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Justice and Law Enforcement: Observations on the Costs and Benefits of an Increased Department of Defense Role in Helping to Secure the Southwest Land Border (open access)

Justice and Law Enforcement: Observations on the Costs and Benefits of an Increased Department of Defense Role in Helping to Secure the Southwest Land Border

Correspondence issued by the Government Accountability Office with an abstract that begins "In order to satisfy the requirement in the Ike Skelton National Defense Authorization Act for Fiscal Year 2011 to report on the security of the southwest land border of the United States, we briefed Congress on July 12, 2011, with our preliminary observations. This is our final report to Congress on the Department of Defense (DOD) issues we addressed in response to the mandate. As directed by the mandate, we assessed: (1) what is known about the costs and benefits of an increased DOD role to help achieve operational control over the southwest land border, including the deployment of additional units, the National Guard, or other DOD personnel; increased use of ground-based mobile surveillance systems by military personnel; and use of additional mobile patrols by military personnel, particularly in rural, high-trafficked areas; and (2) what is known about the costs and benefits of an increased deployment of additional unmanned aerial systems and manned aircraft to provide surveillance; as well as the impact of any increased deployment of unmanned aerial systems or manned aircraft on national airspace use and availability.."
Date: September 12, 2011
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Tax Gap: Should the 3% Withholding Requirement on Payments to Contractors by Government Be Repealed? (open access)

Tax Gap: Should the 3% Withholding Requirement on Payments to Contractors by Government Be Repealed?

This reports discusses tax gaps and withholding, and concerns and legislation regarding these issues in the 112th Congress.
Date: September 12, 2011
Creator: Bickley, James M.
Object Type: Report
System: The UNT Digital Library
Iran Sanctions (open access)

Iran Sanctions

This report focuses on the United States' relationship with Iran and how the Obama Administration is handling prior administrations' economic sanctions against Iran. The Obama Administration's policy approach toward Iran has contrasted with the Bush Administration's by attempting to couple the imposition of sanctions to an active and direct U.S. effort to negotiate with Iran on the nuclear issue. That approach was not initially altered because of the Iranian dispute over its June 12, 2009, elections. However, with subsequent negotiations yielding no firm Iranian agreement to compromise, since early 2010 the Administration has focused on achieving the imposition of additional U.N., U.S., and allied country sanctions whose cumulative effect would be to compel it to accept a nuclear bargain.
Date: September 12, 2011
Creator: Katzman, Kenneth
Object Type: Report
System: The UNT Digital Library
Texas Attorney General Opinion: GA-0885 (open access)

Texas Attorney General Opinion: GA-0885

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Greg Abbott, regarding a legal question submitted for clarification; Process to appoint a person to fill a vacancy or to serve a subsequent term as a member of a board of directors of a regional mobility authority (RQ-0955-GA)
Date: September 12, 2011
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Annual Illness and Injury Surveillance Report: Savannah River Site, 2010 (open access)

Annual Illness and Injury Surveillance Report: Savannah River Site, 2010

The U.S. Department of Energy's (DOE) commitment to assuring the health and safety of its workers includes the conduct of illness and injury surveillance activities that provide an early warning system to detect health problems among workers. The Illness and Injury Surveillance Program monitors illnesses and health conditions that result in an absence, occupational injuries and illnesses, and disabilities and deaths among current workers.
Date: September 12, 2011
Creator: United States. Department of Energy. Office of Health, Safety, and Security.
Object Type: Report
System: The UNT Digital Library
designer phase transitions in lithium-based spinels (open access)

designer phase transitions in lithium-based spinels

When electrons in a metal become correlated with each other, new cooperative behavior can arise. This correlation is magnified when the metal has magnetic ions embedded in it. These atomic magnets try to line up with each other, but in doing so actually create a correlation between the motions of conduction electrons. In turn, these correlated electron motions prevent the magnetic ions from aligning, even at zero Kelvin. When this competition is strongest (at the so-called quantum critical point-QCP) the response of the system can no longer be described using the text book theory for metals. In addition, a range of new phenomena has been seen to emerge in the vicinity of a QCP, such as heavy-fermion superconductivity, coexistence of magnetism and superconductivity and hyper-scaling. The main goal of our research is to try to unravel the details of the feedback mechanism between electron motion and magnetism that lies at the heart of this new physics. We have chosen lithium-based spinel structures as the most promising family of systems to achieve our goal. Known lithium-based spinels Li{sub x}M{sub 2}O{sub 4} [M=V, Ti and Mn] show a variety of ground states: heavy-fermion, superconducting, or geometrically frustrated local moment systems. Li{sub x}M{sub …
Date: September 12, 2011
Creator: Montfrooij, Wouter
Object Type: Report
System: The UNT Digital Library
A Compact X-Band Linac for an X-Ray FEL (open access)

