Physics at hadron colliders: Experimental view (open access)

Physics at hadron colliders: Experimental view

The physics of the hadron-hadron collider experiment is considered from an experimental point of view. The problems encountered in determination of how well the standard model describes collider results are discussed. 53 refs., 58 figs.
Date: August 1, 1987
Creator: Siegrist, J.L.
System: The UNT Digital Library
Transverse energy distributions in Si + nucleus collisions at 10 GeV/nucleon (open access)

Transverse energy distributions in Si + nucleus collisions at 10 GeV/nucleon

Transverse energy distributions have been measured for collisions of 10 GeVnucleon Si with targets of Al, Cu and Pb using a combination of a NaI wall and a uranium based sampling calorimeter. The measured cross sections d..sigma..dE/sub T/ and dE/sub T/d)eta are consistent with full stopping and an increase, with increasing values of E/sub T/, of energy flow into large angles. 4 refs., 7 figs., 2 tabs
Date: August 1, 1987
Creator: Bassalleck, B; Braun-Munzinger, P.; Cleland, W.; G., David; Farooq, A.; Fatyga, M. et al.
System: The UNT Digital Library
Development of highly polished, grazing incidence mirrors for synchrotron radiation beam lines at SSRL (open access)

Development of highly polished, grazing incidence mirrors for synchrotron radiation beam lines at SSRL

New platinum-coated grazing incidence mirrors with low surface roughnesses have been developed to focus bending magnet radiation from the SSRL/SLAC SPEAR storage ring on the entrance slits of two Beam Line VIII grating monochromators. The first mirror in the toroidal grating monochromator (TGM) branch is a cooled SiC cylinder capable of absorbing synchrotron radiation power levels of up to 260 watts without excessive distortion. This mirror deflects the beam vertically through a 12/degree/ angle and focuses it sagitally on the TGM entrance slit plane. The second TGM optical element is a fused-silica spherical mirror with a large radius of curvature that deflects the beam vertically through an additional 12/degree/ and focuses it tangentially with 3/1 demagnification. The first mirror in our spherical grating branch is a 5/degree/-vertically deflecting, cooled SiC toroid designed to focus tangentially on the monochromator entrance slits and sagitally in the exit slits. A 4/degree/-deflecting fused silica mirror is used after the exit sites in each beam line to refocus on to the sample. For this application a thin cylinder is bent to approximate an ellipsoid. The mirrors are now installed at SSRL and performance measurements are planned. Qualitatively the focus of the TGM optics at the …
Date: August 1, 1987
Creator: Tirsell, K. G.; Berglin, E. J.; Fuchs, B. A.; Holdener, F. R.; Humpal, H. H.; Karpenko, V. P. et al.
System: The UNT Digital Library
Similarity solutions of nonlinear partial differential equations invariant to a family of affine groups (open access)

Similarity solutions of nonlinear partial differential equations invariant to a family of affine groups

Problems of technological interest can very often be described by partial differential equations (PDEs) with one dependent and two independent variables (call them c, z, and t, respectively). Many such PDEs are invariant to one-parameter families of one-parameter affine groups. Similarity solutions are solutions of the PDE that are invariant to one group of the family. The great utility of similarity solutions is that they may be calculated by solving an ODE rather than a PDE and are thus much more easily accessible than other solutions. The form of the principal ODE depends, of course, on the form of the PDE, but it can be proved quite generally that the principal ODE is itself invarient to the one-parameter affine group or associated group. because of the invariance of the principal ODE to the associated group, the dependence on the boundary and initial conditions of certain special values of the function y(x), e.g., y(O), y(infinity), y(O), ets., may be predicted a priori without solving the principal ODE. The nonlinear PDE of heat transport in superfluid He-II, is used as an illustration of these ideas in this review.
Date: August 1, 1987
Creator: Dresner, L.
System: The UNT Digital Library
Ultrasonic beam distortion in transversely isotropic media (open access)

