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Towards sub-10 nm resolution zone plates using the overlaynanofabrication processes

Description: Soft x-ray zone plate microscopy has proven to be a valuable imaging technique for nanoscale studies. It complements nano-analytic techniques such as electron and scanning probe microscopies. One of its key features is high spatial resolution. We developed an overlay nanofabrication process which allows zone plates of sub-20 nm zone widths to be fabricated. Zone plates of 15 nm outer zones were successfully realized using this process, and sub-15 nm resolution was achieved with these zone plate… more
Date: January 23, 2008
Creator: Chao, Weilun; Anderson, Erik H.; Fischer, Peter & Kim, Dong-Hyun
Partner: UNT Libraries Government Documents Department
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Search for the decay B^+ \to K_S^0 K_S^0 \pi ^+

Description: The authors search for charmless decays of charged B mesons to the three-body final state K{sub S}{sup 0}K{sub S}{sup 0}{pi}{sup +}. Using a data sample of 423.7 fb{sup -1} collected at the {Upsilon}(4S) resonance with the BABAR detector, corresponding to (465.1 {+-} 5.1) x 10{sup 6} B{bar B} pairs, they find no significant signal and determine a 90% confidence level upper limit on the branching fraction of 5.1 x 10{sup -7}.
Date: February 23, 2009
Creator: Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E. et al.
Partner: UNT Libraries Government Documents Department
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Measurement of ion beam from laser ion source for RHIC EBIS.

Description: Laser ion source (LIS) is a candidate of the primary ion source for the RHIC EBIS. LIS will provide intense charge state 1+ ions to the EBIS for further ionization. We measured plasma properties of a variety of atomic species from C to Au using the second harmonics of Nd:YAG laser (532 nm wave length, up to 0.5 J/6 ns). Since properties of laser produced plasma is different from different species, laser power density for singly charged ion production should be verified experimentally for each a… more
Date: June 23, 2008
Creator: Kanesue,T.; Tamura, J. & Okamura, M.
Partner: UNT Libraries Government Documents Department
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Exact de Rham Sequences of Spaces Defined on Macro-elements in Two and Three Spatial Dimensions

Description: This paper proposes new finite element spaces that can be constructed for agglomerates of standard elements that have certain regular structure. The main requirement is that the agglomerates share faces that have closed boundaries composed of 1-d edges. The spaces resulting from the agglomerated elements are subspaces of the original de Rham sequence of H{sup 1}-conforming, H(curl) conforming, H(div) conforming and piecewise constant spaces associated with an unstructured 'fine' mesh. The proce… more
Date: July 23, 2007
Creator: Pasciak, J. & Vassilevski, P.
Partner: UNT Libraries Government Documents Department
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Production of Neutrals and Their and Effects on the Ion Chargestates in Cathodic Vacuum Arc Plasmas

Description: Cathodic arc plasmas are considered fully ionized and theycontain multiply charged ions, yet, gaseous and metal neutrals can bepresent. It is shown that they can cause a significant reduction of theion charge states as measured far from the cathode spots. Several cathodematerials were used to study the evolution the mean ion charge state as afunction of time after arc ignition. The type of cathode material, arccurrent amplitude, intentionally increased background gas, additionalsurfaces placed … more
Date: May 23, 2007
Creator: Anders, Andre; Oks, Efim M. & Yushkov, Georgy Yu.
Partner: UNT Libraries Government Documents Department
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Plasma Lens for Muon and Neutrino Beams

Description: The plasma lens is examined as an alternate to focusing horns and solenoids for use in a neutrino or muon beam facility. The plasma lens concept is based on a combined high-energy lens/target configuration. The current is fed at electrodes located upstream and downstream from the target where pion capturing is needed. The current flows primarily in the plasma, which has a lower resistivity than the target. A second plasma lens section, with an additional current feed, follows the target to prov… more
Date: June 23, 2008
Creator: Kahn, S. A.; Korenev, S.; Bishai, M.; Diwan, M.; Gallardo, J. C.; Hershcovitch, A. et al.
Partner: UNT Libraries Government Documents Department
open access

On the work distribution for the adiabatic compression of a diluteclassical gas

Description: We consider the adiabatic and quasi-static compression of adilute classical gas, confined in a piston and initially equilibratedwith a heat bath. We find that the work performed during this process isdescribed statistically by a gamma distribution. We use this result toshow that the model satisfies the non-equilibrium work and fluctuationtheorems, but not the fluctation-dissipation relation. We discuss therare but dominant realizations that contribute most to the exponentialaverage of the work,… more
Date: February 23, 2006
Creator: Crooks, Gavin E. & Jarzynski, Christopher
Partner: UNT Libraries Government Documents Department
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The MERIT(nTOF-11) High Intensity Liquid Mercury Target Experiment at the CERN PS

