Coupled Environmental Processes in the Mojave Desert and Implications for ET Covers as Stable Landforms (open access)

Coupled Environmental Processes in the Mojave Desert and Implications for ET Covers as Stable Landforms

Monolayer evapotranspiration (ET) covers are the baseline method for closure of disposal sites for low-level radioactive waste (LLW), mixed LLW, and transuranic (TRU) waste at the Nevada Test Site (NTS). The regulatory timeline is typically 1,000 years for LLW and 10,000 years for TRU waste. Covers for such waste have different technical considerations than those with shorter timelines because they are subject to environmental change for longer periods of time, and because the environmental processes are often coupled. To evaluate these changes, four analog sites (approximately 30, 1,000 to 2,000, 7,000 to 12,500, and 125,000 years in age) on the NTS were analyzed to address the early post-institutional control period (the youngest site), the 1,000-year compliance period for disposal of LLW, and the 10,000-year period for TRU waste. Tests included soil texture, structure, and morphology; surface soil infiltration and hydraulic conductivity; vegetation and faunal surveys; and literature reviews. Separate measurements were made in plant undercanopy and intercanopy areas. The results showed a progressive increase in silt and clay content of surface soils with age. Changes in soil texture and structure led to a fivefold decline in saturated hydraulic conductivity in intercanopy areas, but no change in undercanopies, which were subject …
Date: January 18, 2006
Creator: Shafer, D.; oung, M. Y; Zitzer, S.; McDonald, E. & Caldwell, T.
System: The UNT Digital Library
QCD THERMODYNAMICS WITH ALMOST REALISTIC QUARK MASSES. (open access)

QCD THERMODYNAMICS WITH ALMOST REALISTIC QUARK MASSES.

None
Date: March 18, 2006
Creator: SCHMIDT, C.
System: The UNT Digital Library
Study of Multi-body Charmless B Decays with the BaBar Experiment (open access)

Study of Multi-body Charmless B Decays with the BaBar Experiment

The authors report recent measurements of charmless B decays to the final states K{sup +}K{sup +}K{sup -}, {phi}{phi}K, {eta}'{eta}'K, M{sub S}{sup 0}K{sub S}{sup 0}K{sub L}{sup 0}, {bar {Lambda}}p{pi}{sup +}, K*{sup +}h{sup +}h{sup -} and KX(inclusive). The results were obtained using a data sample of up to 288.5 fb{sup -1} recorded by the BABAR detector at the PEP-II asymmetric B factory at SLAC.
Date: October 18, 2006
Creator: Latham, Thomas E.
System: The UNT Digital Library
Support for the Tenth Workshop on the Physics of Dusty Plasmas (open access)

Support for the Tenth Workshop on the Physics of Dusty Plasmas

Final report for Grant Number DE-FG02-03ER54703.
Date: April 18, 2006
Creator: Thomas, E., Jr.
System: The UNT Digital Library
Exclusive Charmless Semileptonic Decays B ---> X/U L Nu From BaBar (open access)

Exclusive Charmless Semileptonic Decays B ---> X/U L Nu From BaBar

The latest results of exclusive charmless semileptonic decays B {yields} {pi}{ell}v and B {yields} {rho}{ell}v from the BABAR Collaboration are presented. They are based on samples of B{bar B} events recorded on the {Upsilon}(4S) resonance. Several different experimental techniques are compared. Measurements of partial branching fractions in intervals of q{sup 2}, the four-momentum transfer squared, allow a study of the shape of the B {yields} {pi}{ell}v form factor and a comparison with theoretical calculations. The Cabibbo-Kobayashi-Maskawa matrix element |V{sub ub}| is determined using the measured branching fractions combined with recent form-factor predictions.
Date: April 18, 2006
Creator: Dingfelder, J.
System: The UNT Digital Library
Direct Measurement of Geometric and Resistive Wakefields in Tapered Collimators for the International Linear Collider (open access)

Direct Measurement of Geometric and Resistive Wakefields in Tapered Collimators for the International Linear Collider

