Epicyclic Twin-helix Magnetic Structure for Parametric-resonance Ionization Cooling (open access)

Epicyclic Twin-helix Magnetic Structure for Parametric-resonance Ionization Cooling

Para­met­ric-res­o­nance Ion­iza­tion Cool­ing (PIC) is en­vi­sioned as the final 6D cool­ing stage of a high-lu­mi­nos­i­ty muon col­lid­er. Im­ple­ment­ing PIC im­pos­es strin­gent con­straints on the cool­ing chan­nel's mag­net­ic op­tics de­sign. This paper pre­sents a lin­ear op­tics so­lu­tion com­pat­i­ble with PIC. Our so­lu­tion con­sists of a su­per­po­si­tion of two op­po­site-he­lic­i­ty equal-pe­ri­od and equal-strength he­li­cal dipole har­mon­ics and a straight nor­mal quadrupole. We demon­strate that such a sys­tem can be ad­just­ed to meet all of the PIC lin­ear op­tics re­quire­ments while re­tain­ing large ac­cep­tance.
Date: May 1, 2010
Creator: A. Afanasev, R.P. Johnson, Y.S. Derbenev, V.S. Morozov
Object Type: Article
System: The UNT Digital Library
Analysis of Vernier Scans during the PP2PP run in 2009 (pp at 100 GeV/beam) (open access)

Analysis of Vernier Scans during the PP2PP run in 2009 (pp at 100 GeV/beam)

N/A
Date: May 1, 2012
Creator: A., Drees
Object Type: Report
System: The UNT Digital Library
Towards demonstration of electron cooling with bunched electron beam (open access)

Towards demonstration of electron cooling with bunched electron beam

N/A
Date: May 1, 2012
Creator: A., Fedotov
Object Type: Report
System: The UNT Digital Library
Optics modification of the electron collector for the Relativistic Heavy Ion Collider Electron Beam Ion Source (open access)

Optics modification of the electron collector for the Relativistic Heavy Ion Collider Electron Beam Ion Source

N/A
Date: May 1, 2012
Creator: A., Pikin; Alessi, J.G.; Beebe, E.N.; Raparia, D. & Snydstrup, L.
Object Type: Report
System: The UNT Digital Library
Optics modification of the electron collector for the Relativistic Heavy Ion Collider Electron Beam Ion Source (open access)

Optics modification of the electron collector for the Relativistic Heavy Ion Collider Electron Beam Ion Source

N/A
Date: May 1, 2012
Creator: A., Pikin; Alessi, J.G.; Beebe, E.N.; Raparia, D. & Snydstrup, L.
Object Type: Report
System: The UNT Digital Library
Progress of Bep Treatments on Nb at JLAB (open access)

Progress of Bep Treatments on Nb at JLAB

Recent experimental results have indicated that Buffered Electropolishing (BEP) is a promising candidate for the next generation of surface treatment technique for Nb superconducting radio frequency (SRF) cavities to be used in particle accelerators. In order to lay the foundation for using BEP as the next generation surface treatment technique for Nb SRF cavities, some fundamental aspects of BEP treatments for Nb have to be investigated. In this report, recent progress on BEP study at JLab is shown. Improvements on the existing vertical BEP are made to allow water cooling from outside of a Nb single cell cavity in addition to cooling provided by acid circulation so that the temperature of the cavity can be stable during processing. Some investigation on the electrolyte mixture was performed to check the aging effect of the electrolyte. It is shown that good polishing results can still be obtained on Nb at a current density of 171 mA/cm when the BEP electrolyte was at the stationary condition and was more than 1.5 years old.
Date: May 1, 2010
Creator: A.T. Wu, S. Jin, R.A. Rimmer,X.Y. Lu, K. Zhao
Object Type: Article
System: The UNT Digital Library
Porosity in millimeter-scale welds of stainless steel : three-dimensional characterization. (open access)

Porosity in millimeter-scale welds of stainless steel : three-dimensional characterization.