A Compact X-Band Linac for an X-Ray FEL

With the growing demand for FEL light sources, cost issues are being reevaluated. To make the machines more compact, higher frequency room temperature linacs are being considered, specifically ones using C-band (5.7 GHz) rf technology, for which 40 MV/m gradients are achievable. In this paper, we show that an X-band (11.4 GHz) linac using the technology developed for NLC/GLC can provide an even lower cost solution. In particular, stable operation is possible at gradients of 100 MV/m for single bunch operation and 70 MV/m for multibunch operation. The concern, of course, is whether the stronger wakefields will lead to unacceptable emittance dilution. However, we show that the small emittances produced in a 250 MeV, low bunch charge, LCLS-like S-band injector and bunch compressor can be preserved in a multi-GeV X-band linac with reasonable alignment tolerances. The successful lasing and operation of the LCLS [1] has generated world-wide interest in X-ray FELs. The demand for access to such a light source by researchers eager to harness the capabilities of this new tool far exceeds the numbers that can be accommodated, spurring plans for additional facilities. Along with cost, spatial considerations become increasingly important for a hard X-ray machine driven by a …
Date: September 12, 2011
Creator: Adolphsen, Chris; Huang, Zhirong; Bane, Karl L. F.; Li, Zenghai; Zhou, Feng; Wang, Faya et al.
Object Type: Article
System: The UNT Digital Library
Enhanced Densification of SDC Barrier Layers (open access)

Enhanced Densification of SDC Barrier Layers

This technical report explores the Enhanced Densification of SCD Barrier Layers A samaria-doped ceria (SDC) barrier layer separates the lanthanum strontium cobalt ferrite (LSCF) cathode from the yttria-stabilized zirconia (YSZ) electrolyte in a solid oxide fuel cell (SOFC) to prevent the formation of electrically resistive interfacial SrZrO{sub 3} layers that arise from the reaction of Sr from the LSCF with Zr from the YSZ. However, the sintering temperature of this SDC layer must be limited to {approx}1200 C to avoid extensive interdiffusion between SDC and YSZ to form a resistive CeO{sub 2}-ZrO{sub 2} solid solution. Therefore, the conventional SDC layer is often porous and therefore not as impervious to Sr-diffusion as would be desired. In the pursuit of improved SOFC performance, efforts have been directed toward increasing the density of the SDC barrier layer without increasing the sintering temperature. The density of the SDC barrier layer can be greatly increased through small amounts of Cu-doping of the SDC powder together with increased solids loading and use of an appropriate binder system in the screen print ink. However, the resulting performance of cells with these barrier layers did not exhibit the expected increase in accordance with that achieved with the prototypical …
Date: September 12, 2011
Creator: Hardy, John S.; Templeton, Jared W.; Lu, Zigui & Stevenson, Jeffry W.
Object Type: Report
System: The UNT Digital Library
Secondary Waste Form Down-Selection Data Package—Fluidized Bed Steam Reforming Waste Form (open access)

Secondary Waste Form Down-Selection Data Package—Fluidized Bed Steam Reforming Waste Form

The Hanford Site in southeast Washington State has 56 million gallons of radioactive and chemically hazardous wastes stored in 177 underground tanks (ORP 2010). The U.S. Department of Energy (DOE), Office of River Protection (ORP), through its contractors, is constructing the Hanford Tank Waste Treatment and Immobilization Plant (WTP) to convert the radioactive and hazardous wastes into stable glass waste forms for disposal. Within the WTP, the pretreatment facility will receive the retrieved waste from the tank farms and separate it into two treated process streams. These waste streams will be vitrified, and the resulting waste canisters will be sent to offsite (high-level waste [HLW]) and onsite (immobilized low-activity waste [ILAW]) repositories. As part of the pretreatment and ILAW processing, liquid secondary wastes will be generated that will be transferred to the Effluent Treatment Facility (ETF) on the Hanford Site for further treatment. These liquid secondary wastes will be converted to stable solid waste forms that will be disposed of in the Integrated Disposal Facility (IDF). To support the selection of a waste form for the liquid secondary wastes from WTP, Washington River Protection Solutions (WRPS) has initiated secondary waste form testing work at Pacific Northwest National Laboratory (PNNL). In …
Date: September 12, 2011
Creator: Qafoku, Nikolla; Westsik, Joseph H.; Strachan, Denis M.; Valenta, Michelle M. & Pires, Richard P.
Object Type: Report
System: The UNT Digital Library
Five-Year NRHP Re-Evaluation of Historic Buildings Assessment (open access)

