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Brighter Screens for Nondestructive Digital X-ray Radiography

Description: Fine resolution, bright X-ray screens are needed for digital radiography and material characterization at the Y-12 National Security Complex (Y-12). Current technology is simply not adequate for transferring high-energy X-ray images to visible light for demanding digital applications. Low energy radiography and especially emerging tomographic technologies are severely hampered for Y-12 nondestructive evaluation (NDE) applications by dim screens with poor resolution. Also, the development of mor… more
Date: September 15, 2003
Creator: Miller, A. C., Jr.; Bell, Z. W. & Carpenter, D. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Cavity Light-Emitting Diode for Durable, High-Brightness and High-Efficiency Lighting Applications: First Budget Period Technical Report

Description: A COLED device consists of a top electrode (anode) and a bottom electrode (cathode) separated by a thin dielectric layer. In this metal/dielectric stack, numerous small wells, or cavities, are etched through the top electrode and the dielectric layer. These cavities are subsequently filled with LEP molecules. When a voltage is applied between the top and bottom electrodes, holes (from the top electrode) and electrons (from the bottom electrode) are injected into the polymer. Light emission is g… more
Date: September 30, 2009
Creator: Shi, Yijian
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Compressive Phase Contrast Tomography

Description: When x-rays penetrate soft matter, their phase changes more rapidly than their amplitude. Interference effects visible with high brightness sources creates higher contrast, edge enhanced images. When the object is piecewise smooth (made of big blocks of a few components), such higher contrast datasets have a sparse solution. We apply basis pursuit solvers to improve SNR, remove ring artifacts, reduce the number of views and radiation dose from phase contrast datasets collected at the Hard X-Ray… more
Date: September 1, 2010
Creator: Maia, Filipe; MacDowell, Alastair; Marchesini, Stefano; Padmore, Howard A.; Parkinson, Dula Y.; Pien, Jack et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Dark Matter Burners: Preliminary Estimate

Description: We show that a star orbiting close enough to an adiabatically grown supermassive black hole can capture a large number of weakly interacting massive particles (WIMPs) during its lifetime. WIMP annihilation energy release in low- to medium-mass stars is comparable with or even exceeds the luminosity of such stars due to thermonuclear burning. The excessive energy release in the stellar core may result in an evolution scenario different from what is expected for a regular star. The model thus pre… more
Date: September 11, 2006
Creator: Moskalenko, Igor V.; /Stanford U., HEPL & Wai, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Effect of Melting on Target Performance

Description: The brightness of the antiproton source increases as the proton beam spot size on the target is reduced. The RMS beam spot size may be reduced to below {sigma}{sub b} = 0.1 mm, before competing sources of emittance limit the achievable yield. At the same time, the density of energy deposition increases rapidly as the radius is reduced. Thus operation of the target at the highest yields subjects the target to very high peak energy deposition E{sub m}. Fits to the Monte-Carlo calculations of targ… more
Date: September 10, 1991
Creator: Bieniosek, F.M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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EM Structure Based and Vacuum Acceleration

Description: The importance of particle acceleration may be judged from the number of applications which require some sort of accelerated beam. In addition to accelerator-based high energy physics research, non-academic applications include medical imaging and treatment, structural biology by x-ray diffraction, pulse radiography, cargo inspection, material processing, food and medical instrument sterilization, and so on. Many of these applications are already well served by existing technologies and will pr… more
Date: September 27, 2005
Creator: Colby, E. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Experimental Studies of Temporal Electron Beam Shaping at the DUV-FEL Accelerator

Description: The photoinjectors for future short wavelength high brightness accelerator driven light sources need to produce an electron beam with ultra-low emittance. At the DUVFEL facility at BNL, we studied the effect of longitudinally shaping the photocathode laser pulses on the electron beam dynamics. We report on measurements of the longitudinal phase space distributions and the time-resolved transverse beam parameters for both a Gaussian and a flat-top temporal laser pulse profile.
Date: September 28, 2005
Creator: Loos, H.; Doweel, D.; Sheehy, B.; Shen, Y.; Tsang, T.; Wang, X. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The FERMI @ Elettra Technical Optimization Study: General Layoutand Parameters and Physics Studies of Longitudinal Space Charge, theSpreader, the Injector, and Preliminary FEL Performance

Description: The FERMI {at} Elettra facility will make use of the existing GeV linac at Sincrotrone Elettra, which will become available for dedicated FEL applications following the completion of construction of a new injector booster complex for the storage ring. With a new rf photocathode injector, and some additional accelerating sections, this linac will be capable of providing high brightness bunches at 1.2 GeV and up to 50 Hz repetition rates.
Date: September 1, 2005
Creator: Byrd, John; Corlett, John; Doolittle, Larry; Fawley, William; Lidia, Steven; Penn, Gregory et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