Ultrasonic beam distortion in transversely isotropic media

The distortion of beam profiles and skewing of beam energy observed in transmission of ultrasound into a transversely isotropic medium can lead to erroneous interpretations of NDE data for materials such as columnar-grain steels and fiber-reinforced composites. In this paper, results are presentd for the numerical evaluation of the exact Fourier integral representation of transmission of an arbitrary incident field from an isotropic into a transversely isotropic half-space. The problem is fully three-dimensional, i.e., the symmetry axis of the transversely isotropic material is oriented arbitrarily relative to the half-space boundary and angles of incidence. The cases chosen for numerical study were selected from previously unexplained experimental data obtained from the study of propagation in columnar grain steels (welds), and from situations commonly encountered during the inspection of fiber-reinforced composites. Experimental results which give evidence to the numerically observed phenomena are presented. 11 refs., 4 figs.
Date: August 1, 1987
Creator: Roberts, R. A. & Kupperman, D. S.
System: The UNT Digital Library
Comparative studies in direct slow-neutron capture calculations (open access)

Comparative studies in direct slow-neutron capture calculations

Primary E1 transitions due to thermal neutron capture by the nuclides /sup 9/Be, /sup 32,34/S, /sup 40,42,44,46,48/Ca, and /sup 58/Ni are quantitatively interpreted by the Lane-Lynn formula and are compared with recent optical model calculations. The two approaches are equivalent provided the internal region of the nucleus is excluded in the optical model approach. Theoretical justifications for such a procedure are briefly presented. 32 refs., 4 tabs.
Date: August 1, 1987
Creator: Mughabghab, S. F.
System: The UNT Digital Library
Corrosion behavior of vanadium alloys in flowing lithium (open access)

Corrosion behavior of vanadium alloys in flowing lithium

Corrosion data are presented for several vanadium alloys exposed to flowing lithium at 427, 482, and 538/sup 0/C. The corrosion behavior is evaluated by weight change measurements. Metallographic results and data on the nonmetallic element transfer in lithium-exposed specimens are also presented. The influence of alloy composition and exposure conditions on the corrosion behavior of vanadium alloys is discussed. 6 refs., 9 figs., 2 tabs.
Date: August 1, 1987
Creator: Chopra, O. K. & Smith, D. L.
System: The UNT Digital Library
An overview of environmental degradation of materials in nuclear power plant piping systems (open access)

An overview of environmental degradation of materials in nuclear power plant piping systems

Piping in light water reactor (LWR) power systems is affected by several types of environmental degradation: intergranular stress corrosion cracking (IGSCC) of austenitic stainless steel piping in boiling water reactors (BWRs) has required research, inspection, and mitigation programs that will ultimately cost several billion dollars; erosion-corrosion of carbon steel piping has been observed frequently in the secondary systems of both BWRs and pressurized water reactors (PWRs); the effect of the BWR environment can greatly diminish the design margin inherent in the ASME Section III fatigue design curves for carbon steel piping; and cast stainless steels are subject to embrittlement after extended thermal aging at reactor operating temperatures. These problems are being addressed by wide-ranging research programs in this country and abroad. The purpose of this review is to highlight some of the accomplishments of these programs and to note some of the remaining unanswered questions.
Date: August 1, 1987
Creator: Shack, W.J.
System: The UNT Digital Library
Environmentally assisted cracking in light water reactors (open access)

