Powerful, Efficient Electric Vehicle Chargers: Low-Cost, Highly-Integrated Silicon Carbide (SiC) Multichip Power Modules (MCPMs) for Plug-In Hybrid Electric (open access)

Powerful, Efficient Electric Vehicle Chargers: Low-Cost, Highly-Integrated Silicon Carbide (SiC) Multichip Power Modules (MCPMs) for Plug-In Hybrid Electric

ADEPT Project: Currently, charging the battery of an electric vehicle (EV) is a time-consuming process because chargers can only draw about as much power from the grid as a hair dryer. APEI is developing an EV charger that can draw as much power as a clothes dryer, which would drastically speed up charging time. APEI's charger uses silicon carbide (SiC)-based power transistors. These transistors control the electrical energy flowing through the charger's circuits more effectively and efficiently than traditional transistors made of straight silicon. The SiC-based transistors also require less cooling, enabling APEI to create EV chargers that are 10 times smaller than existing chargers.
Date: September 14, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Development of a System for Rapid Detection of Contaminants in Water Supplies Using Magnetic Resonance and Nanoparticles (open access)

Development of a System for Rapid Detection of Contaminants in Water Supplies Using Magnetic Resonance and Nanoparticles

To keep the water supply safe and to ensure a swift and accurate response to a water supply contamination event, rapid and robust methods for microbial testing are necessary. Current technologies are complex, lengthy and costly and there is a need for rapid, reliable, and precise approaches that can readily address this fundamental security and safety issue. T2 Biosystems is focused on providing solutions to this problem by making breakthroughs in nanotechnology and biosensor techniques that address the current technical restrictions facing rapid, molecular analysis in complex samples. In order to apply the T2 Biosystems nucleic acid detection procedure to the analysis of nucleic acid targets in unprocessed water samples, Bacillus thuringeinsis was selected as a model organism and local river water was selected as the sample matrix. The initial assay reagent formulation was conceived with a manual magnetic resonance reader, was optimized using a high throughput system, and transferred back to the MR reader for potential field use. The final assay employing the designed and manufactured instruments was capable of detecting 10 CFU/mL of B. thuringiensis directly within the environmental water sample within 90 minutes. Further, discrimination of two closely related species of Bacilli was accomplished using the methods …
Date: September 14, 2010
Creator: Lowery, Thomas J; Neely, Lori; Chepin, James; Wellman, Parris; Toso, Ken; Murray, Paul et al.
Object Type: Report
System: The UNT Digital Library
Echo-seeding options for LCLS-II (open access)

Echo-seeding options for LCLS-II

The success of LCLS has opened up a new era of x-ray sciences. An upgrade to LCLS is currently being planned to enhance its capabilities. In this paper we study the feasibility of using the echo-enabled harmonic generation (EEHG) technique to generate narrow bandwidth soft x-ray radiation in the proposed LCLS-II soft x-ray beam line. We focus on the conceptual design, the technical implementation and the expected performances of the echo-seeding scheme. We will also show how the echo-seeding scheme allows one to generate two color x-ray pulses with the higher energy photons leading the lower energy ones as is favored in the x-ray pump-probe experiments.
Date: September 14, 2010
Creator: Xiang, Dao
Object Type: Article
System: The UNT Digital Library
Design of the Second-Generation ILC Marx Modulator (open access)

Design of the Second-Generation ILC Marx Modulator

SLAC National Accelerator Laboratory (SLAC) has initiated a program to design and build a Marx-topology modulator to produce a relatively compact, low-cost, high availability klystron modulator for the International Linear Collider (ILC). Building upon the success of the P1 Marx, the SLAC P2 Marx is a second-generation modulator whose design further emphasizes the qualities of modularity and high-availability. This paper outlines highlights of this design and presents single-cell performance data obtained during the proof-of-concept phase of the project.
Date: September 14, 2010
Creator: Kemp, M. A.; Benwell, A.; Burkhart, C.; Larsen, R.; MacNair, D.; Nguyen, M. et al.
Object Type: Article
System: The UNT Digital Library
Early Events in Ionic Liquid Radiation Chemistry (open access)

Early Events in Ionic Liquid Radiation Chemistry

Ionic liquids are interesting and useful materials whose solvation time scales are up to thousands of times longer than in conventional solvents. The extended lifetimes of pre-solvated electrons and other energetic species in ionic liquids has profound consequences for the radiolytic product distributions and reactivity patterns. We use a newly developed, multiplexed variation of pulse-probe spectroscopy to measure the kinetics of the early dynamical and reactive events in ionic liquids.
Date: September 14, 2010
Creator: Wishart, J. F.; Cook, A.; Rimmer, R. D. & Gohdo, M.
Object Type: Article
System: The UNT Digital Library
Characterization of Second Harmonic Afterburner Radiation at the LCLS (open access)