Precise collimation of the beam halo is required in the International Linear Collider (ILC) to prevent beam losses near the interaction region that could cause unacceptable backgrounds for the physics detector. The necessarily small apertures of the collimators lead to transverse wakefields that may result in beam deflections and increased emittance. A set of collimator wakefield measurements has previously been performed in the ASSET region of the SLAC Linac. We report on the next phase of this program, which is carried out at the recently commissioned End Station A (ESA) test facility at SLAC. Measurements of resistive and geometric wakefields using tapered collimators are compared with model predictions from MAFIA and GdfidL and with analytic calculations.
Date: August 18, 2006
Creator: Watson, N. K.; Adeya, D.; Stockton, M. C.; Kolomensky, Y.; Slater, M.; Angal-Kalinin, D. et al.
System: The UNT Digital Library
Measurement of the B+ ->eta l+ nu and B+ -> eta' l+ nu Branching Fractions using Upsilon(4S) -> B Bbar Events Tagged by a Fully Reconstructed B Meson (open access)

Measurement of the B+ ->eta l+ nu and B+ -> eta' l+ nu Branching Fractions using Upsilon(4S) -> B Bbar Events Tagged by a Fully Reconstructed B Meson

We report preliminary measurements of the exclusive charmless semileptonic branching fractions of the B{sup +} {yields} {eta}{ell}{sup +}{nu} and B{sup +} {yields} {eta}'{ell}{sup +}{nu} decays. These measurements are based on 316 fb{sup -1} of data collected at the {Upsilon}(4S) resonance by the BABAR detector. In events in which the decay of one B meson to a hadronic final state is fully reconstructed, the semileptonic decay of the recoiling B meson is identified by the detection of a charged lepton and an {eta} or {eta}'. We measure the branching fraction {Beta}(B{sup +} {yields} {eta}{ell}{sup +}{nu}) = (0.84 {+-} 0.27 {+-} 0.21) x 10{sup -4}, where the first error is statistical and the second one systematic. We also set an upper limit on the branching fraction of {Beta}(B{sup +} {yields} {eta}{ell}{sup +}{nu}) < 1.4 x 10{sup -4} and {Beta}(B{sup +} {yields} {eta}'{ell}{sup +}{nu}) < 1.3 x 10{sup -4} at the 90% confidence level.
Date: August 18, 2006
Creator: D'Orazio, A
System: The UNT Digital Library
A Measurement of CP-violation Parameters in B0B0barMixing using Partially Reconstructed D^{*-}l^+ nu_l Events at BaBar (open access)

A Measurement of CP-violation Parameters in B0B0barMixing using Partially Reconstructed D^{*-}l^+ nu_l Events at BaBar

CP violation in B{sup 0}{bar B}{sup 0} mixing is characterized by the value of the parameter |q/p| being different from 1, and the Standard Model predicts this difference to be smaller than 10{sup -3}. We present a measurement of this parameter using a partial reconstruction of one of the B mesons in the semileptonic channel D*{sup -}{ell}{sup +}{nu}{sub {ell}}, where only the hard lepton and the soft pion from the D*{sup -} {yields} {bar D}{sup 0}{pi}{sup -} decay are reconstructed. The flavor of the other B is determined by means of lepton tagging. The determination of |q/p| is then performed with a fit to the proper time difference of the two B decays. We use a luminosity of 200.8 fb{sup -1}, collected at the {Upsilon}(4S) resonance by the BABAR detector at the PEP-II asymmetrical-energy e{sup +}e{sup -} collider, in the period 1999-2004. We obtain the preliminary result: |q/p| - 1 = (6.5 {+-} 3.4(stat.) {+-} 2.0(syst.)) {center_dot} 10{sup -3}.
Date: August 18, 2006
Creator: Aubert, B.
System: The UNT Digital Library
Comparison Between H-Ion and Heat Cleaning of Cu-Metal Cathodes (open access)

