Potential for luminosity improvement for low-energy RHIC operation with long bunches (open access)

Potential for luminosity improvement for low-energy RHIC operation with long bunches

Electron cooling was proposed to increase luminosity of the RHIC collider for heavy ion beams at low energies. Luminosity decreases as the square of bunch intensity due to the beam loss from the RF bucket as a result of the longitudinal intra beam scattering (IBS), as well as due to the transverse emittance growth because of the transverse IBS. Both transverse and longitudinal IBS can be counteracted with electron cooling. This would allow one to keep the initial peak luminosity close to constant throughout the store essentially without the beam loss. In addition, the phase-space density of the hadron beams can be further increased by providing stronger electron cooling. Unfortunately, the defining limitation for low energies in RHIC is expected to be the space charge. Here we explore an idea of additional improvement in luminosity, on top of the one coming from just IBS compensation and longer stores, which may be expected if one can operate with longer bunches at the space-charge limit in a collider. This approach together with electron cooling may result in about 10-fold improvement in total luminosity for low-energy RHIC program.
Date: February 10, 2012
Creator: A., Fedotov; Blaskiewicz&#44 & M.
Object Type: Report
System: The UNT Digital Library
SUMMARY REPORT DIRECT PUSH TECHNOLOGY BOREHOLES FOR GEOPHYSICAL LOGGING 200-IS-1 OPERABLE UNIT FY2008 (open access)

SUMMARY REPORT DIRECT PUSH TECHNOLOGY BOREHOLES FOR GEOPHYSICAL LOGGING 200-IS-1 OPERABLE UNIT FY2008

None
Date: February 10, 2009
Creator: AK, LEE
Object Type: Report
System: The UNT Digital Library
A novel approach to highly dispersing catalytic materials in coal for gasification. Ninth quarterly report, October 1, 1991--December 31, 1991 (open access)

A novel approach to highly dispersing catalytic materials in coal for gasification. Ninth quarterly report, October 1, 1991--December 31, 1991

This project seeks to develop a technique, based on coal surface properties, for highly dispersing catalysts in coal for gasification and to investigate the potential of using potassium carbonate and calcium acetate mixtures as catalysts for coal gasification. The lower cost and higher catalytic activity of the latter compound will produce economic benefits by reducing the amount of K{sub 2}CO{sub 3} required for high coal char reactivities. As was shown in previous reports, coal loading with potassium or calcium at different pHs produced CO{sub 2} gasification activities which increased in the order pH 6 > pH 10 {much_gt} pH 1. The current report shows that a similar trend was obtained when calcium and potassium were simultaneously loaded and char reaction times were less than about 75 min. Beyond this time, the coal impregnated with catalyst at pH 1 became more reactive, reaching 100% conversion after 1.5h. X-ray diffraction analysis suggest that the catalysts are well dispersed around pH 1 and 6 whereas reduced dispersion as obtained at pH 10. The reactivities are independent of the surface areas of the coals.
Date: February 10, 1992
Creator: Abotsi, G. M. K. & Bota, K. B.
Object Type: Report
System: The UNT Digital Library
A novel approach to highly dispersing catalytic materials in coal for gasification (open access)

A novel approach to highly dispersing catalytic materials in coal for gasification

This project seeks to develop a technique, based on coal surface properties, for highly dispersing catalysts in coal for gasification and to investigate the potential of using potassium carbonate and calcium acetate mixtures as catalysts for coal gasification. The lower cost and higher catalytic activity of the latter compound will produce economic benefits by reducing the amount of K{sub 2}CO{sub 3} required for high coal char reactivities. As was shown in previous reports, coal loading with potassium or calcium at different pHs produced CO{sub 2} gasification activities which increased in the order pH 6 > pH 10 {much gt} pH 1. The current report shows that a similar trend was obtained when calcium and potassium were simultaneously loaded and char reaction times were less than about 75 min. Beyond this time, the coal impregnated with catalyst at pH 1 became more reactive, reaching 100% conversion after 1.5h. X-ray diffraction analysis suggest that the catalysts are well dispersed around pH 1 and 6 whereas reduced dispersion as obtained at pH 10. The reactivities are independent of the surface areas of the coals.
Date: February 10, 1992
Creator: Abotsi, G.M.K. & Bota, K.B.
Object Type: Report
System: The UNT Digital Library
Cross-Sectional Scanning Tunneling Microscopy of InAsSb/InAsP Superlattices (open access)