Description: The MERIT(nTOF-11) experiment is a proof-of-principle test of a target system for a high power proton beam to be used as front-end for a neutrino factory or a muon collider. The experiment took data in autumn 2007 with the fast-extracted beam from the CERN Proton Synchrotron (PS) to a maximum intensity of 30 x 10{sup 12} per pulse. The target system, based on a free mercury jet, is capable of intercepting a 4-MW proton beam inside a 15-T magnetic field required to capture the low energy seconda… more
Date: June 23, 2008
Creator: Ethymiopoulos, I.; Fabich, A.; Palm, M.; Lettry, J.; Haug, F.; Pernegger, H. et al.
Partner: UNT Libraries Government Documents Department
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p-Carbon CNI polarimetry in the AGS and RHIC.

Description: Proton polarization measurements in the AGS (Alternate Gradient Synchrotron) and RHIC (Relativistic Heavy Ion Collider) are based on proton-carbon(pC) and proton-proton elastic scattering in the Coulomb Nuclear Interference (CNI) region. The CNI polarimeters are the essential tools for polarized proton acceleration setup and operation. High intensity recoil nuclei from the scattering of the circulating proton beam in the thin carbon target is efficiently utilized in the silicon strip detectors … more
Date: June 23, 2008
Creator: Huang, H.; Alekseev, I.; Bazilevsky, A.; Bravar, A.; Bunce, G.; Dhawan, S. et al.
Partner: UNT Libraries Government Documents Department
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Geometrically induced metastability and holography

Description: We construct metastable configurations of branes and anti-branes wrapping 2-spheres inside local Calabi-Yau manifolds and study their large N duals. These duals are Calabi-Yau manifolds in which the wrapped 2-spheres have been replaced by 3-spheres with flux through them, and supersymmetry is spontaneously broken. The geometry of the non-supersymmetric vacuum is exactly calculable to all orders of the't Hooft parameter, and to the leading order in 1/N. The computation utilizes the same matr… more
Date: October 23, 2006
Creator: Aganagic, Mina; Aganagic, Mina; Beem, Christopher; Seo, Jihye & Vafa, Cumrun
Partner: UNT Libraries Government Documents Department
open access

Evaluation of OGC Standards for Use in LLNL GIS

Description: Over the summer of 2005, the Lawrence Livermore National Laboratory (LLNL) Computer Applications and Research Department conducted a small project that examined whether Open Geospatial Consortium (OGC) standards might be useful in meeting program mission requirements more effectively. OGC standards are intended to facilitate interoperability between geospatial processing systems to lower development costs and to avoid duplication of effort and vendor lock-in. Some OGC standards appear to be gai… more
Date: June 23, 2006
Creator: Walker, H; Chou, R M; Chubb, K K & Schek, J L
Partner: UNT Libraries Government Documents Department
open access

Landscape predictions from cosmological vacuum selection

Description: In Bousso-Polchinski models with hundreds of fluxes, we compute the effects of cosmological dynamics on the probability distribution of landscape vacua. Starting from generic initial conditions, we find that most fluxes are dynamically driven into a different and much narrower range of values than expected from landscape statistics alone. Hence, cosmological evolution will access only a tiny fraction of the vacua with small cosmological constant. This leads to a host of sharp predictions. Unlik… more
Date: April 23, 2007
Creator: Bousso, Raphael; Bousso, Raphael & Yang, Sheng
Partner: UNT Libraries Government Documents Department
open access

AN OVERVIEW OF THE SNS ACCELERATOR MECHANICAL ENGINEERING.

Description: The Spallation Neutron Source (SNS*) is an accelerator-based neutron source currently nearing completion at Oak Ridge National Laboratory. When completed in 2006, the SNS will provide a 1 GeV, 1.44 MW proton beam to a liquid mercury target for neutron production. SNS is a collaborative effort between six U.S. Department of Energy national laboratories and offered a unique opportunity for the mechanical engineers to work with their peers from across the country. This paper presents an overview o… more
Date: June 23, 2006
Creator: HSEUH, H.; LUDWIG, H.; MAHLER, G.; PAI, C.; PEARSON, C.; RANK, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Analysis of intensity instability threshold at transition in RHIC.

