26 Matching Results

This system will be undergoing maintenance April 18th between 9:00AM and 12:00PM CDT.

Search Results

Results: 1 - 24 next
open access

Studies of Nucleon Form Factors with 12 GeV CEBAF and SuperBigBite

Description: The elastic electromagnetic form factors are among the most fundamental quantities that describe the ground-state structure of the proton and neutron. Precision data of the form factors over a wide kinematical range provide a powerful test of current theories of hadron structure. A number of experiments aiming to measure the electric and magnetic elastic form factors of the neutron, G{sub E}{sup n} and G{sub M}{sup n}, and proton, G{sub E}{sup p}, at very high momentum transfer, up to the range… more
Date: April 1, 2012
Creator: Hansen, Jens-Ole
Partner: UNT Libraries Government Documents Department
open access

ADMINISTRATIVE AND ENGINEERING CONTROLS FOR THE OPERATION OF VENTILATION SYSTEMS FOR UNDERGROUND RADIOACTIVE WASTE STORAGE TANKS

Description: Liquid radioactive wastes from the Savannah River Site are stored in large underground carbon steel tanks. The majority of the waste is confined in double shell tanks, which have a primary shell, where the waste is stored, and a secondary shell, which creates an annular region between the two shells, that provides secondary containment and leak detection capabilities should leakage from the primary shell occur. Each of the DST is equipped with a purge ventilation system for the interior of the … more
Date: November 13, 2013
Creator: Wiersma, B. & Hansen, A.
Partner: UNT Libraries Government Documents Department
open access

Plate Fin Heat Exchanger Model with Axial Conduction and Variable Properties

Description: Future superconducting radio frequency (SRF) cavities, as part of Project X at Fermilab, will be cooled to superfluid helium temperatures by a cryogenic distribution system supplying cold supercritical helium. To reduce vapor fraction during the final Joule-Thomson (J-T) expansion into the superfluid helium cooling bath, counter-flow, plate-fin heat exchangers will be utilized. Due to their compact size and ease of fabrication, plate-fin heat exchangers are an effective option. However, the des… more
Date: June 10, 2011
Creator: Hansen, B. J.; White, M. J. & Klebaner, A.
Partner: UNT Libraries Government Documents Department
open access

Fabrication of 3D Silicon Sensors

Description: Silicon sensors with a three-dimensional (3-D) architecture, in which the n and p electrodes penetrate through the entire substrate, have many advantages over planar silicon sensors including radiation hardness, fast time response, active edge and dual readout capabilities. The fabrication of 3D sensors is however rather complex. In recent years, there have been worldwide activities on 3D fabrication. SINTEF in collaboration with Stanford Nanofabrication Facility have successfully fabricated th… more
Date: June 6, 2012
Creator: Kok, A.; Hansen, T. E.; Hansen, T. A.; Lietaer, N.; Summanwar, A.; Kenney, C. et al.
Partner: UNT Libraries Government Documents Department
open access

Detector design for high-resolution MeV photon imaging of cargo containers using spectral information

Description: Monte Carlo simulations of a pixelated detector array of inorganic scintillators for high spatial resolution imaging of 1-9 MeV photons are presented. The results suggest that a detector array of 0.5 cm x 0.5 cm x 5 cm pixels of bismuth germanate may provide sufficient efficiency and spatial resolution to permit imaging of an object with uncertainties in dimension of several mm. The cross talk between pixels is found to be in the range of a few percent when pixels are shielded by {approx} 1mm o… more
Date: February 1, 2010
Creator: Descalle, M A; Vetter, K; Hansen, A; Daniels, J & Prussin, S G
Partner: UNT Libraries Government Documents Department
open access

Design, Simulation, Fabrication, and Preliminary Tests of 3D CMS Pixel Detectors for the Super-LHC

Description: The Super-LHC upgrade puts strong demands on the radiation hardness of the innermost tracking detectors of the CMS, which cannot be fulfilled with any conventional planar detector design. The so-called 3D detector architectures, which feature columnar electrodes passing through the substrate thickness, are under investigation as a potential solution for the closest operation points to the beams, where the radiation fluence is estimated to reach 10{sup 16} n{sub eq}/cm{sup 2}. Two different 3D d… more
Date: January 1, 2010
Creator: Koybasi, Ozhan; Bortoletto, Daniela; Hansen, Thor-Erik; Kok, Angela; Hansen, Trond Andreas; Lietaer, Nicolas et al.
Partner: UNT Libraries Government Documents Department
open access

A VUV Photoionization Study of the Combustion-Relevant Reaction of the Phenyl Radical (C6H5) with Propylene (C3H6) in a High Temperature Chemical Reactor

Description: We studied the reaction of phenyl radicals (C6H5) with propylene (C3H6) exploiting a high temperature chemical reactor under combustion-like conditions (300 Torr, 1,200-1,500 K). The reaction products were probed in a supersonic beam by utilizing tunable vacuum ultraviolet (VUV) radiation from the Advanced Light Source and recording the photoionization efficiency (PIE) curves at mass-to-charge ratios of m/z = 118 (C9H10+) and m/z = 104 (C8H8+). Our results suggest that the methyl and atomic hyd… more
Date: February 22, 2012
Creator: Manoa, University of Hawaii at; Laboratories, Sandia National; Zhang, Fangtong; Kaiser, Ralf I.; Golan, Amir; Ahmed, Musahid et al.
Partner: UNT Libraries Government Documents Department
open access

Post-Shot Radiation Environment Following Low-Yield Shots Inside the National Ignition Facility