Cross-Sectional Scanning Tunneling Microscopy of InAsSb/InAsP Superlattices

Cross-sectional scanning tunneling microscopy has been used to characterize compositional structure in InAs{sub 0.87}Sb{sub 0.13}/InAs{sub 0.73}P{sub 0.27} and InAs{sub 0.83}Sb{sub 0.17}/InAs{sub 0.60}P{sub 0.40} strained-layer superlattice structures grown by metal-organic chemical vapor deposition. High-resolution STM images of the (110) cross section reveal compositional features within both the InAs{sub x}Sb{sub 1{minus}x} and InAs{sub y}P{sub 1{minus}y} alloy layers oriented along the [{bar 1}12] and [1{bar 1}2] directions--the same as those in which features would be observed for CuPt-B type ordered alloys. Typically one variant dominates in a given area, although occasionally the coexistence of both variants is observed. Furthermore, such features in the alloy layers appear to be correlated across heterojunction interfaces in a manner that provides support for III-V alloy ordering models which suggest that compositional order can arise from strain-induced order near the surface of an epitaxially growing crystal. Finally, atomically resolved (1{bar 1}0) images obtained from the InAs{sub 0.87}Sb{sub 0.13}/InAs{sub 0.73}P{sub 0.27} sample reveal compositional features in the [112] and [{bar 1}{bar 1}2] directions, i.e., those in which features would be observed for CuPt-A type ordering.
Date: February 10, 1999
Creator: Allerman, A. A.; Biefeld, R. M.; Yu, E. T. & Zuo, S. L.
Object Type: Article
System: The UNT Digital Library
Double-shell target design for the NIF: Noncryogenic ignition and nonlinear mix studies for Stockpile Stewardship (open access)

Double-shell target design for the NIF: Noncryogenic ignition and nonlinear mix studies for Stockpile Stewardship

Double-shell ignition is complementary to the baseline approach by virtue of not requiring: (1) cryogenic preparation and fielding, (2) high-contrast pulse-shaping for shock-timing, and (3) demanding x-ray flux symmetry control. The use of simpler low-contrast pulse-shaping potentially allows more benign hohlraum conditions by reducing the risk of laser backscatter. In addition, the associated higher laser fluence threshold for optics damage initiation allows the possibility of more routine high-fluence shots with 2{omega} on the NIF. Based on LDRD-sponsored research in FY01-03 on NIF double-shell ignition target designs, the feasibility of this approach was advanced through both a highly successful implosion campaign on the Omega laser facility and a variety of design improvements for mitigating instability. The double-shell implosion campaign on Omega achieved the important milestone of repeatably demonstrating dominant primary (2.45 MeV) neutron production from the mix-susceptible compressional phase of a double-shell implosion, using fall-line design optimization and exacting fabrication standards. Showing effective control of fuel-pusher mix during final compression is an essential element for achieving ignition. In our studies to control mix by reducing hydrodynamic instability a new pathway for destructive Rayleigh-Taylor growth on the outer surface of the inner shell at ignition scales was identified. However, highly resolved multi-mode …
Date: February 10, 2004
Creator: Amendt, P
Object Type: Report
System: The UNT Digital Library
Review of actinide-sediment reactions with an annotated bibliography (open access)

Review of actinide-sediment reactions with an annotated bibliography

The annotated bibliography is divided into sections on chemistry and geochemistry, migration and accumulation, cultural distributions, natural distributions, and bibliographies and annual reviews. (LK)
Date: February 10, 1976
Creator: Ames, L. L.; Rai, D. & Serne, R. J.
Object Type: Report
System: The UNT Digital Library
Smoothing of ultrathin silver films by transition metalseeding (open access)

