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The Development of the Undulator Controls Module at the Linac Coherent Light Source
The Linac Coherent Light Source, LCLS, at the SLAC National Accelerator Laboratory, SNAL, is the first hard x-ray Free Electron Laser. The Undulator Controls Module, UCM, controls five cams and two translation stages that regulate the position of each of the 33 permanent undulator magnet segments within 10 microns. The UCM package, hardware and software, was designed and built by the Advanced Photon Source at Argonne. Important lessons were learned throughout the collaborative design, installation, testing, and commissioning periods that could be invaluable to future similar controls projects.
Date:
December 11, 2009
Creator:
Alarcon, A. D.
Object Type:
Article
System:
The UNT Digital Library
Timpson & Tenaha News (Timpson, Tex.), Vol. 18, No. 48, Ed. 1 Thursday, December 11, 2003
Weekly newspaper from Timpson, Texas that includes local, state, and national news along with advertising.
Date:
December 11, 2003
Creator:
Alexander, Nancy
Object Type:
Newspaper
System:
The Portal to Texas History
Timpson & Tenaha News (Timpson, Tex.), Vol. 26, No. 50, Ed. 1 Thursday, December 11, 2008
Weekly newspaper from Timpson, Texas that includes local, state, and national news along with advertising.
Date:
December 11, 2008
Creator:
Alexander, Nancy
Object Type:
Newspaper
System:
The Portal to Texas History
Mechanical properties of 20% cold-worked 316 stainless steel irradiated at low dose rate.
To assess the effects of long-term, low-dose-rate neutron exposure on mechanical strength and ductility, tensile properties were measured on irradiated 20% cold-worked Type 316 stainless steel. Samples were prepared from reactor core components retrieved from the EBR-II reactor following final shutdown. Sample locations were chosen to cover a dose range of 1-47 dpa at temperatures from 371-385 C and dose rates from 0.8-2.8 x 10{sup -7} dpa/s. These dose rates are about one order of magnitude lower than those of typical EBR-II in-core experiments. Irradiation caused hardening, with the yield strength (YS) following approximately the same trend as the ultimate tensile strength (UTS). At higher dose, the difference between the UTS and YS decreases, suggesting the work-hardening capability of the material is decreasing with increasing dose. Both the uniform elongation and total elongation decrease up to the largest dose. Unlike the strength data, the ductility reduction showed no signs of saturated at 20 dpa. While the material retained respectable ductility at 20 dpa, the uniform and total elongation decreased to <1 and <3%, respectively, at 47 dpa. Fracture in the 30 dpa specimen is mainly ductile but with local regions of mixed-mode failure, consisting of dimples and microvoids. The fracture …
Date:
December 11, 2001
Creator:
Allen, T. R.; Tsai, H.; Cole, J. I.; Ohta, J.; Dohi, K. & Kusanagi, H.
Object Type:
Article
System:
The UNT Digital Library
Global paths of time-periodic solutions of the Benjamin-Ono equation connecting arbitrary traveling waves
We classify all bifurcations from traveling waves to non-trivial time-periodic solutions of the Benjamin-Ono equation that are predicted by linearization. We use a spectrally accurate numerical continuation method to study several paths of non-trivial solutions beyond the realm of linear theory. These paths are found to either re-connect with a different traveling wave or to blow up. In the latter case, as the bifurcation parameter approaches a critical value, the amplitude of the initial condition grows without bound and the period approaches zero. We propose a conjecture that gives the mapping from one bifurcation to its counterpart on the other side of the path of non-trivial solutions. By experimentation with data fitting, we identify the form of the exact solutions on the path connecting two traveling waves, which represents the Fourier coefficients of the solution as power sums of a finite number of particle positions whose elementary symmetric functions execute simple orbits in the complex plane (circles or epicycles). We then solve a system of algebraic equations to express the unknown constants in the new representation in terms of the mean, a spatial phase, a temporal phase, four integers (enumerating the bifurcation at each end of the path) and one …
Date:
December 11, 2008
Creator:
Ambrose, David M. & Wilkening, Jon
Object Type:
Article
System:
The UNT Digital Library
Perrhenate and Pertechnetate Behavior on Iron and Sulfiur-Bearing Compounds
None
Date:
December 11, 2006
Creator:
Anderson, B. E.
Object Type:
Presentation
System:
The UNT Digital Library
Altus Times (Altus, Okla.), Vol. 105, No. 230, Ed. 1 Thursday, December 11, 2003
Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date:
December 11, 2003
Creator:
Andrews, Mike
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
Review of heavy-quark production at fixed-target experiments
None
Date:
December 11, 2000
Creator:
Appel, Jeffrey A.