Five-Year NRHP Re-Evaluation of Historic Buildings Assessment

The Lawrence Livermore National Laboratory (LLNL) 'Draft Programmatic Agreement among the Department of Energy and the California State Historic Preservation Officer Regarding Operation of Lawrence Livermore National Laboratory' requires a review and re-evaluation of the eligibility of laboratory properties for the National Register of Historic Places (NRHP) every five years. The original evaluation was published in 2005; this report serves as the first five-year re-evaluation. This re-evaluation includes consideration of changes within LLNL to management, to mission, and to the built environment. it also determines the status of those buildings, objects, and districts that were recommended as NRHP-eligible in the 2005 report. Buildings that were omitted from the earlier building list, those that have reached 50 years of age since the original assessment, and new buildings are also addressed in the re-evaluation.
Date: September 12, 2011
Creator: Ullrich, R A & Heidecker, K R
Object Type: Report
System: The UNT Digital Library
A Laser Interferometric Miniature Sensor (open access)

A Laser Interferometric Miniature Sensor

This is the second year of a Phase II Small Business Innovation Research (SBIR) contract geared towards the development of a new seismic sensor. Ground-based seismic monitoring systems have proven to be very capable in identifying nuclear tests, and can provide somewhat precise information on the location and yield of the explosive device. Making these measurements, however, currently requires very expensive and bulky seismometers that are difficult to deploy in places where they are most needed. A high performance, compact device can enable rapid deployment of large scale arrays, which can in turn be used to provide higher quality data during times of critical need. The use of a laser interferometer-based device has shown considerable promise, while also presenting significant challenges. The greatest strength of this optical readout technique is the ability to decouple the mechanical design from the transducer, thus enabling a miniaturized design that is not accessible with conventional sensing techniques. However, the nonlinearity in the optical response must be accounted for in the sensor output. Previously, we had proposed using a force-feedback approach to position the sensor at a point of maximum linearity. However, it can be shown that the combined nonlinearities of the optical response and …
Date: September 12, 2011
Creator: Carr, Dustin W.; Baldwin, Patrick C.; Milburn, Howard & Robinson, David
Object Type: Report
System: The UNT Digital Library
OTEC Advanced Composite Cold Water Pipe: Final Technical Report (open access)

OTEC Advanced Composite Cold Water Pipe: Final Technical Report

Ocean Thermal Energy Conversion can exploit natural temperature gradients in the oceans to generate usable forms of energy (for example, cost-competitive baseload electricity in tropical regions such as Hawaii) free from fossil fuel consumption and global warming emissions.The No.1 acknowledged challenge of constructing an OTEC plant is the Cold Water Pipe (CWP), which draws cold water from 1000m depths up to the surface, to serve as the coolant for the OTEC Rankine cycle. For a commercial-scale plant, the CWP is on the order of 10m in diameter.This report describes work done by LMSSC developing the CWP for LM MS2 New Ventures emerging OTEC business. The work started in early 2008 deciding on the minimum-cost CWP architecture, materials, and fabrication process. In order to eliminate what in previous OTEC work had been a very large assembly/deployment risk, we took the innovative approach of building an integral CWP directly from theOTEC platform and down into the water. During the latter half of 2008, we proceeded to a successful small-scale Proof-of-Principles validation of the new fabrication process, at the Engineering Development Lab in Sunnyvale. During 2009-10, under the Cooperative Agreement with the US Dept. of Energy, we have now successfully validated key elements …
Date: September 12, 2011
Creator: Miller, Dr. Alan & Ascari, Matthew
Object Type: Report
System: The UNT Digital Library
FY11 Level-2 Milestone 3953: TLCC2 contract awarded (open access)