Smoothing of ultrathin silver films by transition metalseeding

The nucleation and coalescence of silver islands on coated glass was investigated by in-situ measurements of the sheet resistance. Sub-monolayer amounts of transition metals (Nb, Ti, Ni, Cr, Zr, Ta, and Mo) were deposited prior to the deposition of silver. It was found that some, but not all, of the transition metals lead to coalescence of silver at nominally thinner films with smoother topology. The smoothing effect of the transition metal at sub-monolayer thickness can be explained by a thermodynamic model of surface energies.
Date: February 10, 2006
Creator: Anders, Andre; Byon, Eungsun; Kim, Dong-Ho; Fukuda, Kentaro & Lim,Sunnie H.N.
Object Type: Article
System: The UNT Digital Library
Detailed Geophysical Fault Characterization in Yucca Flat, Nevada Test Site, Nevada (open access)

Detailed Geophysical Fault Characterization in Yucca Flat, Nevada Test Site, Nevada

Yucca Flat is a topographic and structural basin in the northeastern part of the Nevada Test Site (NTS) in Nye County, Nevada. Between the years 1951 and 1992, 659 underground nuclear tests took place in Yucca Flat; most were conducted in large, vertical excavations that penetrated alluvium and the underlying Cenozoic volcanic rocks. Radioactive and other potential chemical contaminants at the NTS are the subject of a long-term program of investigation and remediation by the U.S. Department of Energy (DOE), National Nuclear Security Administration, Nevada Site Office, under its Environmental Restoration Program. As part of the program, the DOE seeks to assess the extent of contamination and to evaluate the potential risks to humans and the environment from byproducts of weapons testing. To accomplish this objective, the DOE Environmental Restoration Program is constructing and calibrating a ground-water flow model to predict hydrologic flow in Yucca Flat as part of an effort to quantify the subsurface hydrology of the Nevada Test Site. A necessary part of calibrating and evaluating a model of the flow system is an understanding of the location and characteristics of faults that may influence ground-water flow. In addition, knowledge of fault-zone architecture and physical properties is a …
Date: February 10, 2009
Creator: Asch, Theodore H.; Sweetkind, Donald; Burton, Bethany L. & Wallin, Erin L.
Object Type: Report
System: The UNT Digital Library
Finance and supply management project execution plan (open access)

Finance and supply management project execution plan

As a subproject of the HANDI 2000 project, the Finance and Supply Management system is intended to serve FDH and Project Hanford major subcontractor with financial processes including general ledger, project costing, budgeting, and accounts payable, and supply management process including purchasing, inventory and contracts management. Currently these functions are performed with numerous legacy information systems and suboptimized processes.
Date: February 10, 1999
Creator: BENNION, S.I.
Object Type: Report
System: The UNT Digital Library
Software configuration management plan for HANDI 2000 business management system (open access)

Software configuration management plan for HANDI 2000 business management system

The Software Configuration Management Plan (SCMP) describes the configuration management and control environment for HANDI 2000 for the PP and PS software, as well as any custom developed software. This plan establishes requirements and processes for uniform documentation and coordination of HANDI 2000. This SCMP becomes effective as of this document's acceptance and will provide guidance through implementation efforts.
Date: February 10, 1999
Creator: BENNION, S.I.
Object Type: Report
System: The UNT Digital Library
Development of a Fast Microfluidic Mixer for Studies of Protein Folding KineticsFinal Report Cover Page (open access)

Development of a Fast Microfluidic Mixer for Studies of Protein Folding KineticsFinal Report Cover Page

