Direct catalytic conversion of methane and light hydrocarbon gases. Quarterly report No. 7, April 16, 1988--July 15, 1988 (open access)

Direct catalytic conversion of methane and light hydrocarbon gases. Quarterly report No. 7, April 16, 1988--July 15, 1988

The goal of this research is to develop catalysts that directly convert methane and light hydrocarbons to intermediates that later can be converted to either liquid fuels or value-added chemicals, as economics dictate. During this reporting period, much of our effort focused on investigating the stability of the methane reforming catalysts (Task 2) with respect to storage time. Many of these catalysts demonstrated lessened activity when they were reexamined up to 18 months after they ere first synthesized and tested. We also synthesized and tested two new phthalocyanines supported on magnesia (MgO) for examination in the methane oxidation reaction. We reexamined many of the hexaruthenium and tetraruthenium clusters which had been supported on zeolite Y, zeolite 5A, alumina or magnesia. These reexaminations were conducted at relatively slow flow rates (15 ml/min), since previous studies had shown that the lower flow rates maximized the conversion of methane in this reaction. In every case, the catalyst exhibited diminished activity compared to the earlier runs. In addition, the selectivity of the catalysts changed as well; relatively less C{sub 2} and no C{sub 6} was observed in the reactions conducted during this reporting period. In the previous technical report we reported that palladium tetrasulfophthalocyanine …
Date: August 31, 1988
Creator: Wilson, R. B., Jr.; Chan, Yee Wai & Posin, B.M.
Object Type: Report
System: The UNT Digital Library
NDA accountability measurement needs in the DOE plutonium community (open access)

NDA accountability measurement needs in the DOE plutonium community

The purpose of this first ATEX report is to identify the twenty most vital nondestructive assay (NDA) accountability measurement needs in the DOE plutonium community to DOE and to contractor safeguards RandD managers in order to promote resolution of these needs. During 1987, ATEX identified sixty NDA accountability measurement problems, many of which were common to each of the DOE sites considered. These sixty problems were combined into twenty NDA accountability measurement needs that exist within five major areas: NDA ''standards'' representing various nuclear materials and matrix composition; Impure nuclear materials compounds, residues, and wastes; Product-grade nuclear materials; Nuclear materials process holdup and in-process inventory; and Nuclear materials item control and verification. 2 figs.
Date: August 31, 1988
Creator: Ostenak, C.A.
Object Type: Article
System: The UNT Digital Library
Prospects of TEVATRON upgrade (open access)

Prospects of TEVATRON upgrade

Following a brief review of the 1987 Fermilab collider run and the present status of the 1988 run, upgrade plans for the near-term (1988-1992) are described. For further luminosity upgrades beyond 1992, several scenarios are currently being discussed, one of which includes the construction of two new 20 GeV rings which could raise the proton-antiproton collider luminosity by a factor of 50 over the original Tevatron I design. Another possible project, the construction of a high luminosity proton-proton collider, has also been investigated in detail. A third scenario, involving a new Main Injector to replace the Main Ring and a new higher energy superconducting synchrotron, is presently being examined. It is hoped that this will result in a proposal to be submitted to DOE for FY91. The major issues concerning these options are presented. 8 figs., 1 tab.
Date: August 31, 1988
Creator: Syphers, M.J.
Object Type: Article
System: The UNT Digital Library
Reminiscences of a particle physicist (open access)

Reminiscences of a particle physicist

This paper discusses some historical aspects of particle physics. (LSP)
Date: August 31, 1988
Creator: Goldhaber, M.
Object Type: Article
System: The UNT Digital Library
Symmetry breaking: The standard model and superstrings (open access)

Symmetry breaking: The standard model and superstrings

The outstanding unresolved issue of the highly successful standard model is the origin of electroweak symmetry breaking and of the mechanism that determines its scale, namely the vacuum expectation value (vev)v that is fixed by experiment at the value v = 4m//sub w//sup 2///g/sup 2/ = (..sqrt..2G/sub F/)/sup /minus/1/ approx. = 1/4 TeV. In this talk I will discuss aspects of two approaches to this problem. One approach is straightforward and down to earth: the search for experimental signatures, as discussed previously by Pierre Darriulat. This approach covers the energy scales accessible to future and present laboratory experiments: roughly (10/sup /minus/9/ /minus/ 10/sup 3/)GeV. The second approach involves theoretical speculations, such as technicolor and supersymmetry, that attempt to explain the TeV scale. 23 refs., 5 figs.
Date: August 31, 1988
Creator: Gaillard, M. K.
Object Type: Article
System: The UNT Digital Library
Writing SUBROUTINE HOWFAR for EGS4 (open access)

Writing SUBROUTINE HOWFAR for EGS4

The purpose of this note is to provide guidance, in addition to that given in SLAC-265, in writing SUBROUTINE HOWFAR for both simple and complex geometrical situations. Since most complex geometries can be represented in terms of blocks of simpler geometries, a number of geometry subprograms have been created for use within HOWFAR. They are provided as part of the EGS4 Code System, which means that they are located in files on the EGS4 disk under VM/SP at SLAC. They are also on the EGS4 Distribution Tape that is given out on request by the SLAC Radiation Physics Group. What we hope to accomplish with this note is to show how to create EGS4 geometries in a modular fashion, with particular emphasis on using the macro equivalents of the subroutines in order to gain efficiency. It is assumed that the reader is already familiar with EGS4 and understands the role of the variables USTEP, IDISC, and IRNEW as they apply to SUBROUTINE HOWFAR. If not, then the reader is advised to study Appendix 2 of SLAC-265 first. The tutorial chapter may also provide some insight. 5 refs., 10 figs.
Date: August 31, 1988
Creator: Nelson, W. R. & Jenkins, T. M.
Object Type: Report
System: The UNT Digital Library
Magnetic reconnection simulation using the 2. 5D em (electromagnetic) direct implicit code AVANTI (open access)

Magnetic reconnection simulation using the 2. 5D em (electromagnetic) direct implicit code AVANTI

Collisionless reconnection of magnetic field lines depends upon electron inertia effects and details of the electron and ion distribution functions, thus requiring a kinetic description of both. Though traditional explicit PIC techniques provide this description in principle, they are severely limited in parameters by time step constraints. This parameter regime has been expanded by using the recently constructed 2.5 D electromagnetic code AVANTI in this work. The code runs stably with arbitrarily large {Delta}t and is quite robust with respect to large fluctuations occurring due to small numbers of particles per cell. We have found several qualitatively new features. The reconnection process is found to occur in distinct stages: early spontaneous reconnection fed by the free energy of an initial anisotropy in the electron component, coalescence of the resulting small-scale filaments of electron current, accompanied by electron jetting, and oscillatory flow of electrons through the magnetic X-point, superposed on continuing nonlinear growth of ion-mediated reconnection. The time evolution of stage is strongly dependent on M{sub i}/m{sub e}. 12 refs., 6 figs.
Date: August 30, 1988
Creator: Hewett, D. W.; Francis, G. E. & Max, C. E.
Object Type: Article
System: The UNT Digital Library
Ultraviolet-visible-near infrared spectra of 50 samples (open access)

Ultraviolet-visible-near infrared spectra of 50 samples

Under the subject contract, Unidynamics/Phoenix recorded the ultraviolet-visible-near infrared spectra of 50 samples supplied by LANL. A Varian Cary 2300 series spectrophotometer produced the spectral data. The spectrophotometer was interfaced to a Varian D5-15 Data Station, and hard copies of data were made. Baseline corrections throughout the wavelength range were established using Halon as a reference material. Corrected measurements were automatically made by the system on every sample. Two types of sample holders were tried. Before collecting data on the LANL samples, identical samples of PETN were examined using both holders.
Date: August 30, 1988
Creator: Taylor, B.
Object Type: Report
System: The UNT Digital Library
Bibliographical database of radiation biological dosimetry and risk assessment: Part 1, through June 1988 (open access)