A variety of edge joints utilizing a continuous wave Nd:YAG laser have been produced and examined in a 304-L stainless steel to advance fundamental understanding of the linkage between processing and resultant microstructure in high-rate solidification events. Acquisition of three-dimensional reconstructions via micro-computed tomography combined with traditional metallography has allowed for qualitative and quantitative characterization of weld joints in a material system of wide use and broad applicability. The presence, variability and distribution of porosity, has been examined for average values, spatial distributions and morphology and then related back to fundamental processing parameters such as weld speed, weld power and laser focal length.
Date: May 1, 2012
Creator: Aagesen, Larry K. & Madison, Jonathan D.
Object Type: Report
System: The UNT Digital Library
Combined Tevatron upper limit on gg -> H -> W^+W^- and constraints on the Higgs boson mass in fourth-generation fermion models (open access)

Combined Tevatron upper limit on gg -> H -> W^+W^- and constraints on the Higgs boson mass in fourth-generation fermion models

We combine results from searches by the CDF and D0 collaborations for a standard model Higgs boson (H) in the process gg {yields} H {yields} W{sup +}W{sup -} in p{bar p} collisions at the Fermilab Tevatron Collider at {radical}s = 1.o6 TeV. With 4.8 fb{sup -1} of itnegrated luminosity analyzed at CDF and 5.4 fb{sup -1} at D0, the 95% Confidence Level upper limit on {sigma}(gg {yields} H) x {Beta}(H {yields} W{sup +}W{sup -}) is 1.75 pb at m{sub H} = 120 GeV, 0.38 pb at m{sub H} = 165 GeV, and 0.83 pb at m{sub H} = 200 GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, they exclude at the 95% Confidence Level a standard-model-like Higgs boson with a mass between 131 and 204 Gev.
Date: May 1, 2010
Creator: Aaltonen, T.; Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M. et al.
Object Type: Article
System: The UNT Digital Library
$W$ boson polarization measurement in the $t\bar{t}$ dilepton channel using the CDF II Detector (open access)

$W$ boson polarization measurement in the $t\bar{t}$ dilepton channel using the CDF II Detector

We present a measurement of W boson polarization in top-quark decays in t{bar t} events with decays to dilepton final states using 5.1 fb{sup -1} integrated luminosity in p{bar p} collisions collected by the CDF II detector at the Tevatron. A simultaneous measurement of the fractions of longitudinal (f{sub 0}) and right-handed (f{sub +}) W bosons yields the results f{sub 0} = 0.71{sub -0.17}{sup +0.18}(stat) {+-} 0.06(syst) and f{sub +} = -0.07 {+-} 0.09(stat) {+-} 0.03(syst). Combining this measurement with our previous result based on single lepton final states, we obtain f{sub 0} = 0.84 {+-} 0.09(stat) {+-} 0.05(syst) and f{sub +} = -0.16 {+-} 0.05(stat) {+-} 0.04(syst). The results are consistent with standard model expectation.
Date: May 1, 2012
Creator: Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
Object Type: Article
System: The UNT Digital Library
Search for the Production of Scalar Bottom Quarks in $p \bar {p} $ collisions at $\sqrt{s} $ = 1.96 TeV (open access)

Search for the Production of Scalar Bottom Quarks in $p \bar {p} $ collisions at $\sqrt{s} $ = 1.96 TeV

We report on a search for direct scalar bottom quark (sbottom) pair production in p{bar p} collisions at {radical}s = 1.96 TeV, in events with large missing transverse energy and two jets of hadrons in the final state, where at least one of the jets is required to be identified as originating from a b quark. The study uses a CDF Run II data sample corresponding to 2.65 fb{sup -1} of integrated luminosity. The data are in agreement with the standard model. In an R-parity conserving minimal supersymmetric scenario, and assuming that the sbottom decays exclusively into a bottom quark and a neutralino, 95% confidence-level upper limits on the sbottom pair production cross section of 0.1 pb are obtained. For neutralino masses below 70 GeV/c{sup 2}, sbottom masses up to 230 GeV/c{sup 2} are excluded at 95% confidence level.
Date: May 1, 2010
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of et al.
Object Type: Article
System: The UNT Digital Library
Evidence for an anomalous like-sign dimuon charge asymmetry (open access)

Evidence for an anomalous like-sign dimuon charge asymmetry

We measure the charge asymmetry A of like-sign dimuon events in 6.1 fb{sup -1} of p{bar p} collisions recorded with the DO detector at a center of mass energy sqrt s = 1.96 TeV at the Fermilab Tevatron Collider.
Date: May 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
Object Type: Article
System: The UNT Digital Library
Search for scalar bottom quarks and third-generation leptoquarks in p p-bar collisions at sqrt(s) = 1.96 TeV (open access)

Search for scalar bottom quarks and third-generation leptoquarks in p p-bar collisions at sqrt(s) = 1.96 TeV