We designed and fabricated mixing devices that will help us elucidate the mechanisms of protein folding through measurements of folding reaction rates. These devices can be used in studying of other biological systems and are compatible with various spectroscopic observation methods. The project involved development of fabrication processes and setup of a laboratory for assembly and characterization of microfluidic devices, as well as measurements of protein folding kinetics. We produced three variants of the mixer: (1) The ultra fast mixer for Foerster Resonance Energy Transfer measurements (described by Anal. Chem. Article UCRL-JRNL-206676) and MicroTAS Conference Proceedings article (UCRL-JC-153057 ) included in the report; (2) The ultra fast mixer for UV measurements (described by the poster presented at MicroTAS conference (UCRL-POST-207476) included in the report); and (3) The mixer for single molecule measurements (described by the Science article UCRL-JC-153057) included in the report. In these mixers, the channels are narrow, ranging from a few to hundreds of {micro}m, so that the flow is laminar and all of the mixing is achieved through diffusion. Our goal is to develop robust microfluidic mixer with at least 100 times lower consumption rate, shorter dead time and time resolution than commercially available mixers that would …
Date: February 10, 2005
Creator: Bakajin, O
Object Type: Report
System: The UNT Digital Library
Diffusion through Carbon Nanotube Semipermeable membranes (open access)

Diffusion through Carbon Nanotube Semipermeable membranes

None
Date: February 10, 2006
Creator: Bakajin, O
Object Type: Report
System: The UNT Digital Library
Resistive Wall Wake Effect of a Grooved Vacuum Chamber (open access)

Resistive Wall Wake Effect of a Grooved Vacuum Chamber

We investigate the enhancement of the resistive wall impedance of a round, metallic beam pipe with longitudinal grooves.
Date: February 10, 2006
Creator: Bane, K. L. F. & Stupakov, G.
Object Type: Article
System: The UNT Digital Library
Supporting Photovoltaics in Market-Rate Residential NewConstruction: A Summary of Programmatic Experience to Date and LessonsLearned (open access)

Supporting Photovoltaics in Market-Rate Residential NewConstruction: A Summary of Programmatic Experience to Date and LessonsLearned

As a market segment for solar photovoltaic (PV) adoption, new homes have a number of attractive attributes. Homebuyers can easily roll the cost of the PV system into their tax-deductible home mortgage and, with rebates and other financial incentives, potentially achieve an immediate net-positive cash flow from the investment. New homes are amenable to building-integrated photovoltaics (BIPV), which are less susceptible to aesthetic concerns than traditional, rack-mounted systems. The performance of PV systems can be optimized on new homes by taking roof orientation and shading into account when designing the home. Perhaps most importantly, subdivisions with PV systems installed on a large number of homes offer potential cost savings from volume purchases of modules and inverters and from scale economies in system design and installation. Finally, the ability of builders to install PV as a standard feature on multiple homes in new subdivisions offers an opportunity to circumvent the high transaction costs and information-related market barriers typically confronted when each individual homeowner must make a decision about installing PV. Builders may benefit in several ways from incorporating PV into new homes. Builders may gain greater market differentiation, enhanced media exposure, and less community or political opposition to development projects. Additionally, …
Date: February 10, 2006
Creator: Barbose, Galen; Wiser, Ryan & Bolinger, Mark
Object Type: Report
System: The UNT Digital Library
Irradiation of snap system actuator and position sensor assemblies in a vacuum-nuclear environment (open access)

Irradiation of snap system actuator and position sensor assemblies in a vacuum-nuclear environment

None
Date: February 10, 1965
Creator: Basham, S. J.; Rieder, W. G.; Zielenbach, W. J.; Gruber, H. T. & Allgeiger, J. P.
Object Type: Report
System: The UNT Digital Library
Progress on a Vlasov Treatment of Coherent Synchrotron Radiation From Arbitrary Planar Orbits (open access)

Progress on a Vlasov Treatment of Coherent Synchrotron Radiation From Arbitrary Planar Orbits

We report on our progress in the development of a fully self-consistent Vlasov treatment of coherent synchrotron radiation (CSR) effects on particle bunches traveling on arbitrary planar orbits. First we outline our Vlasov approach and the approximation we are currently studying. Then we discuss recent numerical results for a benchmark model studied extensively with codes by several authors.
Date: February 10, 2006
Creator: Bassi, G.; Ellison, J. A. & Warnock, R. L.
Object Type: Article
System: The UNT Digital Library
Fiscal Year 2009 Phased Construction Completion Report for EU Z2-36 in Zone 2, East Tennessee Technology Park, Oak Ridge, Tennessee (open access)

