Tritium experience at RTNS-II (open access)

Tritium experience at RTNS-II

Neutrons are produced at the Rotating Target Neutron Source-II (RTNS-II) by deuteron bombardment of a rotating tritium target. Tritium is released from these targets into the accelerator vacuum system. The vacuum system exhaust is first scrubbed and then vented via the facility stack. Tritium emission from the facility in normal operation with vacuum system exhaust flowing through the scrubber is extremely low, <1 mCi/day. Releases from by-passing the tritium scrubber during roughing of the vacuum system and from accelerator maintenance account for nearly all of the annual 10 Ci release from the facility. Routine target changes have been the cause of most tritium uptake by personnel. A target shipping system has been devised for transport of these targets.
Date: April 25, 1980
Creator: Logan, C. M.; Davis, J. C.; Gibson, T. A.; Heikkinen, D. W.; Schumacher, B. J. & Singh, M. S.
System: The UNT Digital Library
Design and Implementation of a Facility for Discovering New Scintillator Materials (open access)

Design and Implementation of a Facility for Discovering New Scintillator Materials

We describe the design and operation of a high-throughput facility for synthesizing thousands of inorganic crystalline samples per year and evaluating them as potential scintillation detector materials. This facility includes a robotic dispenser, arrays of automated furnaces, a dual-beam X-ray generator for diffractometery and luminescence spectroscopy, a pulsed X-ray generator for time response measurements, computer-controlled sample changers, an optical spectrometer, and a network-accessible database management system that captures all synthesis and measurement data.
Date: April 25, 2008
Creator: Derenzo, Stephen; Derenzo, Stephen E; Boswell, Martin S.; Bourret-Courchesne, Edith; Boutchko, Rostyslav; Budinger, Thomas F. et al.
System: The UNT Digital Library
Chemical Bonding and Structural Information of Black Carbon Reference Materials and Individual Carbonaceous Atmospheric Aerosols (open access)

Chemical Bonding and Structural Information of Black Carbon Reference Materials and Individual Carbonaceous Atmospheric Aerosols

The carbon-to-oxygen ratios and graphitic nature of a rangeof black carbon standard reference materials (BC SRMs), high molecularmass humic-like substances (HULIS) and atmospheric particles are examinedusing scanning transmission X-ray microscopy (STXM) coupled with nearedge X-ray absorption fine structure (NEXAFS) spectroscopy. UsingSTXM/NEXAFS, individual particles with diameter>100 nm are studied,thus the diversity of atmospheric particles collected during a variety offield missions is assessed. Applying a semi-quantitative peak fittingmethod to the NEXAFS spectra enables a comparison of BC SRMs and HULIS toparticles originating from anthropogenic combustion and biomass burns,thus allowing determination of the suitability of these materials forrepresenting atmospheric particles. Anthropogenic combustion and biomassburn particles can be distinguished from one another using both chemicalbonding and structural ordering information. While anthropogeniccombustion particles are characterized by a high proportion ofaromatic-C, the presence of benzoquinone and are highly structurallyordered, biomass burn particles exhibit lower structural ordering, asmaller proportion of aromatic-C and contain a much higher proportion ofoxygenated functional groups.
Date: April 25, 2007
Creator: Hopkins, Rebecca J.; Tivanski, Alexei V.; Marten, Bryan D. & Gilles, Mary K.
System: The UNT Digital Library
Localized Electron States Near a Metal-SemiconductorNanocontact (open access)

Localized Electron States Near a Metal-SemiconductorNanocontact

The electronic structure of nanowires in contact withmetallic electrodes of experimentally relevant sizes is calculated byincorporating the electrostatic polarization potential into the atomisticsingle particle Schrodinger equation. We show that the presence of anelectrode produces localized electron/hole states near the electrode, aphenomenon only exhibited in nanostructures and overlooked in the past.This phenomenon will have profound implications on electron transport insuch nanosystems. We calculate several electrode/nanowire geometries,with varying contact depths and nanowire radii. We demonstrate the changein the band gap of up to 0.5 eV in 3 nm diameter CdSe nanowires andcalculate the magnitude of the applied electric field necessary toovercome the localization.
Date: April 25, 2007
Creator: Demchenko, Denis O. & Wang, Lin-Wang
System: The UNT Digital Library
A Gridded Electron Gun for a Sheet Beam Klystron (open access)