We report the results of a search for pair production of scalar bottom quarks ({tilde b}{sub 1}) and scalar third-generation leptoquarks (LQ{sub 3}) in 5.2 fb{sup -1} of p{bar p} collisions at the D0 experiment of the Fermilab Tevatron Collider. Scalar bottom quarks are assumed to decay to a neutralino ({tilde {chi}}{sub 1}{sup 0}) and a b quark, and we set 95% C.L. lower limits on their production in the (m{sub {tilde b}{sub 1}}, m{sub {tilde {chi}}{sub 1}{sup 0}}) mass plane such as m{sub {tilde b}{sub 1}} > 247 GeV for m{sub {tilde {chi}}{sub 1}{sup 0}} = 0 and m{sub {tilde {chi}}{sub 1}{sup 0}} > 110 GeV for 160 < m{sub {tilde b}{sub 1}} < 200 GeV. The leptoquarks are assumed to decay to a tau neutrino and a b quark, and we set a 95% C.L. lower limit of 247 GeV on the mass of a charge-1/3 third-generation scalar leptoquark.
Date: May 1, 2010
Creator: Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Abolins, Maris A.; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd et al.
Object Type: Article
System: The UNT Digital Library
Measurement of the production fraction times branching fraction $\boldsymbol{ f(b\to\Lambda_{b})\cdot \mathcal{B}(\Lambda_{b}\to J/\psi \Lambda)}$ (open access)

Measurement of the production fraction times branching fraction $\boldsymbol{ f(b\to\Lambda_{b})\cdot \mathcal{B}(\Lambda_{b}\to J/\psi \Lambda)}$

The {Lambda}{sub b}(udb) baryon is observed in the decay {Lambda}{sub b} {yields} J/{psi}{Lambda} using 6.1 fb{sup -1} of p{bar p} collisions collected with the D0 detector at {radical}s = 1.96 TeV. The production fraction multiplied by the branching fraction for this decay relative to that for the decay B{sup 0} {yields} J/{psi}K{sub s}{sup 0} is measured to be 0.345 {+-} 0.034 (stat.) {+-} 0.033 (syst.) {+-} 0.003 (PDG). Using the world average value of f(b {yields} B{sup 0}) {center_dot} {Beta}(B{sup 0} {yields} J/{psi}K{sub s}{sup 0}) = (1.74 {+-} 0.08) x 10{sup -5}, they obtain f(b {yields} {Lambda}{sub b}) {center_dot} {Beta}({Lambda}{sub b} {yields} J/{psi}{Lambda}) = (6.01 {+-} 0.60 (stat.) {+-} 0.58 (syst.) {+-} 0.28 (PDG)) x 10{sup -5}. This measurement represents an improvement in precision by about a factor of three with respect to the current world average.
Date: May 1, 2011
Creator: Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D. et al.
Object Type: Article
System: The UNT Digital Library
Measurement of the $t\bar{t}$ production cross section using dilepton events in $p\bar{p}$ collisions (open access)

Measurement of the $t\bar{t}$ production cross section using dilepton events in $p\bar{p}$ collisions

We present a measurement of the t{bar t} production cross section {sigma}{sub t{bar t}} in p{bar p} collisions at {radical}s = 1.96 TeV using 5.4 fb{sup -1} of integrated luminosity collected with the D0 detector. We consider final states with at least two jets and two leptons (ee, e{mu}, {mu}{mu}), and events with one jet for the the e{mu} final state as well. The measured cross section is {sigma}{sub t{bar t}} = 7.36{sub -0.79}{sup +0.90} (stat + syst) pb. This result combined with the cross section measurement in the lepton + jets final state yields {sigma}{sub t{bar t}} = 7.56{sub -0.56}{sup +0.63}(stat + syst) pb, which agrees with the standard model expectation. The relative precision of 8% of this measurement is comparable to the latest theoretical calculations.
Date: May 1, 2011
Creator: Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D. et al.
Object Type: Article
System: The UNT Digital Library
Model-independent measurement of $\boldsymbol{t}$-channel single top quark production in $\boldsymbol{p\bar{p}}$ collisions at $\boldsymbol{\sqrt{s}=1.96}$ TeV (open access)

Model-independent measurement of $\boldsymbol{t}$-channel single top quark production in $\boldsymbol{p\bar{p}}$ collisions at $\boldsymbol{\sqrt{s}=1.96}$ TeV

