spectra of negative particles were measured for p/minus/W and /sup 16/O/minus/W collisions at 200 GeVupsilon in the rapidity range 0.9< y <1.9. Within the systematic errors of 20% the spectra are indentical in the range 0.05 </rho//perpendicular/<2.0 GeVc. The p/minus/W and /sup 16/O /minus/W spectra exhibit an exponential shape for /rho//perpendicular/>250 MeVc. This is consistent with previous p/minus/A data, but there is a significant excess above this exponential at low… more
Date: January 1, 1987
Creator: Bartels, H.W.
Partner: UNT Libraries Government Documents Department
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Early events in irradiated water. [5-keV electrons]

Description: We propose a model to continue following events from the initial energy deposition (<10/sup -15/ s) through later times at which liquid water can begin to respond chemically to the passage of radiation. We use a Monte Carlo code to calculate the spatial distributions of the chemical species present at times of about 10/sup -11/ s. This information provides the necessary input for diffusion-kinetic calculations to predict the subsequent chemical evolution of the system and measurable transient a… more
Date: January 1, 1980
Creator: Turner, J.E.; Magee, J.L.; Hamm, R.N.; Chatterjee, A.; Wright, H.A. & Ritchie, R.H.
Partner: UNT Libraries Government Documents Department
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Gamma rays from Cygnus X-1: Modeling and nonthermal pair production

Description: The gamma-ray bump observed between 0.5 and 2 MeV in the spectrum of Cygnus X-1 can be interpreted as the thermal emissions from a hot (kT)approximately)400 keV) pair-dominated cloud. We argue that the X-rays and gamma rays are produced in separate emission regions, and calculate the photon-photon pair production rate from X-ray and gamma-ray interactions in the vicinity of Cyg X-1 by employing a simplified geometry for the two emitting regions.
Date: February 1, 1988
Creator: Dermer, C. D. & Liang, E. P.
Partner: UNT Libraries Government Documents Department
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SOILD: A computer model for calculating the effective dose equivalent from external exposure to distributed gamma sources in soil

Description: The SOLID computer model was developed for calculating the effective dose equivalent from external exposure to distributed gamma sources in soil. It is designed to assess external doses under various exposure scenarios that may be encountered in environmental restoration programs. The models four major functional features address (1) dose versus source depth in soil, (2) shielding of clean cover soil, (3) area of contamination, and (4) nonuniform distribution of sources. The model is also capab… more
Date: January 1, 1991
Creator: Chen, S. Y.; LePoire, D.; Yu, C. (Argonne National Lab., IL (United States)); Schafetz, S. (Rockland Community Coll., Suffern, NY (United States)) & Mehta, P. (Fayetteville State Univ., NC (United States))
Partner: UNT Libraries Government Documents Department
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Interface effects on dose distributions in irradiated media

Description: It has long been recognized that nonuniformities in dose distributions may occur in the immediate vicinity of a boundary between two different media. Considerable work has been done to determine interface effects in media irradiated by photons or in media containing ..beta..- or ..cap alpha..-particle emitters. More recently interface effects have become of interest in additional problems, including pion radiotherapy and radiation effects in electronic microcircuits in space vehicles. These pro… more
Date: January 1, 1980
Creator: Wright, H.A.; Hamm, R.N. & Turner, J.E.
Partner: UNT Libraries Government Documents Department
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Germanium detector system for the detection of transuranics at low-activity concentrations in soil. [/sup 241/Am, /sup 240/Pu, /sup 239/Pu, /sup 238/U, /sup 232/Th]

Description: A photon spectroscopy system is described which is designed for the detection of plutonium and /sup 241/Am in soil samples with a minimum turnaround time. Quantification is based upon the 60-keV gamma emitted in /sup 241/Am decay and upon the uranium L x-rays (energies from 13 to 22 keV) emitted by plutonium isotopes during alpha decay. The detector is a single-crystal, intrinsic-germanium-planar detector with a surface area of 21 cm/sup 2/. Sensitivity is increased by incorporating a detector … more
Date: January 1, 1978
Creator: West, L.; Umbarger, C.J. & Dempsey, T.
Partner: UNT Libraries Government Documents Department
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Digital simulation and modeling of nonlinear stochastic systems

Description: Digitally generated solutions of nonlinear stochastic systems are not unique, but depend critically on the numerical integration algorithm used. Some theoretical and practical implications of this dependence are examined. The Ito-Stratonovich controversy concerning the solution of nonlinear stochastic systems is shown to be more than a theoretical debate on maintaining Markov properties as opposed to utilizing the computational rules of ordinary calculus. The theoretical arguments give rise to … more
Date: January 1, 1980
Creator: Richardson, J. M. & Rowland, J. R.
Partner: UNT Libraries Government Documents Department
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Multivariate calibration applied to the quantitative analysis of infrared spectra