Comparison Between H-Ion and Heat Cleaning of Cu-Metal Cathodes

Understanding the quantum efficiency (QE) of a metal photocathode in an s-band RF gun is important to limit the drive laser energy requirement and provide the best quality electron beam. Systematic measurements of the qe vs. wavelength for varying surface contamination have been performed on copper samples using x-ray photoelectron spectroscopy (XPS). The sample is first cleaned to the theoretical limit of QE using a 1 keV hydrogen ion beam. The H-ion beam cleans an area approximately 1cm in diameter and has no effect on the surface roughness while removing essentially all contaminants and lowering the work function to 4.3eV[1]. The sample is then exposed to atmospheric contaminants (nitrogen and oxygen) and measured again with XPS to determine the degree of contamination and their effect on the QE. These results and comparison with theory are presented.
Date: August 18, 2006
Creator: Dowell, D. H.; King, F. K.; Kirby, R. E. & Schmerge, J. F.
System: The UNT Digital Library
The BaBar LST Detector High Voltage System: Design And Implementation (open access)

The BaBar LST Detector High Voltage System: Design And Implementation

In 2004, the first two sextants of the new Limited Streamer Tube (LST) detector were installed in the BABAR experiment to replace the ageing Resistive Plate Chambers (RPCs) as active detectors for the BABAR Instrumented Flux Return (IFR) muon system. Each streamer tube of the new detector consists of 8 cells. The cell walls are coated with graphite paint and a 100 {micro}m wire forms the anode. These wires are coupled in pairs inside the tubes resulting in 4 independent two-cell segments per LST. High voltage (HV) is applied to the 4 segments through a custom connector that also provides the decoupling capacitor to pick up the detector signals from the anode wires. The BABAR LST detector is operated at 5.5 kV. The high voltage system for the LST detector was designed and built at The Ohio State University (OSU HVPS). Each of the 25 supplies built for BaBar provides 80 output channels with individual current monitoring and overcurrent protection. For each group of 20 channels the HV can be adjusted between 0 and 6 kV. A 4-fold fan-out is integrated in the power supplies to provide a total of 320 outputs. The power supplies are controlled through built-in CANbus …
Date: August 18, 2006
Creator: Benelli, Gabriele; Honscheid, Klaus; Lewis, Elizabeth A.; Regensburger, Joseph J. & Smith, Dale S.
System: The UNT Digital Library
Amplitude Linearizers for PEP-II 1.2 MW Klystrons and LLRF Systems (open access)

Amplitude Linearizers for PEP-II 1.2 MW Klystrons and LLRF Systems

The PEP-II B-factory has aggressive current increases planned for luminosity through 2008. At 2.2A (HER) on 4A (LER) currents, we estimate that longitudinal growth rates will be comparable to the damping rates currently achieved in the existing low level RF and longitudinal feedback systems. Prior to having a good non-linear time domain model [1] it was postulated that klystron small signal gain non-linearity may be contributing to measured longitudinal growth rates being higher than linearly predicted growth rates. Five prototype klystron amplitude modulation linearizers have been developed to explore improved linearity in the LLRF system. The linearizers operate at 476 MHz with 15 dB dynamic range and 1 MHz linear control bandwidth. Results from lab measurements and high current beam tests are presented. Future development plans, conclusions from beam testing and ideas for future use of this linearization technique are presented.
Date: July 18, 2006
Creator: Van Winkle, D.; Browne, J.; Fox, J. D.; Mastorides, T.; Rivetta, C. & Teytelman, D.
System: The UNT Digital Library
Modeling Efforts to Aid in the Determination of Process Enrichment Levels for Identifying Potential Material Diversion (open access)

Modeling Efforts to Aid in the Determination of Process Enrichment Levels for Identifying Potential Material Diversion