FY11 Level-2 Milestone 3953: TLCC2 contract awarded

This report documents completion of FY11 L2 milestone No.3953-TLCC2 contract award. This milestone was scheduled for completion on 3/31/11 and was completed on 4/14/11. There is a separate milestone (3856), due at the end of the fiscal year, concerned with installation of the first LLNL SU and early user access. Efforts related to this tri-lab L2 milestone started early in 2010 with the development of tri-lab requirements for the second ASC capacity system procurement. The SOW was then developed along with necessary RFP paperwork and sent to HQ/DOE for their review prior to being released. There was significant delay in getting this step completed which led to this milestone being put at risk for several months. However, once the RFP was approved and released we were able to get the procurement back on track with aggressive proposal response and review timelines.
Date: September 12, 2011
Creator: Carnes, B
Object Type: Report
System: The UNT Digital Library
Machine-Induced Showers Entering the Atlas and CMS Detectors in the LHC (open access)

Machine-Induced Showers Entering the Atlas and CMS Detectors in the LHC

One source of experimental background in the LHC is showers induced by particles hitting the upstream collimators or particles that have been scattered on the residual gas. We estimate the flux and distribution of particles entering the ATLAS and CMS detectors through FLUKA simulations starting either in the tertiary collimators or with inelastic beam-gas interactions. Comparisons to MARS15 results are also presented. Our results can be used as a source term for further simulations of the machine-induced background in the experimental detectors. To ensure optimal performance of the LHC experimental detectors, it is important to understand the background, which can come fromseveral sources. In this article we discuss machine-induced background, caused either by nearby beam losses or interactions between beam particles and the residual gas inside the vacuum pipe. Beam losses outside the experimental interaction regions (IRs) are unavoidable during collider operation. The halo is continuously repopulated and has to be cleaned by the collimation system, so that the losses in the cold magnets are kept at a safe level. The collimation system is located in two dedicated insertions (IR3 and IR7) but a small leakage of secondary and tertiary halo is expected to escape. Some particles make it to …
Date: September 12, 2011
Creator: Bruce, R.; Assmann, R. W.; Boccone, V.; Burkhardt, H.; Cerutti, F.; Ferrari, A. et al.
Object Type: Article
System: The UNT Digital Library
A Two Bunch Beam Position Monitor (open access)

A Two Bunch Beam Position Monitor

A new beam position monitor digitizer module has been designed, tested and tuned at SLAC. This module, the electron-positron beam position monitor (epBPM), measures position of single electron and positron bunches for the SLC, LINAC, PEPII injections lines and final focus. The epBPM has been designed to improve resolution of beam position measurements with respect to existing module and to speed feedback correction. The required dynamic range is from 5 x 10{sup 8} to 10{sup 11} particles per bunch (46dB). The epBPM input signal range is from {+-}2.5 mV to {+-}500 mV. The pulse-to-pulse resolution is less than 2 {mu}m for 5 x 10{sup 10} particles per bunch for the 12 cm long striplines, covering 30{sup o} at 9 mm radius. The epBPM module has been made in CAMAC standard, single width slot, with SLAC type timing connector. 45 modules have been fabricated. The epBPM module has four input channels X{sup +}, X{sup -}, Y{sup +}, Y{sup -} (Fig. 1), named to correspond with coordinates of four striplines - two in horizontal and two in vertical planes, processing signals to the epBPM inputs. The epBPM inputs are split for eight signal processing channels to catch two bunches, first - the …
Date: September 12, 2011
Creator: Medvedko, E.; Aiello, R. & Smith, S.
Object Type: Article
System: The UNT Digital Library
Accelerated Gibbs Sampling for Infinite Sparse Factor Analysis (open access)

Accelerated Gibbs Sampling for Infinite Sparse Factor Analysis

The Indian Buffet Process (IBP) gives a probabilistic model of sparse binary matrices with an unbounded number of columns. This construct can be used, for example, to model a fixed numer of observed data points (rows) associated with an unknown number of latent features (columns). Markov Chain Monte Carlo (MCMC) methods are often used for IBP inference, and in this technical note, we provide a detailed review of the derivations of collapsed and accelerated Gibbs samplers for the linear-Gaussian infinite latent feature model. We also discuss and explain update equations for hyperparameter resampling in a 'full Bayesian' treatment and present a novel slice sampler capable of extending the accelerated Gibbs sampler to the case of infinite sparse factor analysis by allowing the use of real-valued latent features.
Date: September 12, 2011
Creator: Andrzejewski, D M
Object Type: Report
System: The UNT Digital Library
BNL Direct Wind Superconducting Magnets (open access)