Description: Multivariate calibration methods are very useful for improving the precision, accuracy, and reliability of quantitative spectral analyses. Spectroscopists can more effectively use these sophisticated statistical tools if they have a qualitative understanding of the techniques involved. A qualitative picture of the factor analysis multivariate calibration methods of partial least squares (PLS) and principal component regression (PCR) is presented using infrared calibrations based upon spectra of… more
Date: January 1, 1991
Creator: Haaland, D. M.
Partner: UNT Libraries Government Documents Department
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Spectral functions from Quantum Monte Carlo

Description: In his review, D. Scalapino identified two serious limitations on the application of Quantum Monte Carlo (QMC) methods to the models of interest in High {Tc} Superconductivity (HTS). One is the sign problem''. The other is the analytic continuation problem'', which is how to extract electron spectral functions from QMC calculations of the imaginary time Green's functions. Through-out this Symposium on HTS, the spectral functions have been the focus for the discussion of normal state properties … more
Date: January 1, 1989
Creator: Silver, R.N.
Partner: UNT Libraries Government Documents Department
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Feynmann variance-to-mean method

Description: The Feynmann and other fluctuation techniques have been shown to be useful for determining the multiplication of subcritical systems. The moments of the counting distribution from neutron detectors is analyzed to yield the multiplication value. We present the methodology and some selected applications and results and comparisons with Monte Carlo calculations.
Date: January 1, 1985
Creator: Dowdy, E. J.; Hansen, G. E. & Robba, A. A.
Partner: UNT Libraries Government Documents Department
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Development and testing of a Monte Carlo code system for analysis of ionization chamber responses

Description: To predict the perturbation of interactions between radiation and material by the presence of a detector, a differential Monte Carlo computer code system entitled MICAP was developed and tested. This code system determines the neutron, photon, and total response of an ionization chamber to mixed field radiation environments. To demonstrate the ability of MICAP in calculating an ionization chamber response function, a comparison was made to 05S, an established Monte Carlo code extensively used t… more
Date: January 1, 1986
Creator: Johnson, J.O. & Gabriel, T.A.
Partner: UNT Libraries Government Documents Department
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Development and testing of an air quality model for Mexico City

Description: Los Alamos National Laboratory and Instituto Mexicano del Petroleo have embarked on a joint study of options for improving air quality in Mexico City. The intent is to develop a modeling system which can address the behavior of pollutants in the region so that option for improving Mexico City air quality can be properly evaluated. In February of 1991, the project conducted a field program which yielded a variety of data which is being used to evaluate and improve the models. Normally the worst … more
Date: March 2, 1992
Creator: Williams, M. D.; Streit, G. (Los Alamos National Lab., NM (United States)); Cruz, X.; Ruiz, M.; Sosa, G. (Instituto Mexicano de Petroleo, Mexico City (Mexico)); Russell, A. G. et al.
Partner: UNT Libraries Government Documents Department
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Search for W prime and Z prime at CDF

Description: We have searched for heavy charged and neutral vector bosons via the decays W{prime} {yields} ev, W{prime} {yields} {mu}v, Z{prime} {yields} {mu}{mu} in p{bar p} collisions at {radical}s = 1.8 TeV, using data taken with the collider Detector at Fermilab. The nonobservation of these processes leads to a lower limit (95% confidence level) of 520 GeV/c{sup 2} on the mass of the W{prime} and of 412 GeV/C{sup 2} on the mass of the Z{prime}, assuming standard model coupling to fermions. 12 refs., 6 f… more
Date: September 1, 1991
Creator: Fuess, T.
Partner: UNT Libraries Government Documents Department
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Improved numerical techniques for processing Monte Carlo thermal scattering data

Description: As part of a Thermal Benchmark Validation Program sponsored by the Electric Power Research Institute (EPRI), the National Nuclear Data Center has been calculating thermal reactor lattices using the SAM-F Monte Carlo Computer Code. As part of this program a significant improvement has been made in the adequacy of the numerical procedures used to process the thermal differential scattering cross sections for hydrogen bound in H/sub 2/O.
Date: January 1, 1980
Creator: Schmidt, E & Rose, P
Partner: UNT Libraries Government Documents Department
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MLE (Maximum Likelihood Estimator) reconstruction of a brain phantom using a Monte Carlo transition matrix and a statistical stopping rule

Description: In order to study properties of the Maximum Likelihood Estimator (MLE) algorithm for image reconstruction in Positron Emission Tomographyy (PET), the algorithm is applied to data obtained by the ECAT-III tomograph from a brain phantom. The procedure for subtracting accidental coincidences from the data stream generated by this physical phantom is such that he resultant data are not Poisson distributed. This makes the present investigation different from other investigations based on computer-si… more
Date: October 1, 1987
Creator: Veklerov, E.; Llacer, J. & Hoffman, E.J.
Partner: UNT Libraries Government Documents Department
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Monte Carlo computations of the hadronic mass spectrum

