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Modifications of the high-energy transport code (HETC) and comparisons with experimental results

Description: The High-Energy Transport Code HETC has been revised by incorporating a multi-chain fragmentation model to describe particle production from high-energy hadron-nucleus collisions. The revised code is briefly described and its validity is tested by comparing calculated results with experimental data from 29.4 GeV protons incident on an iron-air beam stop and with experimental data from 800 GeV protons incident on a large iron block. Some comparisons with calculated results obtained with other available transport codes; FLUKA82, CASIM, and MARS10 are also included. 18 refs., 3 figs.
Date: January 1, 1987
Creator: Alsmiller, R.G. Jr.; Alsmiller, F.S.; Gabriel, T.A. & Hermann, O.W.
Partner: UNT Libraries Government Documents Department

The emittance and brightness characteristics of negative ion sources suitable for MeV ion implantation

Description: This paper provides the description and beam properties of ion sources suitable for use with ion implantation devices. Particular emphasis is placed on the emittance and brightness properties of state-of-the-art, high intensity, negative ion sources based on the cesium ion sputter principle. (WRF)
Date: January 1, 1987
Creator: Alton, G.D.
Partner: UNT Libraries Government Documents Department

The emittances and brightnesses of high-intensity negative ion sources

Description: The emittances of high-intensity ion beams extracted from cesium sputter negative ion sources equipped with cylindrical and ellipsoidal solid tungsten and spiral-wound tantalum (General Ionex Corporation, Model 860), and cesium surface ionizers have been measured for several ion species, including /sup 12/C/sup -/, /sup 28/Si/sup -/, /sup 58/Ni/sup -/, and /sup 197/Au/sup -/. While certain sets of data from the ellipsoidal and cylindrical geometry ionizer sources suggest a moderate growth in emittance with increasing negative ion beam intensity I over the range of intensities investigated (5 less than or equal to 1 less than or equal to 60 ..mu..A) of perhaps 20%, not all data exhibit this dependence, especially those from the Model 860 source. As well, no evidence of an emittance dependence on ion mass of a monotonic nature was found. The emittances of ion beams at the 80% intensity level from the Model 860 source are found to be higher on the average by factors of 1.8 and 1.7, respectively, than those from sources equipped with ellipsoidal and cylindrical geometry cesium surface ionizers.
Date: January 1, 1987
Creator: Alton, G.D. & McConnell, J.W.
Partner: UNT Libraries Government Documents Department

History of proton linear accelerators

Description: Some personal recollections are presented that relate to the author's experience developing linear accelerators, particularly for protons. (LEW)
Date: January 1, 1987
Creator: Alvarez, L.W.
Partner: UNT Libraries Government Documents Department

High-precision hyperfine structure measurement in slow atomic ion beams by collinear laser-rf double resonance

Description: A new collinear laser-ion beam apparatus for slow ions (1 to 1.5 keV) has been built for measuring the hyperfine structure of metastable levels of ions with laser-rf double resonance technique. Narrow linewidths of approx.60 kHz (FWHM) have been observed for the first time in such systems. As a first application the hyperfine structure of the 4f/sup 7/(/sup 8/S/sup 0/)5d /sup 9/D/sub J//sup 0/ metastable levels of /sup 151,153/Eu/sup +/ has been measured with high precision. 10 refs., 8 figs.
Date: January 1, 1987
Creator: Amarjit Sen, Childs, W.J. & Goodman, L.S.
Partner: UNT Libraries Government Documents Department

Linear Water Influx of an Infinite Aquifer Through a Partially Communicating Fault