Environmentally assisted cracking in light water reactors

Cracking in sensitized austenitic stainless steel (SS) piping and associated components in boiling water reactors (BWRs) has been observed since the mid-1960s. Proposed remedies include procedures that produce a favorable residual stress state in the weld regions, replacement of the piping with materials that are more resistant to SCC, and modification of the reactor coolant environment. During this year, studies that have important implications for all three classes of proposed remedies have been carried out. These studies include fracture-mechanics crack-growth-rate tests on Type 316 NG SS and weld overlay specimens in impurity and high-purity environments, finite-element studies on weldments treated by the Mechanical Stress Improvement Process (MSIP) developed by O'Donnell and Associates, heat-to-heat studies of SCC in alternate alloys such as Types 316 NG and 347 Mod SS, and slow-strain-rate tests for the characterization of a variety of potential reactor coolant impurities. In addition, studies on the corrosion potential of irradiated stainless steel have been performed. This work is intended to provide a better understanding of the conditions associated with irradiation-assisted SCC (IASCC) in the core region.
Date: August 1, 1987
Creator: Shack, W. J.; Kassner, T. F.; Maiya, P. S.; Park, J. Y.; Ruther, W. E.; Kuczay, T. M. et al.
System: The UNT Digital Library
Use of a United States mid-Pacific Island territory for a Pacific Island Repository System (PIRS): Extended summary (open access)

Use of a United States mid-Pacific Island territory for a Pacific Island Repository System (PIRS): Extended summary

The concept of using a mid-ocean island for a geologic high-level waste repository was investigated. The technical advantages include geographical isolation and near-infinite ocean dilution as a backup to repository geological waste isolation. The institutional advantages are reduced siting problems and the potential of creating an international waste repository. Establishment of international waste repository would allow cost sharing, aid US nonproliferation goals, and assure proper disposal of spent fuel from developing countries. The major uncertainties in this concept are rock conditions at waste disposal depths and costs. 13 refs., 2 tabs.
Date: August 1, 1987
Creator: Forsberg, Charles W.
System: The UNT Digital Library
The charge state of iron implanted into sapphire (open access)

The charge state of iron implanted into sapphire

Several techniques (RBS, TEM, CEMS) have been used to characterize sapphire single crystals implanted with iron at room temperature to fluences of 10/sup 16/ to 10/sup 17/ ions cm/sup -2/. At low fluences the as-implanted iron is found mainly in the ferrous state. As the fluence is increased, Fe/sup 3 +/ and metallic iron clusters became dominant. There is a strong correlation between the probability of finding specific configurations of iron ions within four cation coordination shells and the relative amounts of each charge state observed. The superparamagnetic behavior of the clusters suggest that they are of the order of 2 nm in size but the large amount of irradiation-induced damage and residual stress has prevented their imaging by TEM. 13 refs., 7 figs.
Date: August 1, 1987
Creator: McHargue, C. J.; Sklad, P. S.; White, C. W.; Farlow, G. C.; Perez, A.; Kornilios, N. et al.
System: The UNT Digital Library
Experimental Studies of Electromagnetic Properties of Few Body Systems (open access)

Experimental Studies of Electromagnetic Properties of Few Body Systems

An overview is given of some recent and planned experiments which have or will substantially increase our knowledge of the electromagnetic properties of few body systems. Specific examples include the proton and neutron elastic form factors, the deuteron elastic form factors, deuteron threshold electrodisintegration and quasi-elastic scattering, deuteron photodisintegration, and finally measurements of cross sections in deep inelastic scattering from hydrogen, deuterium, and iron. 47 refs., 13 figs. (DWL)
Date: August 1, 1987
Creator: Bosted, P. E.
System: The UNT Digital Library
The role of pre-equilibrium theory in nuclear data evaluation (open access)

The role of pre-equilibrium theory in nuclear data evaluation

We illustrate the utility of preequilibrium plus equilibrium decay models in reproducing neutron and ..gamma..-ray spectra for incident nucleons of approx. = 2 to 20 MeV. We discuss models and theories for calculating preequilibrium nucleon angular distributions and the short comings involved. Attention is focussed on special problems in modelling preequliibrium reactions for target nuclei near shell closures, and possible ways to improve the modelling in these regimes by use of shell model levels to generate few quasi-particle state densities. We show preliminary tests of applicability of preequilibrium models to incident nucleon energies up to 1 GeV and for heavy ion induced reactions at energies up to 300 MeV, areas where modern technology is increasingly seeking nuclear data input. 40 refs., 16 figs.
Date: August 1, 1987
Creator: Blann, M.
System: The UNT Digital Library
Fully developed turbulence via Feigenbaum's period-doubling bifurcations (open access)