Description: This paper summarizes two talks presented at the Orbis Scientiae Meeting, 1982. Monte Carlo results on the mass gap (or glueball mass) and on the masses of the lightest quark-model hadrons are illustrated.
Date: January 1, 1982
Creator: Rebbi, C.
Partner: UNT Libraries Government Documents Department
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Tracking and vertex finding with drift chambers and neural networks

Description: Finding tracks, track vertices and event vertices with neural networks from drift chamber signals is discussed. Simulated feed-forward neural networks have been trained with back-propagation to give track parameters using Monte Carlo simulated tracks in one case and actual experimental data in another. Effects on network performance of limited weight resolution, noise and drift chamber resolution are given. Possible implementations in hardware are discussed. 7 refs., 10 figs.
Date: September 1, 1991
Creator: Lindsey, C.
Partner: UNT Libraries Government Documents Department
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Monte-Carlo approach to the generation of adversary paths

Description: This paper considers the definition of a threat as the sequence of events that might lead to adversary success. A nuclear facility is characterized as a weighted, labeled, directed graph, with critical adversary paths. A discrete-event, Monte-Carlo simulation model is used to estimate the probability of the critical paths. The model was tested for hypothetical facilities, with promising results. (DLC)
Date: January 1, 1977
Partner: UNT Libraries Government Documents Department
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Monte Carlo simulation of a dynamical fermion problem: The light q sup 2 q sup 2 system

Description: We present results from a Guided Random Walk Monte Carlo simulation of the light q{sup 2}{bar q}{sup 2} system in a Coulomb-plus-linear quark potential model using an Intel iPSC/860 hypercube. A solvable model problem is first considered, after which we study the full q{sup 2}{bar q}{sup 2} system in (J,I) = (2,2) and (2,0) sectors. We find evidence for no bound states below the vector-vector threshold in these systems. 17 refs., 6 figs.
Date: January 1, 1991
Creator: Grondin, G. (Toronto Univ., ON (Canada). Dept. of Physics Oak Ridge National Lab., TN (United States))
Partner: UNT Libraries Government Documents Department
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Super high energy heavy ion collisions

Description: Basic theoretical ideas on a phase transition to a plasma of free quarks and gluons in heavy ion collisions are outlined. First results from experiments with oxygen beams at 14.5 GeV/c/N (BNL), 60 and 200 GeV/c/N (CERN) are discussed. 30 refs., 9 figs.
Date: December 1, 1987
Creator: Geist, W.M.
Partner: UNT Libraries Government Documents Department
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Benchmark field study of deep neutron penetration

Description: A unique benchmark neutron field has been established at the Lawrence Livermore National Laboratory (LLNL) to study deep penetration neutron transport. At LLNL, a tandem accelerator is used to generate a monoenergetic neutron source that permits investigation of deep neutron penetration under conditions that are virtually ideal to model, namely the transport of mono-energetic neutrons through a single material in a simple geometry. General features of the Lawrence Tandem (LATAN) benchmark field… more
Date: June 10, 1991
Creator: Morgan, J. F.; Sale, K. (Lawrence Livermore National Lab., CA (USA) ); Gold, R.; Roberts, J. H. & Preston, C. C. (Metrology Control Corp., Richland, WA (USA) )
Partner: UNT Libraries Government Documents Department
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Fragmentation model applied to exclusive final states in photon-photon collisions

Description: Monte Carlo calculations with the Lund string fragmentation model are compared to experimental results on the reactions ..gamma gamma -->..2..pi../sup +/2..pi../sup -/, ..gamma gamma -->..K/sup +/K/sup -/..pi../sup +/..pi../sup -/ and ..gamma gamma -->..p anti p..pi../sup +/..pi../sup -/. It is found, that when the parameters of the Lund model are tuned to low energy, inclusive multi hadron production in photon-photon collisions, the cross sections of exclusive processes near threshold are qual… more
Date: July 1, 1986
Creator: Buijs, A.
Partner: UNT Libraries Government Documents Department
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Photon-Photon Physics with the Mark II at PEP

Description: Photon-photon interactions are studied with the Mark II detector at PEP. The inclusive production of charged hadrons at large transverse momenta and the exclusive production of meson pairs at large invarient mass are compared with recent hard scattering calculations. Copious inclusive production of K/sup 0/'s at large transverse momenta provides evidence for charm production. The radiative width of the f'(1520) is measured via its K/sub s//sup 0/ anti K/sub s//sup 0/ decay mode.
Date: April 1, 1986
Creator: Gidal, G.
Partner: UNT Libraries Government Documents Department
open access

Albedo technique for dose rates in cylindrical annular voids

Description: The angle-dependent albedo formula of French and Wells is combined with the albedo dose rate kernel and the resulting expression is integrated around the cylindrical surfaces representing the pressure vessel and primary shielding. The result is the dose rate above the annulus due to emergent neutrons streaming in the annulus adjacent to the pressure vessel.
Date: January 1, 1980
Creator: McCracken, R.T. & Grimesey, R.A.
Partner: UNT Libraries Government Documents Department
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