Description: This paper presents a linear flow water influx analysis method where the aquifer is separated from the reservoir by a partially communicating fault. Transient pressure distributions are considered both in the reservoir and in the aquifer. Cases where the leaky fault is located within the aquifer can be analyzed with this model given a superposition of constant rate flow periods at the oil-water interface. Constant production rate is specified at the inner boundary, without inner boundary storage and skin. The partially communicating fault is modeled as a boundary skin of infinitesimal thickness having no storage. The aquifer considered in this paper is infinite in the lateral extend. The problem is posed and solved using the Laplace transformation, yielding Laplace solutions of the exponential form. The solutions presented in this paper, along with a set of type curves extend the transient linear flow work presented by Hurst (1958) and by Nabor and Barham (1964). When the inner region, the reservoir, has an infinite permeability and a finite storage, it acts like a tank, where the boundary pressure is equal to average pressure in the inner region. This case is identical to the linear water influx model presented by Hurst (1958). When the inner region has no storage associated with it, the constant inner boundary rate is transmitted to the second infinite region, hence yielding the simple linear flow case presented by Nabor and Barham (1964). This paper extends the current solutions by allowing pressure variations in the reservoir or the inner region as well as in the infinite aquifer. Also, the model presented in this paper considers the effects of skin located at the boundary between the two regions of the system that may be caused by a partially communicating fault separating these two regions. 6 tabs., 14 figs., 12 refs.
Date: January 20, 1987
Creator: Ambastha, Anil K. & Sageev, Abraham
Partner: UNT Libraries Government Documents Department

Angular resolution in underground detectors and a status report of the Soudan II nucleon decay detector

Description: This paper is a status report of the Soudan II honeycomb drift chamber project. It reports on the physics goals, present progress and future schedule of our experiment. It also includes a discussion of the angular resolution of cosmic ray muons which can be achieved in underground detectors, and in particular how to calibrate the resolution using the moon's shadow in cosmic rays. This last point has relevance in trying to understand the angular distributions in the reported observations of underground muons from Cygnus X-3. 12 refs., 9 figs.
Date: January 1, 1987
Creator: Ambats, I.; Ayres, D.; Barrett, W.; Barron, K.; Dawson, J.; Fields, T. et al.
Partner: UNT Libraries Government Documents Department

Performance of the Soudan II honeycomb drift chambers

Description: The Soudan II nucleon decay project is in the process of building 260 identical 5-ton fine grained calorimeter modules for the study of nucleon decay and cosmic ray physics in the Soudan Iron Mine in Minnesota. Several of these modules have been studied on a cosmic ray test stand on the surface at Argonne National Lab. Several have been installed on location in the mine, 700 m under the surface (2200 mwe overburden). In addition, many studies of trigger efficiency, pattern recognition and background rejection have been done using Monte Carlo techniques.
Date: January 1, 1987
Creator: Ambats, I.; Ayres, D.; Barrett, W.; Dawson, J.; Fields, T.; Goodman, M.C. et al.
Partner: UNT Libraries Government Documents Department

Initial results from the Soudan II experiment

Description: This paper reports on progress in the construction, installation and operation of the Soudan II nucleon decay detector.
Date: January 1, 1987
Creator: Ambats, I.; Ayres, D.; Courant, H.; DasGupta, U.; Allison, W.; Barr, G. et al.
Partner: UNT Libraries Government Documents Department

The KIVA-II computer program for transient multidimensional chemically reactive flows with sprays

Description: Since its public release in 1985, the KIVA computer program has been utilized for the time dependent analysis of chemically reacting flows with sprays in two and three space dimensions. This paper describes some of the improvements to the original version that have been made since that time. The new code called KIVA-II is planned for public release in early 1988. KIVA-II improves the earlier version in the accuracy and efficiency of the computational procedure, the accuracy of the physics submodels, and in versatility and ease of use. Numerical improvements include the use of the ICE solution procedure in place of the acoustic subcycling method and the implementation of a quasi-second-order-accurate convection scheme. Major extensions to the physical submodels include the inclusion of an optional k-epsilon turbulence model, and several additions to the spray model. We illustrate some of the new capabilities by means of example solutions. 25 refs., 7 figs.
Date: January 1, 1987
Creator: Amsden, A.A.; Butler, T.D. & O'Rourke, P.J.
Partner: UNT Libraries Government Documents Department

