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Shielding of a hadron in a finite e-beam

Description: The thorough study of coherent electron cooling, the modern cooling technique capable to deal with accelerators operating in the range of few TeVs, rises many interesting questions. One of them is a shielding dynamics of a hadron in an electron beam. Now this effect is computed analytically in the infinite beam approximation. Many effects are drastically different in finite and infinite plasmas. Here we propose a method to compute the dynamical shielding effect in a finite cylindrical plasma - the realistic model of an electron beam in accelerators.
Date: May 20, 2012
Creator: A., Elizarov; Litvinenko, V. & Wang, G.
Partner: UNT Libraries Government Documents Department
open access

Search for High-Mass States with One Lepton Plus Missing Transverse Momentum in Proton-Proton Collisions at $\sqrt{s} with the ATLAS Detector

Description: The ATLAS detector is used to search for high-mass states, such as heavy charged gauge bosons (W{prime},W*), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of ppcollisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 36 pb{sup -1}. No excess beyond standard model expectations is observed. A W{prime} with sequential standard model couplings is excluded at 95% confidence level for masses below 1.49 TeV, and a W* (charged chiral boson) for masses below 1.35 TeV.
Date: June 20, 2012
Creator: Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdelalim, Ahmed Ali; Abdesselam, Abdelouahab; Abdinov, Ovsat et al.
Partner: UNT Libraries Government Documents Department
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In-Flight Measurement of the Absolute Energy Scale of the Fermi Large Area Telescope

Description: The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to survey the gamma-ray sky from 20 MeV to several hundreds of GeV. In this energy band there are no astronomical sources with sufficiently well known and sharp spectral features to allow an absolute calibration of the LAT energy scale. However, the geomagnetic cutoff in the cosmic ray electron-plus-positron (CRE) spectrum in low Earth orbit does provide such a spectral feature. The energy and spectral shape of this cutoff can be calculated with the aid of a numerical code tracing charged particles in the Earth's magnetic field. By comparing the cutoff value with that measured by the LAT in different geomagnetic positions, we have obtained several calibration points between {approx}6 and {approx}13 GeV with an estimated uncertainty of {approx}2%. An energy calibration with such high accuracy reduces the systematic uncertainty in LAT measurements of, for example, the spectral cutoff in the emission from gamma ray pulsars.
Date: September 20, 2012
Creator: Ackermann, M.; Ajello, M.; Allafort, A.; Atwood, W. B.; Axelsson, M.; Baldini, L. et al.
Partner: UNT Libraries Government Documents Department
open access

INDEPENDENT VERIFICATION SURVEY SUMMARY AND RESULTS FOR SUB-SLAB SOILS ASSOCIATED WITH THE FORMER BUILDING K-33, OAK RIDGE, TENNESSEE

Description: At DOE’s request, ORAU conducted confirmatory surveys of the K-33 sub-slab soil during the period of August 2011 through May 2012. The survey activities included visual inspections and measurement and sampling activities. LSRS was forthcoming with information relating to surface scan results. Scans performed by the contractor were of adequate coverage and overall data appear to represent actual site conditions. However, the LSRS technicians failed to identify several areas of elevated direct gamma radiation. Most of the samples taken by ORAU at locations of elevated instrument response were above the remediation concentration for one or more radionuclides of concern (ROC). The contractor was, however, quick to perform additional remediation of areas identified to have contamination above the guidelines. Further investigation by ORAU was not requested once additional remediation was completed. It is presumed the remediation contractor’s future PCCR will present detailed and conclusive evidence that K-33 sub-slab soils either comply or do not comply with record of decision (ROD) criteria. However, ORAU concludes, based on both independent verification (IV) data and data provided by LSRS, that the remediation contractor followed appropriate and applicable procedures and that the associated data adequately represent site conditions.
Date: September 20, 2012
Creator: Altic, Nick A.
Partner: UNT Libraries Government Documents Department
open access

Morocco: Current Issues

Description: This report discusses the current political and foreign policy status of Morocco, especially with regard to its relationship with the United States and its struggles combating terrorism.
Date: June 20, 2012
Creator: Arieff, Alexis
Partner: UNT Libraries Government Documents Department
open access

Senegal: Background and U.S. Relations

Description: Some concerns regarding Senegal include the running of the current Senegalese President for a third term and U.S. financial assistance. The United States has viewed Senegal as an anchor of regional stability and a potential partner in combating transnational security threats, such as terrorism, narcotics trafficking, and maritime piracy. Senegal is a significant contributor of troops to international peacekeeping missions, and thousands of Senegalese peacekeepers have received U.S. training through the State Department's Africa Contingency Operations Training and Assistance (ACOTA) program. Congress plays a role in guiding U.S. policy toward Senegal through its authorization, appropriation, and oversight of foreign assistance and executive branch policies.
Date: February 20, 2012
Creator: Arieff, Alexis
Partner: UNT Libraries Government Documents Department
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Recent Improvements In Interface Management For Hanfords Waste Treatment And Immobilization Plant - 13263