Fully developed turbulence via Feigenbaum's period-doubling bifurcations

Since its publication in 1978, Feigenbaum's predictions of the onset of turbulence via period-doubling bifurcations have been thoroughly borne out experimentally. In this paper, Feigenbaum's theory is extended into the regime in which we expect to see fully developed turbulence. We develop a method of averaging that imposes correlations in the fluctuating system generated by this map. With this averaging method, the field variable is obtained by coarse-graining, while microscopic fluctuations are preserved in all averaging scales. Fully developed turbulence will be shown to be a result of microscopic fluctuations with proper averaging. Furthermore, this model preserves Feigenbaum's results on the physics of bifurcations at the onset of turbulence while yielding additional physics both at the onset of turbulence and in the fully developed turbulence regime.
Date: August 1, 1987
Creator: Duong-van, M.
System: The UNT Digital Library
Physical and chemical characteristics and development of the Changuinola peat deposit of northwestern Panama (open access)

Physical and chemical characteristics and development of the Changuinola peat deposit of northwestern Panama

A peat deposit occupying over 80 square kilometers, and averaging 8 meters in thickness, was discovered on the Caribbean coast of northwestern Panama near the town of Changuinola. This deposit occurs inland (behind) the present beach-barrier shoreline. It is thickest in the center and thins toward all edges (as if domed). The surface vegetation in the central regions consists primarily of ombrotrophic plants (especially sedges, grasses, Sphagnum, Sagittaria, and various scattered shrubs). Toward the edges, the deposit has a surface cover of more minerotrophic plants (such as swamp-forest trees, ferns, and palms). Petrographic/botanical analysis of the deposit with depth reveals the presence of five peat types (swamp-forest, sedge-grass-fern, Sagittaria et al., Nymphaea et al., and Rhizophora). Typically peats of the thick, central portions of the deposit are very low in ash and sulfur (less than 2% ash and 0.3% sulfur). Ash contents tend to increase abruptly at the base and more gradually toward the edges of the deposit and sulfur contents increasing gradually toward the ocean and bay. Vertical and lateral variations in botanical, chemical, and physical properties of this deposit can be related to factors that have controlled: (1) the surrounding rocks and water chemistry; (2) the source vegetation; …
Date: August 1, 1987
Creator: Cohen, A.D.; Raymond, R. Jr.; Thayer, G. & Ramirez, A.
System: The UNT Digital Library
GOLD: Integration of model-based control systems with artificial intelligence and workstations (open access)

GOLD: Integration of model-based control systems with artificial intelligence and workstations

Our experience with model-based accelerator control started at SPEAR. Since that time nearly all accelerator beamlines have been controlled using model-based application programs, for example, PEP and SLC at SLAC. In order to take advantage of state-of-the-art hardware and software technology, the design and implementation of the accelerator control programs have undergone radical changes with time. Consequently, SPEAR, PEP and SLC all use different control programs. Since many of these application programs are embedded deep into the control system, they had to be rewritten each time. Each time this rewriting has occurred a great deal of time and effort has been spent on training physicists and programmers to do the job. Now, we have developed an integrated system called GOLD (Genetic Orbit and Lattice Debugger) for debugging and correcting trajectory errors in accelerator lattices. The system consists of a lattice modeling program (COMFORT), a beam simulator (PLUS), a graphical workstation environment (micro-VAX) and an expert system (ABLE). This paper will describe some of the features and applications of our integrated system with emphasis on the automation offered by expert systems. 5 refs.
Date: August 1, 1987
Creator: Lee, M. & Clearwater, S.
System: The UNT Digital Library
Evidence for bimodal fission in the heaviest elements (open access)