Implementation and optimization of portable standard LISP for the Cray

Description: Portable Standard LISP (PSL), a dialect of LISP developed at the University of Utah, has been implemented on the CRAY-1s and CRAY X-MPs at the Los Alamos National Laboratory and at the National Magnetic Fusion Energy Computer Center at Lawrence Livermore National Laboratory. This implementation was developed using a highly portable model and then tuned for the Cray architecture. The speed of the resulting system is quite impressive, and the environment is very good for symbolic processing. 5 refs., 6 tabs.
Date: January 1, 1987
Creator: Anderson, J.W.; Kessler, R.R. & Galway, W.F.
Partner: UNT Libraries Government Documents Department

Interaction of biological systems with static and ELF electric and magnetic fields

Description: Although background levels of atmospheric electric and geomagnetic field levels are extremely low, over the past several decades, human beings and other life forms on this planet have been subjected to a dramatically changing electromagnetic milieu. An exponential increase in exposure to electromagnetic fields has occurred, largely because of such technological advances as the growth of electrical power generation and transmission systems, the increased use of wireless communications, and the use of radar. In addition, electromagnetic field generating devices have proliferated in industrial plants, office buildings, homes, public transportation systems, and elsewhere. Although significant increases have occurred in electromagnetic field strenghths spanning all frequency ranges, this symposium addresses only the impact of these fields at static and extremely low frequencies (ELF), primarily 50 and 60 Hz. This volume contains the proceedings of the symposium entitled /open quotes/Interaction of biological systems with static and ELF electric and magnetic fields/close quotes/. The purpose of the symposium was to provide a forum for discussions of all aspects of research on the interaction of static and ELF electromagnetic fields with biological systems. These systems include simple biophysical models, cell and organ preparations, whole animals, and man. Dosimetry, exposure system design, and artifacts in ELF bioeffects research were also addressed, along with current investigations that examine fundamental mechanisms of interactions between the fields and biological processes. Papers are indexed separately.
Date: January 1, 1987
Creator: Anderson, L.E.; Kelman, B.J. & Weigel, R.J. (eds.)
Partner: UNT Libraries Government Documents Department

Where does CBT (computer-based training) fit in, now that we know so much. A front end analysis study

Description: Computer-based training (CBT) has now been in existence for over two decades. It has been implemented in both the private sector and government organizations at an exponential rate. Nevertheless, many institutions, particularly educational institutions, have not yet introduced CBT. Our knowledge of what works and what does not, as well as hardware and software advances, has greatly increased in the past few years. This paper addresses many management considerations with respect to CBT. First, we consider the generic environment in which CBT might be used and then issues that affect costs and benefits, including lessons learned by the Cognitive Engineering Design and Research Team (CEDAR) of the Los Alamos National Laboratory in its assessments. The final section gives some ''how-to'' guidelines on increasing the probability of successfully introducing CBT into the training environment. The underlying theme of the paper is that management should be guided by what we now know about costs and benefits in its decisions regarding CBT and fight the lure of ''high tech'' glitter.
Date: January 1, 1987
Creator: Andrews, A.E. & Trainor, M.S.
Partner: UNT Libraries Government Documents Department

Atmospheric releases from severe nuclear accidents: Environmental transport and pathways to man: Modelling of radiation doses to man from Chernobyl releases

Description: The Chernobyl accident released a large amount of highly fractionated radioactive debris, including approximately 89 PBq of /sup 137/Cs. We calculated the resulting collective dose commitment to the Northern Hemisphere via the pathways of external exposure and ingestion of radionuclides withd food. We developed a rural/urban model of external dose and we used the PATHWAY model for ingestion. The results are a collective dose commitment of 630,000 person-Gy over the first year and 1,200,000 person-Gy over 50 years. 13 refs., 1 tab.
Date: January 1, 1987
Creator: Anspaugh, L.R.; Goldman, M. & Catlin, R.J.
Partner: UNT Libraries Government Documents Department