FFAGS for rapid acceleration

Description: When large transverse and longitudinal emittances are to be transported through a circular machine, extremely rapid acceleration holds the advantage that the beam becomes immune to nonlinear resonances because there is insufficient time for amplitudes to build up. Uncooled muon beams exhibit large emittances and require fast acceleration to avoid decay losses and would benefit from this style of acceleration. The approach here employs a fixed-field alternating gradient or FFAG magnet structure … more
Date: September 30, 2002
Creator: Koscielniak, Carol J. Johnstone and Shane
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

FIRST CHARACTERIZATION OF A FULLY SUPERCONDUCTING RF PHOTOINJECTOR CAVITY

Description: As a first step towards a high brightness, high average current electron source for the BERLinPro ERL a fully superconducting photo-injector was developed by HZB in collaboration with JLab, DESY and the A. Soltan Institute. This cavity-injector ensemble is made up of a 1.6-cell superconducting cavity with a superconducting lead cathode deposited on the half-cell backwall. A superconducting solenoid is used for emittance compensation. This system, including a diagnostics beamline, has been insta… more
Date: September 1, 2011
Creator: Neumann, A.; Barday, R.; Jankowiak, A.; Kamps, T.; Knobloch, J.; Kugeler, O. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

FIRST DEMONSTRATION OF ELECTRON BEAM GGENERATION AND CHARACTERIZATION WITH AN ALL SUPERCONDUCTING RADIO-FREQUENCY (SRF) PHOTOINJECTOR*

Description: In preparation for a high brightness, high average current electron source for the energy-recovery linac BERLinPro an all superconducting radio-frequency photoinjector is now in operation at Helmholtz-Zentrum Berlin. The aim of this experiment is beam demonstration with a high brightness electron source able to generate sub-ps pulse length electron bunches from a superconducting (SC) cathode film made of Pb coated on the backwall of a Nb SRF cavity. This paper describes the setup of the experim… more
Date: September 1, 2011
Creator: Kamps, T.; Barday, R.; Jankowiak, A.; Knobloch, J.; Kugeler, O.; Matveenko, A. N. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

High-Average Power Facilities

Description: There has been significant progress in the development of high-power facilities in recent years yet major challenges remain. The task of WG4 was to identify which facilities were capable of addressing the outstanding R&D issues presently preventing high-power operation. To this end, information from each of the facilities represented at the workshop was tabulated and the results are presented herein. A brief description of the major challenges is given, but the detailed elaboration can be f… more
Date: September 5, 2012
Creator: Dowell, David H. & Power, John G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

High Current Density Beamlets from an RF Argon Source for Heavy Ion Fusion Applications

Description: In a new approach to develop high current beams for heavy ion fusion, beam current at about 0.5 ampere per channel can be obtained by merging an array of high current density beamlets of 5 mA each. We have done computer simulations to study the transport of high current density beamlets and the emittance growth due to this merging process. In our RF multicusp source experiment, we have produced a cluster of 61 beamlets using minimum gas flow. The current density from a 0.25 cm diameter aperture… more
Date: September 4, 2003
Creator: Kwan, J W; Grote, D P & Westenskow, G A
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

High Current Ion Source Development for Heavy Ion Fusion

Description: We are developing high-current-density high-brightness sources for Heavy Ion Fusion applications. Heavy ion driven inertial fusion requires beams of high brightness in order to achieve high power density at the target for high target gain. At present, there are no existing ion source types that can readily meet all the driver HIF requirements, though sources exist which are adequate for present experiments and which with further development may achieve driver requirements. Our two major efforts… more
Date: September 4, 2003
Creator: Westenskow, G A; Grote, D P & Kwan, J W
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A High-Energy, Ultrashort-Pulse X-Ray System for the Dynamic Study of Heavy, Dense Materials

Description: Thomson-scattering based x-ray radiation sources, in which a laser beam is scattered off a relativistic electron beam resulting in a high-energy x-ray beam, are currently being developed by several groups around the world to enable studies of dynamic material properties which require temporal resolution on the order of tens of femtoseconds to tens of picoseconds. These sources offer pulses that are shorter than available from synchrotrons, more tunable than available from so-called Ka sources, … more
Date: September 17, 2004
Creator: Gibson, D J
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

