The Cost of Superconducting Magnets as a Function of Stored Energy and Design Magnetic Induction Times the Field Volume (open access)

The Cost of Superconducting Magnets as a Function of Stored Energy and Design Magnetic Induction Times the Field Volume

By various theorems one can relate the capital cost of superconducting magnets to the magnetic energy stored within that magnet. This is particularly true for magnet where the cost is dominated by the structure needed to carry the magnetic forces. One can also relate the cost of the magnet to the product of the magnetic induction and the field volume. The relationship used to estimate the cost the magnet is a function of the type of magnet it is. This paper updates the cost functions given in two papers that were published in the early 1990 s. The costs (escalated to 2007 dollars) of large numbers of LTS magnets are plotted against stored energy and magnetic field time field volume. Escalated costs for magnets built since the early 1990 s are added to the plots.
Date: August 27, 2007
Creator: Green, Mike; Green, M. A. & Strauss, B. P.
Object Type: Article
System: The UNT Digital Library
CRISPR - a Widespread System That Provides Acquired Resistance Against Phages in Bacteria and Archaea (open access)

CRISPR - a Widespread System That Provides Acquired Resistance Against Phages in Bacteria and Archaea

Arrays of clustered, regularly spaced short palindromic repeats (CRISPR) are widespread in the genomes of many bacteria and almost all archaea. These arrays are composed of direct repeats sized 24-47 bp separated by similarly sized non-repetitive sequences (spacers). It was recently experimentally shown that CRISPR arrays, along with a group of associated proteins, confer resistance to phage. Following exposure to phage, bacteria integrate new spacer sequences that are derived from the phage genome. Acquisition of these spacers enables the bacterial cell to shutdown the phage attack, presumably by an RNA-interference-like mechanism. This progress discusses the structure and function of CRISPRs and the implications of his new antiviral mechanisms in bacteria.
Date: November 27, 2007
Creator: Kunin, Victor; Sorek, Rotem; Kunin, Victor & Hugenholtz, Philip
Object Type: Article
System: The UNT Digital Library
On Point Designs for High Gain Fast Ignition (open access)

On Point Designs for High Gain Fast Ignition

Fast ignition research has reached the stage where point designs are becoming crucial to the identification of key issues and the development of projects to demonstrate high gain fast ignition. The status of point designs for cone coupled electron fast ignition and some of the issues they highlight are discussed.
Date: September 27, 2007
Creator: Key, M.; Akli, K.; Beg, F.; Betti, R.; Clark, D. S.; Chen, S. N. et al.
Object Type: Article
System: The UNT Digital Library
ENDF/B-VII.0 Data Testing for Three Fast Critical Assemblies (open access)

ENDF/B-VII.0 Data Testing for Three Fast Critical Assemblies

In this report we consider three fast critical assemblies, each assembly is dominated by a different nuclear fuel: Godiva (U235), Jezebel (Pu239) and Jezebel23 (U233) [1]. We first show the improvement in results when using the new ENDF/B-VII.0 data [2], rather than the older, now frozen, ENDF/B-VI.8 data [3]. We do this using what we call a one code/ multiple library approach, where results from one code (MCNP) are compared using two different data libraries (ENDF/B-VII.0 and VI.8). Next we show that MCNP results are not specific to this one code by using what we call a one data library/multiple code approach; for this purpose we invited many codes to submit results using the ENDF/B-VII.0 data; the most detailed results presented in this report compare MCNP and TART. The bottom line is that we have shown that using the new ENDF/B-VII.0 data library with a variety of transport codes, for the first time we are able to reproduce the expected K-eff values for all three assemblies to within the quoted accuracy of the models, namely 1.0 +/- 0.001. This is a BIG improvement compared to the results obtained using the older ENDF/B-VI.8 data library. Another important result of this study …
Date: July 27, 2007
Creator: Cullen, D. E.; Blomquist, R. N.; Brown, P. N.; Dean, C. J.; Dunn, M. E.; Lee, Y. et al.
Object Type: Report
System: The UNT Digital Library
Monochromatic electron photoemission from diamondoid monolayers (open access)