Characterization of Second Harmonic Afterburner Radiation at the LCLS

During commissioning of the Linac Coherent Light Source (LCLS) x-ray Free Electron Laser (FEL) at the SLAC National Accelerator Laboratory it was shown that saturation lengths much shorter than the installed length of the undulator line can routinely be achieved. This frees undulator segments that can be used to provide enhanced spectral properties and at the same time, test the concept of FEL Afterburners. In December 2009 a project was initiated to convert undulator segments at the down-beam end of the undulator line into Second Harmonic Afterburners (SHAB) to enhance LCLS radiation levels in the 10-20 keV energy range. This is being accomplished by replacement of gap-shims increasing the fixed gaps from 6.8 mm to 9.9 mm, which reduces their K values from 3.50 to 2.25 and makes the segments resonant at the second harmonic of the upstream unmodified undulators. This paper reports experimental results of the commissioning of the SHAB extension to LCLS.
Date: September 14, 2010
Creator: Nuhn, Heinz-Dieter
Object Type: Article
System: The UNT Digital Library
Monte Carlo Studies of the Radiation Fields in the Linac Coherent Light Source Undulators and of the Corresponding Signals in the Cerenkov Beam Loss Monitors (open access)

Monte Carlo Studies of the Radiation Fields in the Linac Coherent Light Source Undulators and of the Corresponding Signals in the Cerenkov Beam Loss Monitors

In 2009 the Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Center started free electron laser (FEL) operation. In order to continue to produce the bright and short-pulsed x-ray laser demanded by FEL scientists, this pioneer hard x-ray FEL requires a perfectly tailored magnetic field at the undulators, so that the photons generated at the electron wiggling path interact at the right phase with the electron beam. In such a precise system, small (>0.01%) radiation-induced alterations of the magnetic field in the permanent magnets could affect FEL performance. This paper describes the simulation studies of radiation fields in permanent magnets and the expected signal in the detectors. The transport of particles from the radiation sources (i.e. diagnostic insert) to the undulator magnets and to the beam loss monitors (BLM) was simulated with the intra nuclear cascade codes FLUKA and MARS15. In order to accurately reproduce the optics of LCLS, lattice capabilities and magnetic fields were enabled in FLUKA and betatron oscillations were validated against reference data. All electron events entering the BLMs were printed in data files. The paper also introduces the Radioactive Ion Beam Optimizer (RIBO) Monte Carlo 3-D code, which was used to read from the …
Date: September 14, 2010
Creator: Santana Leitner, Mario
Object Type: Article
System: The UNT Digital Library
LHC Beam Diffusion Dependence on RF Noise: Models And Measurements (open access)

LHC Beam Diffusion Dependence on RF Noise: Models And Measurements

Radio Frequency (RF) accelerating system noise and non-idealities can have detrimental impact on the LHC performance through longitudinal motion and longitudinal emittance growth. A theoretical formalism has been developed to relate the beam and RF loop dynamics with the bunch length growth [1]. Measurements were conducted at LHC to validate the formalism, determine the performance limiting RF components, and provide the foundation for beam diffusion estimates for higher energies and intensities. A brief summary of these results is presented in this work. During a long store, the relation between the energy lost to synchrotron radiation and the noise injected to the beam by the RF accelerating voltage determines the growth of the bunch energy spread and longitudinal emittance. Since the proton synchrotron radiation in the LHC is very low, the beam diffusion is extremely sensitive to RF perturbations. The theoretical formalism presented in [1], suggests that the noise experienced by the beam depends on the cavity phase noise power spectrum, filtered by the beam transfer function, and aliased due to the periodic sampling of the accelerating voltage signal V{sub c}. Additionally, the dependence of the RF accelerating cavity noise spectrum on the Low Level RF (LLRF) configurations has been predicted …
Date: September 14, 2010
Creator: Mastorides, T.; Rivetta, C.; Fox, J. D.; Van Winkle, D.; Baudrenghien, P.; Butterworth, A. et al.
Object Type: Article
System: The UNT Digital Library
Precise Predictions for W 4 Jet Production at the Large Hadron Collider (open access)

Precise Predictions for W 4 Jet Production at the Large Hadron Collider

We present the first next-to-leading order QCD results for W + 4-jet production at hadron colliders. Total cross sections, as well as distributions in the jet transverse momenta and in the total transverse energy HT, are provided for the initial LHC energy of {radical}s = 7 TeV. We use a leading-color approximation, known to be accurate to 3% for W production with fewer jets. The virtual matrix elements and the most complicated real-emission matrix elements are handled by the BlackHat library, based on on-shell methods. The remaining parts of the calculation, including the integration over phase space, are performed by the SHERPA package.
Date: September 14, 2010
Creator: Berger, C.F.; /MIT, LNS; Bern, Z.; /UCLA; Dixon, Lance J.; /SLAC, /CERN et al.
Object Type: Article
System: The UNT Digital Library
Three-Dimensional Analysis of Frequency-Chirped FELs (open access)

