90 Matching Results

Results open in a new window/tab.

Intelligent optical design program (open access)

Intelligent optical design program

Described is a general approach to the development of computer programs capable of designing image-forming optical systems without human intervention and of improving their performance with repeated attempts. The approach utilizes two ideas: (1) interpretation of technical design as a mapping in the configuration space of technical characteristics and (2) development of an intelligent routine that recognizes global optima. Examples of lens systems designed and used in the development of the general approach are presented, current status of the project is summarized, and plans for the future efforts are indicated.
Date: May 4, 1984
Creator: Bohachevsky, I.O.; Viswanathan, V.K. & Woodfin, G.
System: The UNT Digital Library
Surface modification of solids (open access)

Surface modification of solids

The use of ion beam and pulsed laser processing is reviewed for the near-surface modification of a wide range of materials. The techniques of ion implantation doping, ion beam and laser mixing, and pulsed-laser annealing are stressed with particular emphasis on the nonequilibrium aspects of these processing techniques and on new materials properties which can result. Examples are presented illustrating the utility of these techniques for fundamental materials research as well as practical surface modifications.
Date: May 1, 1984
Creator: Appleton, B. R.
System: The UNT Digital Library
3-D treatment of convective flow in the earth's mantle (open access)

3-D treatment of convective flow in the earth's mantle

A three-dimensional finite-element method is used to investigate thermal convection in the earth's mantle. The equations of motion are solved implicitly by means of a fast multigrid technique. The computational mesh for the spherical problem is derived from the regular icosahedron. The calculation described use a mesh with 43,554 nodes and 81,920 elements and were run on a Cray X. The earth's mantle is modeled as a thick spherical shell with isothermal, free-slip boundaries. The infinite Prandtl number problem is formulated in terms of pressure, density, absolute temperature, and velocity and assumes an isotropic Newtonian rheology. Solutions are obtained for Rayleigh numbers up to approximately 10/sup 6/ for a variety of modes of heating. Cases initialized with a temperature distribution with warmer temperatures beneath speading ridges and cooler temperatures beneath present subduction zones yield whole-mantle convection solutions with surface velocities that correlate well with currently observed plate velocities. 8 references, 6 figures.
Date: May 1, 1984
Creator: Baumgardner, J.R.
System: The UNT Digital Library
Crossed undulator system for a variable polarization synchrotron radiation source (open access)

Crossed undulator system for a variable polarization synchrotron radiation source

A crossed undulator system can produce synchrotron radiation whose polarization is arbitrary and adjustable. The polarization can be linear and modulated between two mutually perpendicular directions, or it can be circular and can be modulated between right and left circular polarizations. The system works on low emittance electron storage rings and can cover a wide spectral range. Topics discussed include the basic principle of the system, the design equations and the limitations in performance.
Date: May 1, 1984
Creator: Kim, K. J.
System: The UNT Digital Library
Focusing twist reflector for electron-cyclotron resonance heating in the Tandem Mirror Experiment-Upgrade (open access)

Focusing twist reflector for electron-cyclotron resonance heating in the Tandem Mirror Experiment-Upgrade

A twist reflector plate is described that linearly polarizes and focuses the TE/sub O/sub 1// circular waveguide mode for heating hot electrons in the thermal barrier of the Tandem Mirror Experiment-Upgrade (TMX-U). The plate polarizing efficiency is 95%, and it has operated satisfactorily at 150 kW power level.
Date: May 1, 1984
Creator: Stallard, B.W.; Coffield, F.E.; Felker, B.; Taska, J.; Christensen, T.E.; Gallagher, N.C. Jr. et al.
System: The UNT Digital Library
Charge-changing collisions (open access)

Charge-changing collisions

Recent results for charge-changing collisions of interest for cyclotrons and other particle accelerators are presented. Scaling rules, where available, are emphasized. 45 references, 11 figures.
Date: May 1, 1984
Creator: Schlachter, A.S.
System: The UNT Digital Library
Analyzing power measurements in high-P/sub perpendicular to//sup 2/ p-p elastic scattering (open access)

Analyzing power measurements in high-P/sub perpendicular to//sup 2/ p-p elastic scattering

