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Large-Signal Injection-Level Spectroscopy of Impurities in Silicon

Description: Deep level defects in silicon are identified by measuring the recombination lifetime as a function of the injection level. The basic models for recombination at deep and shallow centers is developed. The defect used for the theoretical model is the well-known interstitial Fe ion in silicon. Data are presented on silicon samples ranging in defect content from intentionally Fe-doped samples to an ultra-pure float-zone grown sample. These data are analyzed in terms of the injection-level spectrosc… more
Date: October 16, 1998
Creator: Ahrenkiel, R. K. & Johnston, S. W.
Partner: UNT Libraries Government Documents Department
open access

The edge plasma and divertor in TIBER

Description: An open divertor configuration has been adopted for TIBER. Most recent designs, including DIII-D, NET and CIT use open configurations and rely on a dense edge plasma to shield the plasma from the gas produced at the neutralizer plate. Experiments on ASDEX, PDX, D-III, and recently on DIII-D have shown that a dense edge plasma can be produced by re-ionizing most of the gas produced at the plate. This high recycling mode allows a large flux of particles to carry the heat to the plate, so that the… more
Date: October 16, 1987
Creator: Barr, W.L.
Partner: UNT Libraries Government Documents Department
open access

Demountable vacuum seals for fusion reactor applications

Description: Demountable vacuum seals for fusion reactor applications must be compatible with the reactor environment, easily scalable, very reliable and readily maintained by remote handling methods. We are investigating gate valves as well as flanges in our efforts to provide such seals. They are all metal and scalable without becoming massive and require no axial fasteners. Preliminary tests on an initial 30 cm aluminum flange using no soft metal coatings or gaskets have given several vacuum tight closur… more
Date: October 16, 1987
Creator: Batzer, T. H. & Call, W. R.
Partner: UNT Libraries Government Documents Department
open access

Hot Topics in Ultra-Peripheral Ion Collisions

Description: Ultra-peripheral collisions of relativistic heavy ions involve long-ranged electromagnetic interactions at impact parameters too large for hadronic interactions to occur. The nuclear charges are large; with the coherent enhancement, the cross sections are also large. Many types of photonuclear and purely electromagnetic interactions are possible. We present here an introduction to ultra-peripheral collisions, and present four of the most compelling physics topics.
Date: October 16, 2001
Creator: Baur, G.; Bertulani, C. A.; Chiu, M.; Ginzburg, I. F.; Hencken, K.; Klein, S. R. et al.
Partner: UNT Libraries Government Documents Department
open access

Beauty and charm physics at CDF Run II

Description: Using the data samples collected with the CDF Run II detector during the year 2002 and early 2003, new measurements of the production cross-sections and the masses, lifetimes and branching fractions of beauty and charm hadrons are presented. New measurements of the {Lambda}{sub b} mass, lifetime, and branching fractions have greatly improved the current knowledge of bottom baryon properties and decay dynamics. the large charm signals made available by the silicon vertex track trigger have enabl… more
Date: October 16, 2003
Creator: Bishai, M.
Partner: UNT Libraries Government Documents Department
open access

TIBER engineering test reactor (ETR) startup scenarios

Description: A time-dependent Tokamak Systems Code (TTSC) has been developed and used to examine various inductively driven startup scenarios for the TIBER reactor. Radially averaged particle and energy balance equations are solved. In addition, time varying currents in the PF and OH coils are determined from MHD equilibrium and volt-seconds considerations. Less than 20 MW of auxiliary power deposited in the electrons is required to obtain steady-state operations. For this scenario, less than 10% of the tot… more
Date: October 16, 1987
Creator: Blackfield, D. T. & Perkins, L. J.
Partner: UNT Libraries Government Documents Department
open access

W boson cross section and decay properties at the Tevatron

Description: The authors present the first measurements of {sigma}(p{bar p} {yields} W {yields} {ell}{nu}) and {sigma}(p{bar p} {yields} Z {yields} {ell}{ell}) at {radical}s = 1.96 TeV, along with new measurements of W angular-decay distributions in p{bar p} collisions at {radical}s = 1.8 TeV.
Date: October 16, 2002
Creator: Bloom, K.
Partner: UNT Libraries Government Documents Department
open access

The GLAST Large Area Telescope Detector Performance Monitoring

Description: The Large Area Telescope (LAT) is one of two instruments on board the Gamma-ray Large Area Telescope (GLAST), the next generation high energy gamma-ray space telescope. The LAT contains sixteen identical towers in a four-by-four grid. Each tower contains a silicon-strip tracker and a CsI calorimeter that together will give the incident direction and energy of the pair-converting photon in the energy range 20 MeV - 300 GeV. In addition, the instrument is covered by a finely segmented Anti-Coinci… more
Date: October 16, 2007
Creator: Borgland, A. W. & Charles, E.
Partner: UNT Libraries Government Documents Department
open access

Bound states and the Bekenstein bound

Description: We explore the validity of the generalized Bekenstein bound, S<= pi M a. We define the entropy S as the logarithm of the number of states which have energy eigenvalue below M and are localized to a flat space region of width alpha. If boundary conditions that localize field modes are imposed by fiat, then the bound encounters well-known difficulties with negative Casimir energy and large species number, as well as novel problems arising only in the generalized form. In realistic systems, how… more
Date: October 16, 2003
Creator: Bousso, Raphael
Partner: UNT Libraries Government Documents Department
open access