We present a model-independent measurement of t-channel electroweak production of single top quarks in p{bar p} collisions at {radical}s = 1.96 TeV. Using 5.4 fb{sup -1} of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider, and selecting events containing an isolated electron or muon, missing transverse energy and one or two jets originating from the fragmentation of b quarks, we measure a cross section {sigma}(p{bar p} {yields} tqb + X) = 2.90 {+-} 0.59 (stat + syst) pb for a top quark mass of 172.5 GeV. The probability of the background to fluctuate and produce a signal as large as the one observed is 1.6 x 10{sup -8}, corresponding to a significance of 5.5 standard deviations.
Date: May 1, 2011
Creator: Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D. et al.
Object Type: Article
System: The UNT Digital Library
DAKOTA JAGUAR 3.0 user's manual. (open access)

DAKOTA JAGUAR 3.0 user's manual.

JAGUAR (JAva GUi for Applied Research) is a Java software tool providing an advanced text editor and graphical user interface (GUI) to manipulate DAKOTA (Design Analysis Kit for Optimization and Terascale Applications) input specifications. This document focuses on the features necessary to use JAGUAR.
Date: May 1, 2013
Creator: Adams, Brian M.; Bauman, Lara E; Chan, Ethan; Lefantzi, Sophia & Ruthruff, Joseph R.
Object Type: Report
System: The UNT Digital Library
Fish Health Studies Associated with the Kingston Fly Ash Spill, Spring 2009 - Fall 2010 (open access)

Fish Health Studies Associated with the Kingston Fly Ash Spill, Spring 2009 - Fall 2010

On December 22, 2008, over 4 million cubic meters of fly ash slurry was released into the Emory River when a dike surrounding a solid waste containment area at the Tennessee Valley Authority's (TVA) Kingston Fossil Plant ruptured. One component of TVA's response to the spill is a biological monitoring program to assess short- and long-term ecological responses to the ash and associated chemicals, including studies on fish health and contaminant bioaccumulation. These studies were initiated in early Spring 2009 for the purposes of: (1) documenting the levels of fly ash-associated metals in various tissues of representative sentinel fish species in the area of the fly ash spill, (2) determining if exposure to fly ash-associated metals causes short, intermediate, or long-term health effects on these sentinel fish species, (3) assessing if there are causal relationships between exposure to metals and health effects on fish, (4) evaluating, along with information from other ecological and physicochemical studies, the nature and route of contaminant transfer though food chains into higher level consumers, (5) providing important information for the Ecological Risk Assessment (ERA) for the Kingston fly ash project, and (6) serving as an important technology information transfer or model study focused on how …
Date: May 1, 2012
Creator: Adams, Marshall & Fortner, Allison M
Object Type: Report
System: The UNT Digital Library
Bioaccumulation Studies Associated with the Kingston Fly Ash Spill, Spring 2009 - Fall 2010 (open access)

Bioaccumulation Studies Associated with the Kingston Fly Ash Spill, Spring 2009 - Fall 2010

In December 2008, an ash dike at the Tennessee Valley Authority (TVA) Kingston Fossil Plant ruptured, releasing over one billion gallons of coal fly ash into the Emory and Clinch Rivers. Coal fly ash may contain several contaminants of concern, but of these selenium (Se) and arsenic (As) have been highlighted because of their toxicity and tendency to bioaccumulate in aquatic food chains. To assess the potential impact of the spilled fly ash on humans and the environment, a comprehensive biological and environmental monitoring program was established, for which resident aquatic organisms (among other sample media) are collected to determine contaminant exposure and evaluate the risk to humans and wildlife. Studies on bioaccumulation and fish health are major components of the TVA Biological Monitoring Program for the Kingston fly ash project. These studies were initiated in early Spring 2009 for the purposes of: (1) documenting the levels of fly ash-associated metals in various tissues of representative sentinel fish species in the area of the fly ash spill, (2) determining if exposure to fly ash-associated metals causes short, intermediate, or long-term health effects on these sentinel fish species, (3) assessing if there are causal relationships between exposure (to metals) and effects …
Date: May 1, 2012
Creator: Adams, Marshall; Brandt, Craig C & Fortner, Allison M
Object Type: Report
System: The UNT Digital Library
Mechanical design of ceramic beam tube braze joints for NOVA kicker magnets (open access)