Fiscal Year 2009 Phased Construction Completion Report for EU Z2-36 in Zone 2, East Tennessee Technology Park, Oak Ridge, Tennessee

The purpose of this Phased Construction Completion Report (PCCR) is to present fiscal year (FY) 2009 results of Dynamic Verification Strategy (DVS) characterization activities for exposure unit (EU) Z2-36 in Zone 2 at the East Tennessee technology Park (ETTP). The ETTP is located in the northwest corner of the US Department of Energy (DOE) Oak Ridge Reservation in Oak Ridge, Tennessee and encompasses approximately 5000 acres that have been subdivided into three zones--Zone 1 ({approx} 1400 acres), Zone 2 ({approx} 800 acres), and the Boundary Area ({approx} 2800 acres). Zone 2 comprises the highly industrial portion of ETTP and consists of all formerly secured areas of the facility, including the large processing buildings and direct support facilities; experimental laboratories and chemical and materials handling facilities; materials storage and waste disposal facilities; secure document records libraries; and shipping and receiving warehouses. The Record of Decision for Soil, Buried Waste, and Subsurface Structure Actions in Zone 2, East Tennessee Technology Park, Oak Ridge, Tennessee (DOE 2005) (Zone 2 ROD) specifies the future end use for Zone 2 acreage as uncontrolled industrial for the upper 10 ft of soils. Characterization activities in these areas were conducted in compliance with the Zone 2 ROD …
Date: February 10, 2009
Creator: Bechtel Jacobs
Object Type: Report
System: The UNT Digital Library
Clic Cdr - Physics and Detectors: Clic Conceptual Design Report. (open access)

Clic Cdr - Physics and Detectors: Clic Conceptual Design Report.

This report forms part of the Conceptual Design Report (CDR) of the Compact LInear Collider (CLIC). The CLIC accelerator complex is described in a separate CDR volume. A third document, to appear later, will assess strategic scenarios for building and operating CLIC in successive center-of-mass energy stages. It is anticipated that CLIC will commence with operation at a few hundred GeV, giving access to precision standard-model physics like Higgs and top-quark physics. Then, depending on the physics landscape, CLIC operation would be staged in a few steps ultimately reaching the maximum 3 TeV center-of-mass energy. Such a scenario would maximize the physics potential of CLIC providing new physics discovery potential over a wide range of energies and the ability to make precision measurements of possible new states previously discovered at the Large Hadron Collider (LHC). The main purpose of this document is to address the physics potential of a future multi-TeV e{sup +}e{sup -} collider based on CLIC technology and to describe the essential features of a detector that are required to deliver the full physics potential of this machine. The experimental conditions at CLIC are significantly more challenging than those at previous electron-positron colliders due to the much higher …
Date: February 10, 2012
Creator: Berger, E.; Demarteau, M.; Repond, J.; Xia, L. & Weerts, H.
Object Type: Report
System: The UNT Digital Library
An Exact SU(2) Symmetry and Persistent Spin Helix in a Spin-Orbit Coupled System (open access)

An Exact SU(2) Symmetry and Persistent Spin Helix in a Spin-Orbit Coupled System

Spin-orbit coupled systems generally break the spin rotation symmetry. However, for a model with equal Rashba and Dresselhauss coupling constant (the ReD model), and for the [110] Dresselhauss model, a new type of SU(2) spin rotation symmetry is discovered. This symmetry is robust against spin-independent disorder and interactions, and is generated by operators whose wavevector depends on the coupling strength. It renders the spin lifetime infinite at this wavevector, giving rise to a Persistent Spin Helix (PSH). We obtain the spin fluctuation dynamics at, and away, from the symmetry point, and suggest experiments to observe the PSH.
Date: February 10, 2010
Creator: Bernevig, Andrei
Object Type: Article
System: The UNT Digital Library
Hydrogen Absorption in Fluids: An Unexplored Solution for Onboard Hydrogen Storage (open access)

