CSPAD-140k - A Versatile Detector for LCLS Experiments (open access)

CSPAD-140k - A Versatile Detector for LCLS Experiments

None
Date: November 22, 2013
Creator: Herrmann, Sven; Boutet, Sebastian; Duda, Brian; Fritz, David; Haller, Gunther; Hart, Philip et al.
System: The UNT Digital Library
Composite Inelastic Dark Matter (open access)

Composite Inelastic Dark Matter

None
Date: November 22, 2011
Creator: Alves, Daniele S. M.; Behbahani, Siavosh R.; Schuster, Philip & Wacker, Jay G.
System: The UNT Digital Library
Detector Noise Susceptibility Issues for the Future Generation of High Energy Physics Experiments (open access)

Detector Noise Susceptibility Issues for the Future Generation of High Energy Physics Experiments

The front-end electronics (FEE) noise characterization to electromagnetic interference and the compatibility of the different subsystems are important topics to consider for the LHC calorimeter upgrades. A new power distribution scheme based on switching power converters is under study and will define a noticeable noise source very close to the detector's FEE. Knowledge and experience with both FFE noise and electromagnetic compatibility (EMC) issues from previous detectors are important conditions to guarantee the design goals and the good functionality of the upgraded LHC detectors. This paper shows an overview of the noise susceptibility studies performed in different CMS subdetectors. The impact of different FEE topologies in the final sensitivity to electromagnetic interference of the subsystem is analyzed and design recommendations are presented to increase the EMC of the detectors to the future challenging power distribution topologies.
Date: November 22, 2011
Creator: Arteche, F.; Esteban, C.; Iglesias, M.; Rivetta, C. & Arcega, F. J.
System: The UNT Digital Library
Fusion Technologies for Laser Inertial Fusion Energy (LIFE) (open access)

Fusion Technologies for Laser Inertial Fusion Energy (LIFE)

None
Date: November 22, 2011
Creator: Kramer, K. J.; Latkowski, J. F.; Abbott, R. P.; Anklam, T. P.; Dunne, A. M.; El-Dasher, B. S. et al.
System: The UNT Digital Library
New Manufacturing Method for Paper filler and Fiber Material (open access)

New Manufacturing Method for Paper filler and Fiber Material

The study compares commercial available filler products with a new developed “Hybrid Fiber Filler Composite Material” and how main structural, optical and strength properties are affected by increasing the filler content of at least 5% over commercial values. The study consists of: (i) an overview of paper filler materials used in the paper production process, (ii) discusses the manufacturing technology of lime based filler materials for paper applications, (iii) gives an overview of new emerging paper filler technologies, (iv) discusses a filler evaluation of commercial available digital printing paper products, (v) reports from a detailed handsheet study and 12” pilot plant paper machine trial runs with the new Hybrid Fiber Filler Composite Material, and (vi) evaluates and compares commercial filler products and the new Hybrid Fiber Filler Composite Material with a life cycle analyses that explains manufacturing, economic and environmental benefits as they are applied to uncoated digital printing papers.
Date: November 22, 2011
Creator: Doelle, Klaus
System: The UNT Digital Library
Precise Measurement of the K - to Pi -E E- Decay (open access)

Precise Measurement of the K - to Pi -E E- Decay

A sample of 7253 K{sup {+-}} {yields} {pi}{sup {+-}}e{sup +}e{sup -}({gamma}) decay candidates with 1.0% background contamination has been collected by the NA 48/2 experiment at the CERN SPS, which allowed a precise measurement of the decay properties. The branching ratio in the full kinematic range was measured to be BR = (3.11 {+-} 0.12) x 10{sup -7}, where the uncertainty includes also the model dependence. The shape of the form factor W(z), where z = (M{sub ee}/M{sub K}){sup 2}, was parameterized according to several models, and, in particular, the slope {delta} of the linear form factor W(z) = W{sub 0}(1 + {delta}z) was determined to be {delta} = 2.32 {+-} 0.18. A possible CP violating asymmetry of K{sup +} and K{sup -} decay widths was investigated, and a conservative upper limit of 2.1 x 10{sup -2} at 90% CL was established.
Date: November 22, 2011
Creator: Batley, J. R.; Culling, A. J.; Kalmus, G.; Lazzeroni, C.; Munday, D. J.; Slater, M. W. et al.
System: The UNT Digital Library
The SuperB Accelerator: Overview and Lattice Studies (open access)