The analyzing power in 28 GeV/c proton-proton elastic scattering was measured at P/sub perpendicular to//sup 2/ = 5.95 and 6.56 (GEV/c)/sup 2/ y/sub g/ a polarized proton target and an unpolarized proton beam at the Brookhaven National Laboratory AGS. Results indicate that the analyzing power, A, is rising sharply with P/sub perpendicular to//sup 2/. Previous measurements of the analyzing power, A, in p + p ..-->.. p + p suggested a rise in A at large-P/sub perpendicular to//sup 2/, but the statistical uncertainty in the highest point at P/sub perpendicular to//sup 2/ = 5.95 (GeV/c)/sup 2/ made it impossible to determine the magnitude of the increase. In an effort to clarify this situation, we made new measurements of A at P/sub perpendicular to//sup 2/ = 5.95 and 6.56 (GeV/c)/sup 2/. An unpolarized beam of typically 5 x 10/sup 10/ 28 GeV/c protons from the AGS at Brookhaven National Laboratory was incident upon the University of Michigan polarized proton target. This target contains irradiated ammonia beads cooled to 0.5/sup 0/K by a /sup 3/He-/sup 4/He evaporation refrigerator, in a 2.5 T magnetic field. The polarizing transitions are driven by a 70 GHz microwave system. The polarization of the hydrogen protons is …
Date: May 23, 1984
Creator: Raymond, R. S.; Brown, K. A.; Bruni, R. J.; Cameron, P. R.; Crabb, D. G.; Cummings, R. L. et al.
System: The UNT Digital Library
Operational parameters of a 2. 0-MeV RFQ linac (open access)

Operational parameters of a 2. 0-MeV RFQ linac

After extensive upgrading, our radio-frequency quadrupole (RFQ) linac is again installed on the accelerator test stand (ATS). The measured parameters of the RFQ, such as the output transverse emittance, transmitted beam, average energy, and energy spread is presented.
Date: May 7, 1984
Creator: Sander, O. R.; Purser, F. O. & Rusthoi, D. P.
System: The UNT Digital Library
Hadron production in e/sup +/e/sup -/ annihilation at PEP (open access)

Hadron production in e/sup +/e/sup -/ annihilation at PEP

Recent results from PEP on quark and gluon fragmentation are reviewed. Topics include: inclusive stable particle production and resonance production, particle distributions in jets, heavy quark fragmentation, flavor correlation studies and tests of fragmentation models. 37 references.
Date: May 1, 1984
Creator: Hofmann, W.
System: The UNT Digital Library
Ep option at the SSC (open access)

Ep option at the SSC

The possibilities for colliding electrons with the 20 TeV proton beams of the SSC are considered. Kinematics of ep colliding beams is reviewed. Energies that may be possible and interesting are suggested, and detector problems associated with the highly imbalanced collisions are briefly considered.
Date: May 1, 1984
Creator: Prescott, Charles Y.
System: The UNT Digital Library
Quantum chromodynamic evolution of multiquark systems (open access)

Quantum chromodynamic evolution of multiquark systems

We present a new technique which extends the quantum chromodynamic evolution formalism in order to predict the short distance behavior of multiquark wavefunctions. In particular, predictions are given for the deuteron reduced form factor in the high momentum transfer region, and rigorous constraints on the short distance effective force between two baryons are predicted. These new techniques can be generalized in order to analyze the short distance behavior of multibaryon systems.
Date: May 1, 1984
Creator: Ji, C.R. & Brodsky, S.J.
System: The UNT Digital Library
Momentum distributions in hcp, bcc, and liquid /sup 4/He (open access)

Momentum distributions in hcp, bcc, and liquid /sup 4/He

Using Deep Inelastic Neutron Scattering we have measured the nuclear momentum distribution in hcp, bcc and liquid /sup 4/He at constant density over a temperature range 0.96K < T < 4.0K. We find no temperature dependence of the momentum distribution in the hcp solid or the liquid. We also find no difference between the hcp, bcc and liquid phases. The average kinetic energy per atom is lower than the best present theories predict.
Date: May 1, 1984
Creator: Sokol, P.E.; Simmons, R.O.; Price, D.L. & Hilleke, R.O.
System: The UNT Digital Library
Design and operation of the LBL heavy ion RFQ linac (open access)