High Energy X-Ray Source Generation by Short Pulse High Intensity Lasers

Description: We are studying the feasibility of utilizing K{alpha} x-ray sources in the range of 20 to 100 keV as a backlighters for imaging various stages of implosions and high areal density planar samples driven by the NIF laser facility. The hard x-ray K{alpha} sources are created by relativistic electron plasma interactions in the target material after a radiation by short pulse high intensity lasers. In order to understand K{alpha} source characteristics such as production efficiency and brightness as… more
Date: September 2, 2003
Creator: Park, H. S.; Koch, J. A.; Landen, O. L.; Phillips, T. W.; Goldsack, T.; Clark, E. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The Los Alamos Photoinjector Program

Description: Free-electron lasers (FELS) require electron beams of high peak brightness. In this presentation, we describe the design of a compact high-brightness electron source for driving short-wavelength FELs. The experiment uses a laser-illuminated Cs/sub 3/Sb photoemitter located in the first rf cavity of an injector linac. The photocathode source and associated hardware are described. The doubled YAG laser (532 nm), which is used to drive the photocathode, produces 75-ps micropulses at 108-MHz repeti… more
Date: September 1, 1987
Creator: Sheffield, R.L.; Gray, E.R. & Fraser, J.S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Datasets

Description: This report provides a short description of the Atmospheric Radiation Measurement (ARM) microwave radiometer (MWR) RETrievel (MWRRET) Value-Added Product (VAP) algorithm. This algorithm utilizes complimentary physical and statistical retrieval methods and applies brightness temperature offsets to reduce spurious liquid water path (LWP) bias in clear skies resulting in significantly improved precipitable water vapor (PWV) and LWP retrievals. We present a general overview of the technique, input … more
Date: September 30, 2007
Creator: Gaustad, K. L. & Turner, D. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Physics Analyses in the Design of the HFIR Cold Neutron Source

Description: Physics analyses have been performed to characterize the performance of the cold neutron source to be installed in the High Flux Isotope Reactor at the Oak Ridge National Laboratory in the near future. This paper provides a description of the physics models developed, and the resulting analyses that have been performed to support the design of the cold source. These analyses have provided important parametric performance information, such as cold neutron brightness down the beam tube and the va… more
Date: September 27, 1999
Creator: Bucholz, J.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Progress report of FY 1999 activities: Continued development of an integrated sounding system in support of the DOE/ARM experimental program

Description: Both during September 15-30, 1996 and September 15-October 5, 1997, the Environmental Technology Laboratory (ETL) participated in experiments at the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site that was designed to study many of the ways that ARM is measuring water vapor. Because of some inconsistencies between ETL and ARM Microwave radiometers (MWR) during these experiments, called the Water Vapor Intensive Operating Periods (WVIOPs), we applied to both sets of data a ne… more
Date: September 8, 1999
Creator: Westwater, Edgeworth R.; Han, Yong & Leuskiy, Vladimir
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Quantifying Transient States in Materials with the Dynamic Transmission Electron Microscope

Description: The Dynamic Transmission Electron Microscope (DTEM) offers a means of capturing rapid evolution in a specimen through in-situ microscopy experiments by allowing 15 ns electron micrograph exposure times. The rapid exposure time is enabled by creating a burst of electrons at the emitter by ultraviolet pulsed laser illumination. This burst arrives a specified time after a second laser initiates the specimen reaction. The timing of the two Q-switched lasers is controlled by high-speed pulse generat… more
Date: September 21, 2009
Creator: Campbell, Geoffrey H.; LaGrange, Thomas; Kim, Judy S.; Reed, Bryan W. & Browning, Nigel D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Radioluminescent (RL) airfield lighting system program

Description: In 1980, the US Air Force Engineering and Services Center (AFESC) at Tyndall Air Force Base, Florida, requested that the Radioisotope Technology Group of Oak Ridge National Laboratory (ORNL) develop large-scale, tritium-powered, radioluminescent (RL) airfield lighting systems. The RL lighting systems possess the advantages of being portable, requiring no electrical power source, having a long shelf life, and being unaffected by environmental extremes. These characteristics make the RL system we… more
Date: September 1, 1990
Creator: Tompkins, J. A.; Haff, K. W. & Schultz, F. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Research and Development for X-Ray Optics and Diagnostics on the Linac Coherent Source (LCLS)

Description: The Linac Coherent Light Source (LCLS) is a 1.5 to 15 {angstrom} wavelength Free-Electron Laser (PEL), under development at the Stanford Linear Accelerator Center (SLAC). The photon output consists of high brightness, transversely coherent pulses with duration < 300 fs, together with a broad spontaneous spectrum. The output energy density per unit area, pulse duration, repetition rate, and small FEL spot size pose special challenges for optical components and diagnostics downstream of the un… more
Date: September 24, 2002
Creator: Bionta, R. M.; Arthur, J.; Chapman, H.; Craig, B.; Klingmann, J.; Kuba, J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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