The SuperB Accelerator: Overview and Lattice Studies

SuperB aims at the construction of a very high luminosity (10{sup 36} cm{sup -2} s{sup -1}) asymmetric e{sup +}e{sup -} Flavour Factory, with possible location at the campus of the University of Rome Tor Vergata, near the INFN Frascati National Laboratory. In this paper the basic principles of the design and details on the lattice are given. SuperB is a new machine that can exploit novel very promising design approaches: (1) large Piwinski angle scheme will allow for peak luminosity of the order of 10{sup 36} cm{sup -2} s{sup -1}, well beyond the current state-of-the-art, without a significant increase in beam currents or shorter bunch lengths; (2) 'crab waist' sextupoles will be used for suppression of dangerous resonances; (3) the low beam currents design presents reduced detector and background problems, and affordable operating costs; (4) a polarized electron beam can produce polarized {tau} leptons, opening an entirely new realm of exploration in lepton flavor physics. SuperB studies are already proving useful to the accelerator and particle physics communities. The principle of operation is being tested at DAFNE. The baseline lattice, based on the reuse of all PEP-II hardware, fits in the Tor Vergata University campus site, near Frascati. A CDR …
Date: November 22, 2011
Creator: Biagini, M.E.; Boni, R.; Boscolo, M.; Drago, A.; Guiducci, S.; Preger, M. et al.
System: The UNT Digital Library
Testing Event Discrimination over Broad Regions using the Historical Borovoye Observatory Explosion Dataset (open access)

Testing Event Discrimination over Broad Regions using the Historical Borovoye Observatory Explosion Dataset

None
Date: November 22, 2011
Creator: Pasyanos, M E; Ford, S R & Walter, W R
System: The UNT Digital Library
X-Band Crab Cavities for the CLIC Beam Delivery System (open access)

X-Band Crab Cavities for the CLIC Beam Delivery System

The CLIC machine incorporates a 20 mrad crossing angle at the IP to aid the extraction of spent beams. In order to recover the luminosity lost through the crossing angle a crab cavity is proposed to rotate the bunches prior to collision. The crab cavity is chosen to have the same frequency as the main linac (11.9942 GHz) as a compromise between size, phase stability requirements and beam loading. It is proposed to use a HE11 mode travelling wave structure as the CLIC crab cavity in order to minimise beam loading and mode separation. The position of the crab cavity close to the final focus enhances the effect of transverse wake-fields so effective wake-field damping is required. A damped detuned structure is proposed to suppress and de-cohere the wake-field hence reducing their effect. Design considerations for the CLIC crab cavity will be discussed as well as the proposed high power testing of these structures at SLAC. Design of a crab cavity for CLIC is underway at the Cockcroft Institute in collaboration with SLAC. This effort draws on a large degree of synergy with the ILC crab cavity developed at the Cockcroft Institute and other deflecting structure development at SLAC. A …
Date: November 22, 2011
Creator: Burt, G.; Ambattu, P. K.; Dexter, A. C.; Abram, T.; Dolgashev, V.; Tantawi, S. et al.
System: The UNT Digital Library
Analysis of the National Ignition Facility Ignition Hohlraum Energetics Experiments (open access)

Analysis of the National Ignition Facility Ignition Hohlraum Energetics Experiments

A series of forty experiments on the National Ignition Facility (NIF) [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)] to study energy balance and implosion symmetry in reduced- and full-scale ignition hohlraums was shot at energies up to 1.3 MJ. This paper reports the findings of the analysis of the ensemble of experimental data obtained that has produced an improved model for simulating ignition hohlraums. Last year the first observation in a NIF hohlraum of energy transfer between cones of beams as a function of wavelength shift between those cones was reported [P. Michel, et al, Phys of Plasmas, 17, 056305, (2010)]. Detailed analysis of hohlraum wall emission as measured through the laser entrance hole (LEH) has allowed the amount of energy transferred versus wavelength shift to be quantified. The change in outer beam brightness is found to be quantitatively consistent with LASNEX [G. B. Zimmerman and W. L. Kruer, Comments Plasma Phys. Control. Fusion 2, 51 (1975)] simulations using the predicted energy transfer when possible saturation of the plasma wave mediating the transfer is included. The effect of the predicted energy transfer on implosion symmetry is also found to be in good agreement with gated x-ray framing …
Date: November 22, 2010
Creator: Town, R. J.; Rosen, M. D.; Michel, P. A.; Divol, L.; Moody, J. D.; Kyrala, G. A. et al.
System: The UNT Digital Library
SPECTRAL AMPLITUDE AND PHASE EVOLUTION IN PETAWATT LASER PULSES (open access)