Design and operation of the LBL heavy ion RFQ linac

LBL has designed and tested a heavy ion RFQ linac for ions in the mass range of 1 to 40. Designed as part of a preinjector package for synchrotron applications, it is a low duty factor device, operating at 200 MHz with maximum surface fields as high as 28 MV/meter. It is a loop-driven, four vane structure employing several innovative design concepts. These include an exit matcher section, to ensure efficient capture by a following Alvarez linac; advanced mechanical design features, to ensure accurate positioning of the vane pole-tips; and vane coupling rings, to ensure field stabilization and balance. This RFQ has been used on a test bench to accelerate a variety of ions as heavy as silicon, with charge to mass ratios as low as 1/7. Results of the initial operation show that the structure meets all of the design performance criteria, and that it holds promise for a long lifetime of simple and reliable service. This RFQ linac will soon be incorporated into the Bevatron operations program as part of th 200 MHz injector upgrade. A further application of this same RFQ design is in the dedicated Heavy Ion Medical Accelerator presently under study at LBL. Details of …
Date: May 1, 1984
Creator: Gouch, R.A.
System: The UNT Digital Library
Uranium resources and their implications for fission breeder and fusion hybrid development (open access)

Uranium resources and their implications for fission breeder and fusion hybrid development

Present estimates of uranium resources and reserves in the US and the non-Communist world are reviewed. The resulting implications are considered for two proposed breeder technologies: the liquid metal fast breeder reactor (LMFBR) and the fusion hybrid reactor. Using both simple arguments and detailed scenarios from the published literature, conditions are explored under which the LMFBR and fusion hybrid could respectively have the most impact, considering both fuel-supply and economic factors. The conclusions emphasize strong potential advantages of the fusion hybrid, due to its inherently large breeding rate. A discussion is presented of proposed US development strategies for the fusion hybrid, which at present is far behind the LMFBR in its practical application and maturity.
Date: May 15, 1984
Creator: Max, C.E.
System: The UNT Digital Library
Early operating experience with the Brookhaven National Laboratory radio frequency quadrupole accelerator (open access)

Early operating experience with the Brookhaven National Laboratory radio frequency quadrupole accelerator

The Brookhaven National Laboratory polarized H/sup -/ injection program for the AGS utilizes a Radio Frequency Quadrupole (RFQ) for acceleration between the polarized H/sup -/ source and the Alvarez Linac. The RFQ accelerator is now in operation with low beam currents. The results of low and high power rf testing will be reported together with initial results of operation in the polarized H/sup -/ beam line.
Date: May 1, 1984
Creator: Brown, H.; Clifford, T.; Giordano, S.; Khiari, F.; McKenzie-Wilson, R.; Puglisi, M. et al.
System: The UNT Digital Library
Dynamics of angular momentum accumulation in damped nuclear reactions (open access)

Dynamics of angular momentum accumulation in damped nuclear reactions

The dynamical evolution of the correlated angular momentum distribution in a damped nuclear reaction is discussed within the framework of the nucleon exchange transport model. 13 references.
Date: May 1, 1984
Creator: Randrup, J. & Doessing, T.
System: The UNT Digital Library
DT-burning upgrade to MFTF-B (open access)

DT-burning upgrade to MFTF-B

To improve MFTF-B, one must raise the ion energy and the electrostatic confining potential. This requires higher beam energy (200 keV in this case) and, to preserve end-plug adiabaticity and hold higher plasma density in the central cell, a higher level of magnetic field. In the MFTF Upgrade we also want to incorporate the new end plug configuration first invented for the MARS reactor. This new magnet design is compared with the present MFTF-B magnet set. The differences include the addition of a pair of recircularizing coils on the ends to be used in conjunction with the end region pumping and direct converter schemes, the use of a yin-yang pair rather than a baseball-type coil in the transition, and the elimination of the axicell in favor of the simple choke coil. Also, as noted earlier, an axisymmetric mirror cell is imbedded in the central cell.
Date: May 7, 1984
Creator: Thomassen, K. I.; Logan, B. G.; Doggett, J. N. & Coensgen, F. H.
System: The UNT Digital Library
Status report on the ATLAS superconducting linear accelerator (open access)

Status report on the ATLAS superconducting linear accelerator

ATLAS, the Argonne Tandem-Linac Accelerator System, is a project to upgrade the existing Argonne superconducting linac heavy-ion booster which began providing beams of heavy-ions for experimental nuclear research in 1979. When completed ATLAS will provide beams of heavy ions up to approximately mass 130 at energies as high as 25 MeV/A. The construction of ATLAS is approximately 60% complete. First beam from the accelerator is expected in spring of 1985.
Date: May 1, 1984
Creator: Argon, J.; Benaroya, R.; Bogaty, J.; Bollinger, L. M.; Clifft, B. E.; Den Hartog, P. et al.
System: The UNT Digital Library
Computational method for realistic estimates of the dose to active marrow (open access)