Description: A detailed model of the Target Bay (TB) at the National Ignition Facility (NIF) has been developed to estimate the post-shot radiation environment inside the facility. The model includes large number of structures and diagnostic instruments present inside the TB. These structures and instruments are activated by the few nanosecond pulse of neutrons generated during a shot and the resultant gamma dose rates are estimated at various decay times following the shot. The results presented in this pa… more
Date: October 29, 2010
Creator: Sitaraman, S.; Brereton, S.; Dauffy, L.; Hall, J.; Hansen, L.; Khater, H. et al.
Partner: UNT Libraries Government Documents Department
open access

Offshore Code Comparison Collaboration within IEA Wind Task 23: Phase IV Results Regarding Floating Wind Turbine Modeling; Preprint

Description: Offshore wind turbines are designed and analyzed using comprehensive simulation codes that account for the coupled dynamics of the wind inflow, aerodynamics, elasticity, and controls of the turbine, along with the incident waves, sea current, hydrodynamics, and foundation dynamics of the support structure. This paper describes the latest findings of the code-to-code verification activities of the Offshore Code Comparison Collaboration, which operates under Subtask 2 of the International Energy … more
Date: April 1, 2010
Creator: Jonkman, J.; Larsen, T.; Hansen, A.; Nygaard, T.; Maus, K.; Karimirad, M. et al.
Partner: UNT Libraries Government Documents Department
open access

SRF cavity testing status and operating experience

Description: No Description Available.
Date: June 1, 2011
Creator: Soyars, W.; Bossert, R.; Darvde, C.; DeGraff, B.; Dalesandro, A.; Hansen, B. et al.
Partner: UNT Libraries Government Documents Department
open access

Planning Tools for Estimating Radiation Exposure at the National Ignition Facility

Description: A set of computational tools was developed to help estimate and minimize potential radiation exposure to workers from material activation in the National Ignition Facility (NIF). AAMI (Automated ALARA-MCNP Interface) provides an efficient, automated mechanism to perform the series of calculations required to create dose rate maps for the entire facility with minimal manual user input. NEET (NIF Exposure Estimation Tool) is a web application that combines the information computed by AAMI with a … more
Date: October 22, 2010
Creator: Verbeke, J.; Young, M.; Brereton, S.; Dauffy, L.; Hall, J.; Hansen, L. et al.
Partner: UNT Libraries Government Documents Department
open access

A new method to generate dust with astrophysical properties

Description: In interstellar and interplanetary space, the size distribution and composition of dust grains play an important role. For example, dust grains determine optical and ultraviolet extinction levels in astronomical observations, dominate the cooling rate of our Galaxy, and sets the thermal balance and radiative cooling rates in molecular clouds, which are the birth place of stars. Dust grains are also a source of damage and failure to space hardware and thus present a hazard to space flight. To mo… more
Date: April 21, 2010
Creator: Hansen, J. F.; van Breugel, W.; Bringa, E. M.; Graham, G. A.; Remington, B. A.; Taylor, E. A. et al.
Partner: UNT Libraries Government Documents Department
open access

The Mars Hopper: a radioisotope powered, impulse driven, long-range, long-lived mobile platform for exploration of Mars

Description: Planetary exploration mission requirements are becoming more demanding. Due to the increasing cost, the missions that provide mobile platforms that can acquire data at multiple locations are becoming more attractive. Wheeled vehicles such as the MER rovers have proven extremely capable but have very limited range and cannot traverse rugged terrain. Flying vehicles such as balloons and airplanes have been proposed but are problematic due to the very thin atmospheric pressure and the strong, dust… more
Date: February 1, 2011
Creator: Howe, Steven D.; O'Brien, Robert C.; Taitano, William; Crawford, Doug; Jerred, Nathan; Cooley, Spencer et al.
Partner: UNT Libraries Government Documents Department
open access

Robust Optical Richness Estimation with Reduced Scatter

Description: Reducing the scatter between cluster mass and optical richness is a key goal for cluster cosmology from photometric catalogs. We consider various modifications to the red-sequence matched filter richness estimator of Rozo et al. (2009b), and evaluate their impact on the scatter in X-ray luminosity at fixed richness. Most significantly, we find that deeper luminosity cuts can reduce the recovered scatter, finding that {sigma}{sub ln L{sub X}|{lambda}} = 0.63 {+-} 0.02 for clusters with M{sub 500… more
Date: June 7, 2012
Creator: Rykoff, E. S.; Koester, B. P.; Rozo, E.; Annis, J.; Evrard, A. E.; Hansen, S. M. et al.
Partner: UNT Libraries Government Documents Department
open access

The Cold Dark Matter Search test stand warm electronics card

Description: A card which does the signal processing for four SQUID amplifiers and two charge sensitive channels is described. The card performs the same functions as is presently done with two custom 9U x 280mm Eurocard modules, a commercial multi-channel VME digitizer, a PCI to GPIB interface, a PCI to VME interface and a custom built linear power supply. By integrating these functions onto a single card and using the power over Ethernet standard, the infrastructure requirements for instrumenting a Cold D… more
Date: November 1, 2010
Creator: Hines, Bruce; /Colorado U., Denver; Hansen, Sten; /Fermilab; Huber, Martin; /Colorado U., Denver et al.
Partner: UNT Libraries Government Documents Department
open access

Summary for Policy Makers: Intergovernmental Panel on Climate Change Special Report Renewable Energy Sources (SRREN)

Description: The Working Group III Special Report on Renewable Energy Sources and Climate Change Mitigation (SRREN) presents an assessment of the literature on the scientific, technological, environmental, economic and social aspects of the contribution of six renewable energy (RE) sources to the mitigation of climate change. It is intended to provide policy relevant information to governments, intergovernmental processes and other interested parties. This Summary for Policymakers provides an overview of th… more
Date: May 8, 2011
Creator: Arvizu, Dan; Bruckner, Thomas; Christensen, John; Devernay, Jean-Michel; Faaij , Andre; Fischedick, Manfred et al.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen