MONTANA PALLADIUM RESEARCH INITIATIVE (open access)

MONTANA PALLADIUM RESEARCH INITIATIVE

Project Objective: The overarching objective of the Montana Palladium Research Initiative is to perform scientific research on the properties and uses of palladium in the context of the U.S. Department of Energy'™s Hydrogen, Fuel Cells and Infrastructure Technologies Program. The purpose of the research will be to explore possible palladium as an alternative to platinum in hydrogen-economy applications. To achieve this objective, the Initiatives activities will focus on several cutting-edge research approaches across a range of disciplines, including metallurgy, biomimetics, instrumentation development, and systems analysis. Background: Platinum-group elements (PGEs) play significant roles in processing hydrogen, an element that shows high potential to address this need in the U.S. and the world for inexpensive, reliable, clean energy. Platinum, however, is a very expensive component of current and planned systems, so less-expensive alternatives that have similar physical properties are being sought. To this end, several tasks have been defined under the rubric of the Montana Palladium Research Iniative. This broad swath of activities will allow progress on several fronts. The membrane-related activities of Task 1 employs state-of-the-art and leading-edge technologies to develop new, ceramic-substrate metallic membranes for the production of high-purity hydrogen, and develop techniques for the production of thin, defect-free platinum …
Date: May 9, 2012
Creator: McCloskey, John; Douglas, Jay; Young, Trevor; Snyder, Mark; Gurney, Stuart & Peters, Brian
Object Type: Report
System: The UNT Digital Library
Final Report "Structure of Rare Isotopes" (open access)

Final Report "Structure of Rare Isotopes"

The Junior Investigator grant 'Structure of Rare Isotopes' (DE-FG02-07ER41529) supported research in low-energy nuclear theory from September 1, 2007 to August 31, 2010. It was the main goal of the proposed research to develop and optimize an occupation-number-based energy functional for the computation of nuclear masses, and this aim has been reached. Furthermore, progress was made in linking two and three-body forces from low-momentum interactions to pairing properties in nuclear density functionals, and in the description of deformed nuclei within an effective theory.
Date: May 9, 2012
Creator: Papenbrock, Thomas
Object Type: Report
System: The UNT Digital Library
Development of a 402.5 MHz 140 kW Inductive Output Tube (open access)

Development of a 402.5 MHz 140 kW Inductive Output Tube

This report contains the results of Phase I of an SBIR to develop a Pulsed Inductive Output Tube (IOT) with 140 kW at 400 MHz for powering H-proton beams. A number of sources, including single beam and multiple beam klystrons, can provide this power, but the IOT provides higher efficiency. Efficiencies exceeding 70% are routinely achieved. The gain is typically limited to approximately 24 dB; however, the availability of highly efficient, solid state drivers reduces the significance of this limitation, particularly at lower frequencies. This program initially focused on developing a 402 MHz IOT; however, the DOE requirement for this device was terminated during the program. The SBIR effort was refocused on improving the IOT design codes to more accurately simulate the time dependent behavior of the input cavity, electron gun, output cavity, and collector. Significant improvement was achieved in modeling capability and simulation accuracy.
Date: May 9, 2012
Creator: Ives, R. Lawrence & Michael Read, Robert Jackson
Object Type: Report
System: The UNT Digital Library
Efficient Laser-Induced 6 - 8 KeV X-Ray Production From Iron Oxide Aerogel and Foil-Lined Cavity Targets (open access)

Efficient Laser-Induced 6 - 8 KeV X-Ray Production From Iron Oxide Aerogel and Foil-Lined Cavity Targets

None
Date: May 9, 2012
Creator: Perez, F.; Kay, J. J.; Patterson, R.; Kane, J.; Villette, B.; Girard, F. et al.
Object Type: Article
System: The UNT Digital Library
Predictive Capability for Strongly Correlated Systems (open access)

Predictive Capability for Strongly Correlated Systems

Diffusion Monte Carlo methods can give highly accurate results for correlated systems, provided that well optimized trial wave functions with accurate nodal surfaces are employed. The Cornell team developed powerful methods for optimizing all the parameters within a multi-determinant Slater-Jastrow form of the wave function. These include the Jastrow parameters within a flexible electron-electron-nucleus form of the Jastrow function, the parameters multiplying the configuration state functions, the orbital parameters and the basis exponents. The method optimizes a linear combination of the energy and the variance of the local energy. The optimal parameters are found iteratively by diagonalizing the Hamiltonian matrix in the space spanned by the wave function and its first-order derivatives, making use of a strong zero-variance principle. It is highly robust, has become the method of choice for correlated wave function optimization and has been adopted by other QMC groups. This optimization method was used on the first-row atoms and homonuclear diatomic molecules, demonstrating that molecular well depths can be obtained with near chemical accuracy quite systematically at the diffusion Monte Carlo level for these systems. In addition the complete ground-state potential energy curve of the C{sub 2} molecule up to the dissociation limit was obtained, and, size …
Date: May 9, 2012
Creator: Umrigar, Cyrus
Object Type: Report
System: The UNT Digital Library
Beam Measurements at LCLS (open access)

Beam Measurements at LCLS

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Date: May 9, 2012
Creator: Frisch, J.; Akre, R.; Decker, F. J.; Ding, Y.; Dowell, D.; Emma, P. et al.
Object Type: Article
System: The UNT Digital Library
120-Channel, Chronically Implantable, Wireless, Polymer Neural Interface (open access)

120-Channel, Chronically Implantable, Wireless, Polymer Neural Interface

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Date: May 9, 2012
Creator: Tooker, A; Shah, K; Tolosa, V; Sheth, H; Felix, S; Delima, T et al.
Object Type: Article
System: The UNT Digital Library
Homometallic and Heterometallic Antiferromagnetic Rings: Magnetic Properties Studied by Nuclear Magnetic Resonance (open access)