Monochromatic electron photoemission from diamondoid monolayers

We found monochromatic electron photoemission from large-area self-assembled monolayers of a functionalized diamondoid, [121]tetramantane-6-thiol. Photoelectron spectra of the diamondoid monolayers exhibited a peak at the low-kinetic energy threshold; up to 68percent of all emitted electrons were emitted within this single energy peak. The intensity of the emission peak is indicative of diamondoids being negative electron affinity materials. With an energy distribution width of less than 0.5 electron volts, this source of monochromatic electrons may find application in technologies such as electron microscopy, electron beam lithography, and field-emission flatpanel displays.
Date: February 27, 2007
Creator: Yang, Wanli; Yang, Wanli L.; Fabbri, J. D.; Willey, T. M.; Lee, J. R. I.; Dahl, J. E. et al.
Object Type: Article
System: The UNT Digital Library
A HIGH CURRENT, HIGH VOLTAGE SOLID-STATE PULSE GENERATOR FOR THE NIF PLASMA ELECTRODE POCKELS CELL (open access)

A HIGH CURRENT, HIGH VOLTAGE SOLID-STATE PULSE GENERATOR FOR THE NIF PLASMA ELECTRODE POCKELS CELL

A high current, high voltage, all solid-state pulse modulator has been developed for use in the Plasma Electrode Pockels Cell (PEPC) subsystem in the National Ignition Facility. The MOSFET-switched pulse generator, designed to be a more capable plug-in replacement for the thyratron-switched units currently deployed in NIF, offers unprecedented capabilities including burst-mode operation, pulse width agility and a steady-state pulse repetition frequency exceeding 1 Hz. Capable of delivering requisite fast risetime, 17 kV flattop pulses into a 6 {Omega} load, the pulser employs a modular architecture characteristic of the inductive adder technology, pioneered at LLNL for use in acceleration applications, which keeps primary voltages low (and well within the capabilities of existing FET technology), reduces fabrication costs and is amenable to rapid assembly and quick field repairs.
Date: July 27, 2007
Creator: Arnold, P. A.; Barbosa, F.; Cook, E. G.; Hickman, B. C.; Akana, G. L. & Brooksby, C. A.
Object Type: Article
System: The UNT Digital Library
Hydra modeling of experiments to study ICF capsule fill hole dynamics using surrogate targets (open access)

Hydra modeling of experiments to study ICF capsule fill hole dynamics using surrogate targets

In this section the results of HYDRA [1] design simulations will be discussed. The simulations were conducted in two dimensional, RZ geometry, with the fill tube on axis. The radiation transport was treated in the diffusion approximation using 15 energy groups. Opacities were calculated. The equations of state (EOS) for all materials used were from a combined analytic/Thomas-Fermi EOS which uses a modified Cowan model for the ion EOS, and uses a scaled Thomas-Fermi table for the electron EOS.
Date: August 27, 2007
Creator: Elliott, J B
Object Type: Report
System: The UNT Digital Library
Quantifying the importance of orbital over spin correlations in delta-Pu within density-functional theory (open access)

Quantifying the importance of orbital over spin correlations in delta-Pu within density-functional theory

Spin and orbital and electron correlations are known to be important when treating the high-temperature {delta} phase of plutonium within the framework of density-functional theory (DFT). One of the more successful attempts to model {delta}-Pu within this approach has included condensed-matter generalizations of Hund's three rules for atoms, i.e., spin polarization, orbital polarization, and spin-orbit coupling. Here they perform a quantitative analysis of these interactions relative rank for the bonding and electronic structure in {delta}-Pu within the DFT model. The result is somewhat surprising in that spin-orbit coupling and orbital polarization are far more important than spin polarization for a realistic description of {delta}-Pu. They show that these orbital correlations on their own, without any formation of magnetic spin moments, can account for the low atomic density of the {delta} phase with a reasonable equation-of-state. In addition, this unambiguously non-magnetic (NM) treatment produces a one-electron spectra with resonances close to the Fermi level consistent with experimental valence band photoemission spectra.
Date: July 27, 2007
Creator: Soderlind, P & Wolfer, W
Object Type: Article
System: The UNT Digital Library
Extracellular Proteins Limit the Dispersal of BiogenicNanoparticles (open access)