Mechanical design of ceramic beam tube braze joints for NOVA kicker magnets

The NO?A Experiment will construct a detector optimized for electron neutrino detection in the existing NuMI neutrino beam. The NuMI beam line is capable of operating at 400 kW of primary beam power and the upgrade will allow up to 700 kW. Ceramic beam tubes are utilized in numerous kicker magnets in different accelerator rings at Fermi National Accelerator Laboratory. Kovar flanges are brazed onto each beam tube end, since kovar and high alumina ceramic have similar expansion curves. The tube, kovar flange, end piece, and braze foil alloy brazing material are stacked in the furnace and then brazed. The most challenging aspect of fabricating kicker magnets in recent years have been making hermetic vacuum seals on the braze joints between the ceramic and flange. Numerous process variables can influence the robustness of conventional metal/ceramic brazing processes. The ceramic-filler metal interface is normally the weak layer when failure does not occur within the ceramic. Differences between active brazing filler metal and the moly-manganese process will be discussed along with the applicable results of these techniques used for Fermilab production kicker tubes.
Date: May 1, 2010
Creator: Ader, C. R.; Reilly, R. E. & Wilson, J. H.
Object Type: Article
System: The UNT Digital Library
Biological Interactions and Dynamics Science Theme Advisory Panel (BID-STAP) (open access)

Biological Interactions and Dynamics Science Theme Advisory Panel (BID-STAP)

This report contains the charge to the panel, the panel's discussions and panel recommendations.
Date: May 1, 2011
Creator: Ahring, Birgitte K.; Baliga, Nitin S.; Frederickson, James R.; Kaplan, Samuel; Pakrasi, Himadri B.; Pounds, Joel G. et al.
Object Type: Report
System: The UNT Digital Library
Stationary Fuel Cell System Composite Data Products: Data Through Quarter 4 of 2012 (open access)

Stationary Fuel Cell System Composite Data Products: Data Through Quarter 4 of 2012

This presentation from the U.S. Department of Energy's National Renewable Energy Laboratory includes stationary fuel cell system composite data products for data through the fourth quarter of 2012.
Date: May 1, 2013
Creator: Ainscough, C.; Kurtz, J. & Saur, G.
Object Type: Report
System: The UNT Digital Library
Development of a micro flow-through cell for high field NMR spectroscopy. (open access)

Development of a micro flow-through cell for high field NMR spectroscopy.

A highly transportable micro flow-through detection cell for nuclear magnetic resonance (NMR) spectroscopy has been designed, fabricated and tested. This flow-through cell allows for the direct coupling between liquid chromatography (LC) and gel permeation chromatography (GPC) resulting in the possibility of hyphenated LC-NMR and GPC-NMR. The advantage of the present flow cell design is that it is independent and unconnected to the detection probe electronics, is compatible with existing commercial high resolution NMR probes, and as such can be easily implemented at any NMR facility. Two different volumes were fabricated corresponding to between {approx}3.8 and 10 {micro}L detection volume. Examples of the performance of the cell on different NMR instruments, and using different NMR detection probes were demonstrated.
Date: May 1, 2011
Creator: Alam, Todd Michael & McIntyre, Sarah K.
Object Type: Report
System: The UNT Digital Library
CdTe Feedstock Development and Validation: Cooperative Research and Development Final Report, CRADA Number CRD-08-00280 (open access)

CdTe Feedstock Development and Validation: Cooperative Research and Development Final Report, CRADA Number CRD-08-00280

The goal of this work was to evaluate different CdTe feedstock formulations (feedstock provided by Redlen) to determine if they would significantly improve CdTe performance with ancillary benefits associated with whether changes in feedstock would affect CdTe cell processing and possibly reliability of cells. Feedstock also included attempts to intentionally dope the CdTe with pre-selected elements.
Date: May 1, 2011
Creator: Albin, D.
Object Type: Report
System: The UNT Digital Library
Alternative Muon Front-end for the International Design Study (IDS) (open access)

Alternative Muon Front-end for the International Design Study (IDS)

We discuss alternative designs of the muon capture front end of the Neutrino Factory International Design Study (IDS). In the front end, a proton bunch on a target creates secondary pions that drift into a capture channel, decaying into muons. A sequence of RF cavities forms the resulting muon beams into strings of bunches of differing energies, aligns the bunches to (nearly) equal central energies, and initiates ionization cooling. This design is affected by limitations on accelerating gradients within magnetic fields. The effects of gradient limitations are explored, and mitigation strategies are presented.
Date: May 1, 2010
Creator: Alekou, A.; Neuffer, D.; Martini, M.; Prior, G.; Rogers, C.; Stratakis, D. et al.
Object Type: Article
System: The UNT Digital Library