SPECTRAL AMPLITUDE AND PHASE EVOLUTION IN PETAWATT LASER PULSES

The influence of the active gain medium on the spectral amplitude and phase of amplified pulses in a CPA system is studied. Results from a 10-PW example based on Nd-doped mixed glasses are presented. In conclusion, this study shows that, by using spectral shaping and gain saturation in a mixed-glass amplifier, it is possible to produce 124 fs, 1.4 kJ laser pulses. One detrimental effect, the pulse distortion due to resonant amplification medium, has been investigated and its magnitude as well as its compensation calculated.
Date: November 22, 2010
Creator: Filip, C V
System: The UNT Digital Library
Modeling diffusion of electrical appliances in the residential sector (open access)

Modeling diffusion of electrical appliances in the residential sector

This paper presents a methodology for modeling residential appliance uptake as a function of root macroeconomic drivers. The analysis concentrates on four major energy end uses in the residential sector: refrigerators, washing machines, televisions and air conditioners. The model employs linear regression analysis to parameterize appliance ownership in terms of household income, urbanization and electrification rates according to a standard binary choice (logistic) function. The underlying household appliance ownership data are gathered from a variety of sources including energy consumption and more general standard of living surveys. These data span a wide range of countries, including many developing countries for which appliance ownership is currently low, but likely to grow significantly over the next decades as a result of economic development. The result is a 'global' parameterization of appliance ownership rates as a function of widely available macroeconomic variables for the four appliances studied, which provides a reliable basis for interpolation where data are not available, and forecasting of ownership rates on a global scale. The main value of this method is to form the foundation of bottom-up energy demand forecasts, project energy-related greenhouse gas emissions, and allow for the construction of detailed emissions mitigation scenarios.
Date: November 22, 2009
Creator: McNeil, Michael A. & Letschert, Virginie E.
System: The UNT Digital Library
Real-time X-ray Diffraction Measurements of Shocked Polycrystalline Tin and Aluminum (open access)

Real-time X-ray Diffraction Measurements of Shocked Polycrystalline Tin and Aluminum

A new, fast, single-pulse x-ray diffraction (XRD) diagnostic for determining phase transitions in shocked polycrystalline materials has been developed. The diagnostic consists of a 37-stage Marx bank high-voltage pulse generator coupled to a needle-and-washer electron beam diode via coaxial cable, producing line and bremsstrahlung x-ray emission in a 35-ns pulse. The characteristic Kα lines from the selected anodes of silver and molybdenum are used to produce the diffraction patterns, with thin foil filters employed to remove the characteristic Kβ line emission. The x-ray beam passes through a pinhole collimator and is incident on the sample with an approximately 3-mm by 6-mm spot and 1° full-width-half-maximum (FWHM) angular divergence in a Bragg-reflecting geometry. For the experiments described in this report, the angle between the incident beam and the sample surface was 8.5°. A Debye-Scherrer diffraction image was produced on a phosphor located 76 mm from the polycrystalline sample surface. The phosphor image was coupled to a charge-coupled device (CCD) camera through a coherent fiberoptic bundle. Dynamic single-pulse XRD experiments were conducted with thin foil samples of tin, shock loaded with a 1-mm vitreous carbon back window. Detasheet high explosive with a 2-mm-thick aluminum buffer was used to shock the sample. Analysis …
Date: November 22, 2008
Creator: Dane V. Morgan, Don Macy, Gerald Stevens
System: The UNT Digital Library
ALE3D Simulation and Measurement of Violence in a Fast Cookoff Experiment with LX-10 (open access)

ALE3D Simulation and Measurement of Violence in a Fast Cookoff Experiment with LX-10

We performed a computational and experimental analysis of fast cookoff of LX-10 (94.7% HMX, 5.3% Viton A) confined in a 2 kbar steel tube with reinforced end caps. A Scaled-Thermal-Explosion-eXperiment (STEX) was completed in which three radiant heaters were used to heat the vessel until ignition, resulting in a moderately violent explosion after 20.4 minutes. Thermocouple measurements showed tube temperatures as high as 340 C at ignition and LX-10 surface temperatures as high as 279 C, which is near the melting point of HMX. Three micro-power radar systems were used to measure mean fragment velocities of 840 m/s. Photonics Doppler Velocimeters (PDVs) showed a rapid acceleration of fragments over 80 {micro}s. A one-dimensional ALE3D cookoff model at the vessel midplane was used to simulate the heating, thermal expansion, LX-10 decomposition composition, and closing of the gap between the HE (High Explosive) and vessel wall. Although the ALE3D simulation terminated before ignition, the model provided a good representation of heat transfer through the case and across the dynamic gap to the explosive.
Date: November 22, 2006
Creator: McClelland, M. A.; Maienschein, J. L.; Howard, W. M. & Dehaven, M. R.
System: The UNT Digital Library
cctbx news (open access)