Description: The U.S. Department of Energy (DOE), Office of River Protection (ORP) is responsible for management and completion of the River Protection Project (RPP) mission, which comprises both the Hanford Site tank farms operations and the Waste Treatment and Immobilization Plant (WTP). The RPP mission is to store, retrieve and treat Hanford's tank waste; store and dispose of treated wastes; and close the tank farm waste management areas and treatment facilities by 2047. The WTP is currently being designed and constructed by Bechtel National Inc. (BNI) for DOE-ORP. BNI relies on a number oftechnical services from other Hanford contractors for WTP's construction and commissioning. These same services will be required of the future WTP operations contractor. The WTP interface management process has recently been improved through changes in organization and technical issue management documented in an Interface Management Plan. Ten of the thirteen active WTP Interface Control Documents (ICDs) have been revised in 2012 using the improved process with the remaining three in progress. The value of the process improvements is reflected by the ability to issue these documents on schedule.
Date: November 20, 2012
Creator: Arm, Stuart T.; Pell, Michael J.; Van Meighem, Jeffery S.; Duncan, Garth M. & Harrington, Christopher C.
Partner: UNT Libraries Government Documents Department
open access

The Debt Limit: History and Recent Increases

Description: This report discusses how the total debt of the federal government can increase, an historical overview of debt limits, and how the current economic slowdown has led to higher deficits and thereby a series of debt limit increases, as well as legislation related to these increases.
Date: January 20, 2012
Creator: Austin, D. Andrew & Levit, Mindy R.
Partner: UNT Libraries Government Documents Department

Studying Distance Students: Methods, Findings, Actions

Description: In this presentation, the authors discuss methods for assessing the needs of distance students and for effectively gathering input, emphasizing technology that did and did not work. The authors also identify ways to evaluate what was learned and to work with librarians and faculty.
Date: April 20, 2012
Creator: Avery, Elizabeth Fuseler & Wahl, Diane
Partner: UNT Libraries
open access

Hiding a Heavy Higgs Boson at the 7 TeV LHC

Description: A heavy Standard Model Higgs boson is not only disfavored by electroweak precision observables but is also excluded by direct searches at the 7 TeV LHC for a wide range of masses. Here, we examine scenarios where a heavy Higgs boson can be made consistent with both the indirect constraints and the direct null searches by adding only one new particle beyond the Standard Model. This new particle should be a weak multiplet in order to have additional contributions to the oblique parameters. If it is a color singlet, we find that a heavy Higgs with an intermediate mass of 200-300 GeV can decay into the new states, suppressing the branching ratios for the standard model modes, and thus hiding a heavy Higgs at the LHC. If the new particle is also charged under QCD, the Higgs production cross section from gluon fusion can be reduced significantly due to the new colored particle one-loop contribution. Current collider constraints on the new particles allow for viable parameter space to exist in order to hide a heavy Higgs boson. We categorize the general signatures of these new particles, identify favored regions of their parameter space and point out that discovering or excluding them at the LHC can provide important indirect information for a heavy Higgs. Finally, for a very heavy Higgs boson, beyond the search limit at the 7 TeV LHC, we discuss three additional scenarios where models would be consistent with electroweak precision tests: including an additional vector-like fermion mixing with the top quark, adding another U(1) gauge boson and modifying triple-gauge boson couplings.
Date: March 20, 2012
Creator: Bai, Yang; Fan, JiJi & Hewett, JoAnne L.
Partner: UNT Libraries Government Documents Department
open access

Corrugated Pipe as a Beam Dechirper

Description: We have studied the use of a metallic pipe with small corrugations for the purpose of passively dechirping, through its wakefield, a short, intense electron bunch. The corrugated pipe is attractive for this purpose because its wake: (i) has near maximal possible amplitude for a given aperture and (ii) has a relatively large oscillation wave length, even when the aperture is small. We showed how the corrugated structure can satisfy dechirping requirements encountered in the NGLS project at LBNL. We found that a linear chirp of -40 MeV/mm can be induced by an NGLS-like beam, by having it pass through a corrugated, metallic pipe of radius 3 mm, length 8.2 m, and corrugation parameters full depth 450 {mu}m and period 1000 {mu}m. This structure is about 15 times as effective in the role of dechirper as an S-band accelerator structure used passively.
Date: April 20, 2012
Creator: Bane, K. L. F. & Stupakov, G.
Partner: UNT Libraries Government Documents Department
open access