Object Type:
Article
System:
The UNT Digital Library
Modular Optical PDV System
A modular optical photon Doppler velocimetry (PDV) detector system has been developed by using readily available optical components with a 20-GHz Miteq optical detector into eight channels of single-wide modules integrated into a 3U rack unit (1U = 1.75 inches) with a common power supply. Optical fibers were precisely trimmed, welded, and timed within each unit. This system has been used to collect dynamic velocity data on various physics experiments. An optical power meter displays the laser input power to the module and optical power at the detector. An adjustable micro-electromechanical system (MEMS) optical attenuator is used to adjust the amount of unshifted light entering the detector. Front panel LEDs show the presence of power to the module. A fully loaded chassis with eight channels consumes 45 watts of power. Each chassis requires 1U spacing above and below for heat management. Modules can be easily replaced.
Date:
December 11, 2008
Creator:
Araceli Rutkowski, David Esquibel
Object Type:
Article
System:
The UNT Digital Library
Search For the Lepton-Flavor Violating Decays Y(3S)->e tau and Y(3S)->mu tau
Charged lepton-flavor violating processes are extremely rare in the Standard Model, but they are predicted to occur in several beyond-the-Standard Model theories, including Supersymmetry or models with leptoquarks or compositeness. We present a search for such processes in a sample of 117 x 10{sup 6} {Upsilon}(3S) decays recorded with the BABAR detector. We place upper limits on the branching fractions BF({Upsilon}(3S) {yields} e{sup {+-}}{tau}{sup {-+}}) < 5.0 x 10{sup -6} and BF({Upsilon}(3S) {yields} {mu}{sup {+-}}{tau}{sup {-+}}) < 4.1 x 10{sup -6} at 90% confidence level. These results are used to place lower limits on the mass scale of beyond-the-Standard Model physics contributing to lepton-flavor violating decays of the {Upsilon}(3S).
Date:
December 11, 2008
Creator:
Aubert, B.
Object Type:
Article
System:
The UNT Digital Library
Determination of Primordial Metallicity and Mixing in the Type IIP Supernova 1993W
We present the results of a large grid of synthetic spectra and compare them to early spectroscopic observations of SN 1993W. This supernova was discovered close to its explosion date and at a recession velocity of 5400 km/s is located in the Hubble flow. We focus here on two early spectra that were obtained approximately 5 and 9 days after explosion. We parameterize the outer supernova envelope as a power-law density profile in homologous expansion. In order to extract information on the value of the parameters a large number of models was required. We show that very early spectra combined with detailed models can provide constraints on the value of the power law index, the ratio of hydrogen to helium in the surface of the progenitor, the progenitor metallicity and the amount of radioactive nickel mixed into the outer envelope of the supernova. The spectral fits reproduce the observed spectra exceedingly well. The spectral results combined with the early photometry predict that the explosion date was 4.7 {+-} 0.7 days before the first spectrum was obtained. The ability to obtain the metallicity from early spectra make SN IIP attractive probes of chemical evolution in the universe and by showing that …
Date:
December 11, 2002
Creator:
Baron, E.; Nugent, Peter E.; Branch, David; Hauschildt, Peter H.; Turatto, M. & Cappellaro, E.
Object Type:
Article
System:
The UNT Digital Library
Experiences from First Top-Off Injection at the Stanford Synchrotron Radiation Light source
As the Stanford Synchrotron Radiation Lightsource (SSRL) of the SLAC National Accelerator Laboratory (SLAC) is moving toward Top-Off injection mode, SLAC's Radiation Protection Department is working with SSRL on minimizing the radiological hazards of this mode. One such hazard is radiation that is created inside the accelerator concrete enclosure by injected beam. Since during Top-Off injection the stoppers that would otherwise isolate the storage ring from the experimental area stay open, the stoppers no longer prevent such radiation from reaching the experimental area. The level of this stray radiation was measured in April 2008 during the first Top-Off injection tests. They revealed radiation dose rates of up to 18 microSv/h (1.8 millirem/h) outside the experimental hutches, significantly higher than our goal of 1 microSv/h (0.1 millirem/h). Non-optimal injection increased the measured dose rates by a factor two. Further tests in 2008 indicated that subsequent improvements by SSRL to the injection system have reduced the dose rates to acceptable levels. This presentation describes the studies performed before the Top-Off tests, the tests themselves and their major results (both under initial conditions and after improvements were implemented), and presents the controls being implemented for full and routine Top-Off injection.