cctbx news

The 'Computational Crystallography Toolbox' (cctbx, http://cctbx.sourceforge.net/) is the open-source component of the Phenix project (http://www.phenix-online.org/). Most recent cctbx developments are geared towards supporting new features of the phenix.refine application. Thus, the open-source mmtbx (macromolecular toolbox) module is currently being most rapidly developed. In this article we give an overview of some of the recent developments. However, the main theme of this article is the presentation of a light-weight example command-line application that was specifically developed for this newsletter: sequence alignment and superposition of two molecules read from files in PDB format. This involves parameter input based on the Phil module presented in Newsletter No. 5, fast reading of the PDB files with the new iotbx.pdb.input class, simple sequence alignment using the new mmtbx.alignment module, and use of the Kearsley (1989) superposition algorithm to find the least-squares solution for superposing C-alpha positions. The major steps are introduced individually, followed by a presentation of the complete application. The example application is deliberately limited in functionality to make it concise enough for this article. The main goal is to show how the open-source components are typically combined into an application. Even though the example is quite specific to macromolecular crystallography, we believe it …
Date: November 22, 2006
Creator: Grosse-Kunstleve, Ralf W.; Zwart, Peter H.; Afonine, Pavel V.; Ioerger, Thomas R. & Adams, Paul D.
System: The UNT Digital Library
Photo-oxidation of Ge Nanocrystals: Kinetic Measurements by InSitu Raman Spectroscopy (open access)

Photo-oxidation of Ge Nanocrystals: Kinetic Measurements by InSitu Raman Spectroscopy

Ge nanocrystals are formed in silica by ion beam synthesis and are subsequently exposed by selective HF etching of the silica. Under ambient conditions, the exposed nanocrystals are stable after formation of a protective native oxide shell of no more than a few monolayers. However, under visible laser illumination at room temperature and in the presence of O{sub 2}, the nanocrystals rapidly oxidize. The oxidation rate was monitored by measuring the Raman spectra of the Ge nanocrystals in-situ. The intensity ratio of the anti-Stokes to the Stokes line indicated that no significant laser-induced heating of illuminated nanocrystals occurs. Therefore, the oxidation reaction rate enhancement is due to a photo-chemical process. The oxidation rate varies nearly linearly with the logarithm of the laser intensity, and at constant laser intensity the rate increases with increasing photon energy. These kinetic measurements, along with the power dependencies, are described quantitatively by an electron active oxidation mechanism involving tunneling of optically excited electrons through the forming oxide skin and subsequent transport of oxygen ions to the Ge nanocrystal surface.
Date: November 22, 2006
Creator: Sharp, I. D.; Xu, Q.; Yuan, C. W.; Beeman, J. W.; Ager, J. W., III; Chrzan, D. C. et al.
System: The UNT Digital Library
Revisiting the Cape Cod Bacteria Injection Experiment Using a Stochastic Modeling Approach (open access)

Revisiting the Cape Cod Bacteria Injection Experiment Using a Stochastic Modeling Approach

Bromide and resting-cell bacteria tracer tests carried out in a sand and gravel aquifer at the USGS Cape Cod site in 1987 were reinterpreted using a three-dimensional stochastic approach and Lagrangian particle tracking numerical methods. Bacteria transport was strongly coupled to colloid filtration through functional dependence of local-scale colloid transport parameters on hydraulic conductivity and seepage velocity in a stochastic advection-dispersion/attachment-detachment model. Information on geostatistical characterization of the hydraulic conductivity (K) field from a nearby plot was utilized as input that was unavailable when the original analysis was carried out. A finite difference model for groundwater flow and a particle-tracking model of conservative solute transport was calibrated to the bromide-tracer breakthrough data using the aforementioned geostatistical parameters. An optimization routine was utilized to adjust the mean and variance of the lnK field over 100 realizations such that a best fit of a simulated, average bromide breakthrough curve is achieved. Once the optimal bromide fit was accomplished (based on adjusting the lnK statistical parameters in unconditional simulations), a stochastic particle-tracking model for the bacteria was run without adjustments to the local-scale colloid transport parameters. Good predictions of the mean bacteria breakthrough data were achieved using several approaches for modeling components of …
Date: November 22, 2006
Creator: Maxwell, R M; Welty, C & Harvey, R W
System: The UNT Digital Library
Development of an Improved Sodium Titanate for the Pretreatment of High Level Nuclear Waste at the Savannah River Site (open access)