Computational method for realistic estimates of the dose to active marrow

Calculation of absorbed dose to active marrow from photon radiation is a complex problem because electronic equilibrium may not exist in the vicinity of soft tissue-bone mineral interfaces. Snyder et al. recognized the intractable geometry of trabecular bone in their studies of photon transport in the body and formulated marrow dose estimates in a conservative manner. Other investigators have noted that this approach leads to overestimate by factors of 3 or more at low photon energy. In this paper the absorbed dose is formulated in terms of physical and anatomical parameters defining the energy deposition in the marrow space. 17 references, 2 figures, 1 table.
Date: May 11, 1984
Creator: Eckerman, K.F. & Cristy, M.
System: The UNT Digital Library
Logging technology for high-temperature geothermal boreholes (open access)

Logging technology for high-temperature geothermal boreholes

Research in materials, equipment, and instrument development was required in the Hot Dry Rock Energy Extraction Demonstration at Fenton Hill located in northern New Mexico. Results of this extensive development advanced the logging technology in geothermal boreholes to present state-of-the art. The new Phase II Energy Extraction System at the Fenton Hill Test Site will consist of two wellbores drilled to a depth of about 4570 m (15,000 ft) and then connected by a series of hydraulic-induced fractures. The first borehole (EE-2) was completed in May of 1980 at a depth of 4633 m (15,200 ft) of which approximately 3960 m (13,000 ft) is in Precambrian granitic rock. Starting at a depth of approximately 2930 m (9600 ft), the borehole was inclined up to 35/sup 0/ from vertical. Bottom-hole temperature in EE-2 is 320/sup 0/C. The EE-3 borehole was then drilled to a depth of 4236 m (13,900 ft). Its inclined part is positioned directly over the EE-2 wellbore with a vertical separation of about 450 m (1500 ft) between them. Many of the geophysical measurements needed to develop the hot dry rock concept are unique. Most of the routine instruments used in petroleum drilling fail in the hot and …
Date: May 1, 1984
Creator: Dennis, B.R.
System: The UNT Digital Library
Electron cyclotron resonance (ECR) ion sources (open access)

Electron cyclotron resonance (ECR) ion sources

Starting with the pioneering work of R. Geller and his group in Grenoble (France), at least 14 ECR sources have been built and tested during the last five years. Most of those sources have been extremely successful, providing intense, stable and reliable beams of highly charged ions for cyclotron injection or atomic physics research. However, some of the operational features of those sources disagreed with commonly accepted theories on ECR source operation. To explain the observed behavior of actual sources, it was found necessary to refine some of the crude ideas we had about ECR sources. Some of those new propositions are explained, and used to make some extrapolations on the possible future developments in ECR sources.
Date: May 1, 1984
Creator: Jongen, Y.
System: The UNT Digital Library
Workshop on electronic and ionic collision cross sections needed in the modeling of radiation interactions with matter: proceedings (open access)

Workshop on electronic and ionic collision cross sections needed in the modeling of radiation interactions with matter: proceedings

The term modeling in the Workship title refers to the mathematical analysis of the consequences of many collision processes for characterizing the physical stage of radiation actions. It requires as input some knowledge of collision cross sections. Traditionally, work on cross sections and work on the modeling are conducted by separate groups of scientists. It was the purpose of the Workshop to bring these two groups together in a forum that would promote effective communication. Cross-section workers described the status of their work and told what data were available or trustworthy. Modeling workers told what kind of data were needed or were most important. Twenty-two items from the workshop were prepared separately for the data base.
Date: May 1, 1984
Creator: unknown
System: The UNT Digital Library
ASP: a new PEP experiment to measure single photons (open access)

ASP: a new PEP experiment to measure single photons

The design and construction of a new experiment for PEP designed to measure the flux of low energy photons unaccompanied by any additional photons, or charged tracks is described. The device consists of arrays of extruded lead glass bars and PWC's in the central region with lead-scintillator shower counters, drift chambers and PWC's in the forward regions. 9 references.
Date: May 1, 1984
Creator: Hollebeek, R.
System: The UNT Digital Library
Theories of fermion masses (open access)

Theories of fermion masses

We present grand unified theories in which the quark masses and mixing angles are calculated in terms of the lepton masses through simple group theory. The theories contain no small Yukawa couplings. A favored value of the top quark mass is 35 GeV.
Date: May 1, 1984
Creator: Bagger, J.; Dimopoulos, S.; Georgi, H. & Raby, S.
System: The UNT Digital Library