Fundamental noise processes in a laser excited optical filter

Description: A rubidium narrow bandwidth optical filter is being investigated as a device for detecting weak narrow bandwidth radiation. In our configuration, the optical filter is actively pumped (or laser excited, i.e., LEOF). This configuration has a major inherent advantage over a passive optical filter, namely, wavelength versatility. One possible limitation to the Rb LEOF is due to an intrinsic noise source caused by the energy pooling of Rb 5p atoms which are produced by the pump laser. This process, i.e., Rb (5p) + Rb (5p) ..-->.. Rb (5d) + (Rb(5s)) ..-->.. Rb (6p), produces Rb atoms in the 6p state which subsequently emit radiation within the bandwidth of the detection channel (420-323 nm). Hence, this constitutes a noise process since photons are produced at the detector in the absence of narrow bandwidth ''signal'' radiation. Herein, we present preliminary results on kinetic studies of the energy pooling process with the ultimate goal of quantifying the process (rate constant determination) and thus assessing its implications. 4 refs., 3 figs.
Date: January 1, 1987
Creator: Apel, E.C.; Gosnell, T.R.; Shay, T.M. & Samadani, R.
Partner: UNT Libraries Government Documents Department

Alteration of national glass in radioactive waste repository host rocks: A conceptional review

Description: The storage of high-level radioactive wastes in host rocks containing natural glass has potential chemical advantages, especially if the initial waste temperatures are as high as 250/sup 0/C. However, it is not certain how natural glasses will decompose when exposed to an aqueous phase in a repository environment. The hydration and devitrification of both rhyolitic and natural basaltic natural glasses are reviewed in the context of hypothetical thermodynamic phase relations, infrared spectroscopic data and laboratory studies of synthetic glasses exposed to steam. The findings are compared with field observations and laboratory studies of hydrating and devitrifying natural glasses. The peculiarities of the dependence of hydration and devitrification behavior on compositional variation is noted. There is substantial circumstantial evidence to support the belief that rhyolitic glasses differ from basaltic glasses in their thermodynamic stability and their lattice structure, and that this is manifested by a tendency of the former to hydrate rather than devitrify when exposed to water. Further research remains to be done to confirm the differences in glass structure, and to determine both physically and chemically dependent properties of natural glasses as a function of composition.
Date: January 1, 1987
Creator: Apps, J.A.
Partner: UNT Libraries Government Documents Department

Thermal-hydraulic modeling of porous bed reactors

Description: Optimum design of nuclear reactor core requires an iterative approach between the thermal-hydraulic, neutronic and operational analysis. This paper concentrates on the thermal-hydraulic behavior of a hydrogen cooled, small particle bed reactor (PBR). The PBR core, modeled here, consists of a hexagonal array of fuel elements embedded in a moderator matrix. The fuel elements are annular packed beds of fuel particles held between two porous cylindrical frits. These particles, 500 to 600 ..mu..m in diameter, have a uranium carbide core, which is coated by two layers of graphite and an outer coating of zirconium carbide. Coolant flow, radially inward, from the cold frit through the packed bed and hot frit and axially out the channel, formed by the hot frit, to a common plenum. 5 refs., 1 fig., 2 tabs.
Date: January 1, 1987
Creator: Araj, K.J. & Nourbakhsh, H.P.
Partner: UNT Libraries Government Documents Department

Ultra-high temperature direct propulsion

Description: Potential advantages of ultra-high exhaust temperature (3000 K - 4000 K) direct propulsion nuclear rockets are explored. Modifications to the Particle Bed Reactor (PBR) to achieve these temperatures are described. Benefits of ultra-high temperature propulsion are discussed for two missions - orbit transfer (..delta..V = 5546 m/s) and interplanetary exploration (..delta..V = 20000 m/s). For such missions ultra-high temperatures appear to be worth the additional complexity. Thrust levels are reduced substantially for a given power level, due to the higher enthalpy caused by partial disassociation of the hydrogen propellant. Though technically challenging, it appears potentially feasible to achieve such ultra high temperatures using the PBR.
Date: January 1, 1987
Creator: Araj, K.J.; Slovik, G.; Powell, J.R. & Ludewig, H.
Partner: UNT Libraries Government Documents Department