Efforts have been under way at Lawrence Livermore National Laboratory (LLNL) to develop detailed analytical models that simulate enrichment and conversion facilities for the purpose of aiding in the detection of material diversion as part of an overall safeguards strategy. These models could be used to confirm proper accountability of the nuclear materials at facilities worldwide. Operation of an enrichment process for manufacturing commercial reactor fuel presents proliferation concerns including both diversion and the potential for further enrichment to make weapons grade material. While inspections of foreign reprocessing facilities by the International Atomic Energy Agency (IAEA) are meant to ensure that such diversion is not occurring, it must be verified that such diversion is not taking place through both examination of the facility and taking specific measurements such as the radiation fields outside of various process lines. Our current effort is developing algorithms that would be incorporated into the current process models that would provide both neutron and gamma radiation fields outside any process line for the purpose of to determining the most effective locations for placing in-plant monitoring equipment. These algorithms, while providing dose and spectral information, could also be designed to provide detector responses that could be physically …
Date: January 18, 2006
Creator: Guenther, C F; Elayat, H A & O'Connell, W J
System: The UNT Digital Library
On the Nature of Ultraluminous X-Ray Sources, Or What a Black Hole Should Look Like (open access)

On the Nature of Ultraluminous X-Ray Sources, Or What a Black Hole Should Look Like

We derive the luminosity-temperature relation for the accreting black holes (BHs). At the accretion rates below the critical Eddington, the BHs are described by the standard Shakura-Sunyaev model resulting in the L {infinity} T{sup 4} {infinity} M relation. At super-Eddington rates, {dot m} = {dot M}/{dot M}{sub Edd} >> 1, a strong outflow forms within the spherization radius R{sub sp} {infinity} {dot M}. If the angular momentum of the outflowing matter is conserved and typical outflow velocities are of the order of Keplerian, the wind occupies 50-85 per cent of the sky as viewed from the BH, while the region around the rotation axis remains transparent. The bolometric luminosity in such a case is known to exceed the Eddington luminosity by a factor 1 + ln {dot m} and the observed luminosity is 2-7 times higher because of geometrical beaming. An edge-on observer sees only the soft emission from the extended envelope, with the photosphere radius exceeding R{sub sp} by orders of magnitude. The photosphere temperature follows the T{sub ph} {infinity} {dot M}{sup -3/4} or {dot M}{sup -1} relation depending on the velocity profile at R > R{sub sp} (constant velocity or a Keplerian profile). The resulting L-T{sub ph} dependence …
Date: September 18, 2006
Creator: Poutanen, Juri; /Oulu U. /KIPAC, Menlo Park; Fabrika, Sergei; /Stavropol, Astrophys. Observ.; Butkevich, Alexey G.; /Oulu U. /Pulkovo Observ., St. Petersburg et al.
System: The UNT Digital Library
Search for Mechanically-Induced Grain Morphology Changes in Oxygen Free Electrolytic (OFE) Copper (open access)

Search for Mechanically-Induced Grain Morphology Changes in Oxygen Free Electrolytic (OFE) Copper

The deformation of the microscopic, pure metal grains (0.1 to > 1 millimeter) in the copper cells of accelerator structures decreases the power handling capabilities of the structures. The extent of deformation caused by mechanical fabrication damage is the focus of this study. Scanning electron microscope (SEM) imaging of a bonded test stack of six accelerating cells at magnifications of 30, 100, 1000 were taken before simulated mechanical damage was done. After a 2{sup o}-3{sup o} twist was manually applied to the test stack, the cells were cut apart and SEM imaged separately at the same set magnifications (30, 100, and 1000), to examine any effects of the mechanical stress. Images of the cells after the twist were compared to the images of the stack end (cell 60) before the twist. Despite immense radial damage to the end cell from the process of twisting, SEM imaging showed no change in grain morphology from images taken before the damage: copper grains retained shape and the voids at the grain boundaries stay put. Likewise, the inner cells of the test stack showed similar grain consistency to that of the end cell before the twist was applied. Hence, there is no mechanical deformation …
Date: August 18, 2006
Creator: Sanders, Jennifer
System: The UNT Digital Library
Measurement of Decay Amplitudes of B to ccbar K* with an angular analysis, for ccbar=J/Psi, Psi2S and chic1 (open access)

Measurement of Decay Amplitudes of B to ccbar K* with an angular analysis, for ccbar=J/Psi, Psi2S and chic1

