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Recent B Physics Results from the Tevatron

Description: We review recent B physics results from the CDF and D0 experiments in p{bar p} collisions at {radical}(s) = 1.96 TeV. Using a data sample of 1.4-6.0 fb{sup -1} collected by the CDF II detector we present searches for New Physics in B{sub s} sector and some competitive results with B-factories in the B/charm sector. In the first category we report the BR in B{sub s} J/{Psi} f{sub 0}(980) decays and the time-integrated mixing probability ({bar {chi}}) of B mesons. In the second category BR and A{… more
Date: July 1, 2011
Creator: Behari, Satyajit
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Partner: UNT Libraries Government Documents Department
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Understanding of Defect Physics in Polycrystalline Photovoltaic Materials: Preprint

Description: The performance of thin-film solar cells is influenced by the quality of interfaces and formation of defects such as point defects, stacking faults, twins, dislocations, and grain boundaries. It is important to understand the defect physics so that appropriate methods may be developed to suppress the formation of harmful defects. Here, we review our understanding of defect physics in thin-film photovoltaic (PV) materials such as Si, CdTe, Cu(In,Ga)Se2 (CIGS), Cu2ZnSnSe2 (CZTSe), and Cu2ZnSnS2 (… more
Date: July 1, 2011
Creator: Yan, Y.
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Partner: UNT Libraries Government Documents Department
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Physics validation studies for muon collider detector background simulations

Description: Within the broad discipline of physics, the study of the fundamental forces of nature and the most basic constituents of the universe belongs to the field of particle physics. While frequently referred to as 'high-energy physics,' or by the acronym 'HEP,' particle physics is not driven just by the quest for ever-greater energies in particle accelerators. Rather, particle physics is seen as having three distinct areas of focus: the cosmic, intensity, and energy frontiers. These three frontiers a… more
Date: July 1, 2011
Creator: Morris, Aaron Owen
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Physics-Based Stress Corrosion Cracking Component Reliability Model cast in an R7-Compatible Cumulative Damage Framework

Description: This is a working report drafted under the Risk-Informed Safety Margin Characterization pathway of the Light Water Reactor Sustainability Program, describing statistical models of passives component reliabilities.
Date: July 1, 2011
Creator: Unwin, Stephen D.; Lowry, Peter P.; Layton, Robert F.; Toloczko, Mychailo B.; Johnson, Kenneth I. & Sanborn, Scott E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Excited light isoscalar mesons from lattice QCD

Description: I report a recent lattice QCD calculation of an excited spectrum of light isoscalar mesons, something that has up to now proved challenging for lattice QCD. With novel techniques we extract an extensive spectrum with high statistical precision, including spin-four states and, for the first time, light isoscalars with exotic quantum numbers. In addition, the hidden flavour content of these mesons is determined, providing a window on annihilation dynamics in QCD. I comment on future prospects inc… more
Date: July 1, 2011
Creator: Thomas, Christopher
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Final-state interactions in semi-inclusive deep inelastic scattering off the Deuteron

Description: Semi-inclusive deep inelastic scattering off the Deuteron with production of a slow nucleon in recoil kinematics is studied in the virtual nucleon approximation, in which the final state interaction (FSI) is calculated within general eikonal approximation. The cross section is derived in a factorized approach, with a factor describing the virtual photon interaction with the off-shell nucleon and a distorted spectral function accounting for the final-state interactions. One of the main goals of … more
Date: July 1, 2011
Creator: Wim Cosyn, Misak Sargsian
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Partner: UNT Libraries Government Documents Department
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A simultaneous measurement of the $b$-tagging efficiency scale factor and the $t\bar{t}$ Production Cross Section at the Collider Detector at Fermilab

Description: The ability to compare results between Monte Carlo and data is imperative in modern experimental high-energy physics analyses. The b-tagging efficiency Scale Factor (SF) allows for an accurate comparison of b quark identification in data samples and Monte Carlo. This thesis presents a simultaneous measurement of the SF for the SecVtx algorithm and the t{bar t} production cross section using 5.6 fb{sup -1} of p{bar p} collision data at {radical}s = 1.96 TeV collected by the Collider Detector at … more
Date: July 1, 2011
Creator: Hussain, Nazim
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Mechanical Study of Superconducting Parallel-Bar Deflecting/Crabbing Cavities

Description: The superconducting parallel-bar deflecting/crabbing cavities have improved properties compared to conventional cavity structures. It is currently being considered for number of applications. The mechanical design analysis is performed on two designs of the 499 MHz parallel-bar deflecting cavity for the Jefferson Lab 12 GeV upgrade. The main purpose of the mechanical study is to examine the structural stability of the cavities under the operating conditions in the accelerators. The study result… more
Date: July 1, 2011
Creator: H. Park, J.R. Delayen, S.U. De Silva
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Probing the fundamental limit of niobium in high radiofrequency fields by dual mode excitation in superconducting radiofrequency cavities