A Gridded Electron Gun for a Sheet Beam Klystron

This paper describes the development of an electron gun for a sheet beam klystron. Initially intended for accelerator applications, the gun can operate at a higher perveance than one with a cylindrically symmetric beam. Results of 2D and 3D simulations are discussed.
Date: April 25, 2008
Creator: Read, M. E.; Miram, G.; Ives, R. L.; Ivanov, V. & Krasnykh, A.
System: The UNT Digital Library
THE Epsilon*/Lambda BRANCHING RATIO OF Y*1 (open access)

THE Epsilon*/Lambda BRANCHING RATIO OF Y*1

Recently a T = 1 resonance in the {Lambda}{pi} system called Y*{sub 1} has been observed with a mass of 1385 Mev. Two types of resonances have been predicted that might relate this observation to other elementary-particle interactions: (1) P 3/2 resonances in the {Lambda}{pi} and {Sigma}{pi} systems predicted by global symmetry corresponding to the (3/2, 3/2) resonance of the {pi}N system; (2) a spin-1/2 Y-{pi} resonance resulting from a bound state in the KN system. The position and width of the observed Y*{sub 1} resonance agree with both theories, but since the spin and parity have not yet been determined, it is impossible at present to distinguish between the two theoretical interpretations.
Date: April 25, 1961
Creator: Alston, Margaret H.; Alvarez, Luis W.; Eberhard, Philippe; Good,Myron L.; Graziano, William; Ticho, Harold K. et al.
System: The UNT Digital Library
Spin Spectrometer at the ALS and APS (open access)

Spin Spectrometer at the ALS and APS

None
Date: April 25, 2007
Creator: Tobin, J G; Morton, S A; Yu, S W; Komesu, T; Waddill, G D & Boyd, P
System: The UNT Digital Library
CORA: transient analysis code for a cluster of reactor core assemblies (open access)

CORA: transient analysis code for a cluster of reactor core assemblies

The CORA code is a steady state/transient, core thermal hydraulics code for the FFTF Reactor. A brief overview of the code development and use is presented.
Date: April 25, 1979
Creator: Johnson, H. G.
System: The UNT Digital Library
Effect of torus wall flexibility on hydro-structural interaction in BWR containment system (open access)

Effect of torus wall flexibility on hydro-structural interaction in BWR containment system

The MARK I boiling water reactor (BWR) containment system is comprised of a light-bulb-shaped reactor compartment connected through vent pipes to a torus-shaped and partially water-filled pressure suppression chamber, or the wetwell. During either a normally occurring safety relief valve (SRV) discharge or a hypothetical loss-of-coolant accident (LOCA), air or steam is forced into the wetwell water pool for condensation and results in hydrodynamically induced loads on the torus shell. An analytical program is described which employs the finite element method to investigate the influence of torus wall flexibility on hydrodynamically induced pressure and the resultant force on the torus shell surface. The shell flexibility is characterized by the diameter-to-thickness ratio which is varied from the perfectly rigid case to the nominal plant condition. The general conclusion reached is that torus wall flexibility decreases both the maximum pressure seen by the shell wall and the total vertical load resulted from the hydrodynamically induced pressure.
Date: April 25, 1979
Creator: Lu, S.C.H.; McCauley, E.W. & Holman, G.S.
System: The UNT Digital Library
Tritium management in fusion synfuel designs (open access)

Tritium management in fusion synfuel designs

Two blanket types are being studied: a lithium-sodium pool boiler and a lithium-oxide- or lithium-sodium pool boiler and a lithium-oxide- or aluminate-microsphere moving bed. For each, a wide variety of current technology was considered in handling the tritium. Here, we show the pool boiler with the sulfur-iodine thermochemical cycle first developed and now being piloted by the General Atomic Company. The tritium (T/sub 2/) will be generated in the lithium-sodium mixture where the concentration is approx. 10 ppM and held constant by a scavenging system consisting mainly of permeators. An intermediate sodium loop carries the blanket heat to the thermochemical cycle, and the T/sub 2/ in this loop is held to 1 ppM by a similar scavenging system. With this design, we have maintained blanket inventory at 1 kg of tritium, kept thermochemical cycle losses to 5 Ci/d and environmental loss to 10 Ci/d, and held total plant risk inventory at 7 kg tritium.
Date: April 25, 1980
Creator: Galloway, T.R.
System: The UNT Digital Library
Toward automating the database design process (open access)

Toward automating the database design process

One organization's approach to designing complex, interrelated databases is described. The problems encountered and the techniques developed are discussed. A set of software tools to aid the designer and to produce an initial database design directly is presented. 5 figures.
Date: April 25, 1979
Creator: Asprey, P.L.
System: The UNT Digital Library
Physics possibilities at LHC/SSC (open access)

Physics possibilities at LHC/SSC

This document reviews some recent work on physics simulations for SSC/LHC. Included are reviews of some of the recent developments in physics simulations for the SSC/LHC and comments upon the requirements that are placed upon detectors by the need to extract specific physics signatures. The material in the various EOI/LOI documents submitted to the SCC Laboratory and the work done at the Aachen LHC workshop are discussed. In the following discussion 1 SSC (LHC) year corresponds to an integrated luminosity of 10 (100) fb{sup {minus}1}. 41 refs., 14 figs.
Date: April 25, 1991
Creator: Hinchliffe, I.
System: The UNT Digital Library
Ductile crack initiation in the Charpy V-notch test (open access)

Ductile crack initiation in the Charpy V-notch test

Initiation and growth of a crack in the Charpy V-notch test was investigated by performing both static and impact controlled deflection tests. Test specimens were deformed to various deflections, heat-tinted to mark crack extension and broken apart at low temperature to allow extension measurements. Measurement of the crack extension provided an estimate of crack initiation as defined by different criteria. Crack initiation starts well before maximum load, and is dependent on the definition of ''initiation''. Using a definition of first micro-initiation away from the ductile blunting, computer model predictions agreed favorably with the experimental results.
Date: April 25, 1978
Creator: Server, W. L.; Norris, D. M., Jr. & Prado, M. E.
System: The UNT Digital Library
Instrumenting a pressure suppression experiment for a Mark I boiling water reactor: another measurements engineering challenge (open access)

Instrumenting a pressure suppression experiment for a Mark I boiling water reactor: another measurements engineering challenge

A /sup 1///sub 5/-scale test facility of a pressure-suppression system from a Mark I boiling water reactor was instrumented with seven types of transducers to obtain high-accuracy, dynamic loading data during a hypothetical loss-of-coolant accident. A total of 27 air tests have been completed with an average of 175 transducers recorded for each test. An end-to-end calibration of the total measurement system was run to establish accuracy of the data. The instrumentation verified the analysis of the dynamic loading of the pressure-suppression system.
Date: April 25, 1978
Creator: Shay, W.M.; Brough, W.G. & Miller, T.B.
System: The UNT Digital Library
Electrochemical Hydrogen Sensor for Safety Monitoring (open access)

Electrochemical Hydrogen Sensor for Safety Monitoring

A hydrogen safety sensor is presented which provides high sensitivity and fast response time when operated in air. The target application for the sensor is external deployment near systems using or producing high concentrations of hydrogen. The sensor is composed of a catalytically active metal-oxide sensing electrode and a noble metal reference electrode attached to an yttria-stabilized zirconia (YSZ) electrolyte. The sensing approach is based on the difference in oxidation rate of hydrogen on the different electrode materials. Results will be presented for a sensor using a sensing electrode of tin-doped indium oxide (ITO). Response to H{sub 2}, and cross-sensitivity to hydrocarbon and H{sub 2}O are discussed.
Date: April 25, 2003
Creator: Martin, L. P.; Pham, A. Q. & Glass, R. S.
System: The UNT Digital Library
IMPROVEMENT OF CdMnTe DETECTOR PERFORMANCE BY MnTe PURIFICATION (open access)