We perform the first three-dimensional measurement of the amplitudes of B {yields} {psi}(2S)K* and B {yields} {chi}{sub c1}K* decays and update our previous measurement for B {yields} J/{psi} K*. We use a data sample collected with the BABAR detector at the PEP-II storage ring, representing 232 million produced B{bar B} pairs. The longitudinal polarization of decays to the 1{sup ++} {chi}{sub c1} meson together with a K* meson, is found to be larger than that for the decay to the 1{sup --} {Psi} mesons. No direct CP-violating charge asymmetry is observed.
Date: August 18, 2006
Creator: Aubert, B.
System: The UNT Digital Library
Optimization of Gas Generation Testing of Contact-Handled Transuranic Solidified (open access)

Optimization of Gas Generation Testing of Contact-Handled Transuranic Solidified

The Contact-Handled Transuranic Waste Authorized methods for Payload Control (CH-TRAMPAC) requires that drums containing Waste Type IV (solidified organic waste) must be evaluated by gas generation testing (GGT) because a G-value, a measure of gas generation potential, has not been determined for Waste Type IV.
Date: May 18, 2006
Creator: Shokes, Tamara; Liekhus, Kevin J.; Bowman, Vivian & Schweinsberg, Eric
System: The UNT Digital Library
High Precision SC Cavity Diagnostics with HOM Measurements (open access)

High Precision SC Cavity Diagnostics with HOM Measurements

Experiments at the FLASH linac at DESY have demonstrated that the Higher Order Modes induced in Superconducting Cavities can be used to provide a variety of beam and cavity diagnostics. The centers of the cavities can be determined from the beam orbit which produces minimum power in the dipole HOM modes. The phase and amplitude of the dipole modes can be used as a high resolution beam position monitor, and the phase of the monopole modes to measure the beam phase relative to the accelerator RF. Beam orbit feedback which minimizes the dipole HOM power in a set of structures has been demonstrated. For most SC accelerators, the existing HOM couplers provide the necessary signals, and the down mix and digitizing electronics are straightforward, similar to those for a conventional BPM.
Date: August 18, 2006
Creator: Frisch, Josef; Hendrickson, Linda; McCormick, Douglas; May, Justin; Molloy, Stephen & Ross, Marc
System: The UNT Digital Library
Measurement of Time-dependent CP Asymmetries in B^0 --> K^0_s K^0_s K^0_s Decays (open access)

Measurement of Time-dependent CP Asymmetries in B^0 --> K^0_s K^0_s K^0_s Decays

The authors present an updated measurement of the time-dependent CP-violating asymmetry in B{sup 0} {yields} K{sub S}{sup 0}K{sub S}{sup 0}K{sub S}{sup 0} decays based on 347 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The authors obtain the CP asymmetries S{sub f} = -0.66 {+-} 0.26 {+-} 0.08 and C{sub f} = -0.14 {+-} 0.22 {+-} 0.05, where the first uncertainties are statistical and the second systematic.
Date: August 18, 2006
Creator: Aubert, B.
System: The UNT Digital Library
Observation of the decays B- to Ds(*)+ K- pi- (open access)

Observation of the decays B- to Ds(*)+ K- pi-

The authors report first observations of the decays B{sup -} {yields} D{sub s}{sup (*)+} K{sup -}{pi}{sup -}, using 292 fb{sup -1} of data collected at the {Upsilon}(4S) resonance energy by the BABAR detector at the PEP-II e{sup +}e{sup -} collider. The branching fractions are measured to be {Beta}(B{sup -} {yields} D{sub s}{sup +}K{sup -}{pi}{sup -}) = (1.88 {+-} 0.13 {+-} 0.41) {center_dot} 10{sup -4} and {Beta}(B{sup -} {yields} D{sub s}{sup *+}K{sup -}{pi}{sup -}) = (1.84 {+-} 0.19 {+-} 0.40) {center_dot} 10{sup -4}.
Date: August 18, 2006
Creator: Aubert, B.
System: The UNT Digital Library
Lepton Flavor Violation in Tau Decays at BABAR (open access)