Evidence for bimodal fission in the heaviest elements

We have measured the mass and kinetic-energy partitioning in the spontaneous fission of five heavy nuclides: /sup 258/Fm, /sup 259/Md, /sup 260/Md /sup 258/No, and /sup 260/(104). Each was produced by heavy-ion reactions with either /sup 248/Cm, /sup 249/Bk, or /sup 254/Es targets. Energies of correlated fragments from the isotopes with millisecond half lives, /sup 258/No and /sup 260/(104), were measured on-line by a special rotating-wheel instrument, while the others were determined off-line after mass separation. All fissioned with mass distributions that were symmetric. Total-kinetic-energy distributions peaked near either 200 or 235 MeV. Surprisingly, because only a single Gaussian energy distribution had been observed previously in actinide fission, these energy distributions were skewed upward or downward from the peak in each case, except for /sup 260/(104), indicating a composite of two energy distributions. We were able to fit accurately two Gaussian curves to the gross energy distributions from the four remaining nuclides. From the multiple TKE distributions and the shapes of the mass distributions, we conclude that there is a low-energy fission component with liquid-drop characteristics which is admixed with a much higher-energy component due to closed fragment shells. We now have further evidence for this conclusion from measurements of …
Date: August 1, 1987
Creator: Hulet, E. K.; Wild, J. F.; Lougheed, R. W.; Dougan, R. J.; Landrum, J. H.; Dougan, A. D. et al.
System: The UNT Digital Library
Fossil Energy Materials Program conference proceedings (open access)

Fossil Energy Materials Program conference proceedings

The US Department of Energy Office of Fossil Energy has recognized the need for materials research and development to assure the adequacy of materials of construction for advanced fossil energy systems. The principal responsibility for identifying needed materials research and for establishing a program to address these needs resides within the Office of Technical Coordination. That office has established the Advanced Research and Technology Development (AR and TD) Fossil Energy Materials Program to fulfill that responsibility. In addition to the AR and TD Materials Program, which is designed to address in a generic way the materials needs of fossil energy systems, specific materials support activities are also sponsored by the various line organizations such as the Office of Coal Gasification. A conference was held at Oak Ridge, Tennessee on May 19-21, 1987, to present and discuss the results of program activities during the past year. The conference program was organized in accordance with the research thrust areas we have established. These research thrust areas include structural ceramics (particularly fiber-reinforced ceramic composites), corrosion and erosion, and alloy development and mechanical properties. Eighty-six people attended the conference. Papers have been entered individually into EDB and ERA. (LTN)
Date: August 1, 1987
Creator: Judkins, R.R. (comp.)
System: The UNT Digital Library
Ground state partial radiative widths of /sup 207/Pb + n resonances and M1 and E2 strengths in /sup 208/Pb (open access)

Ground state partial radiative widths of /sup 207/Pb + n resonances and M1 and E2 strengths in /sup 208/Pb

Ground state partial radiative widths of neutron resonances in /sup 207/Pb + n have been measured. A resonance analysis has been carried out in a complete manner below 700 keV neutron energy, and for selected strongly radiation resonances up to 1 MeV. The total magnetic dipole strength detected above neutron separation energy is only 6.8 ..mu../sub 0//sup 2/, but the observed appreciable fragmentation of the M1 strength suggests that considerable strength is missed at excitation energies above 8 MeV. The electric quadrupole strength observed between neutron separation energy and 8.2 MeV is distributed rather uniformly, and corresponds to 4.9% of the energy-weighted sum-rule for isoscalar E2 transitions. 10 refs., 2 figs.
Date: August 1, 1987
Creator: Weigmann, H.; Koehler, R.; Poortmans, F.; Raman, S. & Wartena, J.A.
System: The UNT Digital Library
The role of basic research in society (open access)