Extracellular Proteins Limit the Dispersal of BiogenicNanoparticles

High spatial-resolution secondaryion microprobespectrometry, synchrotron radiation Fourier-transform infraredspectroscopy and polyacrylamide gel analysis demonstrate the intimateassociation of proteins with spheroidal aggregates of biogenic zincsulfide nanocrystals, an example of extracellular biomineralization.Experiments involving synthetic ZnS nanoparticles and representativeamino acids indicate a driving role for cysteine in rapid nanoparticleaggregation. These findings suggest that microbially-derivedextracellular proteins can limit dispersal of nanoparticulatemetal-bearing phases, such as the mineral products of bioremediation,that may otherwise be transported away from their source by subsurfacefluid flow.
Date: April 27, 2007
Creator: Moreau, John W.; Weber, Peter K.; Martin, Michael C.; Gilbert,Benjamin; Hutcheon, Ian D. & Banfield, Jillian F.
Object Type: Article
System: The UNT Digital Library
Gauge Mediation Simplified (open access)

Gauge Mediation Simplified

None
Date: January 27, 2007
Creator: Murayama, Hitoshi & Nomura, Yasunori
Object Type: Article
System: The UNT Digital Library
Relativistic Many-body Moller-Plesset Perturbation Theory Calculations of the Energy Levels and Transition Probabilities in Na- to P-like Xe Ions (open access)

Relativistic Many-body Moller-Plesset Perturbation Theory Calculations of the Energy Levels and Transition Probabilities in Na- to P-like Xe Ions

Relativistic multireference many-body perturbation theory calculations have been performed on Xe{sup 43+}-Xe{sup 39+} ions, resulting in energy levels, electric dipole transition probabilities, and level lifetimes. The second-order many-body perturbation theory calculation of energy levels included mass shifts, frequency-dependent Breit correction and Lamb shifts. The calculated transition energies and E1 transition rates are used to present synthetic spectra in the extreme ultraviolet range for some of the Xe ions.
Date: March 27, 2007
Creator: Vilkas, M J; Ishikawa, Y & Trabert, E
Object Type: Article
System: The UNT Digital Library
Assembly and Test of a Support Structure for 3.5 m Long Nb3Sn Racetrack Coils. (open access)

Assembly and Test of a Support Structure for 3.5 m Long Nb3Sn Racetrack Coils.

The LHC Accelerator Research Program (LARP) is currently developing 4 m long Nb{sub 3}Sn quadrupole magnets for a possible upgrade of the LHC Interaction Regions (IR). In order to provide a reliable test bed for the fabrication and test of long Nb{sub 3}Sn coils, LARP has started the development of the long racetrack magnet LRS01. The magnet is composed of two 3.6 m long racetrack coils contained in a support structure based on an aluminum shell pre-tensioned with water-pressurized bladders and interference keys. For the phase-one test of the assembly procedure and loading operation, the structure was pre-stressed at room temperature and cooled down to 77 K with instrumented, solid aluminum 'dummy coils'. Mechanical behavior and stress homogeneity were monitored with strain gauges mounted on the shell and the dummy coils. The dummy coils were replaced with reacted and impregnated Nb{sub 3}Sn coils in a second assembly procedure, followed by cool-down to 4.5 K and powered magnet test. This paper reports on the assembly and loading procedures of the support structure as well as the comparison between strain gauge data and 3D model predictions.
Date: August 27, 2007
Creator: Ferracin, P.; Ambrosio, G.; Anerella, M.; Caspi, S.; Cheng, D. W.; Felice, H. et al.
Object Type: Article
System: The UNT Digital Library
METHODOLOGY AND CALCULATIONS FOR THE ASSIGNMENT OF WASTE GROUPS FOR THE LARGE UNDERGROUND WASTE STORAGE TANKS AT THE HANFORD SITE (open access)