Bibliographical database of radiation biological dosimetry and risk assessment: Part 1, through June 1988

This database was constructed to support research in radiation biological dosimetry and risk assessment. Relevant publications were identified through detailed searches of national and international electronic databases and through our personal knowledge of the subject. Publications were numbered and key worded, and referenced in an electronic data-retrieval system that permits quick access through computerized searches on publication number, authors, key words, title, year, and journal name. Photocopies of all publications contained in the database are maintained in a file that is numerically arranged by citation number. This report of the database is provided as a useful reference and overview. It should be emphasized that the database will grow as new citations are added to it. With that in mind, we arranged this report in order of ascending citation number so that follow-up reports will simply extend this document. The database cite 1212 publications. Publications are from 119 different scientific journals, 27 of these journals are cited at least 5 times. It also contains reference to 42 books and published symposia, and 129 reports. Information relevant to radiation biological dosimetry and risk assessment is widely distributed among the scientific literature, although a few journals clearly dominate. The four journals publishing the …
Date: August 29, 1988
Creator: Straume, T.; Ricker, Y. & Thut, M.
Object Type: Report
System: The UNT Digital Library
Fixed target issues for the Tevatron Upgrade (open access)

Fixed target issues for the Tevatron Upgrade

The Tevatron Upgrade poses some interesting prospects for the Fixed-Target program if an option to extract the high energy proton beam is preserved. This paper presents a summary of the advantages of increased energy for fixed target experiments, and evaluates some of the more challenging technical issues. In particular, Bottom production, muon and neutrino interactions, and polarized /bar p/ experiments would benefit substantially from a higher energy primary beam. The new Main Injector will also be important for fixed target experiments as a source for test beams and intense kaon and neutrino beams. 4 refs., 2 tabs.
Date: August 29, 1988
Creator: Stefanski, R.
Object Type: Report
System: The UNT Digital Library
Acceleration of compact toroid plasma rings for fusion applications (open access)

Acceleration of compact toroid plasma rings for fusion applications

We describe experimental results for a new type of collective accelerator based on magnetically confined compact torus (CT) plasma rings and discuss applications to both inertial and magnetic fusion. We have demonstrated the principle of CT acceleration in the RACE device with acceleration of 0.5 mg ring masses to 400 km/s and 0.02 mg ring masses to 1400 km/s at greater than or equal to30% efficiency. Scaling the CT accelerator to the multi-megajoule level could provide an efficient, economical driver for inertial fusion (ICF) or magnetically insulated inertial fusion. Efficient conversion to x-rays for driving hohlraum-type ICF targets has been modeled using a radiation-hydrodynamics code. At less demanding conditions than required for ICF, a CT accelerator can be applied to fueling and current drive in tokamaks. Fueling is accomplished by injecting CTs at the required rate to sustain the particle inventory and at a velocity sufficient to penetrate to the magnetic axis before CT dissolution. Current drive is a consequence of the magnetic helicity content of the CT, which is approximately conserved during reconnection of the CT fields with the tokamak. Major areas of uncertainty in CT fueling and current drive concern the mechanism by which CTs will stop in …
Date: August 26, 1988
Creator: Hartman, C. W.; Barr, W. L.; Eddleman, J. L.; Gee, M.; Hammer, J. H.; Ho, S. K. et al.
Object Type: Article
System: The UNT Digital Library
Dating shallow groundwater using sup 3 H- sup 3 He and sup 85 Kr (open access)