Description: The beam intensity of ion beams in RHIC is limited by a fast transverse instability at transition, driven by the machine impedance and electron clouds. For gold and deuteron beams we analyze the dependence of the instability threshold on beam and machine parameters from recent operational data and dedicated experiments. We fit the machine impedance to the experimental data.
Date: June 23, 2008
Creator: Fischer, W.; Blaskiewicz, M.; Cameron, P.; Montag, C. & Ptitsyn, V.
Partner: UNT Libraries Government Documents Department
open access

A FOUR-DIMENSIONAL VLASOV SOLVER FOR MICROBUNCHING INSTABILITY INTHE INJECTION SYSTEM FOR X-RAY FELS

Description: The micro-bunching instability (MBI) is seeded by small charge-density fluctuations in the electron bunches, and is successively amplified by the combined effect of space charge and coherent synchrotron radiation, as the beam travels through magnetic compressors. The quantitative understanding of this effect demands for accurate numerical simulations. Here we report on the progress of an upgrading of a 2D Vlasov solver code toward a 4D grid-based Vlasov solver, including also the transversedyna… more
Date: June 23, 2008
Creator: Venturini, Marco; Migliorati, Mauro; Schiavi, Angelo; Dattoli, Giuseppe & Venturini, Marco
Partner: UNT Libraries Government Documents Department
open access

Feedback damper system for quadrupole oscillations after transition at RHIC.

Description: The heavy ion beam at RHIC undergoes strong quadrupole oscillations just after it crosses transition, which leads to an increase in bunch length making rebucketing less effective. A feedback system was built to damp these quadrupole oscillations and in this paper the characteristics of the system and the results obtained are presented and discussed.
Date: June 23, 2008
Creator: Abreu, N.; Blaskiewicz, M.; Brennan, J. M. & Schultheiss, C.
Partner: UNT Libraries Government Documents Department
open access

CRYSTALLINE BEAMS AT HIGH ENERGIES.

Description: Previously it was shown that by crystallizing each of the two counter-circulating beams, a much larger beam-beam tune shift can be tolerated during the beam-beam collisions; thus a higher luminosity can be reached for colliding beams [1]. On the other hand, crystalline beams can only be formed at energies below the transition energy ({gamma}{sub T}) of the accelerators [2]. In this paper, we investigate the formation of crystals in a high-{gamma}{sub T} lattice that also satisfies the maintenan… more
Date: June 23, 2006
Creator: WEI, J.; OKAMOTO, H.; YURI, Y.; SESSLER, A. & MACHIDA, S.
Partner: UNT Libraries Government Documents Department
open access

A Dramatically Reduced Size in the Gantry Design for the Proton-Carbon Therapy.

Description: Gantries in the proton/carbon cancer therapy machines represent the major cost and are of the largest size. This report explains a new way to the gantry design. The size and cost of the gantries are reduced and their use is simplified by using the fixed magnetic field. The ''new'' gantry is made of a very large momentum acceptance non-scaling Fixed Field Alternating Gradient (FFAG) quarter and half arc beam lines. The gantry is made of combined function magnets with a very strong focusing and s… more
Date: June 23, 2006
Creator: Trbojevic, D.; Gupta, R.; Parker, B.; Keil, E. & Sessler, A. M.
Partner: UNT Libraries Government Documents Department
open access

PASSIVITY BREAKDOWN AND EVOLUTION OF LOCALIZED CORROSION ON TYPE 316L STAINLESS STEEL

Description: Passivity breakdown of 316L SS in the presence of aggressive Cl{sup -} and inhibitive NO{sub 3}{sup -} anions has been experimentally studied and the results have been interpreted in terms of the Point Defect Model (PDM). By introducing the competitive adsorption of Cl{sup -} and NO{sub 3}{sup -} into surface oxygen vacancies at the passive film/solution interface, the PDM yields a critical breakdown potential (V{sub c}) that is predicted to vary linearly with log[Cl{sup -}], or with log ([Cl{s… more
Date: October 23, 2006
Creator: S. Yang, G. Engelhardt, and D. D. Macdonald
Partner: UNT Libraries Government Documents Department
open access

Lattices for High-Power Proton Beam Acceleration and Secondary Beam Collection and Cooling.

Description: Rapid cycling synchrotrons are used to accelerate high-intensity proton beams to energies of tens of GeV for secondary beam production. After primary beam collision with a target, the secondary beam can be collected, cooled, accelerated or decelerated by ancillary synchrotrons for various applications. In this paper, we first present a lattice for the main synchrotron. This lattice has: (a) flexible momentum compaction to avoid transition and to facilitate RF gymnastics (b) long straight sectio… more
Date: June 23, 2006
Creator: Wang, S.; Wei, J.; Brown, K.; Gardner, C.; Lee, Y. Y.; Lowenstein, D. et al.
Partner: UNT Libraries Government Documents Department
open access

Review of U.S. Neutrino Factory Studies

Description: We summarize the status of the two U.S. feasibility studies carried out by the Neutrino Factory and Muon Collider Collaboration (NFMCC) along with recent improvements to Neutrino Factory design developed during the American Physical Society (APS) Neutrino Physics Study. Suggested accelerator topics for the International Scoping Study (ISS) are also indicated.
Date: August 23, 2005
Creator: Zisman, Michael S.
Partner: UNT Libraries Government Documents Department
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