Lepton Flavor Violation in Tau Decays at BABAR

Searches for lepton flavor violating tau {yields} l gamma, tau {yields} lhh decays at the BABAR experiment are presented. Upper limits on the branching ratios are obtained at the level of O(10{sup -7}) at 90% confidence level.
Date: January 18, 2006
Creator: Banerjee, Swagato
System: The UNT Digital Library
Design and Testing of Gproto Bunch-by-bunch Signal Processor (open access)

Design and Testing of Gproto Bunch-by-bunch Signal Processor

A prototype programmable bunch-by-bunch signal acquisition and processing channel with multiple applications in storage rings has been developed at SLAC. The processing channel supports up to 5120 bunches with bunch spacings as close as 1.9 ns. The prototype has been tested and operated in five storage rings: SPEAR-3, DAINE, PEP-II, KEKB, and ATF damping ring. The testing included such applications as transverse and longitudinal coupled-bunch instability control, bunch-by-bunch luminosity monitoring, and injection diagnostic. In this contribution the prototype design will be described and its operation will be illustrated with the data measured at the above-mentioned accelerators.
Date: July 18, 2006
Creator: Teytelman, D.; Rivetta, C.; Van Winkle, D.; Akre, R.; Fox, J. & Krasnykh, A.
System: The UNT Digital Library
Cosmological Constant and Axions in String Theory (open access)

Cosmological Constant and Axions in String Theory

String theory axions appear to be promising candidates for explaining cosmological constant via quintessence. In this paper, we study conditions on the string compactifications under which axion quintessence can happen. For sufficiently large number of axions, cosmological constant can be accounted for as the potential energy of axions that have not yet relaxed to their minima. In compactifications that incorporate unified models of particle physics, the height of the axion potential can naturally fall close to the observed value of cosmological constant.
Date: August 18, 2006
Creator: Svrcek, Peter
System: The UNT Digital Library
Measurements of the Field Quality in Superconducting Dipoles at High Ramp Rates. (open access)

Measurements of the Field Quality in Superconducting Dipoles at High Ramp Rates.

Several recent applications of superconducting magnets require the magnets to be operated at high ramp rates and at frequencies of several Hertz. Brookhaven National Laboratory (BNL) has recently designed and built prototypes of superconducting dipole magnets that can be ramped at a fairly high rate (1 T/s or more). For accelerator applications, it is also crucial that the magnets maintain good field quality even at high ramp rates. In order to characterize the field quality of magnets at high ramp rates, a measurement system consisting of 16 printed circuit tangential coils has been developed. The coil system is held stationary while the magnet is ramped. This paper describes the techniques used for the measurements and data analysis, and presents the results of measurements at ramp rates of up to 4 T/s in a prototype dipole built at BNL for GSI.
Date: September 18, 2006
Creator: Jain, A.; Escallier, J.; Ganetis, G.; Louie, W.; Marone, A.; Thomas, R. et al.
System: The UNT Digital Library
Recursive Construction of Higgs-Plus-Multiparton Loop Amplitudes:The Last of the \phi-nite Loop Amplitudes (open access)

Recursive Construction of Higgs-Plus-Multiparton Loop Amplitudes:The Last of the \phi-nite Loop Amplitudes

We consider a scalar field, such as the Higgs boson H, coupled to gluons via the effective operator H tr G{sub {mu}{nu}} G{sup {mu}{nu}} induced by a heavy-quark loop. We treat H as the real part of a complex field {phi} which couples to the self-dual part of the gluon field-strength, via the operator {phi} tr G{sub SD {mu}{nu}} G{sub SD}{sup {mu}{nu}}, whereas the conjugate field {phi} couples to the anti-self-dual part. There are three infinite sequences of amplitudes coupling {phi} to quarks and gluons that vanish at tree level, and hence are finite at one loop, in the QCD coupling. Using on-shell recursion relations, we find compact expressions for these three sequences of amplitudes and discuss their analytic properties.
Date: August 18, 2006
Creator: Berger, Carola F.; Del Duca, Vittorio & Dixon, Lance J.
System: The UNT Digital Library