Dating shallow groundwater using sup 3 H- sup 3 He and sup 85 Kr

Determining the age of groundwater from monitoring wells can greatly aid in understanding a hydrologic system. Groundwater dating techniques have been used to estimate residence times ranging from about 1000 to 50,000 years. While such measurements have been very useful in hydrothermal and geochemical studies and in the development of groundwater supplies, they have been of limited use in contaminant studies associated with shallow groundwater systems since residence times are often much less than 1000 years.
Date: August 26, 1988
Creator: Solomon, D.K.
Object Type: Report
System: The UNT Digital Library
Dating shallow groundwater using {sup 3}H-{sup 3}He and {sup 85}Kr (open access)

Dating shallow groundwater using {sup 3}H-{sup 3}He and {sup 85}Kr

Determining the age of groundwater from monitoring wells can greatly aid in understanding a hydrologic system. Groundwater dating techniques have been used to estimate residence times ranging from about 1000 to 50,000 years. While such measurements have been very useful in hydrothermal and geochemical studies and in the development of groundwater supplies, they have been of limited use in contaminant studies associated with shallow groundwater systems since residence times are often much less than 1000 years.
Date: August 26, 1988
Creator: Solomon, D. K.
Object Type: Report
System: The UNT Digital Library
Design study of a medical proton linac for neutron therapy (open access)

Design study of a medical proton linac for neutron therapy

This paper describes a design study which establishes the physical parameters of the low energy beam transport, radiofrequency quadrupole, and linac, using computer programs available at Fermilab. Beam dynamics studies verify that the desired beam parameters can be achieved. The machine described here meets the aforementioned requirements and can be built using existing technology. Also discussed are other technically feasible options which could be attractive to clinicians, though they would complicate the design of the machine and increase construction costs. One of these options would allow the machine to deliver 2.3 MeV protons to produce epithermal neutrons for treating brain tumors. A second option would provide 15 MeV protons for isotope production. 21 refs., 33 figs.
Date: August 26, 1988
Creator: Machida, S. & Raparia, D.
Object Type: Article
System: The UNT Digital Library
Process hazards review of the 904-A trench (open access)

Process hazards review of the 904-A trench

The 904-A trench is an enclosed underground concrete containment for high level and low level radioactive waste lines between the main Laboratory Building 773-A and waste storage and shipping Building 776-A. The waste generated in laboratories and other facilities in 773-A flows by gravity into the high level and low level drain lines, which proceed from 773-A through the 904-A trench. The trench ends at 776-2A, where the underground was handling tanks for both high level and low level liquids are located. The trench serves to contain any leaks originating in the drain lines. The trench is sloped downward toward the Building 776-2A pipe gallery. Any liquid collected from the sump can be pumped automatically to a waste tank sampled. The review of the 904-A trench system included a study of the trench and piping itself, as well as a study of the high level and low level drain lines from the laboratories to the trench. The present review emphasized on examination of the hazards involved in chemical reactions in the drain lines, misuse of the drains, and criticality. The following items were examined: Process Hazards Review of the Liquid Waste Collection System, Nuclear Criticality Review of the High Level …
Date: August 26, 1988
Creator: Snyder, D. E.
Object Type: Report
System: The UNT Digital Library
Current to Pressure Transducers for the Argon & Nitrogen Dewars (open access)

Current to Pressure Transducers for the Argon & Nitrogen Dewars

A current to pressure (I/P) transducer will be used in the D-Zero piping system. The transducer is necessary to precisely control the control valve positioners located at the argon and nitrogen dewars. A 4-20 rnA signal will come from the PLC function of the TI565. This electric signal must be converted by the transducer to a pneumatic signal of 3-15 psi which will position the actuator. By doing this, the valve can be opened or closed to any adjusted amount from the control room or a remote I/P controller. A total of 9 transducers will be used at the dewars. The nitrogen dewar will have 3 that are located outside and will have to be weatherproof. The argon dewar will have 6, located inside, that will have to be explosion proof or intrinsically safe.
Date: August 25, 1988
Creator: Serges, T. J.
Object Type: Report
System: The UNT Digital Library
Measurements of Neutrons in Enclosures and Outside of Shielding at the Tevatron (open access)