Three-Dimensional Analysis of Frequency-Chirped FELs

Frequency-chirped free-electron lasers (FELs) are useful to generate a large photon bandwidth or a shorter x-ray pulse duration. In this paper, we present a three-dimensional analysis of a high-gain FEL driven by the energy-chirped electron beam. We show that the FEL eigenmode equation is the same for a frequency-chirped FEL as for an undulator-tapered FEL. We study the transverse effects of such FELs including mode properties and transverse coherence.
Date: September 14, 2010
Creator: Zhirong, Huang
Object Type: Article
System: The UNT Digital Library
LHC RF System Time-Domain Simulation (open access)

LHC RF System Time-Domain Simulation

Non-linear time-domain simulations have been developed for the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC). These simulations capture the dynamic behavior of the RF station-beam interaction and are structured to reproduce the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They are also a valuable tool for the study of diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Results from these studies and related measurements from PEP-II and LHC have been presented in multiple places. This report presents an example of the time-domain simulation implementation for the LHC.
Date: September 14, 2010
Creator: Mastorides, T. & Rivetta, C.
Object Type: Report
System: The UNT Digital Library
Algorithm for Computation of Electromagnetic Fields of An Accelerated Short Bunch Inside a Rectangular Chamber (open access)

Algorithm for Computation of Electromagnetic Fields of An Accelerated Short Bunch Inside a Rectangular Chamber

We discuss the feasibility of an application of an implicit finite-difference approximation to calculate the fields of a relativistic bunch moving with no restriction inside a vacuum chamber. We assume that a bunch trajectory is not straight but is inside a vacuum chamber or its branch. The bunch can be deflected by the fields of bending magnets. The bunch can be short enough to produce coherent synchrotron radiation (CSR). Accelerator physicists believe that electromagnetic phenomena of charged beams are governed by Maxwell's equations together with Newton's equations for particle dynamics. To understand the behavior of the beams and radiated fields we just need to find a solution to these equations for the case, which can fully describe the real accelerator environment. So, at first we make a model, which contains all the necessary components, but at the same time can be easily 'inserts' into the equations. Sometimes, it is possible to find analytical solutions, but usually they are only work for one-dimensional cases and rarer for two-dimension cases. To find a solution in general we may transform the equations into a equivalent finite-difference form and solve them using computers. We can find a lot of finite-difference schemes, which approximate Maxwell's …
Date: September 14, 2010
Creator: Novokhatski, Alexander & Sullivan, Michael
Object Type: Article
System: The UNT Digital Library
Application for a Permit to Operate a Class III Solid Waste Disposal Site at the Nevada Test Site Area 5 Asbestiform Low-Level Solid Waste Disposal Site (open access)

Application for a Permit to Operate a Class III Solid Waste Disposal Site at the Nevada Test Site Area 5 Asbestiform Low-Level Solid Waste Disposal Site

The NTS solid waste disposal sites must be permitted by the state of Nevada Solid Waste Management Authority (SWMA). The SWMA for the NTS is the Nevada Division of Environmental Protection, Bureau of Federal Facilities (NDEP/BFF). The U.S. Department of Energy's National Nuclear Security Administration Nevada Site Office (NNSA/NSO) as land manager (owner), and National Security Technologies (NSTec), as operator, will store, collect, process, and dispose all solid waste by means that do not create a health hazard, a public nuisance, or cause impairment of the environment. NTS disposal sites will not be included in the Nye County Solid Waste Management Plan. The NTS is located approximately 105 kilometers (km) (65 miles [mi]) northwest of Las Vegas, Nevada (Figure 1). The U.S. Department of Energy (DOE) is the federal lands management authority for the NTS, and NSTec is the Management and Operations contractor. Access on and off the NTS is tightly controlled, restricted, and guarded on a 24-hour basis. The NTS has signs posted along its entire perimeter. NSTec is the operator of all solid waste disposal sites on the NTS. The Area 5 RWMS is the location of the permitted facility for the Solid Waste Disposal Site (SWDS). The …
Date: September 14, 2010
Creator: Programs, NSTec Environmental
Object Type: Report
System: The UNT Digital Library
CO2 Removal using a Synthetic Analogue of Carbonic Anhydrase (open access)