Date:
December 11, 2009
Creator:
Bauer, J. M.; Liu, J. C.; Prinz, A. & Rokni, S. H.
Object Type:
Article
System:
The UNT Digital Library
Waveshifters and Scintillators for Ionizing Radiation Detection
Scintillation and waveshifter materials have been developed for the detection of ionizing radiation in an STTR program between Ludlum Measurements, Inc. and the University of Notre Dame. Several new waveshifter materials have been developed which are comparable in efficiency and faster in fluorescence decay than the standard material Y11 (K27) used in particle physics for several decades. Additionally, new scintillation materials useful for fiber tracking have been developed which have been compared to 3HF. Lastly, work was done on developing liquid scintillators and paint-on scintillators and waveshifters for high radiation environments.
Date:
December 11, 2007
Creator:
Baumgaugh, B.; Bishop, J.; Karmgard, D.; Marchant, J.; McKenna, M.; Ruchti, R. et al.
Object Type:
Report
System:
The UNT Digital Library
National Environmental Education Act of 1990: Overview, Implementation, and Reauthorization Issues
This report presents an overview of the National Environmental Education Act of 1990, discusses appropriations, examines the Environmental Protection Agency's (EPA's) implementation of the act, and analyzes reauthorization issues relevant to legislation introduced in recent Congresses.
Date:
December 11, 2006
Creator:
Bearden, David M.
Object Type:
Report
System:
The UNT Digital Library
Environmental Protection Agency: FY2007 Appropriations Highlights
None
Date:
December 11, 2006
Creator:
Bearden, David M. & Esworthy, Robert
Object Type:
Report
System:
The UNT Digital Library
SUSY Without Prejudice
We begin an exploration of the physics associated with the general CP-conserving MSSM with Minimal Flavor Violation, the pMSSM. The 19 soft SUSY breaking parameters in this scenario are chosen so as to satisfy all existing experimental and theoretical constraints assuming that the WIMP is a thermal relic, i.e., the lightest neutralino. We scan this parameter space twice using both flat and log priors for the soft SUSY breaking mass parameters and compare the results which yield similar conclusions. Detailed constraints from both LEP and the Tevatron searches play a particularly important role in obtaining our final model samples. We find that the pMSSM leads to a much broader set of predictions for the properties of the SUSY partners as well as for a number of experimental observables than those found in any of the conventional SUSY breaking scenarios such as mSUGRA. This set of models can easily lead to atypical expectations for SUSY signals at the LHC.
Date:
December 11, 2008
Creator:
Berger, Carola F.; Gainer, James S.; Hewett, JoAnne L. & Rizzo, Thomas G.
Object Type:
Article
System:
The UNT Digital Library
Dynamic Imaging of Surface Motion with a Stereo Borescope
A new stereo borescope has been investigated that would provide a time-resolved calibrated method of recording the motion and deformation of a three-dimensional (3-D) surface during explosively driven dynamic shock experiments at the Nevada Test Site. In these experiments, geometries would likely prove to be incompatible with conventional direct optical systems. Single line-of-sight borescopes lack adequate depth-of-field for quantitative imaging of the 3-D surface. To improve depth-of-field and provide time resolution, a stereo borescope has been fabricated for use with a nine-frame framing camera. At one end, stereo optics couple light from the dynamic surface into a pair of flexible 1-mm-diameter correlated fiber-optic bundles. At the other end, small-format lenses (~3 mm) interface with the framing camera, which is set up to simultaneously record the separate-perspective views. All nine frames could be recorded in a period as short as 1.8 μs, and spatial resolution is optimized to 11 line-pairs per mm. To achieve pseudo 3-D depth perception, photogrammetric analysis has been demonstrated with commercial software from ADAM technology (Australia). This paper presents the results from time-resolved stereo images of dynamic surfaces collected in a series of high-explosives experiments at the National Security Technologies, LLC, “Boom Box” in Santa Barbara, CA. …
Date:
December 11, 2008
Creator:
Berninger, Michael & Baker, Stuart
Object Type:
Article
System:
The UNT Digital Library
Near Edge X-Ray Absorption Fine Structure Spectroscopy with X-Ray Free-Electron Lasers
We demonstrate the feasibility of Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy on solids by means of femtosecond soft x-ray pulses from a free-electron laser (FEL). Our experiments, carried out at the Free-Electron Laser at Hamburg (FLASH), used a special sample geometry, spectrographic energy dispersion, single shot position-sensitive detection and a data normalization procedure that eliminates the severe fluctuations of the incident intensity in space and photon energy. As an example we recorded the {sup 3}D{sub 1} N{sub 4,5}-edge absorption resonance of La{sup 3+}-ions in LaMnO{sub 3}. Our study opens the door for x-ray absorption measurements on future x-ray FEL facilities.