METHODOLOGY AND CALCULATIONS FOR THE ASSIGNMENT OF WASTE GROUPS FOR THE LARGE UNDERGROUND WASTE STORAGE TANKS AT THE HANFORD SITE

This document categorizes each of the large waste storage tanks into one of several categories based on each tank's waste characteristics. These waste group assignments reflect a tank's propensity to retain a significant volume of flammable gases and the potential of the waste to release retained gas by a buoyant displacement event. Revision 7 is the annual update of the calculations of the flammable gas Waste Groups for DSTs and SSTs. The Hanford Site contains 177 large underground radioactive waste storage tanks (28 double-shell tanks and 149 single-shell tanks). These tanks are categorized into one of three waste groups (A, B, and C) based on their waste and tank characteristics. These waste group assignments reflect a tank's propensity to retain a significant volume of flammable gases and the potential of the waste to release retained gas by a buoyant displacement gas release event. Assignments of waste groups to the 177 double-shell tanks and single-shell tanks, as reported in this document, are based on a Monte Carlo analysis of three criteria. The first criterion is the headspace flammable gas concentration following release of retained gas. This criterion determines whether the tank contains sufficient retained gas such that the well-mixed headspace flammable …
Date: December 27, 2007
Creator: Fowler, K. D.
Object Type: Report
System: The UNT Digital Library
Aligned vertical fractures, HTI reservoir symmetry, and Thomsenseismic anisotropy parameters (open access)

Aligned vertical fractures, HTI reservoir symmetry, and Thomsenseismic anisotropy parameters

The Sayers and Kachanov (1991) crack-influence parametersare shown to be directly related to Thomsen (1986) weak-anisotropyseismic parameters for fractured reservoirs when the crack density issmall enough. These results are then applied to seismic wave propagationin reservoirs having HTI symmetry due to aligned vertical fractures. Theapproach suggests a method of inverting for fracture density from wavespeed data.
Date: June 27, 2007
Creator: Berryman, James G.
Object Type: Article
System: The UNT Digital Library
Chapter 8: Selective Stoichiometric and Catalytic Reactivity in the Confines of a Chiral Supramolecular Assembly (open access)

Chapter 8: Selective Stoichiometric and Catalytic Reactivity in the Confines of a Chiral Supramolecular Assembly

Nature uses enzymes to activate otherwise unreactive compounds in remarkable ways. For example, DNases are capable of hydrolyzing phosphate diester bonds in DNA within seconds,[1-3]--a reaction with an estimated half-life of 200 million years without an enzyme.[4] The fundamental features of enzyme catalysis have been much discussed over the last sixty years in an effort to explain the dramatic rate increases and high selectivities of enzymes. As early as 1946, Linus Pauling suggested that enzymes must preferentially recognize and stabilize the transition state over the ground state of a substrate.[5] Despite the intense study of enzymatic selectivity and ability to catalyze chemical reactions, the entire nature of enzyme-based catalysis is still poorly understood. For example, Houk and co-workers recently reported a survey of binding affinities in a wide variety of enzyme-ligand, enzyme-transition-state, and synthetic host-guest complexes and found that the average binding affinities were insufficient to generate many of the rate accelerations observed in biological systems.[6] Therefore, transition-state stabilization cannot be the sole contributor to the high reactivity and selectivity of enzymes, but rather, other forces must contribute to the activation of substrate molecules. Inspired by the efficiency and selectivity of Nature, synthetic chemists have admired the ability of enzymes …
Date: September 27, 2007
Creator: University of California, Berkeley; Laboratory, Lawrence Berkeley National; Raymond, Kenneth; Pluth, Michael D.; Bergman, Robert G. & Raymond, Kenneth N.
Object Type: Book
System: The UNT Digital Library
Modeling Highly Pathogenic Avian Influenza in the US Poultry Industry (open access)

Modeling Highly Pathogenic Avian Influenza in the US Poultry Industry

None
Date: September 27, 2007
Creator: Hullinger, P; Melius, C; Robertson, A & Tammero, L
Object Type: Report
System: The UNT Digital Library
LARP Long Nb3Sn Quadrupole Design. (open access)

LARP Long Nb3Sn Quadrupole Design.