Hydrogen Absorption in Fluids: An Unexplored Solution for Onboard Hydrogen Storage

Adoption of hydrogen (H{sub 2}) vehicles has been advocated for decades as an ecological ideal, capable of eliminating petroleum consumption as well as tail-pipe air pollution and carbon dioxide (CO{sub 2}) from automobiles. Storing sufficient hydrogen fuel onboard still remains a great technological challenge, despite recent advances in lightweight automotive materials, hybrid-electric drivetrains and fuel cells enabling 60-100 mpg equivalent H{sub 2}-fueled automobiles. Future onboard hydrogen storage choices will be pivotal, with lasting strategic consequences for the eventual scale, shape, security, investment requirements, and energy intensity of the H{sub 2} refueling infrastructure, in addition to impacts on automotive design, cost, range, performance, and safety. Multiple hydrogen storage approaches have been examined and deployed onboard prototype automobiles since the 1970's. These include storing H{sub 2} as a cryogenic liquid (LH{sub 2}) at temperatures of 20-25 Kelvin, compressing room temperature H{sub 2} gas to pressures as high as 10,000 psi, and reversible chemical absorption storage within powdered metal hydrides (e.g. LaNi{sub 5}H{sub 6}, TiFeH{sub 2}, MgH{sub 2}, NaAlH{sub 4}) which evolve H{sub 2} when warmed. Each of these approaches face well-known fundamental physical limits (thermal endurance, volume, and weight, respectively). This report details preliminary experiments investigating the potential of a new approach …
Date: February 10, 2005
Creator: Berry, G D
Object Type: Report
System: The UNT Digital Library
Investigation into the repetition-rate limitations of magnetic switches (open access)

Investigation into the repetition-rate limitations of magnetic switches

The use of magnetic switches to generate high power pulses has opened up a whole new spectrum of possibilities. Here we describe an investigation into the maximum repetition rates possible with these devices.
Date: February 10, 1982
Creator: Birx, D. L.; Reginato, L. L. & Schmidt, J. A.
Object Type: Article
System: The UNT Digital Library
A survey of the current experimental database for lower hybrid current-drive and heating (open access)

A survey of the current experimental database for lower hybrid current-drive and heating

The proposed ITER design may rely heavily on Lower Hybrid waves to provide heating, current drive, MHD stabilization through current profile modification and transformer recharging. This paper presents a detailed survey of recent LH experimental results from PLT, Alcator C, ASDEX, Petula-B, FT and JT-60. Current drive and heating efficiencies are given, as well as regimes where sawteeth and m = 1 and 2 oscillations are stabilized. In addition, in ASDEX and JT-60, LH waves in combination with neutral beams, (a possible ITER scenario) experiments are examined. Finally, the current drive efficiency for ITER is obtained by extrapolating from the LHCD database. Assuming 12 MW of LH power, approximately 4.5 to 5.6 MA of current could be driven in ITER. However, the high density (/ovr /n///sub e/ = 8 /times/ 10/sup 19/ m/sup /minus/3/) and high temperature (/ovr/T///sub e/ = 21 keV) will preclude wave penetration to the center. Assuming a narrow N/sub /parallel// spectrum (1.2 /approx lt/ N/sub /parallel// /approx lt/ 2) the LH waves should be absorbed within the outer half of the plasma. 43 refs., 18 figs., 10 tabs.
Date: February 10, 1988
Creator: Blackfield, D. T.
Object Type: Article
System: The UNT Digital Library
RECOVERY FROM RADIATION INJURY IN MICE AND ITS EFFECT ON LD$sub 50$ FOR DURATIONS OF EXPOSURE UP TO SEVERAL WEEKS (open access)

RECOVERY FROM RADIATION INJURY IN MICE AND ITS EFFECT ON LD$sub 50$ FOR DURATIONS OF EXPOSURE UP TO SEVERAL WEEKS

None
Date: February 10, 1954
Creator: Blair, H.A.
Object Type: Report
System: The UNT Digital Library