Holocene lahars and their byproducts along the historical path of the White River between Mount Rainier and Seattle: Geological Society of America Field Trip

Description: Clay-poor lahars of late Holocene age from Mount Rainier change down the White River drainage into lahar-derived fluvial and deltaic deposits that filled an arm of Puget Sound between the sites of Auburn and Seattle, 110-150 km downvalley from the volcano's summit. Lahars in the debris-flow phase left cobbly and bouldery deposits on the walls of valleys within 70 km of the summit. At distances of 80-110 km, transitional (hyperconcentrated) flows deposited pebbles and sand that coat terraces in … more
Date: October 16, 2003
Creator: Brown, Thomas A.; Zehfuss, Paul H.; Atwater, Brian F.; Vallance, James W. & Brenniman, Henry
Partner: UNT Libraries Government Documents Department
open access

RF Phase Stability and Electron Beam Characterization for the PLEIADES Thomson X-Ray Source

Description: We report on the performance of an S-band RF photocathode electron gun and accelerator for operation with the PLEIADES Thomson x-ray source at LLNL. To produce picosecond, high brightness x-ray pulses, picosecond timing, terahertz bandwidth diagnostics, and RF phase control are required. Planned optical, RF, x-ray and electron beam measurements to characterize the dependence of electron beam parameters and synchronization on RF phase stability are presented.
Date: October 16, 2002
Creator: Brown, W J; Hartemann, F V; Tremaine, A M; Springer, P T; Le Sage, G P; Barty, C P J et al.
Partner: UNT Libraries Government Documents Department
open access

Modeling of thermal effects on TIBER II (Tokamak Ignition/Burn Experimental Reactor) divertor during plasma disruption

Description: Mapping the disruption power flow from the mid-plane of the TIBER Engineering Test Reactor to its divertor and calculating the resulting thermal effects are accomplished through the modification and coupling of three presently existing computer codes. The resulting computer code TADDPAK (Thermal Analysis Divertor during Disruption PAcKage) provides three-dimensional graphic presentations of time and positional dependent thermal effects on a poloidal cross section of the double-null-divertor con… more
Date: October 16, 1987
Creator: Bruhn, M. L. & Perkins, L. J.
Partner: UNT Libraries Government Documents Department
open access

Inferences drawn from shock-enhanced turbulent mixing analyses

Description: This discussion concerns analyses of physical shock-tube and shock-boundary layer interaction experiments, supplemented by computations. The basic issue is that of evaluating the influence of reflected shock waves on enhancing the balance of turbulent kinetic energy and resultant turbulent materials mixing during implosion and shock reflection intervals. Increases in random velocity amplitudes of a factor of 5 or greater implying turbulent kinetic energy increases of a factor of 12 or more have… more
Date: October 16, 1987
Creator: Buckingham, A.C.
Partner: UNT Libraries Government Documents Department
open access

The GLAST LAT Instrument Science Operations Center

Description: The Gamma-ray Large Area Space Telescope (GLAST) is scheduled for launch in late 2007. Operations support and science data processing for the Large Area Telescope (LAT) instrument on GLAST will be provided by the LAT Instrument Science Operations Center (ISOC) at the Stanford Linear Accelerator Center (SLAC). The ISOC supports GLAST mission operations in conjunction with other GLAST mission ground system elements and supports the research activities of the LAT scientific collaboration. The ISOC… more
Date: October 16, 2007
Creator: Cameron, Robert A.
Partner: UNT Libraries Government Documents Department
open access

Microwave Superheaters for Fusion

Description: The microwave superheater uses the synchrotron radiation from a thermonuclear plasma to heat gas seeded with an alkali metal to temperatures far above the temperature of material walls. It can improve the efficiency of the Compact Fusion Advanced Rankine (CFAR) cycle described elsewhere in these proceedings. For a proof-of-principle experiment using helium, calculations show that a gas superheat ..delta..T of 2000/sup 0/K is possible when the wall temperature is maintained at 1000/sup 0/K. The … more
Date: October 16, 1987
Creator: Campbell, R. B.; Hoffman, M. A. & Logan, B. G.
Partner: UNT Libraries Government Documents Department
open access

Large-Scale CORBA-Distributed Software Framework for NIF Controls

Description: The Integrated Computer Control System (ICCS) is based on a scalable software framework that is distributed over some 325 computers throughout the NIF facility. The framework provides templates and services at multiple levels of abstraction for the construction of software applications that communicate via CORBA (Common Object Request Broker Architecture). Various forms of object-oriented software design patterns are implemented as templates to be extended by application software. Developers ex… more
Date: October 16, 2001
Creator: Carey, R W; Fong, K W; Sanchez, R J; Tappero, J D & Woodruff, J P
Partner: UNT Libraries Government Documents Department
open access

Validation of Electrical-Impedance Tomography for Measurements of Material Distribution in Two-Phase Flows

Description: A series of studies is presented in which an electrical-impedance tomography (EXT) system is validated for two-phase flow measurements. The EIT system, developed at Sandia National Laboratories, is described along with the computer algorithm used for reconstructing phase volume fraction profiles. The algorithm is first tested using numerical data and experimental phantom measurements, with good results. The EIT system is then applied to solid-liquid and gas-liquid flows, and results are compare… more
Date: October 16, 1998
Creator: Ceccio, S. L.; George, D. L.; O'Hern, T. J.; Shollenberger, K. A. & Torczynski, J. R.
Partner: UNT Libraries Government Documents Department
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