A major milestone for the LHC Accelerator Research Program (LARP) is the test, by the end of 2009, of two 4m-long quadrupole magnets (LQ) wound with Nb{sub 3}Sn conductor. The goal of these magnets is to be a proof of principle that Nb{sub 3}Sn is a viable technology for a possible LHC luminosity upgrade. The design of the LQ is based on the design of the LARP Technological Quadrupoles, presently under development at FNAL and LBNL, with 90-mm aperture and gradient higher than 200 T/m. The design of the first LQ model will be completed by the end of 2007 with the selection of a mechanical design. In this paper we present the coil design addressing some fabrication technology issues, the quench protection study, and three designs of the support structure.
Date: August 27, 2007
Creator: Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S. et al.
Object Type: Article
System: The UNT Digital Library
CANCELLED Microwave Ion Source and Beam Injection for anAccelerator-Driven Neut ron Source (open access)

CANCELLED Microwave Ion Source and Beam Injection for anAccelerator-Driven Neut ron Source

An over-dense microwave driven ion source capable of producing deuterium (or hydrogen) beams at 100-200 mA/cm{sup 2} and with atomic fraction > 90% was designed and tested with an electrostatic low energy beam transport section (LEBT). This ion source was incorporated into the design of an Accelerator Driven Neutron Source (ADNS). The other key components in the ADNS include a 6 MeV RFQ accelerator, a beam bending and scanning system, and a deuterium gas target. In this design a 40 mA D{sup +} beam is produced from a 6 mm diameter aperture using a 60 kV extraction voltage. The LEBT section consists of 5 electrodes arranged to form 2 Einzel lenses that focus the beam into the RFQ entrance. To create the ECR condition, 2 induction coils are used to create {approx} 875 Gauss on axis inside the source chamber. To prevent HV breakdown in the LEBT a magnetic field clamp is necessary to minimize the field in this region. Matching of the microwave power from the waveguide to the plasma is done by an autotuner. They observed significant improvement of the beam quality after installing a boron nitride liner inside the ion source. The measured emittance data are compared …
Date: February 27, 2007
Creator: Vainionpaa, J. H.; Gough, R.; Hoff, M.; Kwan, J. W.; Ludewigt, B. A.; Regis, M. J. et al.
Object Type: Article
System: The UNT Digital Library
Cross sections for short pulse single and double ionization ofhelium (open access)

Cross sections for short pulse single and double ionization ofhelium

In a previous publication, procedures were proposed for unambiguously extracting amplitudes for single and double ionization from a time-dependent wavepacket by effectively propagating for an infinite time following a radiation pulse. Here we demonstrate the accuracy and utility of those methods for describing two-photon single and one-photon double ionization of helium. In particular it is shown how narrow features corresponding to autoionizing states are easily resolved with these methods.
Date: November 27, 2007
Creator: Palacios, Alicia; Rescigno, Thomas N. & McCurdy, C. William
Object Type: Article
System: The UNT Digital Library
Nondestructive Neutron And Gamma-Ray Technologies Applied To GNEP And Safeguards (open access)

Nondestructive Neutron And Gamma-Ray Technologies Applied To GNEP And Safeguards

In recent years, LLNL has developed methods for diagnosing significant quantities of special nuclear material (SNM). Homeland security problems have recently focused our attention on detection of shielded highly enriched uranium (HEU), which is a weak signal problem. Current and advanced safeguards applications will require working in the opposite extreme of strong but buried signals. We will review some of the technologies that have been developed at LLNL for homeland security applications and discuss how they might be used in support of international safeguards.
Date: June 27, 2007
Creator: Dougan, A D; Snyderman, N; Ham, Y; Nakae, L; Dietrich, D; Kerr, P et al.
Object Type: Article
System: The UNT Digital Library
Deterministic processing of alumina with ultra-short laser pulses (open access)