Development of an Improved Sodium Titanate for the Pretreatment of High Level Nuclear Waste at the Savannah River Site

High-level nuclear waste produced from fuel reprocessing operations at the Savannah River Site (SRS) requires pretreatment to remove {sup 137}Cs, {sup 90}Sr and alpha-emitting radionuclides (i.e., actinides) prior to disposal onsite as low level waste. Separation processes planned at SRS include caustic side solvent extraction, for {sup 137}Cs removal, and sorption of {sup 90}Sr and alpha-emitting radionuclides onto monosodium titanate (MST). The predominant alpha-emitting radionuclides in the highly alkaline waste solutions include plutonium isotopes {sup 238}Pu, {sup 239}Pu and {sup 240}Pu. This paper describes recent results to produce an improved sodium titanate material that exhibits increased removal kinetics and capacity for {sup 90}Sr and alpha-emitting radionuclides compared to the baseline MST material.
Date: November 22, 2005
Creator: Hobbs D. T.; Poirier, M. R.; Barnes, M. J.; Stallings, M. E. & Nyman, M. D.
System: The UNT Digital Library
Implementation of Localized Corrosion in the Performance Assessment Model for Yucca Mountain (open access)

Implementation of Localized Corrosion in the Performance Assessment Model for Yucca Mountain

None
Date: November 22, 2005
Creator: JAIN V - BSC, SEVOUGIAN DS - SNL , MATTIE PD - SNL , MON KG - ANP , MACKINNON RJ - SNL
System: The UNT Digital Library
Last Annotation of Fugu rubripes at JGI (open access)

Last Annotation of Fugu rubripes at JGI

None
Date: November 22, 2005
Creator: Salamov, Asaf; Terry, Astrid; Putnam, Nicholas; Rokhsar, Dan; Grigoriev, Igor; Eddie, Loh et al.
System: The UNT Digital Library
SPENT NUCLEAR FUEL: RESEARCH NEEDS (open access)

SPENT NUCLEAR FUEL: RESEARCH NEEDS

None
Date: November 22, 2005
Creator: Ewing, R. and Peters, M.
System: The UNT Digital Library
SYNTHESIS OF ORGANICALLY TEMPLATED NANOPOROUS TIN (II/IV) PHOSPHATE FOR RADIONUCLIDE AND METAL SEQUESTRATION (open access)

SYNTHESIS OF ORGANICALLY TEMPLATED NANOPOROUS TIN (II/IV) PHOSPHATE FOR RADIONUCLIDE AND METAL SEQUESTRATION

Nanoporous tin (II/IV) phosphate materials, with spherical morphology, have been synthesized using cetyltrimethylammonium chloride (CH{sub 3}(CH{sub 2}){sub 16}N(CH{sub 3}){sub 5}Cl) as the surfactant. The structure of the material is stable at 500 C; however, partial oxidation of the material occurs with redox conversion of Sn{sup 2+} to SN{sup 4+}, resulting in a mixed Sn(II)/Sn(IV) material.
Date: November 22, 2005
Creator: WELLMAN DM, MATTIGOD SV, PARKER KE, HEALD SM , WANG C, FRYXELL GE
System: The UNT Digital Library
Transmutation analysis of realistic low-activation steels for magnetic fusion reactors and IFMIF (open access)

Transmutation analysis of realistic low-activation steels for magnetic fusion reactors and IFMIF

A comprehensive transmutation study for steels considered in the selection of structural materials for magnetic and inertial fusion reactors has been performed in the IFMIF neutron irradiation scenario, as well as in the ITER and DEMO ones for comparison purposes. An element-by-element transmutation approach is used in the study, addressing the generation of: (1) H and He and (2) solid transmutants. The IEAF-2001 activation library and the activation code ACAB were applied to the IFMIF transmutation analysis, after proving the applicability of ACAB for transmutation calculations of this kind of intermediate energy systems.
Date: November 22, 2005
Creator: Cabellos, O; Sanz, J; Garc?a-Herranz, N; D?az, S; Reyes, S & Piedloup, S
System: The UNT Digital Library
Broadband THz response of a resonantly excited high-densityexciton gas (open access)

Broadband THz response of a resonantly excited high-densityexciton gas

The density-driven crossover of electron-hole pairs frominsulating to conducting states is observed via the internal 1s-2pexciton resonance. Decreasing interparticle distance induces strongshifts and broadening, and ultimately the disappearance of the excitonicresonance.
Date: November 22, 2004
Creator: Huber, Rupert; Kaindl, Robert A.; Schmid, Benjamin A. & Chemla,Daniel S.
System: The UNT Digital Library