Homometallic and Heterometallic Antiferromagnetic Rings: Magnetic Properties Studied by Nuclear Magnetic Resonance

The aim of the present thesis is to investigate the local magnetic properties of homometallic Cr{sub 8} antiferromagnetic (AFM) ring and the changes occurring by replacing one Cr{sup 3+} ion with diamagnetic Cd{sup 2+} (Cr{sub 7}Cd) and with Ni{sup 2+} (Cr{sub 7}Ni). In the heterometallic ring a redistribution of the local magnetic moment is expected in the low temperature ground state. We have investigated those changes by both {sup 53}Cr-NMR and {sup 19}F-NMR. We have determined the order of magnitude of the transferred hyperfine coupling constant {sup 19}F - M{sup +} where M{sup +} = Cr{sup 3+}, Ni{sup 2+} in the different rings. This latter result gives useful information about the overlapping of the electronic wavefunctions involved in the coordinative bond.
Date: May 9, 2012
Creator: Casadei, Cecilia
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Project X RFQ EM Design (open access)

Project X RFQ EM Design

Project X is a proposed multi-MW proton facility at Fermi National Accelerator Laboratory (FNAL). The Project X front-end would consist of an H- ion source, a low-energy beam transport (LEBT), a CW 162.5 MHz radio-frequency quadrupole (RFQ) accelerator, and a medium-energy beam transport (MEBT). Lawrence Berkeley National Laboratory (LBNL) and FNAL collaboration is currently developing the designs for various components in the Project X front end. This paper reports the detailed EM design of the CW 162.5 MHz RFQ that provides bunching of the 1-10 mA H- beam with acceleration from 30 keV to 2.1 MeV.
Date: May 9, 2012
Creator: Romanov, Gennady; Hoff, Matthew; Li, Derun; Staples, John & Virostek, Steve
Object Type: Article
System: The UNT Digital Library
Modeling Multi-Bunch X-band Photoinjector Challenges (open access)

Modeling Multi-Bunch X-band Photoinjector Challenges

An X-band test station is being developed at LLNL to investigate accelerator optimization for future upgrades to mono-energetic gamma-ray technology at LLNL. The test station will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. Of critical import to the functioning of the LLNL X-band system with multiple electron bunches is the performance of the photoinjector. In depth modeling of the Mark 1 LLNL/SLAC X-band rf photoinjector performance will be presented addressing important challenges that must be addressed in order to fabricate a multi-bunch Mark 2 photoinjector. Emittance performance is evaluated under different nominal electron bunch parameters using electrostatic codes such as PARMELA. Wake potential is analyzed using electromagnetic time domain simulations using the ACE3P code T3P. Plans for multi-bunch experiments and implementation of photoinjector advances for the Mark 2 design will also be discussed.
Date: May 9, 2012
Creator: Marsh, R A; Anderson, S G; Gibson, D J & Barty, C J
Object Type: Article
System: The UNT Digital Library
PACKAGING CERTIFICATION PROGRAM METHODOLOGY FOR DETERMINING DOSE RATES FOR SMALL GRAM QUANTITIES IN SHIPPING PACKAGINGS (open access)

PACKAGING CERTIFICATION PROGRAM METHODOLOGY FOR DETERMINING DOSE RATES FOR SMALL GRAM QUANTITIES IN SHIPPING PACKAGINGS

The Small Gram Quantity (SGQ) concept is based on the understanding that small amounts of hazardous materials, in this case radioactive materials (RAM), are significantly less hazardous than large amounts of the same materials. This paper describes a methodology designed to estimate an SGQ for several neutron and gamma emitting isotopes that can be shipped in a package compliant with 10 CFR Part 71 external radiation level limits regulations. These regulations require packaging for the shipment of radioactive materials, under both normal and accident conditions, to perform the essential functions of material containment, subcriticality, and maintain external radiation levels within the specified limits. By placing the contents in a helium leak-tight containment vessel, and limiting the mass to ensure subcriticality, the first two essential functions are readily met. Some isotopes emit sufficiently strong photon radiation that small amounts of material can yield a large dose rate outside the package. Quantifying the dose rate for a proposed content is a challenging issue for the SGQ approach. It is essential to quantify external radiation levels from several common gamma and neutron sources that can be safely placed in a specific packaging, to ensure compliance with federal regulations. The Packaging Certification Program (PCP) …
Date: May 9, 2012
Creator: Nathan, S.; Loftin, B.; Abramczyk, G. & Bellamy, S.
Object Type: Article
System: The UNT Digital Library
CW Room Temperature Re-Buncher for the Project X Front End (open access)

CW Room Temperature Re-Buncher for the Project X Front End

At Fermilab there is a plan to construct the Project X Injector Experiment (PXIE) facility - a prototype of the front end of the Project X, a multi-MW proton source based on superconducting linac. The construction and successful operations of this facility will validate the concept for the Project X front end, thereby minimizing the primary technical risk element within the Project. The room temperature front end of the linac contains an ion source, an RFQ accelerator and a Medium Energy Beam Transport (MEBT) section comprising a high bandwidth bunch selective chopper. The MEBT length is about 10 m, so three re-bunching CW cavities are used to support the beam longitudinal dynamics. The paper reports a RF design of the re-bunchers along with preliminary beam dynamic and thermal analysis of the cavities.
Date: May 9, 2012
Creator: Romanov, Gennady; Awida, Mohamed H.; Chen, Meiyu; Gonin, Ivan V.; Kazakov, Sergey; Kostin, Roman et al.
Object Type: Article
System: The UNT Digital Library