Plasmon resonance absorption in layered structures of silver with periodic corrugation

Description: Plasmon resonance absorption in periodically corrugated layered structures of silver was studied by the photoacoustic method. The layered structures were self-supporting and corrugated with a period of 1888 nm and amplitude varying from 6 to 12 nm, depending on the thickness. Experimental results of resonance absorption of 633-nm photons were analyzed in terms of the propagation and damping constants of coupled modes of surface plasmons. The coupling efficiency of incident photons to these modes was found to be strongly dependent on corrugation amplitude and layer thickness.
Date: January 1, 1987
Creator: Arakawa, E.T.; Inagaki, T. & Goudonnet, J.P.
Partner: UNT Libraries Government Documents Department

Point vortex dynamics: Recent results and open problems

Description: The concept of point vortex motion, a classical model in the theory of two-dimensional, incompressible fluid mechanics, was introduced by Helmholtz in 1858. Exploration of the solutions to these equations has made fitful progress since that time as the point vortex model has been brought to bear on various physical situations: atomic structure, large-scale weather patterns, ''vortex street'' wakes, vortex lattices in superfluids and superconductors, etc. The point vortex equations also provide an interesting example of transition to chaotic behavior. We give a brief historical introduction to these topics and develop two of them in particular to the point of current understanding: steadily moving configurations of point vortices; and collision dynamics of vortex pairs. 26 refs.
Date: January 1, 1987
Creator: Aref, H.; Kadtke, J.B.; Zawadzki, I.; Campbell, L.J. & Eckhardt, B.
Partner: UNT Libraries Government Documents Department

Design of a transuranic VUV spectrometer

Description: Most of our present knowledge about the physics of 5f systems derives from studies of uranium and its compounds. This is particularly true in the case of photoemission measurements where the intense radioactivity has prevented studies at synchrotron sources. The development of a transuranic VUV spectrometer capable of safe operation at a synchrotron source would represent a giant step in 5f research. This paper describes the conceptual design of such a spectrometer.
Date: January 1, 1987
Creator: Arko, A.J.
Partner: UNT Libraries Government Documents Department

Microwave-induced air breakdown in a free air geometry

Description: We report on trial experiments, using an open geometry, to measure the breakdown behavior of short, intense microwave pulses in low pressure air.
Date: January 1, 1987
Creator: Armstrong, W.T.; Roussel-Dupre, R.A.; Karl, R.; Buchwald, M.I. & Graham, G.
Partner: UNT Libraries Government Documents Department

Scientific considerations in the design of the Mars observer gamma-ray spectrometer

Description: Cosmic-ray primary and secondary particles induce characteristic gamma-ray and neutron emissions from condensed bodies in our solar system. These characteristic emissions can be used to obtain qualitative and quantitative elemental analyses of planetary surfaces from orbital altitudes. Remote sensing gamma-ray spectroscopy has been successfully used to obtain elemental composition of the Moon and Mars during United States Apollo 15 and 16 missions and the Soviet Luna and Mars missions. A remote sensing gamma-ray and neutron spectrometer will be included aboard the United States Mars Observer Mission. If proper care is not taken in the design of the spectrometer and choice of materials in the construction of the detector system and spacecraft, the sensitivity of these remote sensing spectrometers can be greatly degraded. A discussion of these design and material selection problems is presented. 16 refs., 5 figs., 3 tabs.
Date: January 1, 1987
Creator: Arnold, J.R.; Boynton, W.V.; Englert, P.; Feldman, W.C.; Metzger, A.E.; Reedy, R.C. et al.
Partner: UNT Libraries Government Documents Department

Non-resonant field generation

Description: Production of fields for particle acceleration by pulse technology is reviewed. Special attention is focussed on several recently proposed schemes for generation of very high gradients, both in metallic structures and plasmas. Ongoing and planned experimental activities in these areas are discussed. 24 refs., 6 figs., 5 tabs.
Date: January 1, 1987
Creator: Aronson, S.H.
Partner: UNT Libraries Government Documents Department