Superconducting RF systems for eRHIC

Description: The proposed electron-hadron collider eRHIC will consist of a six-pass 30-GeV electron Energy Recovery Linac (ERL) and one of RHIC storage rings operating with energy up to 250 GeV. The collider design extensively utilizes superconducting RF (SRF) technology in both electron and hadron parts. This paper describes various SRF systems, their requirements and parameters.
Date: May 20, 2012
Creator: Belomestnykh, S.; Ben-Zvi, Ilan; Brutus, J. C. & Hahn, H.
Partner: UNT Libraries Government Documents Department
open access

ANALYTICAL RESULTS OF MOX COLEMANITE CONCRETE SAMPLE PBC-44.2

Description: The Mixed Oxide Fuel Fabrication Facility (MFFF) will use colemanite bearing concrete neutron absorber panels credited with attenuating neutron flux in the criticality design analyses and shielding operators from radiation. The Savannah River National Laboratory is tasked with measuring the total density, partial hydrogen density, and partial boron density of the colemanite concrete. Sample PBC-44.2 was received on 9/20/2012 and analyzed. The average total density measured by the ASTM method C 642 was 2.03 g/cm{sup 3}, within the lower bound of 1.88 g/cm3. The average partial hydrogen density was 6.64E-02 g/cm{sup 3} as measured using method ASTM E 1311 and met the lower bound of 6.04E-02 g/cm{sup 3}. The average measured partial boron density was 1.70E-01 g/cm{sup 3} which met the lower bound of 1.65E-01 g/cm{sup 3} measured by the ASTM C 1301 method.
Date: December 20, 2012
Creator: Best, D.; Cozzi, A. & Reigel, M.
Partner: UNT Libraries Government Documents Department
open access

ANALYTICAL RESULTS OF MOX COLEMANITE CONCRETE SAMPLES POURED AUGUST 29, 2012

Description: The Mixed Oxide Fuel Fabrication Facility (MFFF) will use colemanite bearing concrete neutron absorber panels credited with attenuating neutron flux in the criticality design analyses and shielding operators from radiation. The Savannah River National Laboratory is tasked with measuring the total density, partial hydrogen density, and partial boron density of the colemanite concrete. Samples poured 8/29/12 were received on 9/20/2012 and analyzed. The average total density of each of the samples measured by the ASTM method C 642 was within the lower bound of 1.88 g/cm{sup 3}. The average partial hydrogen density of samples 8.6.1, 8.7.1, and 8.5.3 as measured using method ASTM E 1311 met the lower bound of 6.04E-02 g/cm{sup 3}. The average measured partial boron density of each sample met the lower bound of 1.65E-01 g/cm{sup 3} measured by the ASTM C 1301 method. The average partial hydrogen density of samples 8.5.1, 8.6.3, and 8.7.3 did not meet the lower bound. The samples, as received, were not wrapped in a moist towel as previous samples and appeared to be somewhat drier. This may explain the lower hydrogen partial density with respect to previous samples.
Date: December 20, 2012
Creator: Best, D.; Cozzi, A. & Reigel, M.
Partner: UNT Libraries Government Documents Department
open access

Hadron Physics at the Charm and Bottom Thresholds and Other Novel QCD Physics Topics at the NICA Accelerator Facility

Description: The NICA collider project at the Joint Institute for Nuclear Research in Dubna will have the capability of colliding protons, polarized deuterons, and nuclei at an effective nucleon-nucleon center-of mass energy in the range {radical}s{sub NN} = 4 to 11 GeV. I briefly survey a number of novel hadron physics processes which can be investigated at the NICA collider. The topics include the formation of exotic heavy quark resonances near the charm and bottom thresholds, intrinsic strangeness, charm, and bottom phenomena, hidden-color degrees of freedom in nuclei, color transparency, single-spin asymmetries, the RHIC baryon anomaly, and non-universal antishadowing.
Date: June 20, 2012
Creator: Brodsky, Stanley J.
Partner: UNT Libraries Government Documents Department
open access

Assessment and Mitigation of Diagnostic-Generated Electromagnetic Interference at the National Ignition Facility

Description: Electromagnetic interference (EMI) is an ever-present challenge at laser facilities such as the National Ignition Facility (NIF). The major source of EMI at such facilities is laser-target interaction that can generate intense electromagnetic fields within, and outside of, the laser target chamber. In addition, the diagnostics themselves can be a source of EMI, even interfering with themselves. In this paper we describe EMI generated by ARIANE and DIXI, present measurements, and discuss effects of the diagnostic-generated EMI on ARIANE's CCD and on a PMT nearby DIXI. Finally we present some of the efforts we have made to mitigate the effects of diagnostic-generated EMI on NIF diagnostics.
Date: April 20, 2012
Creator: Brown, C. G.; Ayers, M. J.; Felker, B.; Ferguson, W.; Holder, J P; Nagel, S. R. et al.
Partner: UNT Libraries Government Documents Department
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