IMPROVEMENT OF CdMnTe DETECTOR PERFORMANCE BY MnTe PURIFICATION

Residual impurities in manganese (Mn) are a big obstacle to obtaining high-performance CdMnTe (CMT) X-ray and gamma-ray detectors. Generally, the zone-refining method is an effective way to improve the material's purity. In this work, we purified the MnTe compounds combining the zone-refining method with molten Te, which has a very high solubility for most impurities. We confirmed the improved purity of the material by glow-discharge mass spectrometry (GDMS). We also found that CMT crystals from a multiply-refined MnTe source, grown by the vertical Bridgman method, yielded better performing detectors.
Date: April 25, 2011
Creator: Kim, K. H.; Bolotnikov, A. E.; Camarda, G. S.; Tappero, R.; Hossain, A.; Cui, Y. et al.
System: The UNT Digital Library
Cosmography From Two-Image Lens Systems: Overcoming the Lens Profile Slope Degeneracy (open access)

Cosmography From Two-Image Lens Systems: Overcoming the Lens Profile Slope Degeneracy

None
Date: April 25, 2013
Creator: Suyu, S.H. & /UC, Santa Barbara /KIPAC, Menlo Park
System: The UNT Digital Library
Mechanical design aspects of a tandem mirror fusion reactor (open access)

Mechanical design aspects of a tandem mirror fusion reactor

Two ''plugs'' of dense plasma at either end of a central solenoid cell form the basis of a new mirror fusion power plant concept. A central cell blanket design is presented. Modules on crawler tracks serviced by remote welding and handling machines of very simple design are important features resulting from linear axisymmetric geometry. Three blanket designs are considered and the best one presented in some detail. It has lithium as the breeder material, helium cooled. ''Plug'' magnet field strengths must be high. A novel magnet is presented to satisfy the physics of the end plugs. Beam sources at 1,200 KV present special problems. Methods of voltage standoff, arc damage control, and neutralization are discussed. New secondary containment ideas are presented to allow removable roof sections of balanced design.
Date: April 25, 1977
Creator: Neef, W. S. Jr.
System: The UNT Digital Library
Geochemistry of Delaware Basin groundwaters (open access)

Geochemistry of Delaware Basin groundwaters

Fluids from various formations were sampled and analyzed in order to characterize groundwaters in the Delaware Basin. Waters were analyzed for solute content and/or stable isotope ratios (D/H and /sup 18/O//sup 16/O). Three lines of geochemical arguments are summarized, in order to present the natures and probable origins of analyzed fluids: solute chemistry, thermodynamic modelling of low-temperature aqueous species, and stable isotope ratios. (JGB)
Date: April 25, 1977
Creator: Lambert, S. J.
System: The UNT Digital Library
Searches for Leptonic B Decays at BaBar (open access)

Searches for Leptonic B Decays at BaBar

Measurements of the branching fractions of purely leptonic decays of B-mesons translate into constraints in the plane of the charged Higgs mass versus tan {beta} which are relatively insensitive to the particular theoretical model. Using the full BABAR dataset of 450 million B-decays we search for these decays. No significant signal is found in the decays into electrons or muons and we set upper limits on the branching fractions of the order of a 10{sup -6} at 90% confidence level. We measure the branching fraction of B {yields} {tau}{mu} to be (1.7 {+-} 0.6) x 10{sup -4}.
Date: April 25, 2012
Creator: Nelson, Silke
System: The UNT Digital Library
Dissecting the Gravitational Lens B1608 656. I. Lens Potential Reconstruction (open access)

Dissecting the Gravitational Lens B1608 656. I. Lens Potential Reconstruction

None
Date: April 25, 2013
Creator: Suyu, S. H.; Marshall, P. J.; Blandford, R. D.; Fassnacht, C. D.; Koopmans, L. V. E.; McKean, J. P. et al.
System: The UNT Digital Library
Precious Metal Recovery from Fuel Cell MEA's (open access)