Measurements of Neutrons in Enclosures and Outside of Shielding at the Tevatron

The characteristics of the spectra of neutrons produced by the losses of accelerated proton beams both within accelerator enclosures and outside of shielding has been determined from measurements at various locations around the Fermilab Tevatron and its associated experimental areas. The measurements were performed with a multisphere spectrometer consisting of either /sup 6/LiI scintillators or /sup 6,7/LiF TLD's placed at the centers of moderating polyethylene spheres with diameters ranging from 5.08 to 45.7 cm. The fluence and dose equivalent energy distributions and average quality factors obtained from spectrum unfolding calculations are summarized for this accelerator environment. 22 refs., 8 figs., 3 tabs.
Date: August 25, 1988
Creator: Cossairt, J. D.; Elwyn, A. J.; Freeman, W. S.; Salsbury, W. C. & Yurista, P. M.
Object Type: Article
System: The UNT Digital Library
Final optic protection designs for ICF containment chambers (open access)

Final optic protection designs for ICF containment chambers

The output from a laser-driven high-fain ICF target in the laboratory microfusion facility (LMF) target chamber could produce enough x-rays, shrapnel, and debris to severely damage the laser's final optics. If the final optics were left unprotected, the replacement and reinstallation costs for each beam would exceed $40K. Assuming the laser has 68 beams, the replacement costs for each shot could reach $2.7M. To avoid these excessive costs, we must design a reliable optics protection system. This requires that we define the hazardous environment to which the optics are exposed. The geometrical layout for the 68 beams of the 10 megajoule laser shows the final optics placed at 25 meters from the target. The final optic will be a 2--5 cm thick debris shield ($40K each) which will be placed in front of a $200K focussing lens. Each of the 68 beams will deliver 150 kJ of 0.35 ..mu..m (3..omega..) light and will consist of either a 4 /times/ 4 or a 2 /times/ 8 array of beamlets, with each beamlet aperture having dimensions of 29 cm /times/ 29cm. This produces a 3..omega.. energy density at the final optic of 12J/cm/sup 2/ average and 225-30J/cm/sup 2/peak. 8 refs., 4 figs., …
Date: August 23, 1988
Creator: Nilson, David G. & Woodworth, John G.
Object Type: Article
System: The UNT Digital Library
Ion dip spectroscopy of cold molecules and ions. Progress report (open access)

Ion dip spectroscopy of cold molecules and ions. Progress report

During the past year, the main emphasis in this research program has been on multiphoton ionization spectroscopy of aromatic clusters. This is being pursued in addition to continuing work in areas of ion dip spectroscopy and ion fragmentation spectroscopy. The program has the overall objective of developing improved ultrasensitive molecular detection methods based on multiphoton laser spectroscopy. Photoionization techniques are employed due to their extreme sensitivity combined with mass selectivity. The combination of these two features has led to the current capability to study molecular clusters of specific sizes with high spectral resolution. Clusters are formed in abundance in a supersonic expansion, where they are excited and ionized by an ultraviolet laser beam. The studies reported here are principally based on simple resonant excitation of clusters, followed by one-photon ionization. For the naphthalene clusters, a single laser wavelength suffices for both excitation steps. Additional investigations have been carried out to measure excited state cluster ionization spectra and cluster ion fragmentation spectra. Results from these measurements are not yet sufficiently advanced to report in detail, however the preliminary data support the importance of recently proposed new fundamental ionization mechanisms in clusters. This brief report summarizes results described in more detail in …
Date: August 23, 1988
Creator: Wessel, J.E.
Object Type: Report
System: The UNT Digital Library
Microwave Heating and Current Drive in Tokamaks (open access)