Description: We have studied thermal breakdown in several multicell superconducting radiofrequency cavity by simultaneous excitation of two TM{sub 010} passband modes. Unlike measurements done in the past, which indicated a clear thermal nature of the breakdown, our measurements present a more complex picture with interplay of both thermal and magnetic effects. JLab LG-1 that we studied was limited at 40.5 MV/m, corresponding to B{sub peak} = 173 mT, in 8{pi}/9 mode. Dual mode measurements on this quench in… more
Date: July 1, 2011
Creator: Eremeev, Grigory; Geng, Rongli & Palczewski, Ari
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Partner: UNT Libraries Government Documents Department
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Design of Superconducting Multi-Spoke Cavities for High-Velocity Applications

Description: Superconducting spoke cavities have been designed and tested for particle velocities up to {beta}{sub 0} ~ 0.6 and are currently being designed for velocities up to {beta}{sub 0} = 1. We present the electromagnetic designs for two-spoke cavities operating at 325 MHz for {beta}{sub 0} = 0.82 and {beta}{sub 0} = 1.
Date: July 1, 2011
Creator: Hopper, C. S. & Delayen, J. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Quench studies of ILC cavities

Description: Quench limits accelerating gradient in SRF cavities to a gradient lower than theoretically expected for superconducting niobium. Identification of the quenching site with thermometry and OST, optical inspection, and replica of the culprit is an ongoing effort at Jefferson Lab aimed at better understanding of this limiting phenomenon. In this contribution we present our finding with several SRF cavities that were limited by quench.
Date: July 1, 2011
Creator: Eremeev, Grigory; Geng, Rongli; Palczewski, Ari & Dai, Jin
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Preliminary Test Results from 650 MHz Single Cell Medium Beta Cavities for Project X

Description: We have fabricated two single cell 650 MHz {beta}=0.61 cavities of a JLab design, which possibly can be used for the proposed Project X proton linac application. Both cavities were manufactured at JLab from RRR>250 niobium sheet of 4 mm thickness using standard techniques such as deep drawing, electron beam welding, buffered chemical polishing, hydrogen degassing heat treatment, high pressure ultrapure water rinsing and clean room assembly. Initially cavity no. 1 was -- after final surface trea… more
Date: July 1, 2011
Creator: Marhauser, Frank; Kneisel, Peter; Burrill, Andrew; Kushnick, Peter & Rimmer, R. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Commissioning Cornell OSTs for SRF cavity testing at Jlab

Description: Understanding the current quench limitations in SRF cavities is a topic#11;essential for any SRF accelerator that requires high fields. This understanding crucially depends on correct and precise quench identification. Second sound quench detection in superfluid liquid helium with oscillating superleak transducers is a technique recently applied at Cornell University as a fast and versatile method for quench identification in SRF cavities. Having adopted Cornell design, we report in this contri… more
Date: July 1, 2011
Creator: Eremeev, Grigory
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Fabrication, Tuning, Treatment and Testing of Two 3.5 Cell Photo-Injector Cavities for the ELBE Linac

Description: As part of a CRADA (Cooperative Research and Development Agreement) between Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and Thomas Jefferson Lab National Accelerator Facility (TJNAF) we have fabricated and tested two 1.3 GHz 3.5 cell photo-injector cavities from polycrystalline RRR niobium and large grain RRR niobium, respectively. The cavity with the better performance will replace the presently used injector cavity in the ELBE linac. The cavities have been fabricated and pre-tuned at TJNAF, w… more
Date: July 1, 2011
Creator: Arnold, A.; Murcek, P.; Teichert, J.; Xiang, R.; Eremeev, G. V.; Kneisel, P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Designs of Superconducting Parallel-Bar Deflecting Cavities for Deflecting/Crabbing Applications

Description: The superconducting parallel-bar cavity is a deflecting/crabbing cavity with attractive properties, compared to other conventional designs, that is currently being considered for a number of applications. The new parallel-bar design with curved loading elements and circular or elliptical outer conductors have improved properties compared to the designs with rectangular outer conductors. We present the designs proposed as deflecting cavities for the Jefferson Lab 12 GeV upgrade and for Project-X… more
Date: July 1, 2011
Creator: Delayen, J. R. & De Silva, S. U.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Analysis of HOM Properties of Superconducting Parallel-Bar Deflecting/Crabbing Cavities

Description: The superconducting parallel-bar cavity is currently being considered for a number of deflecting and crabbing applications due to improved properties and compact design geometries. The 499 MHz deflecting cavity proposed for the Jefferson Lab 12 GeV upgrade and the 400 MHz crab cavity for the proposed LHC luminosity upgrade are two of the major applications. For high current applications the higher order modes must be damped to acceptable levels to eliminate any beam instabilities. The frequenci… more
Date: July 1, 2011
Creator: S.U. De Silva, J.R. Delayen
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Higher Order Mode Properties of Superconducting Two-Spoke Cavities

Description: Multi-Spoke cavities lack the cylindrical symmetry that many other cavity types have, which leads to a more complex Higher Order Mode (HOM) spectrum. In addition, spoke cavities offer a large velocity acceptance which means we must perform a detailed analysis of the particle velocity dependence for each mode's R/Q. We present here a study of the HOM properties of two-spoke cavities designed for high-velocity applications. Frequencies, R/Q and field profiles of HOMs have been calculated and are … more
Date: July 1, 2011
Creator: Hopper, C. S.; Delayen, J. R. & Olave, R. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Superconducting DC and RF Properties of Ingot Niobium

Description: The thermal conductivity, DC magnetization and penetration depth of large-grain niobium hollow cylindrical rods fabricated from ingots, manufactured by CBMM subjected to chemical and heat treatment were measured. The results confirm the influence of chemical and heat-treatment processes on the superconducting properties, with no significant dependence on the impurity concentrations in the original ingots. Furthermore, RF properties, such as the surface resistance and quench field of the niobium… more
Date: July 1, 2011
Creator: Pashupati Dhakal, Gianluigi Ciovati, Peter Kneisel, Ganapati Rao Myneni
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Detailed Surface Analysis Of Incremental Centrifugal Barrel Polishing (CBP) Of Single-Crystal Niobium Samples

Description: We performed Centrifugal Barrel Polishing (CBP) on single crystal niobium samples/coupons housed in a stainless steel sample holder following the polishing recipe developed at Fermi Lab (FNAL) in 2011 \cite{C. A. Cooper 2011}. Post CBP, the sample coupons were analyzed for surface roughness, crystal composition and structure, and particle contamination. Following the initial analysis each coupon was high pressure rinsed (HRP) and analyzed for the effectiveness of contamination removal. We were … more
Date: July 1, 2011
Creator: Palczewski, Ari D.; Tian, Hui; Trofimova, Olga & Reece, Charles E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Study on Electro-Polishing Process by Niobium-Plate Sample With Artificial Pits

Description: The Electro-polishing (EP) process is the best candidate of final surface-treatment for the production of ILC cavities. Nevertheless, the development of defects on the inner-surface of the Superconducting RF cavity during EP process has not been studied by experimental method. We made artificial pits on the surface of a Nb-plate sample and observed the development of the pit-shapes after each step of 30um-EP process where 120um was removed by EP in total. This article describes the results of t… more
Date: July 1, 2011
Creator: T. Saeki, H. Hayano, S. Kato, M. Nishiwaki, M. Sawabe, W.A. Clemens, R.L. Geng, R. Manus, P.V. Tyagi
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Characterization of Large Grain Nb Ingot Microstructure Using OIM and Laue Methods

Description: Large grain niobium is being examined for fabricating superconducting radiofrequency cavities as an alternative to using rolled sheet with fine grains. It is desirable to know the grain orientations of a niobium ingot slice before fabrication, as this allows heterogeneous strain and surface roughness effects arising from etching to be anticipated. Characterization of grain orientations has been done using orientation imaging microscopy (OIM), which requires destructive extraction of pieces from… more
Date: July 1, 2011
Creator: D. Kang, D.C. Baars, T.R. Bieler, G. Ciovati, C. Compton, T.L. Grimm, A.A. Kolka
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Partner: UNT Libraries Government Documents Department
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SIMS and TEM Analysis of Niobium Bicrystals

Description: The behaviour of interstitial impurities(C,O,N,H) on the Nb surface with respect to grain boundaries may affect cavity performance. Large grain Nb makes possible the selection of bicrystal samples with a well defined grain boundary. In this work, Dynamic SIMS was used to analyze two Nb bicrystal samples, one of them heat treated and the other non heat treated (control). H levels were found to be higher for the non heat treated sample and a difference in the H intensity and sputtering rate was a… more
Date: July 1, 2011
Creator: Maheshwari, P; Griffis, D P; Stevie, F A; Zhou, C; Ciovati, G; Myneni, R et al.
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Partner: UNT Libraries Government Documents Department
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Raman Spectroscopy as a Probe of Surface Oxides and Hydrides on Niobium

Description: Raman microscopy/spectroscopy has been used in conjunction with AFM, tunneling and magnetic susceptibility to identify surface oxides and hydrides on annealed, recrystallized foils of high purity Nb and on single crystals of cavity grade Nb. Cold worked regions of the Nb foil as well as rough regions near grain boundaries showed clear evidence of ordered hydride phases which were identified by VASP phonon calculations. Cold worked regions also displayed enhanced surface paramagnetism. Surface e… more
Date: July 1, 2011
Creator: J. Zasadzinski, B. Albee, S. Bishnoi, C. Cao, G. Ciovati, L.D. Cooley, D.C. Ford, Th. Proslier
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Summary of the Symposium on Ingot Nb and New Results on Fundamental Studies of Large Grain Nb

Description: The First International Symposium on the Superconducting Science and Technology of Ingot Niobium was held at Jefferson Lab in September 2010. Significant activities are taking place at laboratories and universities throughout the world to address several aspects related to the science and technology of Ingot Nb: from ingot production to mechanical, thermal and superconducting properties. A summary of the results presented at the Symposium is given in this contribution. New results on the superc… more
Date: July 1, 2011
Creator: G. Ciovati, P. Dhakal, R. Myneni
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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