BNL Direct Wind Superconducting Magnets

BNL developed Direct Wind magnet technology is used to create a variety of complex multi-functional multi-layer superconducting coil structures without the need for creating custom production tooling and fixturing for each new project. Our Direct Wind process naturally integrates prestress into the coil structure so external coil collars and yokes are not needed; the final coil package transverse size can then be very compact. Direct Wind magnets are produced with very good field quality via corrections applied during the course of coil winding. The HERA-II and BEPC-II Interaction Region (IR) magnet, J-PARC corrector and Alpha antihydrogen magnetic trap magnets and our BTeV corrector magnet design are discussed here along with a full length ILC IR prototype magnet presently in production and the coils that were wound for an ATF2 upgrade at KEK. A new IR septum magnet design concept for a 6.2 T combined-function IR magnet for eRHIC, a future RHIC upgrade, is introduced here.
Date: September 12, 2011
Creator: Parker, B.; Anerella, M.; Escallier, J.; Ghosh, A.; Jain, A.; Marone, A. et al.
Object Type: Article
System: The UNT Digital Library
ARM Cloud Retrieval Ensemble Data Set (ACRED) (open access)

ARM Cloud Retrieval Ensemble Data Set (ACRED)

This document describes a new Atmospheric Radiation Measurement (ARM) data set, the ARM Cloud Retrieval Ensemble Data Set (ACRED), which is created by assembling nine existing ground-based cloud retrievals of ARM measurements from different cloud retrieval algorithms. The current version of ACRED includes an hourly average of nine ground-based retrievals with vertical resolution of 45 m for 512 layers. The techniques used for the nine cloud retrievals are briefly described in this document. This document also outlines the ACRED data availability, variables, and the nine retrieval products. Technical details about the generation of ACRED, such as the methods used for time average and vertical re-grid, are also provided.
Date: September 12, 2011
Creator: Zhao, C.; Xie, S.; Klein, S. A.; McCoy, R.; Comstock, J. M.; Delanoë, J. et al.
Object Type: Report
System: The UNT Digital Library
Modeling the Dynamics of Compromised Networks (open access)

Modeling the Dynamics of Compromised Networks

Accurate predictive models of compromised networks would contribute greatly to improving the effectiveness and efficiency of the detection and control of network attacks. Compartmental epidemiological models have been applied to modeling attack vectors such as viruses and worms. We extend the application of these models to capture a wider class of dynamics applicable to cyber security. By making basic assumptions regarding network topology we use multi-group epidemiological models and reaction rate kinetics to model the stochastic evolution of a compromised network. The Gillespie Algorithm is used to run simulations under a worst case scenario in which the intruder follows the basic connection rates of network traffic as a method of obfuscation.
Date: September 12, 2011
Creator: Soper, B & Merl, D M
Object Type: Report
System: The UNT Digital Library
THREE-DIMENSIONAL THERMAL MODELING ANALYSIS OF CST MEDIA FOR THE SMALL ION EXCHANGE PROJECT (open access)

THREE-DIMENSIONAL THERMAL MODELING ANALYSIS OF CST MEDIA FOR THE SMALL ION EXCHANGE PROJECT

The Small Column Ion Exchange (SCIX) project is designed to accelerate closure of High Level Waste (HLW) tanks at the Savannah River Site (SRS). The SRS tanks store HLW in three forms: sludge, saltcake, and supernate. An in-tank ion exchange process is being designed to treat supernate and dissolved saltcake waste. Through this process, radioactive cesium from the salt solution is adsorbed into Crystalline Silicotitanate (CST) ion exchange media packed within a flow-through column. A packed column loaded with radioactive cesium generates significant heat from radiolytic decay. The waste supernate solution within the ion exchange bed will boil around 120 C. Solution superheating above the boiling point within the column could lead to violent hazardous energy releases. System heating from loaded CST is also of concern in other process modules, such as the waste tank. Due to tank structural integrity concerns, the wall temperature limit for the SRS waste tanks is 100 C. The transfer of cesium-loaded CST to the tank could result in localized hot spots on the tank floor and walls which may exceed this limit. As a result, thermal modeling calculations have been conducted to predict the maximum temperatures achievable both in the column and in the …
Date: September 12, 2011
Creator: Lee, S. & King, W.
Object Type: Report
System: The UNT Digital Library
Software Construction and Composition Tools for Petascale Computing SCW0837 Progress Report (open access)

Software Construction and Composition Tools for Petascale Computing SCW0837 Progress Report