Microwave Heating and Current Drive in Tokamaks

The use of powerful microwave sources provide unique opportunities for novel and efficient heating and current-drive schemes in the electron-cyclotron and lower-hybrid ranges of frequencies. Free- electron lasers and relativistic klystrons are new sources that have a number of technical advantages over conventional, lower-intensity sources; their use can lead to improved current-drive efficiencies and better penetration into a reactor-grade plasma in specific cases. This paper reports on modeling of absorption and current drive, in intense-pulse and quasilinear regimes, and on analysis of parametric instabilities and self-focusing. 16 refs., 2 figs.
Date: August 23, 1988
Creator: Cohen, B. I.; Cohen, R. H.; Kerbel, G. D.; Logan, B. G.; Matsuda, Y.; McCoy, M. G. et al.
Object Type: Article
System: The UNT Digital Library
Design and modelling of a 5 MeV radio frequency electron gun (open access)

Design and modelling of a 5 MeV radio frequency electron gun

The Accelerator Test Facility (ATF) at Brookhaven National Laboratory is a linac-laser complex for research into laser acceleration and for the generation of coherent radiation from electron beams. In order to achieve the design 50 MeV output emittance (..gamma..sigma/sub x/sigma/sub x/') of less than 3 /times/ 10/sup /minus/5/ m rad a high brightness electron gun is required. This paper describes computations and measurements made on a full scale brass model of a 1-1/2 cell, ..pi..-mode, resonant, disc loaded, radiofrequency gun structure which has been designed for this purpose. 7 refs., 9 figs., 6 tabs.
Date: August 22, 1988
Creator: Batchelor, K.; Sheehan, J. & Woodle, M.
Object Type: Report
System: The UNT Digital Library
Flux creep in a TEVATRON cable (open access)

Flux creep in a TEVATRON cable

We have measured the slow magnetization decay of a short sample (2.3 cm) of Tevatron cable in fields up to 0.3 T. The special susceptometer in development for these measurements is based on a commercial SQUID and is described in detail. The observed decay is logarithmic in time as expected from flux creep in the NbTi filaments. A strong correlation was found between the decay and the magnetization status of the sample. It is too early yet to present a quantitative correlation between what we observed and the decay observed in the sextupole component of Tevatron dipoles. The detailed understanding of this phenomenon may be instrumental in guiding the search for efficient superconducting synchrotron operational procedures. 3 refs., 5 figs.
Date: August 22, 1988
Creator: Kuchnir, M. & Tollestrup, A.V.
Object Type: Article
System: The UNT Digital Library
Induction-linac based free-electron laser amplifiers for plasma heating (open access)

Induction-linac based free-electron laser amplifiers for plasma heating

We describe an induction-linac based free-electron laser amplifier that is presently under construction at the Lawrence Livermore National Laboratory. It is designed to produce up to 2 MW of average power at a frequency of 250 GHz for plasma heating experiments in the Microwave Tokamak Experiment. In addition, we shall describe a FEL amplifier design for plasma heating of advanced tokamak fusion devices. This system is designed to produce average power levels of about 10 MW at frequencies ranging form 280 to 560 GHz. 7 refs., 1 tab.
Date: August 22, 1988
Creator: Jong, R.A.
Object Type: Article
System: The UNT Digital Library
Studies of time dependence of fields in TEVATRON superconducting dipole magnets (open access)

Studies of time dependence of fields in TEVATRON superconducting dipole magnets

The time variation in the magnetic field of a model Tevatron dipole magnet at constant excitation current has been studied. Variations in symmetry allowed harmonic components over long time ranges show a log t behavior indicative of ''flux creep.'' Both short time range and long time range behavior depend in a detailed way on the excitation history. Similar effects are seen in the remnant fields present in full-scale Tevatron dipoles following current ramping. Both magnitudes and time dependences are observed to depend on details for the ramps, such as ramp rate, flattop duration, and number of ramps. In a few magnets, variations are also seen in symmetry unallowed harmonics. 9 refs., 10 figs.
Date: August 22, 1988
Creator: Hanft, R. W.; Brown, B. C.; Herrup, D. A.; Lamm, M. J.; McInturff, A. D. & Syphers, M. J.
Object Type: Article
System: The UNT Digital Library