Precious Metal Recovery from Fuel Cell MEA's

In 2003, Engelhard Corporation received a DOE award to develop a cost-effective, environmentally friendly approach to recover Pt from fuel cell membrane electrode assemblies (MEA’s). The most important precious metal used in fuel cells is platinum, but ruthenium is also added to the anode electrocatalyst if CO is present in the hydrogen stream. As part of the project, a large number of measurements of Pt and Ru need to be made. A low-cost approach to measuring Pt is using the industry standard spectrophotometric measurement of Pt complexed with stannous chloride. The interference of Ru can be eliminated by reading the Pt absorbance at 450 nm. Spectrophotometric methods for measuring Ru, while reported in the literature, are not as robust. This paper will discuss the options for measuring Pt and Ru using the method of UV-VIS spectrophotometry
Date: April 25, 2004
Creator: Shore, Lawrence
System: The UNT Digital Library
The eukaryotic translation elongation factor eEF1A2 induces neoplastic properties and mediates tumorigenic effects of ZNF217 in precursor cells of human ovarian carcinomas (open access)

The eukaryotic translation elongation factor eEF1A2 induces neoplastic properties and mediates tumorigenic effects of ZNF217 in precursor cells of human ovarian carcinomas

Ovarian epithelial carcinomas (OEC) frequently exhibit amplifications at the 20q13 locus which is the site of several oncogenes, including the eukaryotic elongation factor EEF1A2 and the transcription factor ZNF217. We reported previously that overexpressed ZNF217 induces neoplastic characteristics in precursor cells of OEC. Unexpectedly, ZNF217, which is a transcriptional repressor, enhanced expression of eEF1A2. In this study, array comparative genomic hybridization, single nucleotide polymorphism and Affymetrix analysis of ZNF217-overexpressing cell lines confirmed consistently increased expression of eEF1A2 but not of other oncogenes, and revealed early changes in EEF1A2 gene copy numbers and increased expression at crisis during immortalization. We defined the influence of eEF1A2 overexpression on immortalized ovarian surface epithelial cells, and investigated interrelationships between effects of ZNF217 and eEF1A2 on cellular phenotypes. Lentivirally induced eEF1A2 overexpression caused delayed crisis, apoptosis resistance and increases in serum-independence, saturation densities, and anchorage independence. siRNA to eEF1A2 reversed apoptosis resistance and reduced anchorage independence in eEF1A2-overexpressing lines. Remarkably, siRNA to eEF1A2 was equally efficient in inhibiting both anchorage independence and resistance to apoptosis conferred by ZNF217 overexpression. Our data define neoplastic properties that are caused by eEF1A2 in nontumorigenic ovarian cancer precursor cells, and suggest that eEF1A2 plays a role in mediating ZNF217-induced …
Date: April 25, 2008
Creator: Sun, Yu; Wong, Nicholas; Guan, Yinghui; Salamanca, Clara M.; Cheng, Jung Chien; Lee, Jonathan M. et al.
System: The UNT Digital Library
Growth of detector-grade CZT by Traveling Heater Method (THM): An advancement (open access)

Growth of detector-grade CZT by Traveling Heater Method (THM): An advancement

In this present work we report the growth of Cd{sub 0.9}Zn{sub 0.1}Te doped with In by a modified THM technique. It has been demonstrated that by controlling the microscopically flat growth interface, the size distribution and concentration can be drastically reduced in the as-grown ingots. This results in as-grown detector-grade CZT by the THM technique. The three-dimensional size distribution and concentrations of Te inclusions/precipitations were studied. The size distributions of the Te precipitations/inclusions were observed to be below the 10-{micro}m range with the total concentration less than 10{sup 5} cm{sup -3}. The relatively low value of Te inclusions/precipitations results in excellent charge transport properties of our as-grown samples. The ({mu}{tau}){sub e} values for different as-grown samples varied between 6-20 x 10{sup -3} cm{sup 2}/V. The as-grown samples also showed fairly good detector response with resolution of {approx}1.5%, 2.7% and about 3.8% at 662 keV for quasi-hemispherical geometry for detector volumes of 0.18 cm{sup 3}, 1 cm{sup 3} and 4.2 cm{sup 3}, respectively.
Date: April 25, 2011
Creator: ROY, U.N.; JAMES, R.; WEILER, S.; STEIN, J.; GROZA, M.; BURGER, A. et al.
System: The UNT Digital Library