The role of basic research in society

This report contains general remarks on the rate of accelerators, especially the Superconducting Super Collider, in the advancement of modern scientific knowledge. (LSP)
Date: August 1, 1987
Creator: Seaborg, G. T.
System: The UNT Digital Library
The Application of Photoconductive Detectors to the Measurement of X-Ray Production in Laser Produced Plasmas (open access)

The Application of Photoconductive Detectors to the Measurement of X-Ray Production in Laser Produced Plasmas

Photoconductive detectors (PCDs) offer an attractive alternative for the measurement of pulsed x-rays from laser produced plasmas. These devices are fast (FWHM approx.100 ps), sensitive and simple to use. We have used InP, GaAs, and Type IIa diamond as PCDs to measure x-rays emission from 100 eV to 100 keV. Specifically, we have used these detectors to measure total radiation yields, corona temperatures, and hot electron generated x-rays from laser produced plasmas. 5 refs., 4 figs.
Date: August 1, 1987
Creator: Kania, D.R.; Bell, P. & Trebes, J.
System: The UNT Digital Library
Calculated sputtering and atomic displacement cross-sections for applications to medium voltage analytical electron microscopy (open access)

Calculated sputtering and atomic displacement cross-sections for applications to medium voltage analytical electron microscopy

The development of medium voltage electron microscopes having high brightness electron sources and ultra-high vacuum environments has been anticipated by the microscopy community now for several years. The advantages of such a configuration have been discussed to great lengths, while the potential disadvantages have for the most part been neglected. The most detrimental of these relative to microcharacterization are the effects of electron sputtering and atomic displacement to the local specimen composition. These effects have in the past been considered mainly in the high voltage electron microscope regime and generally were ignored in lower voltage instruments. Recent experimental measurements have shown that the effects of electron sputtering as well as radiation induced segregation can be observed in conventional transmission electron microscopes. It is, therefore, important to determine at what point the effects will begin to manifest themselves in the new generation of medium voltage analytical electron microscopes. In this manuscript we present new calculations which allow the individual experimentalist to determine the potential threshold levels for a particular elemental system and thus avoid the dangers of introducing artifacts during microanalysis. 12 refs., 3 figs.
Date: August 1, 1987
Creator: Bradley, C.R. & Zaluzec, N.J.
System: The UNT Digital Library
/sup 252/Cf-source-driven neutron noise measurements of subcriticality for a slab tank containing aqueous Pu-U nitrate (open access)

/sup 252/Cf-source-driven neutron noise measurements of subcriticality for a slab tank containing aqueous Pu-U nitrate

In order to study nuclear criticality safety related to the development of fast breeder technology, /sup 252/Cf-source-driven neutron noise analysis measurements were performed with a Pu-U nitrate solution in a slab tank of various heights and thickness varying 11.43 cm to 19.05 cm. The results and conclusions of these experiments are (1) a capability to measure the subcriticality of a multiplying system of slab geometry to a k/sub eff/ as low as 0.7 was demonstrated, (2) calculated neutron multiplication factors agreed with those from the experiments within approx.0.02, and (3) the applicability of the method for plutonium solution systems was demonstrated. This paper describes measurements in which the height of the slab was varied for a fixed thickness and the thickness varied for a fixed height, which are the first applications of this measurement method to slab geometry.
Date: August 1, 1987
Creator: Mihalczo, J.T.; Blakeman, E.D.; Ragan, G.E.; Kryter, R.C.; Robinson, R.C. & Seino, H.
System: The UNT Digital Library
Pion production in the quark compound Bag model of NN scattering (open access)

Pion production in the quark compound Bag model of NN scattering

The quark compound Bag model of NN scattering is reviewed and extended to study pion-production from NN collisions. 12 refs., 6 figs., 1 tab.
Date: August 1, 1987
Creator: Lee, T. S. H.
System: The UNT Digital Library