Date:
December 11, 2009
Creator:
Bernstein, D.P.; Acremann, Y.; Scherz, A.; Burkhardt, M.; Stohr, J.; Beye, M. et al.
Object Type:
Article
System:
The UNT Digital Library
Cloture Attempts on Nominations
Cloture is the only means by which the Senate can vote to limit debate on a matter, and thereby overcome a possible filibuster. Until 1949, cloture could not be invoked on nominations, and before 1980 this action was attempted only twice. From 1949 through 2002, cloture was sought on 35 nominations, and invoked on 21. Only three of the 35 nominees were not confirmed; all three were among those on whom the Senate rejected cloture. Except in the 103rd Congress (1993-1994), most of the nominations involved have been judicial. The 103rd and 107th Congress are the only ones in which cloture was sought on more than three nominations.
Date:
December 11, 2002
Creator:
Beth, Richard S.
Object Type:
Report
System:
The UNT Digital Library
Islam: Sunnis and Shiites. December 2006
This report includes a historical background of the Sunni-Shiite split and discusses the differences in religious beliefs and practices between and within each Islamic sect as well as their similarities.
Date:
December 11, 2006
Creator:
Blanchard, Christopher M.
Object Type:
Report
System:
The UNT Digital Library
Electron cloud instabilities in the Proton Storage Ring andSpallation Neutron Source
Electron cloud instabilities in the Los Alamos ProtonStorage Ring (PSR) and those foreseen forthe Oak Ridge SpallationNeutron Source (SNS) are examined theoretically, numerically, andexperimentally.
Date:
December 11, 2002
Creator:
Blaskiewicz, M.; Furman, M. A.; Pivi, M. & Macek, R. J.
Object Type:
Article
System:
The UNT Digital Library
Environmental Protection: New Approaches
This report summarizes briefly a number of "new approaches," grouped under the following categories: Information: Approaches to improve the quantity and quality of information to enhance the knowledge base underlying environ- mental decisions (e.g., risk assessment, cost-benefit analysis).Public Sector Processes: Approaches to restructure governmental processes for making environmental decisions (e.g., devolution). Incentives: Approaches that emphasize incentives as opposed to regulatory or financial penalties for achieving environmental ends. Approaches that rely on markets and common law for environmental decisions to the extent possible. Approaches to inculcate environmental values in public or private managerial decisions (e.g., sustainability).
Date:
December 11, 2000
Creator:
Blodgett, John E.
Object Type:
Report
System:
The UNT Digital Library
Revisiting the 'Buy versus Build' Decision for Publicly Owned Utilities in California Considering Wind and Geothermal Resources
The last two decades have seen a dramatic increase in the market share of independent, nonutility generators (NUGs) relative to traditional, utility-owned generation assets. Accordingly, the ''buy versus build'' decision facing utilities--i.e., whether a utility should sign a power purchase agreement (PPA) with a NUG, or develop and own the generation capacity itself--has gained prominence in the industry. Very little of this debate, however, has focused specifically on publicly owned electric utilities, and with few exceptions, renewable sources of supply have received similarly scant attention. Contrary to historical treatment, however, the buy versus build debate is quite relevant to publicly owned utilities and renewables because publicly owned utilities are able to take advantage of some renewable energy incentives only in a ''buy'' situation, while others accrue only in a ''build'' situation. In particular, possible economic advantages of public utility ownership include: (1) the tax-free status of publicly owned utilities and the availability of low-cost debt, and (2) the renewable energy production incentive (REPI) available only to publicly owned utilities. Possible economic advantages to entering into a PPA with a NUG include: (1) the availability of federal tax credits and accelerated depreciation schedules for certain forms of NUG-owned renewable energy, and …
Date:
December 11, 2001
Creator:
Bolinger, Mark; Wiser, Ryan & Golove, William
Object Type:
Article
System:
The UNT Digital Library
Variations on supersymmetry breaking and neutrino spectra
The problem of generating light neutrinos within supersymmetric models is discussed. It is shown that the hierarchy of scales induced by supersymmetry breaking can give rise to suppression factors of the correct order of magnitude to produce experimentally allowed neutrino spectra.
Date:
December 11, 2000
Creator:
Borzumati, F.; Hamaguchi, K.; Nomura, Y. & Yanagida, T.
Object Type:
Article
System:
The UNT Digital Library