The majority of scientific software is distributed as source code. As the number of library dependencies and supported platforms increases, so does the complexity of describing the rules for configuring and building software. In this project, we have performed an empirical study of the magnitude of the build problem by examining the development history of two DOE-funded scientific software projects. We have developed MixDown, a meta-build tool, to simplify the task of building applications that depend on multiple third-party libraries. The results of this research indicate that the effort that scientific programmers spend takes a significant fraction of the total development effort and that the use of MixDown can significantly simplify the task of building software with multiple dependencies.
Date: September 12, 2011
Creator: Epperly, T W & Hochstein, L
Object Type: Report
System: The UNT Digital Library
Tevatron Electron Lenses: Design and Operation (open access)

Tevatron Electron Lenses: Design and Operation

Fermilab's Tevatron is currently the world's highest energy accelerator in which tightly focused beams of 980 GeV protons and antiprotons collide at two dedicated interaction points (IPs). Both beams share the same beam pipe and magnet aperture and, in order to avoid multiple detrimental head-on collisions, the beams are placed on separated orbits everywhere except the main IPs by using high-voltage (HV) electrostatic separators. The electromagnetic beam-beam interaction at the main IPs together with the long-range interactions between separated beams adversely affect the collider performance, reducing the luminosity integral per store (period of continuous collisions) by 10-30%. Tuning the collider operation for optimal performance becomes more and more cumbersome as the beam intensities and luminosity increase. The long-range effects which (besides being nonlinear) vary from bunch to bunch are particularly hard to mitigate. A comprehensive review of the beam-beam effects in the Tevatron Collider Run II can be found in Ref. [1]. The beam-beam effects have been the dominating sources of beam loss and lifetime limitations in the Tevatron proton-antiproton collider [1]. Electron lenses were originally proposed for compensation of electromagnetic long-range and head-on beam-beam interactions of proton and antiproton beams [2]. Results of successful employment of two electron lenses …
Date: September 12, 2011
Creator: Shiltsev, Vladimir; Bishofberger, Kip; Kamerdzhiev, Vsevolod; Kozub, Sergei; Kufer, Matthew; Kuznetsov, Gennady et al.
Object Type: Article
System: The UNT Digital Library
NID Copper Sample Analysis (open access)

NID Copper Sample Analysis

The current focal point of the nuclear physics program at PNNL is the MAJORANA DEMONSTRATOR, and the follow-on Tonne-Scale experiment, a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay (0νββ). This experiment requires the use of germanium isotopically enriched in 76Ge. The MAJORANA DEMONSTRATOR is a DOE and NSF funded project with a major science impact. The DEMONSTRATOR will utilize 76Ge from Russia, but for the Tonne-Scale experiment it is hoped that an alternate technology, possibly one under development at Nonlinear Ion Dynamics (NID), will be a viable, US-based, lower-cost source of separated material. Samples of separated material from NID require analysis to determine the isotopic distribution and impurities. DOE is funding NID through an SBIR grant for development of their separation technology for application to the Tonne-Scale experiment. The Environmental Molecular Sciences facility (EMSL), a DOE user facility at PNNL, has the required mass spectroscopy instruments for making isotopic measurements that are essential to the quality assurance for the MAJORANA DEMONSTRATOR and for the development of the future separation technology required for the Tonne-Scale experiment. A sample of isotopically separated copper was provided by NID to PNNL in January …
Date: September 12, 2011
Creator: Kouzes, Richard T. & Zhu, Zihua
Object Type: Report
System: The UNT Digital Library
Photoionizing Trapped Highly Charged Ions with Synchrotron Radiation (open access)

Photoionizing Trapped Highly Charged Ions with Synchrotron Radiation

Photoabsorption by highly charged ions plays an essential role in astrophysical plasmas. Diagnostics of photoionized plasmas surrounding binary systems rely heavily on precise identification of absorption lines and on the knowledge of their cross sections and widths. Novel experiments using an electron beam ion trap, FLASH EBIT, in combination with monochromatic synchrotron radiation allow us to investigate ions in charge states hitherto out of reach. Trapped ions can be prepared in any charge state at target densities sufficient to measure absorption cross sections below 0.1 Mb. The results benchmark state-of-the-art predictions of the transitions wavelengths, widths, and absolute cross sections. Recent high resolution results on Fe{sup 14+}, Fe{sup 15+}, and Ar{sup 12+} at photon energies up to 1 keV are presented.
Date: September 12, 2011
Creator: Crespo, J. R.; Simon, M.; Beilmann, C.; Rudolph, J.; Steinbruegge, R.; Eberle, S. et al.
Object Type: Article
System: The UNT Digital Library