CO2 Removal using a Synthetic Analogue of Carbonic Anhydrase

Project attempts to develop a synthetic analogue for carbonic anhydrase and incorporate it in a membrane for separation of CO2 from coal power plant flue gas. Conference poster presents result of first 9 months of project progress including concept, basic system architecture and membrane properties target, results of molecular modeling for analogue - CO2 interaction, and next steps of testing analogue resistance to flue gas contaminants.
Date: September 14, 2010
Creator: Cordatos, Harry
Object Type: Article
System: The UNT Digital Library
LLNL's Precision Compton Scattering Light Source (open access)

LLNL's Precision Compton Scattering Light Source

None
Date: September 14, 2010
Creator: Hartemann, F.; Albert, F.; Anderson, S.; Bayramian, A.; Cross, R.; Ebbers, C. et al.
Object Type: Article
System: The UNT Digital Library
Silicide Characterization at Alumina-Niobium Interfaces (open access)

Silicide Characterization at Alumina-Niobium Interfaces

None
Date: September 14, 2010
Creator: McKeown, J T; Radmilovic, V R; Gronsky, R & Glaeser, A M
Object Type: Article
System: The UNT Digital Library
Ab Initio Theory of Light-Ion Reactions (open access)

Ab Initio Theory of Light-Ion Reactions

None
Date: September 14, 2010
Creator: Navratil, P; Quaglioni, S & Roth, R
Object Type: Article
System: The UNT Digital Library
Thermal Expansion of LX-17, PBX 9502 and Ultrafine TATB (open access)

Thermal Expansion of LX-17, PBX 9502 and Ultrafine TATB

None
Date: September 14, 2010
Creator: Souers, P. C.; Lewis, P.; Hoffman, M. & Cunningham, B.
Object Type: Report
System: The UNT Digital Library
Observation of new resonances decaying to $D\pi$ and $D^*\pi$ in inclusive $e^ e^-$ collisions near $\sqrt{s} (open access)

Observation of new resonances decaying to $D\pi$ and $D^*\pi$ in inclusive $e^ e^-$ collisions near $\sqrt{s}

The authors present a study of the D{sup +}{pi}{sup -}, D{sup 0}{pi}{sup +}, and D*{sup +}{pi}{sup -} systems in inclusive e{sup +}e{sup -} {yields} c{bar c} interactions in a search for new excited D meson states. they use a dataset, consisting of {approx} 454 fb{sup -1}, collected at center-of-mass energies near 10.58 GeV by the BABAR detector at the SLAC PEP-II asymmetric-energy collider. They observe, for the first time, candidates for the radial excitations of the D{sup 0}, D*{sup 0}, and D*{sup +}, as well as the L = 2 excited states of the D{sup 0} and D{sup +}, where L is the orbital angular momentum of the quarks.
Date: September 14, 2010
Creator: del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J. et al.
Object Type: Article
System: The UNT Digital Library
Search for the Rare Decay B -> K nu nubar (open access)

Search for the Rare Decay B -> K nu nubar

We present a search for the rare decays B{sup +} {yields} K{sup +}{nu}{bar {nu}} and B{sup 0} {yields} K{sup 0}{nu}{bar {nu}} using 459 million B{bar B} pairs collected with the BABAR detector at the SLAC National Accelerator Laboratory. Flavor-changing neutral-current decays such as these are forbidden at tree level but can occur through one-loop diagrams in the Standard Model (SM), with possible contributions from new physics at the same order. The presence of two neutrinos in the final state makes identification of signal events challenging, so reconstruction in the semileptonic decay channels B {yields} D{sup (*)}l{nu} of the B meson recoiling from the signal B is used to suppress backgrounds. We set an upper limit at the 90% confidence level of 1.3 x 10{sup -5} on the total branching fraction for B{sup +} {yields} K{sup +}{nu}{bar {nu}}, and 5.6 x 10{sup -5} for B{sup 0} {yields} K{sup 0}{nu}{bar {nu}}. We additionally report partial branching fractions in two ranges of di-neutrino mass squared for B{sup +} {yields} K{sup +}{nu}{bar {nu}}.
Date: September 14, 2010
Creator: del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J. et al.
Object Type: Article
System: The UNT Digital Library
Investigating Chemical and Molecular Changes in Uranium Oxyfluoride Particles using NanoSIMS and Micro-Raman Spectroscopy (open access)

Investigating Chemical and Molecular Changes in Uranium Oxyfluoride Particles using NanoSIMS and Micro-Raman Spectroscopy

None
Date: September 14, 2010
Creator: Kips, R.; Kristo, M. J.; Crowhurst, J.; Hutcheon, I. D.; Stefaniak, E. A. & Aregbe, Y.
Object Type: Article
System: The UNT Digital Library