Deterministic processing of alumina with ultra-short laser pulses

Ultrashort pulsed lasers can accurately ablate materials which are refractory, transparent, or are otherwise difficult to machine by other methods. The typical method of machining surfaces with ultrashort laser pulses is by raster scanning, or the machining of sequentially overlapping linear trenches. Experiments in which linear trenches were machined in alumina at various pulse overlaps and incident fluences are presented, and the dependence of groove depth on these parameters established. A model for the machining of trenches based on experimental data in alumina is presented, which predicts and matches observed trench geometry. This model is then used to predict optimal process parameters for the machining of trenches for maximal material removal rate for a given laser.
Date: June 27, 2007
Creator: Furmanski, J; Rubenchik, A M; Shirk, M D & Stuart, B C
Object Type: Article
System: The UNT Digital Library
The Helium Cooling System and Cold Mass Support System for theMICE Coupling Solenoid (open access)

The Helium Cooling System and Cold Mass Support System for theMICE Coupling Solenoid

The MICE cooling channel consists of alternating threeabsorber focus coil module (AFC) and two RF coupling coil module (RFCC)where the process of muon cooling and reacceleration occurs. The RFCCmodule comprises a superconducting coupling solenoid mounted around fourconventional conducting 201.25 MHz closed RF cavities and producing up to2.2T magnetic field on the centerline. The coupling coil magnetic fieldis to produce a low muon beam beta function in order to keep the beamwithin the RF cavities. The magnet is to be built using commercialniobium titanium MRI conductors and cooled by pulse tube coolers thatproduce 1.5 W of cooling capacity at 4.2 K each. A self-centering supportsystem is applied for the coupling magnet cold mass support, which isdesigned to carry a longitudinal force up to 500 kN. This report willdescribe the updated design for the MICE coupling magnet. The cold masssupport system and helium cooling system are discussed indetail.
Date: August 27, 2007
Creator: Wang, L.; Wu, H.; Li, L. K.; Green, M. A.; Liu, C. S.; Li, L. Y. et al.
Object Type: Article
System: The UNT Digital Library
Facility Safety Plan CMS Complexes (open access)

Facility Safety Plan CMS Complexes

None
Date: July 27, 2007
Creator: Cooper, G A
Object Type: Report
System: The UNT Digital Library
FRONT-END ASIC FOR HIGH RESOLUTION X-RAY SPECTROMETERS. (open access)

FRONT-END ASIC FOR HIGH RESOLUTION X-RAY SPECTROMETERS.

We present an application specific integrated circuit (ASIC) for high-resolution x-ray spectrometers. The ASIC is designed to read out signals from a pixelated silicon drift detector (SDD). Each hexagonal pixel has an area of 15 mmz and an anode capacitance of less than 100 fF. There is no integrated Field Effect transistor (FET) in the pixel, rather, the readout is done by wirebonding the anodes to the inputs of the ASIC. The ASIC provides 14 channels of low-noise charge amplification, high-order shaping with baseline stabilization, and peak detection with analog memory. The readout is sparse and based on low voltage differential signaling. An interposer provides all the interconnections required to bias and operate the system. The channel dissipates 1.6 mW. The complete 14-pixel unit covers an area of 210 mm{sup 2}, dissipates 12 mW cm{sup -2}, and can be tiled to cover an arbitrarily large detection area. We measured a preliminary resolution of 172 eV at -35 C on the 6 keV peak of a {sup 55}Fe source.
Date: October 27, 2007
Creator: De Geronimo,G.; Chen, W.; Fried, J.; Li, Z.; Pinelli, D. A.; Rehak, P. et al.
Object Type: Article
System: The UNT Digital Library